The uses of microbes

Answers provided by

• Professor Nicola Stanley-Wall FRSE
• Professor Sarah Coulthurst FRSE
• Professor J. Ross Fitzgerald FRSE
• Professor Paul Hoskisson FRSE
• Professor Malcolm White FRSE
• Professor Matthew Holden FRSE

How can microbes be useful?

Microbes are incredibly useful, and we use them in our everyday life – often without realising it. Almost half of the oxygen we breathe is made by certain bacteria living in the sea. Many of our foods need microbes to do the hard work that we cannot, such as converting chemicals in the food into flavours or helping the food last longer on the supermarket shelves. Bread, cheese, yoghurt, coffee, chocolate, beer, and vinegar are just a few foods that require microbes for their production. Many other foods contain ingredients that are also made by microbes, such as the citric acid added to many fizzy drinks and other foods. We also require microbes to help us farm the fruits and vegetables we eat. Microbes are very important for the health of soil to allow plants to grow better. Some microbes also associate with the fruits and vegetables we farm to help them capture nitrogen from the air to help them grow and in return, the plants supply the microbes with food to help them grow in a process called symbiosis. Microbes living inside us also help us to digest the foods we eat. Lots of our medicines are also made by microbes such as antibiotics and microbes are also important in helping us to treat the wastewater in our sewage systems helping the water to become safe for release into rivers and the sea.

How can microbes be used in medicines?

Some of our most important medicines are made by microbes that live in soil. Some of these microbes make antibiotics and we can use these to help kill the bad microbes that make us sick. Antibiotics were first discovered by Sir Alexander Fleming, a Scottish scientist, who noticed that when a certain type of microbe grew in his work by accident, the bacteria he was trying to grow were killed. This discovery has saved the lives of many people and is one of the most important breakthroughs in medicine. Some related microbes can also make other medicines that can help to cure people infected with parasites, some make chemicals that can help combat cancer and some microbes can even help people who have had organ transplants.

How many microbes are in the world?

Micro-organisms are ubiquitous in nature, being present in water, soil, air, and on the surface and interior of all animals. Within a single human, it is estimated there are about 38 trillion bacterial cells (many more than there are human cells). It is very complex to estimate the total number of microbes in the world, but one estimate for bacteria only is 5 million trillion trillion. A combined total for all microbes would be many more times than this and possibly into the quadrillions. One estimate for the total biomass of bacteria in the world is about 70 billion metric tonnes.

Can microbes defend themselves against viruses?

Yes! Microbes have lots of different defence systems that they use to destroy viruses before the virus kills them. Some of these are like scissors that snip the viral DNA into pieces to stop replication. These scissors are now used by scientists to build useful DNA structures and to cure genetic diseases. Without microbial defence enzymes a lot of the genetic engineering scientists do would be impossible! As microbes are our distant ancestors, we inherited a lot of our defence systems against viruses like Covid-19 from microbes – so there are lots of reasons to be grateful for microbes!

Answers provided by

• Professor Nicola Stanley-Wall FRSE
• Professor Sarah Coulthurst FRSE
• Professor J. Ross Fitzgerald FRSE
• Professor Paul Hoskisson FRSE
• Professor Malcolm White FRSE
• Professor Matthew Holden FRSE

How can microbes be useful?

Microbes are incredibly useful, and we use them in our everyday life – often without realising it. Almost half of the oxygen we breathe is made by certain bacteria living in the sea. Many of our foods need microbes to do the hard work that we cannot, such as converting chemicals in the food into flavours or helping the food last longer on the supermarket shelves. Bread, cheese, yoghurt, coffee, chocolate, beer, and vinegar are just a few foods that require microbes for their production. Many other foods contain ingredients that are also made by microbes, such as the citric acid added to many fizzy drinks and other foods. We also require microbes to help us farm the fruits and vegetables we eat. Microbes are very important for the health of soil to allow plants to grow better. Some microbes also associate with the fruits and vegetables we farm to help them capture nitrogen from the air to help them grow and in return, the plants supply the microbes with food to help them grow in a process called symbiosis. Microbes living inside us also help us to digest the foods we eat. Lots of our medicines are also made by microbes such as antibiotics and microbes are also important in helping us to treat the wastewater in our sewage systems helping the water to become safe for release into rivers and the sea.

How can microbes be used in medicines?

Some of our most important medicines are made by microbes that live in soil. Some of these microbes make antibiotics and we can use these to help kill the bad microbes that make us sick. Antibiotics were first discovered by Sir Alexander Fleming, a Scottish scientist, who noticed that when a certain type of microbe grew in his work by accident, the bacteria he was trying to grow were killed. This discovery has saved the lives of many people and is one of the most important breakthroughs in medicine. Some related microbes can also make other medicines that can help to cure people infected with parasites, some make chemicals that can help combat cancer and some microbes can even help people who have had organ transplants.

How many microbes are in the world?

Micro-organisms are ubiquitous in nature, being present in water, soil, air, and on the surface and interior of all animals. Within a single human, it is estimated there are about 38 trillion bacterial cells (many more than there are human cells). It is very complex to estimate the total number of microbes in the world, but one estimate for bacteria only is 5 million trillion trillion. A combined total for all microbes would be many more times than this and possibly into the quadrillions. One estimate for the total biomass of bacteria in the world is about 70 billion metric tonnes.

Can microbes defend themselves against viruses?

Yes! Microbes have lots of different defence systems that they use to destroy viruses before the virus kills them. Some of these are like scissors that snip the viral DNA into pieces to stop replication. These scissors are now used by scientists to build useful DNA structures and to cure genetic diseases. Without microbial defence enzymes a lot of the genetic engineering scientists do would be impossible! As microbes are our distant ancestors, we inherited a lot of our defence systems against viruses like Covid-19 from microbes – so there are lots of reasons to be grateful for microbes!