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

The post How Microbes Clean our Drinking Water appeared first on Bacterialworld.
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

The post Microbes as biofertilizers appeared first on Bacterialworld.
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

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

But as we know all this plastic is seriously hurting our planet, the animals on it, the plants and also ourselves. Not only plastic is incredibly stable and its breakdown products can be found almost everywhere, but producing plastics takes a massive toll.

Producing plastics hurts our planet

Making plastic materials is an energy-rich process that requires extracting and burning fossil fuels and petroleum. Chemicals from petroleum are extracted and combined into long chains called polymers.

However, petroleum and fossil fuels are resources that are limited. Plus, burning fossil fuels releases a lot of carbon dioxide, which leads to climate change and air pollution.

Currently, it is still easier and cheaper to make new plastics than recycling and reusing the already plastic items. Plastics are very durable, so it takes a lot of energy to break them down and melt them into a reusable form.

The idea is to find a greener and more sustainable way to make plastics.

Gladly, there is—bacterial-generated plastics!

Bio-plastics from bacteria

Many bacteria produce products that we use in our daily lives, from fermented foods like yoghurt, kombucha and beer to biofertilizers and ethanol that we use for biofuels. For example, the bacterium Escherichia coli, commonly known as E. coli, produces many medicines, like antibiotics and insulin used for diabetic treatment.

So, asking bacteria to make plastic isn’t that hard to believe.

How do bacteria make bio-plastics? 

Plastics are long chains of smaller units called plastic monomers. These monomers can look different, which finally make the different kinds of plastics.

When bacteria have too much energy inside their cells, they produce a lot of these monomers. They then link these monomers into polymers to store energy.

Interestingly, different bacteria can produce different kinds of monomers. And different combinations of these monomers make different plastic polymers.

When living organisms like bacteria or fungi produce plastics, these plastics are called bio-plastics.

For example, several microorganisms, such as Burkholderia xenovorans and Pseudomonas strains produce the polymer polyhydroxyalkanoate (PHA). In these cases, PHA serves to store carbon and energy during times of hunger.

You can understand PHA as fat in our bodies; the bacteria store energy and carbon for when they need the extra energy. But instead of viewing PHAs as fat, researchers are learning ways to use these polymers to create sustainable, biodegradable bio-plastics!

Engineering bacteria to produce bio-plastics

By learning how to use building blocks already made in nature, we can create plastics that are a lot healthier for the planet. But first, scientists need to make sure bacteria can produce enough bioplastic polymers to meet the worldwide demand.

To achieve this, even bacteria need some engineering help from scientists to produce more of the bio-plastics. Maybe engineering bacteria sounds scary, but it just means adding genetic material to a bacterial cell so that the cell knows how to produce the wanted product.

Genetic engineering is how E. coli makes insulin. And that same E. coli can also be engineered to make bio-based polymers.

One group even engineered E. coli to produce common plastic building blocks from the simple sugar glucose. Glucose is an abundant and renewable starting material, making bacterially produced plastics more sustainable than processes that rely on fossil fuels. Plus, this one-step process using E. coli is much simpler than the current way to make plastics.

But it is not just E. coli that scientists are trying to use to make bio-plastics. Researchers engineered both the bacteria Novosphingobium aromaticivorans and Ralstonia eutropha to produce biopolymer building blocks. However, we still need more research to optimize the process.

Benefits of bacterial bio-plastics

The plastics made by bacteria require less burning of fossil fuels, while many precursors used by bacteria are also sustainable. Both reducing non-renewable resources and instead using renewable resources makes bio-plastics a healthier and ‘greener’ option for the planet.

Additionally, some of the bio-plastics are more biodegradable than conventional plastics. Because these polymers are already natural products, other microorganisms and natural processes already know how to break them down and release natural products back into the environment.

Synthetic polymers found in traditional plastics are meant to last forever and can take decades to break down! This means that all the plastic trash fills up our landfills and oceans.

One study found that a bio-plastic item had a lower environmental impact as compared to a traditional plastic item over the item’s lifetime. That’s because the production of bio-plastics emits fewer greenhouse gases, uses fewer fossil fuels, and produces fewer toxins as compared to traditional plastic production.

