Whatever you do throughout your day, you are constantly bringing microbes onto and into your body. Especially when eating, you introduce a mix of microbes into your gastrointestinal tract.

In this dark, airless place, microbes flourish, working tirelessly to keep you in good shape. They improve your body’s health starting from the gut and strengthen your gut’s defences by fighting off unwelcome intruders.

Gut bacteria break down the food you eat from which they produce all sorts of molecules. The most important ones are called short-chain fatty acids. These small molecules impact the health of your gut and your overall body.

Here, we’re looking at gut bacteria that produce short-chain fatty acids and how they maintain the health of your gut. We’ll also explore ways to help bacteria make even more of these beneficial molecules.

Let’s start by understanding how your gut protects your body.

The mucus layer of the gut as a first line of defence

The food you eat passes through your body, yet it is always in contact with your body’s outer layer of cells. Only in the gastrointestinal tract do your gut cells absorb molecules from food and transport them into the body.

This means the outer layer of your gut, the so-called epithelium, faces away from the body and is in constant contact with the outside. One of its main jobs is to prevent harmful components from getting too close or even entering the body.

That is why goblet cells, which are special gut epithelial cells, produce a thick, slimy mucus. As they constantly secrete mucus, the cells actively push everything away from the epithelium, while the ever-growing mucus layer sits like a protective shield on top of the the intestinal epithelium.

When the mucus layer is too thin or broken, harmful microbes and bacteria can come into contact with the gut. This can trigger inflammatory immune responses, resulting in chronic diseases such as inflammatory bowel diseases.

Commensal gut bacteria produce short-chain fatty acids

While this slimy physical barrier is already a strong first line of defence for your gut, you can also rely on your gut microbes. Those that reside in and on your body over a long time are called commensal microbes.

One way to make them stay with you is by feeding them their favourite foods. Gut bacteria eat what you eat, while some commensals like Ruminococcus gnavus and Akkermansia muciniphila also eat the mucus in your gut.

And from your food, the majority of gut commensals prefer the dietary fibre. That is the indigestible part of plant-based foods as it passes through your small intestine unchanged. Once it reaches the large intestine, your gut bacteria get to work.

They break down the fibre, ferment it and produce all sorts of molecules from it. The most important group of molecules are the short-chain fatty acids, including acetate, propionate and butyrate.

The commensals Bacteroides thetaiotaomicron, Bifidobacterium longum, Eubacterium and Blautia coccoides are actually some of the best-known producers of short-chain fatty acids. Just by eating a lot of dietary fibre, you increase both the different microbial strains growing in your gut and the amount of short-chain fatty acids they make.

How short-chain fatty acids improve gut health

From the gut, short-chain fatty acids diffuse through the mucus and reach the epithelial layer. Here, they bind to receptors on the goblet cells and activate certain pathways.

They trigger goblet cells to grow and produce more mucus. This increasing mucus layer, in turn, protects more effectively against harmful bacteria while providing more food for your commensals.

For example, two gut bacteria, Akkermansia muciniphila and Blautia coccoides, produce the short-chain fatty acids acetate and propionate. Both molecules trigger gut cells to make more mucus, improving gut health and feeding commensal bacteria while fighting off intruders. In mice, Bifidobacterium longum induces the growth of mucus, likely by producing acetate.

The diet-microbiome-gut health connection

Now, let’s tie all these pieces together: By eating plant-based fibres, you feed your beneficial gut bacteria. These digest and ferment the fibre and produce short-chain fatty acids, which bind to your gut cells and trigger them to produce more mucus. This increasing mucus layer shields off your gut while feeding your gut bacteria.

Generally, the more fibre we eat, the more beneficial bacteria live in our guts. They become more active at digesting fibre since they lose their appetite for the mucus.

Beneficial bacteria like Blautia can even be found in human stool after 12 weeks of eating high-fibre diets. Hence, it seems that the commensal Blautia decides to settle down in your gut depending on what you eat. So, by eating food full of fibre, you can attract helpful bacteria to you.

On the other hand, when you eat little fibre, your gut bacteria start eating your mucus layer, since their preferred substrate is not available. This can lead to inflammation and other gut health issues.

You are what you and your bacteria eat

When considering the role of your gut bacteria for your health, the saying “you are what you eat” may take on a new meaning.

By eating a lot of different plant fibres, you’re not just feeding yourself — you’re also feeding the bacteria in your gut. Your food gives them the right fuel to produce short-chain fatty acids that strengthen your gut’s protective layer and gut health. This, in turn, impacts the health of your body, mind and cardiovascular system and even your emotional and mental wellbeing.

Hence, by eating more veggies, fruits and seeds with lots of fibre, you influence which types of bacteria live close to and inside of you. So, what you eat affects how you feel, quite literally from the inside out.

Your gut bacteria will thank you for that extra serving of vegetables. To show their gratitude, they’ll provide you with all the good stuff to keep you healthy.

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Bacterialworld - A blog about bacteria: from scientific studies to vivid stories about the fascinating bacterial world

The term “sustainability” was introduced. This concept focuses on a world in which we live well within the resources of our planet, today and tomorrow. Based on environmental, social and economic sustainability, the United Nations launched the 17 Sustainable Development Goals in 2015.

The idea was to combine science, society and technology to reach these goals and create a healthier planet and society. Fortunately, among the many contributors to this mission, we also have our tiny friends—microbes.

About the role of microbes in sustainability development

Microbes have existed for billions of years, making up 99% of our ecosystem. They have been breaking down waste, recycling matter and helping maintain balance on Earth long before humans arrived.

Considering that microbes and bacteria influence most of the 17 Sustainable Development Goals, scientists aim to use their superpowers for the sustainable development of our planet. So, let’s look in more detail at how microbes impact planetary sustainability:

Goal 2: Zero Hunger

Microbes are directly and indirectly involved in food production and agriculture.

• Microbes ferment food, increasing its shelf life and nutritional value. Tasty and staple foods like bread, yoghurt, cheese, sourdough, chocolate, sauerkraut, kombucha, cider, idli, beer and wine are indeed products of fermentation
• They fix nitrogen in the soil, naturally improving soil fertility and crop growth
• They help restore carbon in the soil, supporting good farming practices

Some microbes are even food themselves! Many bacteria and fungi are protein sources for both humans and animals. They are grown from agricultural and industrial waste and purified to meet food quality standards. This so-called ‘Single-cell protein‘ or microbial protein is now being explored as an eco-friendly and nutritious alternative to animal-derived protein.

Goal 3: Good Health and Well-being

While some bacteria do cause disease, many others do the exact opposite:

• Bacteria are used as factories to produce life-saving antibiotics, cholesterol-lowering and anti-cancer drugs
• Bacteria can be engineered to produce vaccines and therapeutic agents or transport drugs within the human body
• Probiotic bacteria, those that, when taken in appropriate amounts, are beneficial to human health, improve digestion, boost immunity and enhance our overall well-being

Goal 6: Clean Water and Sanitation

Yes, some bacteria can contaminate water and you surely want to keep these out of your water. Yet, other microbes do the opposite:

• They break down organic waste in water treatment plants
• They can clean up oil spills and even neutralise toxic chemicals, helping recycle water for reuse

Goal 7: Affordable and Clean Energy

One of our global challenges is to reduce our dependence on non-renewable fossil fuels for electricity and energy.

