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

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

And more and more people become aware that a plant-based diet is not only better for your health, but also for our planet. Hence, the focus on agriculture right now is to become more sustainable to grow enough plant-based food for everyone.

This means that we need to find better ways to support plant growth and protect plants from diseases. Unfortunately, several plants pathogens make plants sick, so they die or do not grow enough crops.

Currently, we use fertilizers and pesticides to protect plants from pathogens. However, these chemicals are bad for the environment long-term as they contaminate the soil and water.

Hence, we need to find ways to protect plants by either getting rid of dangerous intruders or by strengthening the immune systems of plants.

Enter bacteria and their superpowers.

They do both.

What is biocontrol?

Some bacteria that live in or on plants are called biocontrol agents. These organisms are harmless to the plant and have two main functions: They protect the plant from pests and diseases and support its growth and crops.

Some of these organisms additionally strengthen the plant’s immune system or resistance – again to protect the plant from disease and help it grow.

One such biocontrol agent is the bacterium Pseudomonas putida. It grows near the roots of many plants where it produces helpful molecules for the plant.

And plants are clever too as they make sure that only the right types of bacteria grow near them. For this, several plants release specific molecules through their roots that help Pseudomonas putida grow. The bacterium senses these molecules so that they activate the bacterium’s chemotaxis system.

Now, Pseudomonas putida uses its flagellum to swim towards these molecules. This movement ultimately leads the bacterium to the plant that released the molecules.

Pseudomonas putida as a biocontrol agent

Once the bacterium “found” the plant, it settles down near it and starts building biofilms. Within these biofilms, the bacteria are connected with each other and with the plant. Like this, they can easily exchange molecules and information with each other and with the plant and build close relationships.

Pseudomonas putida now produces molecules to help the plant grow. For example, some molecules extend the tips of the roots so that the plant can better take up nutrients from the soil.

Pseudomonas putida also breaks down complex nutrients in the soil that the plant use. This basically feeds the plant the needed nutrients. Other molecules from the bacterium activate the overall immune system of plants so that plant pathogens have a harder time infecting the plant.

Altogether, Pseudomonas putida has similar features as biofertilizers that help plants grow.

How does bacterial biocontrol protect plants against intruders?

Pseudomonas putida can also directly fight off plant pathogens to protect their plant hosts. For this, it uses two strategies: It either holds back essential nutrients from plant pathogens or kills the intruder.

Not sure which strategy is more evil though…

Pseudomonas putida keeps essential nutrients to inhibit plant pathogens

All living organisms need iron to live and grow. And one efficient strategy to prevent other microbes from growing is by stealing iron from them.

Our immune system does it as well: All iron in our body is bound to specific transporters. Like this, no free iron swims in our blood for microbes to use. This defence mechanism is one of the first strategies of our immune systems to keep harmful bacteria from growing inside our bodies.

Similarly, Pseudomonas putida produces many different iron transporters that bind iron very efficiently. Like this, no free iron is present in the soil that other microbes could use.

Yet, this is not all. Pseudomonas putida is quite a naughty one since it can also steal iron-loaded transporters from other bacteria. This not only prevents the other bacteria from using the iron, but it also helps Pseudomonas putida grow.

Pseudomonas putida kills intruding plant pathogens

Lastly, Pseudomonas putida is a real fighter when it comes to protecting its host plant. This bacterium uses a special nanoweapon to kill plant pathogens.

Our bacterial fighter carries a bow and arrow and is not afraid of using them to keep intruders off the plant. Pseudomonas putida actively shoots arrows together with lethal toxins into other bacteria to kill them. Many bacteria use this killer machine, called the type 6 secretion system. But interestingly, Pseudomonas putida seems to have a more efficient killing device than others.

Scientists proved that with a simple experiment. When different plant pathogens were growing inside plant leaves, the leaves got sick. However, when Pseudomonas putida was additionally living in the leaves, the plant leaves did not get sick.