In all these ways, bacterial bio-plastics are making the Earth greener.

A greener future with bacterial bio-plastics

Plastic pollution is a threat to our planet. These items overflow our landfills and oceans, where they sicken us and wildlife. In 2010 alone, it was estimated that up to 12.7 million metric tons of plastic ended up in the oceans! All this plastic hurts aquatic life and our planet’s marine ecosystems.

Luckily, scientists and engineers are exploring ways for bacteria to reduce our plastic pollution, both by creating bioplastics and degrading already produced plastics.

Using bacteria and bacterial enzymes, we can soon produce biodegradable plastics with less energy. From food to medicine to plastics, microbes are important for producing items we need to live.

However, even with microbes’ help, we can all play a part by reducing our plastic consumption, buying reusable over disposable products and recycling our plastics appropriately.

Along with microbes, we can save the planet!

Takeaway messages from this week’s article

• Plastic production is a major burden on the planet
• Bacteria can produce the building blocks for bio-plastics
• Bio-plastics start with sustainable precursors and are more environmentally friendly as compared to fossil fuel-derived plastics

The post Bacteria produce green bio-plastics appeared first on Bacterialworld.
Bacterialworld - A blog about bacteria: from scientific studies to vivid stories about the fascinating bacterial world

Everywhere in the world, you can find plastics, from grocery bags to pens to spandex leggings.

We use plastics because they are lightweight, flexible, and durable.

But their durability is also their biggest drawback. Plastic takes a long time to decompose, which becomes a huge burden for our environment and planet.

The plastic problem

But let’s start by looking at what plastic exactly is.

Plastics are made up of smaller monomer units that link together and form a chain called a polymer. Different monomers have different chemical structures. Different combinations of these plastic monomers make different types of plastics. That’s how a flexible grocery bag and a sturdy toothbrush can both be made from plastic.

It is like a brick building. There are many types of bricks, and different varieties of bricks are combined to build different sorts of buildings.

No matter the type of plastic, the links between two plastic monomers are very strong. This is what makes plastic so sturdy but also why it takes so long for plastics to break down naturally.

A typical plastic grocery bag takes 10-20 years to break down while a plastic bottle can take 100-450 years.

Currently, recycling plastics requires a lot of heat and chemicals to break the strong bonds between the monomers. Once those bonds are broken, the monomers can be reused to make something new.

As you can see, the recycling process is very energy-dependent, so we generally manage to recycle less than 10% of plastics. That means most plastic waste ends up burned (12%) or in landfills or oceans (79%) where it can sicken wildlife. One group predicted that 4.8 to 12.7 million metric tons of plastic had ended up in the oceans in 2010 alone! This causes major problems for aquatic life.

Plastic-degrading bacteria to the rescue

Gladly, we have some super bacteria that help us find new ways to degrade and recycle plastic. This will make the whole process easier, greener and less energy-intensive.

The key is plastic-degrading bacteria that have special enzymes to break down different types of plastics. Even though enzymes are proteins that speed up chemical reactions, most of these are fairly slow when it comes to degrading plastic polymers. Many of them still need high temperatures to perform best, which means a lot of energy input for recycling.

But recently, scientists discovered the bacterium Ideonella sakaiensis 201-F6 that can ‘eat’ plastic.

Yes, you read correctly.

Ideonella sakaiensis secretes an enzyme that breaks down the links between plastic monomers. These smaller monomers give the bacterium energy and building blocks. Just like how humans cut bread into slices to make it easier to eat, Ideonella sakaiensis breaks down plastic into smaller pieces to eat.

But Ideonella sakaiensis isn’t the only bacterium that loves eating plastic.

A recent study found that a strain of Pseudomonas eats polyurethane, another commonly used plastic polymer.

Other microbes like eating plastic too

And it’s not only bacteria that can be found in plastic-rich environments to degrade our plastic pollution. Also, other microorganisms evolved to eat plastic.