• Bacteria come to the rescue as they produce bioelectricity from organic material, the so-called cable bacteria, conducting electrons across a few centimetres
• Bacteria can convert renewable materials like agricultural and industrial by-products into clean liquid biofuels, offering eco-friendly alternatives to fossil-derived fuels

Goals 9 and 12: Industry, Innovation and Infrastructure & Responsible Production and Consumption

One way to protect our environment is to produce essential materials from renewable sources and recycle waste in industries – an approach called circular economy. Some microbes can degrade organic material, while others produce various chemicals and necessary materials. That is why microbes play a key role in this sustainability area.

• Bacteria can produce the building blocks required to make plastics from renewable materials
• Bio-based plastics are broken down more quickly than conventionally produced plastics, saving our lands and oceans from plastic pollution

Goal 13: Climate Action

Despite ongoing efforts, greenhouse gas emissions remain high due to human activity, leading to adverse climate change. It is expected that the global temperature will rise by 2.5°C by 2050.

• Microbes can capture and convert greenhouse gases like carbon dioxide into low-carbon fuels and useful value-added chemicals
• Some microbes transform carbon dioxide into organic material, which other species use

Since microbes have been maintaining the carbon balance in the ecosystem for ages, they are essential players in curbing climate change. Yet microbes are adapting and changing their behaviour according to climate change. Understanding the relationship between the production and consumption of greenhouse gases by microbes and climate change can help us restore balance sooner rather than later!

Goal 14: Life Below Water

Pollution from human activities is impacting our oceans. We see that the residuals of medicines, caffeine from the coffee we consume, harmful waste from industries, plastics and heavy metals go right into the ocean.

All of this often has a negative effect on marine ecosystems. Gladly, microbes can help break down these harmful pollutants. They use toxic substances as food and convert them into less toxic by-products, water and carbon dioxide. This is called bioremediation, a process that keeps our waters and marine ecosystems clean and healthy.

Goal 15: Life on Land

All life on land needs food. We depend directly and indirectly (through animals) on plants for our everyday nutrition. Plants get their essential nutrients from soil, with microbes having a huge impact on the amount and availability of soil nutrients.

• Microbes help in converting atmospheric nitrogen into a usable form in the soil for plants to use. They also help in making insoluble phosphorous, potassium and sulphur in soil accessible for plants to take up. In doing so, microbes act as biofertilisers as an alternative to chemical fertilisers.
• They are also key players in our food system by preventing the growth of harmful microorganisms that can cause crop diseases, becoming an alternative to chemical pesticides.

Microbes in the ecosystem work in groups to transport chemicals between the atmosphere and land, maintaining a natural balance. However, with human activity, the microbial communities are affected and disturbed. While we still don’t fully understand the extent of their role in ecosystem functioning, it is possible that supporting co-living microbial communities in the environment can help restore the ecosystem.

Goal 16: Peace, Justice and Strong Institutions

Throughout history, the growing demand for better food, resources, health and living conditions has often led human societies to compete—and sometimes even to go to war. But as we’ve seen, microbes offer solutions and services across various spheres of our needs. So microbes can even help us promote harmony and peace – one of the foundations of social sustainability.

How microbes can support achieving sustainability

We’re now beginning to understand the power of microbes in moving towards a greener planet. So next time you want to make an impact on the health of our planet, you can also include microbes in your decision-making.

You could, for example, choose products responsibly produced using bio-based processes, encouraging industries to shift to circular bioeconomy. Composting waste from your kitchen to be used as biofertiliser is a great way to use microbial superpowers on a small-scale level.

There’s still a long way to go in terms of large-scale production and applications, but progress is underway. By recognising and harnessing the potential of microbes, we can make a difference and move a step closer towards the UN Sustainable Development Goals. The future of sustainability might just depend on microbes, their superpowers and the innovative ways we choose to work with them.

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Bacterialworld - A blog about bacteria: from scientific studies to vivid stories about the fascinating bacterial world

Consider the scent of a ripe cheese or a glass of wine—these aromas come from bacteria and other microbes. Even less pleasant odours, like old sweat, smelly feet or a mouldy apple, are thanks to molecules produced by microbes.

Let’s explore the fascinating world of bacterial smells, their origins and what we can learn from them.

Microbial smells come from volatile organic compounds

All microbes produce volatile organic compounds as part of their metabolism. These molecules are generally gaseous and vaporous, allowing us, animals and even plants to smell and react to them.

Depending on their environment, the substrate they use, pH, salt concentration and temperature, microbes produce various volatile organic compounds. These can range from simple gases like carbon dioxide or ammonia to organic acids such as isovaleric acid or large and complex steroid derivatives.

For both microbes and us, volatile organic compounds serve as a means of communication and information. As we’ll see, these small compounds play crucial roles in microbial communities and their survival. On the other hand, for us, certain volatile organic compounds signal to our brains that bacteria are present, indicating that something may not be safe to eat or drink.

Some bacterial odorous molecules have a dual nature: indole, produced by gut bacteria from food, gives faeces its characteristic odour. Yet, at low concentrations, indole has a flowery scent and is even used in perfumes.

Bacteria attract animals with earthy smells

Do you recall the scent of fresh rain? That earthy, musty smell comes from a molecule called geosmin, produced by bacteria of the Streptomyces family.

Streptomyces live in the soil, where they produce soil material and form long thread-like filaments. To survive and spread, they use the volatile organic compound geosmin.

When these bacteria release their spores into the soil, they cover them with both antibiotics and geosmin. While the antibiotics protect the spores from other microbes, geosmin attracts small insect-like animals. These creatures eat the spores and distribute them in the environment.

In this case, geosmin signals a food source to the animals as the spores nourish the animals. At the same time, the spores use the animals for transport to new areas. Once conditions improve, the spores develop into bacteria and start forming their filaments in the soil.

Also mosquitoes are attracted to the smell of geosmin in ponds and waters. Here, cyanobacteria produce the molecule, so the mosquitoes decide to lay their eggs here as the bacteria are food sources for the larvae.

Bacteria produce characteristic food smells

Other pleasant and unique bacterial smells come from the fermentation of fruit, vegetables or milk. During this process, bacteria produce compounds that give food not only their characteristic tastes but also aromas.

As an ancient fermentation product, vinegar has a very characteristic sour smell due to volatile organic compounds produced by microbes. Mainly bacteria from the Lactobacillus and Leuconostoc families and some yeasts degrade the sugars of cereals or fruits to produce acids and alcohols.