Finally, the scientists let the plant pathogens grow together with a Pseudomonas putida bacterium that could not shoot its bow and arrow. Now, the plant leaves got sick again and the plants suffered from the plant pathogens.

These results show that Pseudomonas putida uses its bow and arrow to actively kill other harmful bacteria to protect plants. Even though the experiment was done in plant leaves, scientists are convinced that something similar happens in the root area of plants.

Bacteria as biocontrol agent to save our planet?

As soon as we better understand how exactly this plant warden protects its host from harmful bacteria, we could use Pseudomonas putida on a large scale. This would improve the health of plants so that they can grow more and better crops.

Hence, such a biocontrol agent would eventually help us have more food available for everyone.

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

Even though about 70% of the Earth’s surface is covered by water, a majority of that water we cannot drink.

The water that is available to drink can also be contaminated with toxic chemicals or certain microorganisms that would sicken us.

But not all microbes are bad. In fact, many microbes are helping us save our planet. One way of doing this is by cleaning up our drinking water.

We don’t have enough clean freshwater

Everyone needs water to drink.

Humans can only drink freshwater, which makes up less than 3% of the world’s water supply. Freshwater is found in lakes, rivers, and streams. It is also locked away in the icecaps as glaciers, up in the atmosphere as water vapor, and deep in the soil as groundwater.

Of the small amount of freshwater easily accessible to us, we have used or contaminated much of that freshwater. Agricultural practices have diverted many sources of freshwater for animals and crops. Climate change and warmer temperatures cause farmers to use more freshwater resources as well. And global industrial practices can lead to toxic chemicals entering the environment and water.

This means that now we have less freshwater available to drink than ever.

We have learned ways to clean our drinking water, but this requires a lot of chemicals, energy, and money. Good thing microbes can help us decontaminate our drinking water in faster, easier, and cheaper ways.

Microbes clean water by filtering out bad bacteria

Drinking certain types of bacteria can make us sick. You have probably heard of outbreaks of E. coli or Salmonella leading to people being ill.

These microbes normally live in animals’ digestive tracks and are excreted in their wastes. They can enter the water system from runoff from farms, and ingesting them can make us really unwell. Luckily, microbes can help remove pathogenic bacteria from our water.

A simple method of water filtration includes having water flow over a bed of microbes and sand to remove any contaminates, called ‘slow sand filtration.’ At the top of the sand is a gelatinous layer of microbes, known as a biofilm. In such a biofilm live various bacteria, fungi, protozoa, archaea, and other aquatic microorganisms.

This layer is the so-called Schmutzdecke, which is German for “dirty layer.” As water flows over this biofilm, microbes in the Schmutzdecke trap and consume particles and pathogenic microbes. Every Schmutzdecke layer has a unique community of microbes based on the contaminants in the water. In this way, beneficial microbes remove harmful ones and decontaminate our drinking water.

Slow sand filters can purify away 90-99% of contaminating bacteria! The Schmutzdecke removes most of the fecal contaminating bacteria like E. coli. This system does not involve the use of chemical disinfectants, which can select possibly pathogenic bacteria that become resistant to decontamination efforts.

Also, the Schmutzdecke feeds on the microbes and organic matter found in the contaminated water. Hence, slow sand filters are a cheap and low-maintenance way to filter water in resource-limited areas throughout the world.

Microbes clean our drinking water by preventing bacterial build-up

The Schmutzdecke is an example of a community of microbes filtering water to remove pathogenic microbes and make the water safe to drink. But decontaminating water does not always need a whole community of microbes. Sometimes just one part of a microbe is enough to clean the water. In fact, researchers have found a protein from bacteria that can help stop bacterial contamination.

Pathogenic bacteria like Pseudomonas aeruginosa can contaminate water lines that carry water to homes and businesses. To let other P. aeruginosa know they have found a place to stay, bacterial cells send messages to each other in the form of chemical molecules. This communication system, called quorum sensing, allows bacteria to ‘sense’ the number of other bacteria, (a ‘quorum’) around them.