Isolated from landfill soil, the fungi Trichoderma viride breaks down plastic found in the landfill. The marine fungus Zalerion maritimum degraded small pieces of plastic, called microplastics, found throughout the oceans.

Harnessing microbial superpowers

Gladly, researchers are well on the way to using the power of microbes to help recycle plastics.

The bacterium Ideonella sakaiensis uses the enzyme PETase to break down a common type of plastic called polyethylene terephthalate (PET). Scientists hope to use the bacteria with their PETase enzymes in bioreactors to degrade plastic polymers. This would reduce the energy input needed for recycling.

But to achieve this, scientists need to better understand how PETase binds and degrades PET. For this, they determined the 3-D structure of the enzyme.

Based on these data, scientists tried to increase the efficiency of PET degradation, for which they slightly changed the protein structure of the enzyme. This already improved the degradation rate of the enzyme, but they continue to modify and improve PETase activity. Hopefully, this ongoing improvement will bring us a much more efficient plastic-degrading PETase enzyme that we can use for recycling plastics.

The plastic-degrading power of microbial communities

Additionally, communities of bacteria and microbes have the possibility of acting as plastic-degrading bioreactors. Researchers found a marine microbial biofilm that broke down weathered plastics. They then added bacteria, which they already knew would degrade plastic, to the biofilm. This addition increased the plastic degrading efficiency of the community.

And it looks as if nature already evolved a system to address our plastic waste. A bacterial community isolated from a plastic-processing plant degraded plastic at higher levels as compared to a formulated community of laboratory bacterial strains.

Why was that?

Well, when scientists looked at the genes of the native community, they found new bacterial strains. And these strains of bacteria most likely evolved to degrade plastic better than known strains.

Just imagine what types of plastic-degrading microbes scientists may find if they continue to look for them!

Let’s hope that one day we can implement microbial enzymes and communities in plastic recycling processing.

A cleaner future thanks to plastic-degrading bacteria

Plastics continue to pollute our planet. As these items fill landfills and oceans, they break into smaller and smaller pieces that are easily consumed by and sicken wildlife. Small microplastics can act as a surface for pathogenic and antibiotic-resistant bacteria to live on and spread. And microplastics have even been found in human drinking water.

Plus, the more plastic we lose to pollution the less plastic is available to recycle and reuse. This means more plastic needs to be produced using non-renewable fossil fuels. And we all know that fossil fuels are not sustainable as they contribute to air and water pollution as well as climate change. All of these factors compound the present plastic problem the planet faces today.

With more research, let’s hope we can find more bacteria that are able to degrade plastic polymers. By using microbes and microbial enzymes, possibly we can reduce overall plastic waste. However, even with microbes’ help, we can all play a part and reduce our plastic consumption. That means, buying reusable over disposable products and recycling plastics appropriately.

Along with microbes, we can save the planet!

Take-away messages from this week’s article

• Plastic pollution is a major problem for the planet
• Plastic is hard to break down, but some bacteria degrade plastic thanks to their special enzymes
• Communities of bacteria and microbes can work together to degrade and recycle plastic

The post Plastic Degrading Microbes For a Cleaner Future appeared first on Bacterialworld.
Bacterialworld - A blog about bacteria: from scientific studies to vivid stories about the fascinating bacterial world

What does stress mean for bacteria?

For humans, stress can come from juggling work, family, exercise, entertainment, and whatever else life throws at us (like a world-wide pandemic!). Bacteria also can get stressed; however, they experience and react to stress differently than us. Salmonella enterica is a great example of a bacterium that has many ways to deal with different stress in its life.

You’ve probably heard of Salmonella enterica because it can cause food poisoning. While there are many different strains of this bacterium, I’ll only be discussing the ones that lead to food poisoning and I’ll refer to it as Salmonella in this post. Unfortunately, there are about 1.3 million food poisoning infections a year from Salmonella.

About the pathogen Salmonella

Salmonella naturally lives in the guts of chickens, so handling chickens or eating undercooked or raw eggs could put you at risk of getting sick. That’s why you’re not supposed to eat raw cookie dough (even though it’s so good). Good hand hygiene and cooking meat and foods thoroughly reduce the risk of getting sick.