Also, the fine aromas of wine and cheese come from the many volatile organic compounds bacteria and yeasts produce during fermentation. They include alcohols, aldehydes, ketones, lactones, esters as well as many other classes of chemicals. As you probably know, depending on the origin of the grapes or milk, the ripening temperature and the microbes added, the resulting product can taste and smell entirely different.

However, the unpleasant smell of rotten foods is also due to bacterial metabolic activity. Meat, fish and eggs contain molecules like choline and trimethylamine oxide. Over time, bacteria break these down into trimethylamine. Your brain likely recognises this off-flavour as a sign of food decay, triggering you to reject rotten foods to protect your health.

Bacteria create your unique body odour

Interestingly, your body odour changes based on what you eat and which microbes and bacteria you introduce into and onto your body. Depending on your diet and health, your body secretes different mixes of sweat—generally a watery mixture of minerals, amino acids, fats, urea and antimicrobial substances.

Although your skin produces odourless sweat all over the body, some areas are more hospitable for bacteria and microbes than others. Consider your armpits, where your main body odour originates: They contain more sweat glands and slightly different hair follicles, making them moister and more enclosed. With more water and nutrients available, your armpits are very microbe-friendly.

Consequently, the microbial communities in your armpits can differ completely from the rest of your body. Here, three bacteria—Corynebacterium striatum, Corynebacterium jeikeium and Staphylococcus haemolyticus—have special strategies to survive the high salt content of sweat and even use the urea in sweat as food.

They break down the molecules in sweat into volatile organic compounds that together give each person their unique body odour. For example, sulphur-containing compounds, often with strong onion-like smells, are produced by Corynebacteria.

Our sweat also contains lactic acid and glycerol, from which Staphylococcus and Propionibacteria produce acetic and propionic acid. These molecules directly impact your body odour as they evaporate leaving a pungent smell or supporting the growth of other bacteria. But our smelly sweat has advantages too: After eating citrus fruits, people’s sweat contains limonene, a mosquito-repellent possibly generated by skin bacteria.

Bacteria are responsible for smelly feet

Another significant area of your body directly impacted by bacteria and their smell-creating superpowers is your feet.

Our feet actually contain the highest variety of microbial communities, with Staphylococcus, Corynebacterium and Brevibacterium being the most common. These bacteria feed on skin particles, urea and the amino acids in sweat.

For example, Staphylococcus epidermidis, a normal resident of human skin, degrades the amino acid leucine into isovaleric acid. Unfortunately, this molecule has a powerful, rancid cheese-like odour—the reason for smelly feet.

Fortunately, other bacteria, like Brevibacterium, Micrococcus and Kytococcus, can completely degrade both leucine and isovaleric acid, thus preventing the unpleasant smell. As usual, it comes down to having the friendly bacteria around.

Bacterial smells in your life

As we’ve seen, the world of bacterial smells is fascinating and complex. From the earthy smell of rain to the rancid odour of sweaty feet, bacteria play crucial roles in creating the smells that surround us.

These microbial odours are not just curiosities; they have important functions in nature and human biology. They can act as communication signals between microbes, influence animal behaviour, make our food smell delicious and even impact our unique body odour. So, embrace the microbial world with all its facets, colours and smells!

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Bacterialworld - A blog about bacteria: from scientific studies to vivid stories about the fascinating bacterial world

Whatever it was, chances are high that part of your food was fermented by microbes. As exceptionally healthy and tasty as fermented foods are, these would not exist if it weren’t for microbes and their fermentation superpowers.

Yet, microbial fermentation is a lot more than processing food and giving it a new taste or aroma. Indeed, depending on who you ask, microbial fermentation means slightly different concepts.

For once, fermentation is a metabolic pathway in some microbes and organisms. It is an energy-saving way to degrade and metabolise substrates and produce complex and energy-rich fermentation products.

Secondly, microbial fermentation describes the process of preserving food based on the fermentation pathway. For this, we let microbes break apart and ferment food in a controlled manner, eventually producing well-known fermented foods, like yoghurt, beer and chocolate.

Lastly, the industrial process of growing microbes in big cultures is often called microbial fermentation. The goal of this process is for microbes to produce a specific product – and often they do so through the fermentation pathway.

As you can see, the different definitions for microbial fermentation are grounded on the same principle: microbes degrading substrates and making fermentation products from them. Here, we will look closer at the biochemistry of microbial fermentation and explore some examples of where this microbial superpower naturally occurs and how we make use of it.

The biochemistry of microbial fermentation

From the view of a biochemist, fermentation is first of all a metabolic pathway to conserve energy. Most organisms gain energy from opening chemical bonds of molecules. This releases the energy-rich electrons that are bound within the bond. They then save these electrons in other molecules or fuel cellular machineries.

Most microbes have one preferred substrate for their metabolism. For many, this is glucose, the same sugar that our cells preferably burn and degrade. By degrading glucose, they (and us) produce several intermediary products, the most important one being pyruvate. This degradation process sets free several electrons, which microbes save in a molecule called ATP. ATP is the main fuel for microbial growth machines, swimming motors or transporters.

Sometimes microbes find themselves in environments with an excess of their preferred substrate. In this case, setting free all the energy would produce a lot of heat, damaging or even burning the cell. Hence, as an alternative, energy-conserving pathway, they switch to fermentation metabolism.

During this pathway, they degrade the substrate only partly, thus not extracting all available electrons from it. Instead, they use one of the intermediary products and bind it to another molecule in an energy-neutral reaction. This conserves the electrons and energy within the fermentation product.

What makes fermentation so fascinating: Many species have unique fermentation pathways. Depending on their genes, they branch off the fermentation pathway at any intermediate and produce different molecules.

For example, from pyruvate, some microbes produce ethanol, which we use for beer or wine production, and others produce lactic acid, like for yoghurt production. Other microbes ferment substrates like citrate or succinate and produce complex molecules like caffeine or colourful biopigments.

By conserving the high-energy electrons in the fermentation products, microbes produce fewer ATP molecules. Hence, they have less energy available at that moment. But if they need energy later, they can break down the fermentation product to extract the electrons. Often though, their energy levels are so high, that they even export the product to get rid of it.

Fermentation is thus a way for microbes to process molecules and conserve energy. Gladly, we learned to make use of this pathway as microbes help us convert energy-rich substrates into beneficial products.

Microbial fermentation for food preservation

One source of energy-rich substrates are carbohydrate and fibre-rich foods, which is why these are some preferred environments for microbes. By fermenting fruits, vegetables, milk and grains, microbes can grow and spread on seemingly any plant-based substrate.

Gladly, we learned to grow microbes and ferment food in controlled environments, making food fermentation one of the oldest human technologies. Throughout history, many cultures have optimised different fermentation processes and created all kinds of products.

Food fermentation can include adding so-called starter microbes to the food or using those microbes that naturally live in the foodstuff. These microbes break apart the carbohydrate component of the foodstuff to fuel their fermentation pathways.