If enough P. aeruginosa cells grow in the same area and send the same message, they will start to form a biofilm. Just like the Schmutzdecke, biofilms act as a gelatinous layer and are difficult to break up. That’s where that special bacterial protein comes in to help stop biofilm formation.

This protein is called AiiA_DH82 and comes from the deep-sea bacterium Bacillus velezensis (DH82 strain). AiiADH82 binds and degrades the chemical messages that bacteria use to communicate with each other.

Without those chemical signals, bacteria do not know they should start forming a biofilm. Adding AiiA_DH82 to P. aeruginosa cultures decreased bacterial growth and significantly inhibited biofilm formation in P. aeruginosa-contaminated water. Scientists hope one day to apply the AiiA_DH82 protein to water lines and drinking fountains. In these, bacteria could group to reduce bacterial contamination and keep our drinking water safe.

Microbes clean our drinking water

People everywhere need clean water for cooking, cleaning, and drinking. However, clean drinking water is a limited resource. Toxic chemicals or pathogenic microbes can pollute our water. Current methods to purify water cost a lot of energy and money.

We are fortunate that microbes are here to help us clean up our water and our environment. As the global population increases, using microbes to clean drinking water is a cheaper, sustainable and more environmentally friendly way to produce the needed levels of clean water. A great example of how microbes are making our world better.

Along with microbes, we can save the planet!

Take away messages from this week’s article:

• Clean drinking water is a limited and necessary resource for everyone on the planet
• Microbes can clean polluted drinking water by reducing the growth of pathogenic bacteria
• Microbial decontamination of drinking water is a sustainable and inexpensive way to provide clean drinking water to our increasing global population

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

And with an increasing global population, it will be important to find ways to increase the world’s food supply in sustainable ways.

Adding microbial communities, called biofertilizers, to soil can increase crop yield and plant health all without adding any toxic chemicals.

Lucky for us that microbes once again can help save our planet by addressing our global food crisis.

A global challenge

While the global population grows to almost 8 billion people, the land for agriculture remains limited. One way to meet this growing challenge is to increase the quantity of food produced on the same amount of land.

In the past, farmers added expensive chemical fertilizers to their crops. These meant to increase important soil nutrients – specifically nitrogen and phosphorus – and help the plants produce more food.

Unfortunately, these chemicals enter and pollute nearby water systems, harming our health as well as the health of our planet. Plus, producing these chemical fertilizers releases greenhouse gases that add to climate change.

One sustainable method to increase crop production is to add microbial communities to agricultural plants; so-called microbial biofertilizers.

Microbes as biofertilizers

These biofertilizers are soil microorganisms that provide nutrients, stimulate growth, and improve plant health. Also, biofertilizers are more sustainable, less toxic, and cheaper than traditional fertilizers.

Here, we will look at what biofertilizers actually do and how these microbes work for the plants.

Helping plants get nutrients

All living organisms need nitrogen, but not all nitrogen found in the soil is in a useable form. In fact, nitrogen is a major limiting nutrient for plants because most nitrogen in the soil is in a form that plants cannot use.

Hence, microorganisms first need to “fix” the nitrogen and then convert it into a usable form. For this, bacteria make an enzyme called nitrogenase that converts nitrogen from atmospheric nitrogen (N₂) to ammonia (NH₃). Now, plants can absorb this nitrogen form and use it for energy and growth.

Some plants have evolved to work with bacteria to make it easier for them to absorb the fixed nitrogen. For example, the roots of certain legume plants include special root nodules. In these live nitrogen-fixing bacteria called Rhizobia. When chickpea seeds were grown together with these bacteria, their yield increased 250%. Also, adding Bradyrhizobium species to mung bean plants promoted plant growth and yield and plants had a higher tolerance to insecticides.