However, if by any chance a Salmonella bacterium makes its way into our bodies, it travels to the small intestine. Here, it will start to reproduce, leading to diarrhea and stomach cramps associated with food poisoning.

But if you think about it, it has to be challenging for Salmonella to live in all those different environments, from chicken guts to the inside of eggs to human stomachs and intestines. Each of these environments has a different temperature, pH, and different nutrients. And the change of just one of these conditions is “stress” for the bacterium. That’s where having the ability to deal with stress comes in handy for Salmonella.

Let’s look at each of these challenges for Salmonella bacteria and how they deal with stress.

How Salmonella handles temperature stress

Salmonella likes to grow in the warm environments of chicken and human guts.

And like humans, bacteria also react to being too cold. This can happen when Salmonella lives in a chicken egg and a chicken lays this egg. All of a sudden, Salmonella lives in outside temperatures. But instead of bundling up with some hot cocoa and a blanket, Salmonella makes proteins to protect itself.

When bacteria are too cold, the genetic information (DNA, RNA) stiffens and adopts a shape that’s hard for the cell to use. This is why the cell makes special proteins that protect the shape of DNA at colder temperatures.

Thus, the cell ‘blankets’ its genetic information to protect it and use it properly.

How Salmonella copes with acid stress

After coping with changing temperatures, Salmonella continues its journey to the human intestine. We consume Salmonella bacteria through contaminated food (like that raw cookie dough). Then they make their way down to the human stomach.

But our stomachs are very acidic. This is to help us break down food and kill pathogens. In acidic environments, proteins start to misfold and get destroyed, making them useless to the cell.

However, Salmonella and other pathogens know how to cope with this acidic attack. They produce so-called chaperones. These are special proteins that protect other proteins from misfolding. This keeps all other proteins active and thus the cell alive.

How Salmonella saves energy when food is limited

Now that Salmonella has survived the highly acidic stomach, it enters the intestines where it can find food and grow. Lots of bacteria live in our guts and all compete for the same amount of food.

For cells to grow, they need energy that comes from food. When food sources are limited, Salmonella cells will conserve energy by ‘turning off’ proteins that consume energy.

But why not just get rid of that protein if the cell does not need it anymore? The problem is, making proteins takes energy. If the cell needs the protein it just trashed in the future, the cell must invest more energy into making that protein again. By turning the protein off, the protein is not destroyed and can be used again later when conditions are better.

It is similar to changing from a green light to a red light at a traffic light. The red light halts cars from moving at specific times but does not destroy the car. Once traffic conditions favor that direction, the traffic light turns green and the cars can respond quickly and move through the intersection.

Similarly, Salmonella turns off its proteins in such a way that it can later remove the modification and restore the activity of the protein. Like this, Salmonella can respond quickly and turn on the protein when food becomes available. Once more food becomes available, Salmonella settles into the gut by eating, growing, and reproducing.

Unfortunately, as Salmonella gets comfortable in its new home, we become uncomfortable with fever, stomach aches, and diarrhoea. Now that sounds stressful!

Salmonella knows how to deal with stress

All these mechanisms of stress management allow Salmonella to thrive in a wide variety of environments. From chickens to humans, the road to pathogenesis is wrought with stressful situations. And lucky for Salmonella, it knows just how to deal with each of these situations of stress.

The ability to respond to stressful situations is common to bacteria, and each bacterium possesses its own set of proteins and pathways to handle stress and even aid in bacterial virulence.

So just like us, bacteria have to handle a lot of stress in their lives. But the more we learn about how pathogens like Salmonella deal with stress, the better we can fight them!

Take away messages from this week’s article

• Bacteria encounter many stresses in the environment
• They have various pathways to respond to different types of stress
• The ability to deal with varied environments and stress allows pathogens like Salmonella greater virulence and resilience

The post How does Salmonella deal with stress – a bacterial journey through the human body appeared first on Bacterialworld.
Bacterialworld - A blog about bacteria: from scientific studies to vivid stories about the fascinating bacterial world