The resulting fermentation products can be beneficial vitamins, antioxidants or molecules that change the aroma, taste, texture or stability of the foodstuff. The degradation and modification of the food itself and the accumulation of fermentation products, over time, make our well-loved cheeses, coffee, bread, chocolate, beer, wine, kombucha, yoghurt or kimchi.

For example, thanks to microbes, cheese and yoghurt taste and smell differently than the original milk. Coffee and chocolate get their complex and unique aromas only thanks to the microbial fermentation of coffee and cocoa beans.

During fermentation, many bacteria produce strong acids from the original substrate. Thus, the resulting food becomes acidic and sour, which prevents other microbes from growing and spoiling the food. That’s why food fermentation became an efficient way to conserve food. Many vegetables, like cabbages, pickles or olives, are thus preserved into sauerkraut or kimchi, sour pickles and olives, and the like. Also making kombucha, kefir or cheese are ways to preserve the original tea or milk.

When fermenting cereals, yeasts mainly produce carbon dioxide or ethanol. Carbon dioxide, for example, in sourdough bread makes the bread rise. In the beer-brewing and wine-making processes, yeast produces ethanol as well as several beneficial and aromatic molecules that give beers and wines their tasteful and diverse aromas.

About the microbes involved in food processing

Each fermented food has a unique community of microbes that changes with the fermentation process over time. With the rise of one microbial species, the pH of the food might change or a certain substrate becomes available, which might kill one species or feed and thus help another one grow.

In many vegetable-based fermentation products, lactic acid bacteria, such as Leuconostoc, Lactobacillus and Weissella, are the primary microbes. They produce acids which prevent food-spoiling microbes from growing. The acids also give the resulting kimchi and sauerkraut their sour and acidic tastes. On the contrary, in alkaline-fermented foods of Asia and Africa and in bean-fermented foods, such as tempeh, miso or natto, Bacillus bacteria are usually responsible for the fermentation process.

In milk fermentation, bacterial cultures are of two types: Lactococcus, Lactobacillus, Leuconostoc and Streptococcus bacteria that acidify the milk. This denatures the milk and produces yoghurt-type products, such as yoghurt, buttermilk and kefir.

As a second step during the cheese-making process, Brevibacterium, Propionibacterium, Debaryomyces, Geotrichum and Penicillium are added. These bacteria and fungi produce more complex molecules and give the ripening cheese its unique flavour, texture and aroma.

For cereal fermentation, yeasts are the most widely used microorganisms, producing beer, sourdough bread, sake and whiskey. For bread-making, the principal yeast is Saccharomyces cerevisiae. Other Saccharomyces species, as well as Torulaspora, Hanseniaspora and Pichia are responsible for fermenting most cereal-based drinks.

How the human body benefits from fermentation

As we’ve learned above, many fermented foods are full of microbes – as long as the food was not heated or pasteurized. Hence, when eating fermented foods, you also take in the microbes in and on the food. And these are ready to settle in your body, feed off your food and do some more fermentation.

After arriving in your gastrointestinal tract, the microbes start digesting part of your food too. They degrade the plant cell structures of vegetables, fruits, cereals, seeds and nuts as well as non-digestible fibres. This releases sugars which gut microbes ferment to short-chain fatty acids and gases, like methane. These fermentation products have beneficial effects on your digestion, mental and gut health as well as your immune system.

Hence, by eating fermented foods you gain beneficial microbes – some of them are the so-called probiotics. And by eating plant-based foods you give your gut microbes the appropriate food to ferment, which is what makes some of them prebiotics.

But this is not the only place where microbial fermentation takes place in your body. For example, Lactobacillus bacteria are the key players within the vaginal microbiome and their fermentation activities influence the health of women.

Within the vaginal tract, host cells provide Lactobacillus with glycogen. From this, the bacterium sets free glucose and ferments it to produce lactic acid and hydrogen peroxide. These molecules decrease the pH creating an acidic environment within the vagina. This acidity kills some pathogenic microorganisms directly and prevents others from growing. Hence, by feeding residential Lactobacillus bacteria, the body helps them grow and in return they protect it.

Microbial fermentation as a pillar of industrial production

The more we learn about microbes, bacteria and their fermentation pathways, the better we can use their metabolic superpowers for our own good. Especially the biotechnology and food industry are making great use of microbial fermentation.

We now grow microbes in big batches and harvest fermentation products, like bioethanol, lactic acid or vitamin B12. In many cases, microbes grow on plant-based products or even ferment waste into usable and, thus, green products. As you can guess, food fermentation based on appropriate starter cultures is taking place on large scales to produce many of our beloved foods.

As such, microbial fermentation is an essential part of our lives. Not only as a fundamental process in cellular metabolism and thus human health, microbial fermentation has become a key pillar in food production and preservation as well as industrial production.

As a sustainable tool to produce plant-based foodstuffs, pharmaceuticals and fuels, microbial fermentation may even play a crucial role in our journey towards a greener and more resilient future. Just another reason to be grateful to microbes and their fascinating superpowers.

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Bacterialworld - A blog about bacteria: from scientific studies to vivid stories about the fascinating bacterial world

Below are a few ways how bacterial research is and continues to make advancements in modern science.

Treatment Courses

Microbiologists working in diagnostic laboratories perform tests on samples which come from either humans or animals.  Doctors or veterinarians analyse these samples to detect the susceptibility or resistance of bacteria to antimicrobial drugs. This kind of research is incredibly important when it comes to discussing the right courses of treatment and future preventative measures that can be taken.

Similarly, biochemists and microbiologists analyse body fluids to identify if and which disease-causing organisms are present. With this bacterial research, doctors can adequately diagnose patients to ensure that they get the right treatment plan in the shortest time possible. Also, the research done by biochemists helps nurses and doctors alike to understand what will and won’t work for certain patients.

Food Health

With microbiological techniques, food preservation is possible. Thanks to modern science and continual research, microbiologists can identify pathogens in food products. These pathogens, if left alone, can end up spoiling the goods and make us sick.

By examining multiple food samples, researchers can determine if contaminants are present and what kind they are. For instance, the type of bacteria that may be found. The results of such examinations help scientists assess the products that are dangerous to human health and those that are not.

Manufacturing Foods

Microbial fermentation helps break down larger food components into simple ones. It is one of the most natural ways for improving vitamin, protein and anti-nutrient content as well as enhancing the flavour and appearance of food.

Fermentation processes are based on microbes like yeast and bacteria that change the food matrix of fruits, vegetables or beverages. Fermented foods include sourdough bread, beers, wine, yoghurt, sauerkraut, kimchi and even cheese.

Medicine

Studying how the human immune system works is incredibly important. To shed light on this question, microbiologists and immunologists work closely together to unravel how pathogens overcome the immune shield of the body. Based on this knowledge, they can then aim to find strategies to fend pathogens off.