Cyanobacteria also help plants fix nitrogen. When wheat plants grew together with cyanobacteria species Calothrix ghosei, Hapalosiphon intricatus, and Nostoc species, they grew higher and had more grain. Additionally, co-cultivation with Nostoc or Anabaena species resulted in increased root length and wheat plant nitrogen levels. Cyanobacteria are important nitrogen-fixing bacteria in aquatic environments too, especially for rice production.

Helping plants grow

Besides nitrogen, soil bacteria can provide plants with many nutrients, vitamins, and plant hormones. These are called phytohormones. Phytohormones promote plant growth by acting as signaling molecules to regulate plant metabolism and stress response.

When Rhizobia bacteria grew together with the mustard plant Brassica juncea and produced phytohormones, the plants grew better. Also, in corn (maize), inoculation with Azospirillum brasilense resulted in increased plant growth correlated with elevated phytohormone levels.

Over 80% of Rhizobia bacteria produce the major phytohormone indole-3-acetic acid (IAA). This phytohormone regulates plant growth, cell differentiation, and stress response. Thus, when bacteria secrete indole-3-acetic acid, it promotes root growth. This helps plants take up nutrients better.

In addition to a single bacterial species, communities of microbes help plants stay healthy and grow. Archaea, bacteria and fungi all associate with the roots of plants and synergistically provide nutrients to the plant. Researchers are studying these communities to understand important microbial interactions. The aim is to design microbial communities specific to each crop that promote higher crop production in the future. Just think, one day you could order a biofertilizer optimized for your unique climate, soil, and plant!

Fighting plant enemies

Not only do microbes provide their hosts with nutrients to promote growth, they also protect their hosts from deadly pathogens. Especially fungal pathogens are known enemies that threaten plants.

For example, Pseudomonas and Bacillus strains release toxic chemicals such as hydrogen cyanide to inhibit fungi that infect coffee plants. Other Bacillus strains produce antifungal molecules and simultaneously increase corn (maize) seedling growth. The bacterium Ochrobactrum anthropi TRS‐2 can fight fungi, and application of this bacterium on tea plants decreased brown root rot caused by the fungi Phellinus noxius.

Some bacteria even produce biofilms on the roots of plants as a barrier against invading fungal pathogens!

Agricultural crops are also prone to infection by nematodes, commonly called roundworms. Nematophagous bacteria can deter nematode growth by sending out toxins, and competing for nutrients. For example, Pasteuria penetransbacteria infects nematodes, while Pseudomonas strains can produce antibiotics against nematodes that infect potato plants. No matter the pathogen, soil bacteria have evolved ways to promote and protect their host plant.

Microbial biofertilizers assist our global challenge

As the world’s population increases, we will need sustainable and inexpensive ways to increase agricultural production. Just as microbes add nutrients and flavors to our meals, bacteria can nourish our crops as well. Plus, biofertilizers are a greener, healthier, and less expensive alternative to traditional chemical fertilizers.

So, next time you go out into your garden, think about adding some biofertilizers like compost or manure instead of chemicals to help your fruits and vegetables grow.

Along with bacteria, we can help save the planet!

Take away messages from this week’s article:

• The increasing human population is creating a global food crisis 
• Microbes can act as biofertilizers by providing important nutrients and helping promote plant growth
• Microbial biofertilizers are a sustainable and inexpensive way to increase global food production

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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

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

Everything is connected and our lives depend more and more on technology and electrical devices.

All electronic materials that we use, are produced with lots of energy, harsh processing and/or toxic chemicals. Many electronic devices and batteries are considered disposable. But these are not recyclable or biodegradable and they are often filled with toxic materials. 

So, just as plastic waste is an environmental burden, all electronic waste is becoming an increasing problem for both the environment and our health.

But also for this problem, bacteria provide a green and sustainable solution: Microbial nanowires.

What are microbial nanowires?

Some bacteria can produce protein structures that work like electric cables. Researchers don’t fully understand the details yet. But somehow bacteria use these protein structures to send and receive electrons. Hence, they produce electricity.

And microbial nanowires don’t just substitute synthetic electric cables, they are also lasting. Bacteria-produced nanowires can withstand temperatures up to 100 °C, extreme pH conditions and protein-destroying chemicals. 

And they are green!

Most electronic components that we synthesise, consist of some sort of metal to conduct electricity. Yet, microbial nanowires do not contain such toxic metals and are thus considered harmless to the environment.

Which microbes produce green nanowires?

Many bacteria form cable-like structures that they send out of the cell. Researchers call these structures pili and they have different functions. For example, bacteria can use them to send or receive genetic material.

The bacterium Geobacter sulfurreducens produces this such a type of pilus, but with one difference: Its pilus can conduct electricity. This is why researchers call it an e-pili.

Other bacteria, like Shewanella oneidensis, produce nanowires that they produce from outer membrane vesicles. Outer membrane vesicles are blebs from the membrane of a bacterium. And in the membrane of the vesicles are electron transporters through which electrons hop. The vesicles then extend and eventually become a nanowire with the ability to conduct electricity.

Researchers even found archaea that produce so-called e-archaella. These work similarly to e-pili and help archaea to exchange electrons with their environment.

Why do bacteria produce microbial nanowires?

Researchers don’t fully understand why bacteria use nanowires to conduct electricity. But they are convinced that bacteria produce nanowires for food.

When bacteria produce the nanowires, they immediately transport them outside of the cell. They stay connected with the cable while the cable reaches out to new nutrient sources.

For example, bacteria can connect their nanowires with solid metal oxide particles. By transferring electrons to the metal oxides, they become soluble and the bacteria can use the metal for their metabolism. Like this, microbial nanowires function as arms for bacteria. They try to reach metals that are otherwise too far away from the bacterium.

Also, bacteria produce these nanowires in biofilms or cell aggregates. This looks as if bacteria form electrical networks to exchange electrons. However, it is not clear yet to researchers what the advantage of such a microbial electrical network is.

How can we use microbial nanowires?

Yes, electronics are meant to help us bring our thoughts and ideas to life in creative ways. So, maybe it is about time to use life for electronics as well. This is how e-biologics were born. 

Researchers learned under which conditions bacteria produce a lot of e-pili. They then cut them off the bacteria, dry them and fix them. These green microbial nanowires have even higher conductivities than when connected to bacteria. 

Therefore, microbial nanowires can be sustainable solutions to our increasing electronic waste problem. 

And what about degradation?

As often, when Nature knows how to produce something, it also knows how to destroy it. So, you could throw out your broken bacteria-produced electronic component onto the compost pile. And the bacteria would take care of them and degrade them.

Microbial nanowires are very robust and conduct electricity. Hence, they could be conducting components in electronic devices such as biosensors, light-emitting diodes and organic solar cells.

Researchers are also trying to increase the conductivity of microbial nanowires. For example, the bacterium Geobacter metallireducens produces a nanowire that conducts electricity 5,000 times better than the one from Geobacter sulfurreducens. By understanding the differences between these two structures, researchers can create nanowires with even higher conductivity.

Bacteria powered devices

We know that cable bacteria can conduct electricity over distances up to 7 cm Yet, microbial nanowires are even more remarkable. Usually, proteins are bad electron conductors. But again, bacteria created masterpieces by developing protein structures that are great electron conductors. 

Now it is up to researchers learning to handle e-pili to produce e-cables that one day we might use in our electrical devices.

And who knows maybe one day, we will have self-powering devices that contain bacterial biofilms producing their own electricity.

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

Microbes are necessary for many of our favorite foods, such as bread, cheese, and chocolate, and the beverages we wash them down with, like beer and wine!

With the holidays fast approaching, let’s look at how microbes play a central role in the holiday menu.