Microbiologists are further investigating how “good microbes” help our body function. By better understanding how the human microbiota works and supports us, researchers are aiming to find new strategies to use the microbiota to keep us healthy and fit.

Since the human microbiota also impacts disease and treatment progresses, researchers are currently looking into ways to support the microbiota. This would eventually improve treatments and support the health of people.

The Future of Microbiology

There’s something positive on the horizon regarding the future of microbiology. All of the scientific shifts have brought about new opportunities in different areas of study: food manufacturing, fermentation, medicine and treatment. Such developments will only be beneficial to human life and the environment around us.

Proper, up-to-date Microbiology Laboratory Equipment is an essential part of any microbiology lab no matter the type of research. Advancements in the technology used by microbiologists help accelerate their research and progress in discovering new pathogens and treatments.

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Bacterialworld - A blog about bacteria: from scientific studies to vivid stories about the fascinating bacterial world

Those bacteria that call your gut their home are the so-called commensal bacteria. Luckily, they have a special superpower: They can protect us from bacteria that cause infections and make us sick. For this, our commensal gut bacteria developed some extraordinary strategies to defend these pathogens.

So, by nurturing our friendly gut bacteria, you are also strengthening your protection against diseases. Here, we will look at what kind of bacterial wars are going on in your gut and how your gut bacteria defend pathogens and keep you healthy.

Your gut bacteria defend pathogens with toxic molecules

Bacteria have many different means to kill other microbes, competitors or even their own siblings. Often, these bacteria produce molecules that are toxic to their prey, which means they inhibit cellular proteins or machineries. Without these machineries, the prey is then lacking an essential cell function to grow or survive, so that it eventually dies.

Interestingly, gut bacteria produce and deliver many different toxic molecules of various shapes and sizes, functions and even origins.

Gut bacteria produce bacteriocins

Many bacteria produce molecules that are like antibiotics specifically to kill bacteria. These are called bacteriocins.

Some bacteriocins are simple and small molecules, while others can be big and fancy. However, they all have a similar goal: they bind to a specific target in the prey bacterium and prevent that target from working properly.

So, no wonder that many bacteria in our gut microbiome produce bacteriocins that are toxic to pathogenic intruders. Also, we carry a lot of different bacteria in our guts and they all produce different bacteriocins. Hence, incoming pathogens face this huge load of toxic molecules making it really difficult to establish themselves in our intestines.

For example, one bacterium that loves the warmth and lack of oxygen in our gut is the bacterium Ruminococcus gnavus. And this one produces at least two bacteriocins, Ruminococcin A and C, that are toxic against human gut pathogens like Clostridium perfringens.

Other friendly gut bacteria, like Escherichia coli or Blautia producta, also produce bacteriocins that are toxic to pathogens, like Enterococcus faecalis. And some of their bacteriocins can even impact our gut cells by activating and strengthening our immune response.

Gut bacteria produce short chain fatty acids from fibres

Another way to protect against pathogenic gut bacteria is directly related to your diet. When we eat a lot of fibres, which are non-digestible carbohydrates, our friendly gut bacteria break these up. From these fibres, they produce small molecules that are called short-chain fatty acids, which have many positive health benefits for our overall wellbeing.

Interestingly, when we have a lot of these short-chain fatty acids in our intestine, the pH drops. This is already pretty difficult for most pathogenic bacteria, as not many can handle this acidic environment.

Plus, short-chain fatty acids diffuse into pathogenic gut bacteria where the pH drops as well. This can disturb many cellular machineries from functioning properly and not many bacteria have the right tools to defend against this attack, so they’ll die.

Gut bacteria convert bile acids into toxic compounds

To better digest the fats in food, our liver produces bile acids. These molecules bind fatty acids and lipids so that we can take them up better into our bodies.

But some of our friendly gut bacteria can convert these primary bile acids from our liver. For example, one of these bacteria, Clostridium scindens, transforms them into secondary bile acids that can bind the lipids of bacterial membranes.

Like this, secondary bile acids open the membranes of some pathogenic gut bacteria, like Staphylococcus aureus, Bacteroides thetaiotaomicron or Clostridoides difficile. This eventually kills the intruders and keeps our guts pathogen-free.

Killing pathogens with bow and arrow

Yes, also direct bacterial wars are happening in our guts! And they are nasty!

Some bacteria use tiny little bows to shoot deadly arrows into other bacteria. And these arrows can be incredibly toxic so the shot bacterium has barely any chance to survive the attack.

Luckily, our gut bacteria use their bows and arrows to defend against gut pathogens. For example, commensal bacterium Bacteroides fragilis has three different bows and can shoot various arrows. And research showed that this bacterial friend can protect us from bacteria that otherwise cause intestinal diseases.

Interestingly, Bacteroides fragilis is not opposed to hit’n’kill its own toxic bacterial siblings since some members of his family can indeed make us sick. But our friendly Bacteroides fragilis collected many different immunity proteins against its evil siblings so that their toxic arrows cannot harm it. Instead, Bacteroides fragilis keeps shooting and killing until we are safe from the pathogenic sibling.

Keeping nutrients from pathogenic gut bacteria

Another important way how gut bacteria defend pathogens is by keeping nutrients away from them. In all mixed microbial communities, bacteria fight for nutrients, especially for metals like iron, zinc but also sulphur sources.

Luckily, our gut bacteria developed some sneaky ways to steal these metals from gut pathogenic bacteria. By sending out special proteins that bind these metals very tightly, the commensals make sure to keep these metals from the pathogens. And if the pathogenic bacteria don’t have enough of these essential metals, they won’t survive and will eventually die.

Strengthening the mucus layer to block pathogenic gut bacteria

When you think about it, your gut is not part of your body – even though it is inside of you. All the food that we eat, stays within this digestion tube (mouth, oesophagus, stomach, intestines) until it comes out on the other side.

And to protect us from harmful microbes and molecules, we need to have a clear physical barrier from the content of the tube. This barrier is the so-called epithelial layer, which is covered by a slimy mucus on the outside. And this sticky slime helps keep off intruding microbes so that they cannot breach through the epithelial wall and get into our bodies.

Luckily, our helpful gut bacteria help us maintain this slimy defence wall. As bacteria produce SCFAs close to the mucus layer, the epithelial wall produces more slime. And if the slime gets thicker, gut pathogenic bacteria have more difficulties getting into our bodies.

To help the slime grow, some bacteria adapted very well to the conditions within the gut. For example, the friendly gut bacteria Akkermansia muciniphila and Ruminococcus gnavus cut off the very end of the mucus layer and feed themselves with them. This does not harm the mucus itself, but it keeps these bacteria close by. And this in turn triggers the epithelial wall to produce more mucus. So, everyone wins.

How to help your gut bacteria defend pathogens

Now, that you better understand how your gut microbiome defends pathogenic gut bacteria, make sure you support them keeping you healthy. By feeding your gut bacteria the right foods, you will help them be comfortable and happy in your gut. And when the right bacteria grow within you, they will gratefully protect you from nasty intruders!