Microbes Help Make What You Eat

Microbes are everywhere, including your food. Not only known for food spoilage, but some microbes also help preserve and add flavor to foods. In a process called microbial fermentation, microbes convert sugars in foods into different compounds, such as alcohols or acids.

Bread

Microbes are also necessary to produce our foods. Many holiday meals include special bread that depends on the microorganism yeast. Bread making usually uses the yeast Saccharomyces cerevisiae to eat the sugar in bread dough to make carbon dioxide (CO₂) bubbles that expand and rise the bread.

Microbes can also give bread some of its flavors. Sourdough bread gained popularity during the COVID-19 pandemic because of the ease of culturing the sourdough yeast, called a starter. Sourdough’s unique flavor comes from the starter’s mixture of yeast and lactic acid bacteria. These Lactobacillus bacteria ferment and produce lactic acid, which gives sourdough that ‘sour’ taste and helps to prevent the bread from going stale.

Cheese

After making your holiday loaf, you will need to put something on those slices. Cheese is one of my favorite bread sidekicks and appears on many holiday menus.

Like bread, cheese requires a starter culture of bacteria to convert the sugars in the milk into acids such as lactic acid. Next, during cheese ‘ripening,’ added secondary microbial cultures give each cheese its unique flavor and texture. These secondary cultures can include bacteria, yeast, or even mold, like in the case of blue cheese, and all help produce those much-loved flavors.

Microbes Help Make What You Drink

Bread and cheese are delicious, but they are even better when paired with a nice beverage. Luckily, microbes help make some delicious drinks as well.

Beer

One of the oldest microbially-made drinks is beer. Beer dates back over 5,000 years, though recent evidence suggests people first fermented beer over 13,000 years ago! Like today’s beer, ancient cultures ground grains in large vats and exposed them to yeast that would eat the sugars and ferment it into alcohol and CO₂.

This process adds flavor to the drink as well as many nutrients and essential B vitamins. Most importantly, the alcohol kills possible contaminates and makes the water safe to consume. Adding hops aids its antimicrobial activity by inhibiting Gram-positive bacteria.

While the first beers relied on wild yeast strains naturally found in the air and dust, today’s brewers add specific strains of yeast for desired alcohol and flavor profiles. Or they might add bacteria. Many Belgian ales have Brettanomyces yeasts to produce their notable sour flavor, while German Berliner Weisse beers are fermented by Saccharomyces cerevisiae and Lactobacillus bacteria.

Wine

If beer is not your thing, possibly you will want a nice glass of wine this holiday season. You can thank microbes for that too.

Wine is produced when yeast ferment grapes, yielding both alcohol and CO₂ like for beer. Microbes are important not only for fermenting grapes, but specific yeast, fungi, and bacteria are important for keeping grapes healthy.

Additionally, some fungi are critical to produce specific wines. Botrytis cinerea is a fungus that helps to dry out and concentrate the sugars of a grape through a so-called ‘noble rot’. These grapes produce a sweet dessert wine called a botrytized wine. However, if Botrytis cinerea infects grapes during moist conditions, this ‘gray rot’ destroys the grape crop. Thus, having the right microbiome is important for agriculture just as it is for humans.

Kombucha

If you don’t like beer or wine, you can always try kombucha. This non-alcoholic beverage is produced from acetic acid bacteria and yeasts called a “tea fungus” that ferment tea. The bacteria and yeasts live symbiotically in a biofilm clump called a scoby (“symbiotic culture of bacteria and yeast”). Here, microbes work together to convert the sugars into acids that give the tea a nice tart flavor.

And don’t forget dessert!

Cakes, candies, and cookies are all staples of the holidays. These sweet treats would not be the same without microbes to add flavor and rise.

My favorite sweet, chocolate, comes from cacao beans that are initially fermented for many days by wild yeasts and bacteria. This process breaks down the beans and leads to the production of those oh so yummy chocolate flavors. Just another reason to love microbes!