Another idea for researchers is to use what they have learned to keep you healthy. The idea is to develop probiotics or prebiotics that help us defend against nasty pathogens. For example, you might take pills containing toxins against pathogenic gut bacteria or probiotics with bacteria that can fight off pathogens.

Whatever it may be, you can always help your gut bacteria be happy in your intestines by eating the right things. That means lots of fibre and veggies! ?

The post How bacteria in your gut microbiome defend pathogens appeared first on Bacterialworld.
Bacterialworld - A blog about bacteria: from scientific studies to vivid stories about the fascinating bacterial world

Energy to grow, to move, to fight, to produce stuff and also to reproduce.

Generally, living organisms get this energy from food. It fuels us, just as it fuels animals, plants and bacteria.

But where exactly is this energy in food? How do bacteria and other living organisms access this energy? And what do they do if their favourite food is not around?

To answer these questions, let’s look at how molecules store energy.

How do living organisms gain energy?

Each chemical bond between atoms contains energy. Hence, a molecule that is made of many atoms and thus many chemical bonds, contains energy. When such a chemical bond opens, it releases energy in the form of electrons.

Depending on the kind of chemical bond within the molecule, these electrons can have higher or lower energy levels. Thus, they contain more or less energy.

So, to obtain energy from molecules, organisms need to break apart molecules and extract the electrons with high energy. But this is not as easy as it sounds. Chemical bonds are quite tight and it actually requires energy to break them open.

Hence, organisms need to have the right sets of proteins that can break open specific chemical bonds in molecules. These kinds of proteins are called enzymes. So, only if an organism has enzymes to break apart glucose, it can use glucose to extract its electrons and obtain energy.

Interestingly, most organisms do exactly that. They break apart glucose into smaller products and take the freed electrons. In that case, glucose is the so-called electron donor.

Now, these electrons need to go somewhere, since they are full of energy. So, organisms save this energy by transferring these electrons onto other molecules. These molecules have lower energy levels, hence they like to take up electrons. We call these molecules electron acceptors.

But finding the right electron acceptor is not as easy as it sounds.

The many steps from an electron donor to an electron acceptor

Imagine you stand on a high wall and want to get down onto the ground. You could take one big jump to reach the ground. But then you would risk that this high fall would give you so much energy that you might break your knees.

So, you could take a set of stairs, that brings you to the ground in multiple steps. Each step only releases a small chunk of energy but they would definitely not hurt you.

It is the same with electrons from donors with a lot of energy. Transferring these electrons to a final electron acceptor would free up too much energy at once. This could actually burn a cell. Hence, organisms transfer these electrons onto intermediate electron acceptors.

Each of these transfer steps only releases a small chunk of energy that keep organisms warm but also fuel cellular processes. In bacteria, these transfer processes happen in their membranes, where the released energy is directly used.

Here, the released electrons energise flagella so that bacteria can swim. Electrons can also activate transporters so that bacteria can import or export stuff. Not needed electrons and their energies are stored in energy-saving molecules like ATP.

This whole process of electron transfer from a donor to its final acceptor is generally what researchers call cellular or – more specifically – bacterial respiration.

Which molecules do bacteria use for cellular respiration?

Cellular respiration fuels most living organisms. And glucose is a molecule with one of the highest energy levels. Hence, breaking down glucose to extract its electrons is the most common in living organisms.

Animals do it. Fungi do it. So, bacteria are no exception to it.

And as a final electron acceptor, most organisms use oxygen. This molecule has a very low energy level and is basically everywhere so most organisms transfer their electrons to it.

This is what we call aerobic respiration (which is what we generally do as well). But it comes with great risk.

The downside of aerobic bacterial respiration

As soon as an oxygen molecule is fuelled with just one electron, it becomes hyperreactive. Such a semi-activated oxygen molecule can basically react with any compound in a cell and damage it.

This is what makes aerobic respiration quite dangerous. So, every organism aims to hide these reactive oxygen molecules in the membrane.

Yet, it can happen that such a reactive oxygen molecule escapes the membrane. In this case, a special protein binds it and breaks it apart. So, every organism that does aerobic respiration has this same kind of protective protein to get rid of reactive oxygen molecules.

This means that whenever scientists find a new microbe, they first test whether this new microbe has these proteins. To test this, they add a bit of hydrogen peroxide to the bacterial colony. When bubbles come out of the bacteria, it means that they do aerobic respiration. In this case, they have the enzymes to break apart the reactive oxygen molecule and produce oxygen from it.

Which other molecules can bacteria use as energy source?

As we said, most bacteria use glucose as an energy source for cellular respiration. However, there are also many fancy exceptions. And these exceptions make the bacterial – and microbial – world so colourful and diverse.

While many bacteria can extract electrons from many different organic acids and amino acids, some use sulphur compounds. Some bacteria also break apart greenhouse gases like methane, carbon monoxide or even hydrogen gas. Since these bacteria might be helpful in tackling our climate problems, they are of particular interest to researchers!

What does bacterial respiration look like without oxygen?

We surely need our oxygen for respiration. Yet, many bacteria and fungi can live with only small amounts of it or even no oxygen at all.

In this case, they do anaerobic respiration. This basically means that they don’t transfer their electrons to oxygen as an electron acceptor.

Instead, many bacteria have enzymes to transfer their electrons to different electron acceptors. And these depend on what the bacteria have available around them. These electron acceptors can be nitrate or sulphate compounds, salts like arsenate or even metals like iron and gold.

Also, in many microbes, anaerobic respiration is closely related to microbial fermentation. In this case, the bacteria break apart glucose but produce molecules that do not require oxygen.

Just think about yeast that produces ethanol in beer and wine. Or lactic acid bacteria in your sauerkraut and yoghurt that produce lactic acid to make the food more acidic. Lastly, there are fungi like Zymomonas mobilis that produce huge amounts of ethanol from glucose.

Bacterial respiration makes the microbial world diverse

As we have seen, bacteria learned to use various sources to gain energy. They created the right enzymes to extract electrons from fancy high-energy molecules.

And then they learned to transfer these electrons onto even fancier molecules to gain the most energy. Some of these processes even involve bacteria producing shiny gold!

In my opinion, these truly amazing superpowers make the bacterial world so incredibly colourful and fascinating!

The post How bacteria gain energy from cellular respiration to fuel life appeared first on Bacterialworld.
Bacterialworld - A blog about bacteria: from scientific studies to vivid stories about the fascinating bacterial world

But have you ever asked yourself where yogurt comes from and how it is made from milk? Do you know why yogurt tastes so sour and yet delicious?

What if I told you that yogurt only tastes like this thanks to bacteria and their superpowers?

Yes, bacteria not only produce delicious chocolate, wine, beer or bread. But it is also bacteria that make yogurt from milk.

Here, we will look at which bacteria produce yogurt and what makes it so creamy, sour but also healthy.

What’s in your yogurt?