Welcome Microbes to Your Next Meal

Microbes are vital for giving us so many of the foods and flavors we love. From foods like bread, cheese, and chocolate or drinks like beer, wine or kombucha, microbial fermentation plays an important role in many of our favorite dishes. Fermented foods give us flavors, vitamins, and additional food preservation.

These foods can also help maintain healthy digestive systems. Yoghurt, which is another fermented milk product, contains beneficial bacteria that can help maintain a balanced microbiome.

Not only do microbes help save the planet, but they also save our meals and our health too. So this holiday season, remember to incorporate microbial dishes into your menu.

The post Microbially Powered Meals: How microbes help make our foods appeared first on Bacterialworld.
Bacterialworld - A blog about bacteria: from scientific studies to vivid stories about the fascinating bacterial world

Vaccines helped eradicate deadly diseases like smallpox.

And for over a century, researchers developed vaccines according to Pasteur’s principle. They isolated the microorganism and inactivated it. Then they injected the now harmless microorganism into people. 

Now these people were vaccinated.

Their immune systems would detect this foreign microorganism and develop antibodies against it. The next time this person gets infected with the real microorganism, the antibodies would be ready to fight the intruder.

New challenges for researchers

But unfortunately, developing vaccines is not always that easy.

Especially, when researchers have trouble growing an organism in the lab. As it is the case with the hepatitis C virus. And then there are nasty pathogens like Neisseria meningitidis. These know too well how to hide from the immune system and cause deadly meningitis. Or to fight a clever virus like HIV, we need help from extra skilled parts of our immune system. Let alone a virus as SARS-CoV-2 that emerged from nowhere and for which we need a vaccine real quick.

To develop vaccines against these microorganisms, researchers needed a new strategy. They try to find new vaccines that activate the immune system and trigger it to produce antibodies. These antibodies have to detect a specific piece of foreign microorganism. Often, this is a protein from the surface of the virus or the bacterium: the so-called antigen. 

But not every antigen is a good antigen that activates the immune system.

Hence, researchers need to produce and test different antigens. And for this, they rely on fancy technologies and super-efficient helpers: bacteria. Here, we will look at how researchers use bacteria in the hunt for vaccines. 

Bacterial pets in the lab

For some researchers, the bacterium Escherichia coli is a dear lab pet. They know exactly how to grow, change, regulate, mutate, shock and kill this bacterium. And they appreciate that their favourite lab bacterium can carry big chunks of DNA and produce almost any protein.

So, to produce and test antigens, researchers need to make DNA with a gene for an antigen.

Bacterial machines to produce DNA

To produce any piece of DNA, researchers use a special DNA production machine from the bacterium Thermus aquaticus. This bacterium lives in hot regions, so its enzymes only work at hot temperatures. 

Hence, researchers can control this DNA production machine by regulating the temperature. And like this, they can produce any gene they need.

Bacterial machines to cut and paste DNA

The problem is that the gene alone is not stable. This is why researchers need to put this gene (in blue in the picture below) into a plasmid. Plasmids are stable DNA circles (in yellow), that bacteria recognise and produce. 

To link these two pieces of DNA together, researchers use special scissors. These scissors cut the gene and the plasmid so that they now work like puzzle pieces. They can only fit together. 

These scissors also come from bacteria and, interestingly, every bacterium has its own type of scissors. This means researchers can produce many different puzzle pieces that always work in pairs.

Next, the plasmid and the gene need to be glued together. And for this, researchers use a glue stick from a virus. And yes, it works like the plaster in the picture.

Finally, we have a big chunk of DNA with a gene for an antigen.

Now, researchers need to produce this antigen.

Guess what, they use bacteria for that too!

Bacteria are protein production machines

First, the plasmid with the gene for the antigen needs to go inside the bacterial cell. For that, researchers electrocute the bacteria together with the plasmid. Yes, electrocute them! Poor bacteria!

But this brings the plasmids into the bacteria.

Next, researchers grow these bacteria with the plasmid. The bacteria now produce a lot of that plasmid and a lot of that antigen (blue).

Next, researchers need to kill the bacteria and clean the antigens from them.

With all the antigens produced now, the fun experiments can get started. 

Finding the best antigen for a vaccine

Generally, researchers produce many different antigens to find the best one as a vaccine. The best antigen is the one that binds to an antibody the tightest.

To test all the antigens, researchers do an experiment that is funnily called ELISA. And they can do this ELISA experiment only thanks to bacteria.

Some bacteria from the Streptomyces family produce the protein streptavidin. This protein binds very, very tightly to the vitamin biotin. Obviously, researchers make use of these two proteins in the lab.

In the simplest version of an ELISA experiment, researchers glue antigens to a surface (yellow, blue and green). Then, they add liquids with different antibodies (grey) to these antigens to test which one binds most tightly. 

These antibodies are linked to a biotin molecule (grey circle). Next, the researchers add streptavidin (green) that is linked to an enzyme. Now, only if the antibody bound the antigen, the streptavidin can bind the biotin. And if that happens, the enzyme can change the colour of the liquid. 

Like this, researchers can test many different antigens and “see” for which the colour changes. These are the ones that bound to an antibody.

Researchers need to repeat all these steps many times; each time changing the antigen a bit to make it more efficient.

But eventually, this antigen becomes a vaccine.

And just as bacteria produced the antigen in the lab, they might have to do that in large amounts to produce the masses of vaccines needed.

About vaccines produced by bacteria

Bacteria can produce different proteins and therefore different vaccines.

For example, the vaccine against the hepatitis E virus is completely made by bacteria. Bacteria produce the envelope proteins of the virus. These then assemble and build the virus structure. This vaccine now has the same structure as the virus, but it is inactive and harmless since no viral DNA is inside the envelope. 

Some vaccines also have components from different organisms. 

Our immune system can very well detect the sugars on the surface of bacteria. Hence, researchers attach some of these sugars to vaccines. Like this, they attract the big players of the immune system to the vaccine. This activates the immune system so that it develops antibodies against the vaccine.

Researchers also linked bacterial proteins to vaccines. Here, researchers found that bacterial toxins or proteins from the bacterial surface attract and activate the immune system. But not to worry, researchers worked out how to inactivate the toxin so that the vaccine is not harmful.

Not all vaccines are produced by bacteria

Lastly, researchers developed new strategies to produce vaccines without bacteria. And they even use this strategy for some vaccine candidates against SARS-CoV-2 that causes the COVID-19 disease.

These vaccines only contain a piece of RNA enveloped in a lipid membrane. And, yes, this concept looks a lot like bacterial outer membrane vesicles that transport DNA or drugs. 

In this case, our body produces the protein – the antigen – from the RNA. This again activates the immune system and triggers it to make antibodies against the antigen.

So while the delivery mode of the vaccine is pretty different, the way to activate the immune system is still the same.

Bacteria are important in the hunt for vaccines

Some microorganisms are real burdens to the world population. Hence, researchers had to come up with new strategies to tackle them. There is no vaccine against the nasty SARS-CoV-2 yet, and maybe the final vaccine will be produced completely independent of bacteria. But still, bacteria are massively helping researchers in the lab. 

They are amazing little machines to produce proteins or transport DNA or drugs. And they evolved helpful enzymes that every lab researcher uses daily. No biology-related research would work without the amazing mechanisms of bacteria.

Ever since the pandemic started, a lot of people ask me whether we can have bacteria kill the nasty SARS-CoV-2. I doubt it will be a direct fight between bacteria and viruses. But I am convinced that in the end bacteria and their superpowers will save this planet.

Researching and writing this post was possible due to the Journalism Research Grant from the Berlin Science Week.

it’s been a great first adventure as a proper science journalist at the #BerlinScienceWeek https://t.co/ZlJFOb9e18

— Sarah Wettstadt (@DrBommel) November 6, 2020

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