Yogurt would not exist if it wasn’t for our bacterial friends. Interestingly, it only takes two bacterial species to create this white creamy dream that we call yogurt. These two bacteria are Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus.

Within milk, these two bacteria live in a symbiotic relationship. This means they help each other grow and survive. And together, they produce delicious yogurt.

These two bacteria make many molecules that give yogurt its characteristic flavor. These include lactic acid and other acids like acetoin, acetate, acetaldehyde. Because of all these acids, yogurt tastes quite sour.

Also, our two bacteria produce exopolysaccharides. Generally, bacteria use these to make biofilms. But in this case, the exopolysaccharides with their long sugar chains make the yogurt creamy and viscous.

Thanks to bacteria and the milk content, there are also a lot of healthy molecules in yogurt: proteins that are rich in energy, calcium, and vitamins B2, B6 and B12.

How is yogurt made?

It seems that all we need to make delicious yogurt are milk, our two bacterial species Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus and the right temperature. We call these two bacterial species the yogurt starter cultures.

But before their superpowers produce yogurt from milk, the milk needs to be prepared. This is basically to get rid of all the other stuff that we don’t need.

So, to kill all other microbes that might spoil our yogurt, the milk is heated to 95 °C. You might know this process as pasteurization.

After the milk cooled down to about 40 °C, our two starter bacteria are added. Next, the mix is filled into cups and sealed. The cups are then stored in a warm room – something researchers call incubation. During this incubation time, the bacteria can get to work and use their superpowers.

This means that our two bacteria start a process called microbial fermentation. They break down the milk sugar lactose and produce lactic acid and other acids.

Due to all the acids, the pH of the milk drops and it becomes sour. Now, the acids denature the milk proteins – this is the same process that you see when you heat an egg: it becomes harder and loses its fluidity. The milk becomes more viscous and gets a gel-like texture and creaminess.

Why is yogurt good for you?

We already saw that yogurt has a lot of good stuff and some studies showed that it is healthy for us because of all these molecules. But how do these vitamins, proteins and short-chain fatty acids impact our health?

For example, yogurt stimulates the immune cells that are in our guts. This improves our immune system so that it can better fight bad intruders.

Our two starter bacteria also break down some of the milk proteins and produce so-called bioactive peptides. Our guts like these peptides a lot. Hence, it transports them into our bodies where they have health benefits.

Also, the sugars in yogurt are prebiotics. This means they are the right food for other bacteria that live in our guts and that keep us healthy.

Plus, yogurt is full of protein that our bodies need to grow muscles and stay strong. Interestingly, yogurt protein has two important fractions: whey and casein protein.

The whey protein is considered a “fast protein”. This means, our body digests this type of protein faster which gives us energy immediately after eating yogurt.

The other fraction is casein or the “slow protein”. This type of protein clots in our stomach because of the acids. But our body can digest this protein clot only slowly. Hence, the casein protein gives us energy even up to 7h after eating yogurt. Like this, yogurt helps with satiety so that in general we need to eat less.

Lastly, the short-chain fatty acids in yogurt have lots of health benefits for us. They regulate the blood glucose level, insulin resistance and inhibit our appetite.

Now you have a lot of reasons to include yogurt in your daily diet plan!

What is probiotic yogurt?

Researchers found that the two starter bacteria Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus do not survive the acidity in our stomachs. Hence, they do not arrive in our guts and have no impact on our gut microbiota.

However, yogurt is a great vehicle to transport other probiotic microorganisms into our bodies. Probiotics are organisms that “when administered in adequate amounts, confer a health benefit on the host”. Also, probiotics need to be safe, well-characterized and stable while the yogurt is waiting on the shelf to be eaten.

Hence, many yogurt companies now add beneficial probiotics to yogurt. These are bacteria like Lactobacillus casei, Lactobacillus acidophilus or Bifidobacterium.

These bacteria have beneficial effects on our digestion and immune system. They help the right bacteria in our guts to grow, meaning they keep our gut microbiota healthy.

For example, in one study, researchers added a Lactobacillus casei species to yogurt and gave it to children with acute diarrhea. After a few days, these children had fewer symptoms and less abdominal pain thanks to the yogurt mix.

Is (probiotic) yogurt on your diet plan yet?

Here, we looked at two new superhero bacteria that produce the fermented creamy white dream. Even though they might not survive the passage into our bodies, they produce a lot of healthy molecules for us. Hence, they have an indirect health benefit on our bodies.

Plus, yogurt is a great vehicle to transport other probiotic bacteria into our bodies. And it seems that by eating yogurt regularly you can indeed change your gut microbiome and bring in some helpful bacteria.

So, thank bacteria for their superpowers and for providing us with this delicious food!

The post What’s in your yogurt? appeared first on Bacterialworld.
Bacterialworld - A blog about bacteria: from scientific studies to vivid stories about the fascinating bacterial world

Many organisms learned to produce bioethanol: plants, fungi and yes, also bacteria. And they can use many different substrates to do so: plants and wood or food waste. You probably know the alcoholic smell of over-ripe fruits or juices.

So, why not use this bacterial superpower to help us with our energy crisis? Let’s look at another possibility of how bacteria could save the health of our planet by producing alternative energy sources.

Where does bioethanol come from?

Microbes can produce ethanol in a process called microbial fermentation. This means that they break down sugars to produce ethanol and energy for the cell.

This process also takes place when producing wine and beer or rising bread dough.

But to produce biofuels, it gets a bit messier because the substrates often come from food or plant waste. And often, uncharacterised microbial communities cover them.

In these cases, the microbial communities work together to make use of all the components of the waste.

For example, the walls of plant cells contain very rigid and long sugar molecules – so-called polymers. Certain bacteria can break down these long polymers into single sugar molecules.

Then, other organisms – often yeast strains – produce ethanol from the sugar molecules in the fermentation process. And when producing beer or wine or rising bread, it is usually our good old friend the baker’s yeast that produces the ethanol for us.

But when it comes to producing bioethanol, we need a lot of it and we need it fast. How lucky are we that one bacterium produces bioethanol a lot more efficiently than yeast strains?

Meet Zymomonas mobilis – the fastest bacterial bioethanol producer.

Why does Zymomonas mobilis not get drunk?

From every single sugar molecule, Zymomonas mobilis produces two ethanol molecules. As you can imagine, Zymomonas mobilis produces a lot of ethanol during its lifetime. So much, it would get you and me super drunk and would damage our bodies irreversibly. But ethanol is not just toxic for us – it also is for bacteria.

Ethanol is a so-called chaotropic compound. This means it disturbs the organisation of biological macromolecules. Hence, proteins and DNA can get disrupted and lose their function. Like this, the bacterial outer envelope gets completely disorganised and bacterial cells lose their stability.

Because of that, most bacteria cannot stand the tiniest bit of ethanol as they get drunk and become intoxicated.

But not Zymomonas mobilis.

This bacterium can live on ethanol without losing it. It knows very well how to protect itself from the toxic effects of ethanol.

Zymomonas mobilis carries a special sugar in its outer envelope. Because of these sugar molecules, a water layer surrounds the membrane. And this water layer blocks the ethanol from coming into contact with the membrane. Hence, the sugar-water shield protects the membrane and the bacterium.

Also, Zymomonas mobilis produces a biofilm that blocks ethanol from entering the bacterial community. And researchers also found that when Zymomonas mobilis lives in biofilms, it produces even more ethanol.

This sounds like something to create communities of Zymomonas mobilis biofilms that efficiently produce ethanol on an industrial scale.

Zymomonas mobilis as an efficient biofuel-producer

Researchers are already on it to use this superhero bacterium to tackle our energy crisis. They are looking into feeding Zymomonas mobilis different substrates from food leftovers or plant waste.

Unfortunately, our superhero bacterium cannot break down the long sugar polymers from plant cells. This means that for industrial processes, the food or plant waste needs to be pre-treated to break down the polymers. But this step also increases costs and processing time.

An alternative is to use other bacteria or microbes that can break down the polymers into single sugar molecules.

Zymomonas mobilis then uses its very efficient sugar transporters to import the sugar molecules into the bacterium. Now, the bacterium can ferment the sugars and produce bioethanol.

Can you see how this is yet another example of how microbes feed each other?

So far, this process is not optimised for huge-scale industrial applications. But it seems clear that it might be bacteria that help us with yet another crisis.

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Bacterialworld - A blog about bacteria: from scientific studies to vivid stories about the fascinating bacterial world

What’s your New Year’s resolution?

Are you trying to eat healthier by eating microbially fermented foods full of nutrients?

Or do you want to be more friendly to the environment by using green bio-plastics?

Keeping this planet green and healthy is a great New Year’s resolution. And one that microbes can help us with.

For example, microbes can degrade and remove the toxic pollution that we have produced. They do that in a process called microbial bioremediation.

Just another way microbes help save the planet.

Our pollution problem

Oil spills, chemical leaks, industrial discharge. We hear about these types of toxic pollution all too often. Increased urbanization, industrialization, and utilization of natural resources pollute and contaminate the environment, which is unhealthy to humans and the planet.

Unfortunately, it is much easier to spill oil or leak a chemical than it is to clean it up. Especially, if the pollution compound is toxic. Cleaning up these types of pollution is costly and may be harmful to the environment.

Why microbial bioremediation?

How lucky are we that microbes can make cleaning up these messes easier? Our microbial friends can degrade and detoxify environmental pollution. This process is called microbial bioremediation.

Microbes absorb or eat toxic pollutants. They then break them down into harmless compounds. This process is a more cost-effective and environmentally friendly method to clean up toxic pollution.

Cleaning up after oil spills

We use petroleum oil in multiple ways, from powering our cars and homes to manufacturing plastics and medicines. Most petroleum oil is found deep in the ground and it takes much energy and expense to pump the oil to the surface.

Unfortunately, sometimes we spill some of that oil. The 2010 Deepwater Horizon oil spill in the Gulf of Mexico is the largest known oil spill and it released 4.9 million barrels of oil into the ocean! What an environmental disaster!

Petroleum oil is a type of fossil fuel full of different organic compounds called hydrocarbons. They contain hydrogen (“hydro”) and carbon molecules. For us humans, ingesting these compounds would be deadly.

So, when that oil disaster happened in 2010, microbiologists and their microbial friends came to the rescue. Luckily, some microbes have special enzymes that recognize and degrade hydrocarbons into smaller compounds. They then use these smaller compounds to grow and reproduce.

Microbes eating hydrocarbons

Many bacteria can degrade petroleum oil. For example, a special Pseudomonas aeruginosa strain can break down oil droplets and grow on petroleum oil with nothing else to eat.

Additional Pseudomonas strains as well as Bacillus subtilis strains are capable of eating hydrocarbons too.

Researchers have also found communities of bacteria working together to degrade and remove petroleum oil. And they are now developing ways to implement these bacterial communities for cleaning up oil spills from contaminated soil and water.

Fungi are also used for bioremediation, called mycoremediation (“myco” refers to fungus). Researchers discovered 16 different fungi species that degrade hydrocarbons in crude oil.

The superhero fungi Trichoderma viridae, Aspergillus flavus and Varicosporium elodeae have the highest rates of degradation. And the Exophiala xenobiotica fungus degrades a hydrocarbon compound found in car gasoline.

Scientists are working to use these microbes in larger bioremediation projects as greener and cheaper ways to clean up oil spills.

Detoxifying heavy metal contamination

Oil spills are not the only toxic pollution generated by us humans. Through many industrial processes, we release heavy metals such as copper, lead, and mercury. Once in the environment, heavy metals can enter the food supply and accumulate in our bodies. Unfortunately, these can lead to health issues and sometimes even cancer.

Removing heavy metals from contaminated water and soils is costly, time-consuming, and ineffective at low concentrations of the contaminate. Good thing microbes can make this process faster and more efficient.

They help remove heavy metals through a process called biosorption. Microbial cell walls are made up of proteins and sugars with a slightly negative charge. Metals have a positive charge.

Thus, microbes can attract and bind these toxic metals. This means microbes act like magnets and pull out the toxic metals from the environment.

Many microbes can absorb a variety of metals. But these microbes also need to protect themselves from toxic metals. For this, they have special enzymes that transform the metals into less toxic forms inside the cell.

However, even microbes cannot survive if the concentration of toxic metals is too high. So, it is important to find microbes that can tolerate high levels of metals and detoxify them. Scientists have discovered some Aspergillus species that can survive high concentrations of copper and nickel metals.

These microbes must also be superb at decontaminating. One rockstar strain of Aspergillus flavus removed over 97% of mercury contamination. And two Pseudomonas species strains removed over 75% of copper, lead, and zinc contamination. Microbes like these will be vital for removing future heavy metal contamination.

Microbes creating a cleaner future

There are a lot of toxic materials in our world. As human activity increases, so too does the amount of toxic pollution we create on our planet. The results of oil spills and heavy metal contamination hurt our human health as well as the health of our planet.

Luckily, microbes have evolved ways to survive and detoxify these types of pollution. Our microbial friends can help remove these toxins and clean up messes created by us. By harnessing the power of microbes, bioremediation projects address our pollution problem and work to make our planet a greener and healthier place. And that’s a great New Year’s resolution!

Along with microbes, we can save the planet!

Take away messages from this week’s article:

• Toxic pollution is a major problem for the health of humans and our planet
• Microbes can detoxify environmental pollution in a process called microbial bioremediation
• Microbial bioremediation is an environmentally friendly and relatively inexpensive way to clean up toxic pollution

The post Microbial bioremediation: microbes cleaning-up our toxic messes appeared first on Bacterialworld.
Bacterialworld - A blog about bacteria: from scientific studies to vivid stories about the fascinating bacterial world