What Does E. coli Eat?

Escherichia coli, commonly known as E. coli, is a remarkable bacterium with a rich history of study and discovery.

It is an integral part of the human gut microbiome and plays essential roles in digestion and overall gut health.

But what exactly does E. coli consume to sustain its existence? E. coli’s presence in the human gut is not accidental; it has coevolved with us, establishing a symbiotic relationship.

While some strains of E. coli can cause illnesses, many are harmless and even beneficial.

To understand its behavior and significance, it’s essential to investigate the question: What Does E. coli Eat?

Short Answer: What Does E. coli Eat?

E. coli is capable of utilizing several compounds as carbon sources for food. However, glucose is the preferred carbon source, and its rapid utilization depends on the phosphoenolpyruvate: carbohydrate phosphotransferase system. 

E. coli are normally heterotrophs, that is, organisms that ingest organic compounds such as glucose for food, but a new study has shown that they can be turned into autotrophs that consume carbon dioxide from the atmosphere and turn it into biomass.

In a study, after approximately 200 days, lab-evolved E. coli relied completely on carbon dioxide from the air to generate biomass while taking in formate as a necessary ingredient for the chemical reactions.  

This ability displayed by E. coli is one that can be applied in the field of biotechnology for more biofuel and food production.

Because of its versatility and adaptability in the laboratory and in the field of biotechnology, E. coli is considered a “workhorse.” 

Growth Requirements of E. coli 

The right mix of basic elements, growth factors, and environmental requirements is necessary for E. coli to thrive. 

Carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur are some of the basic chemical elements required to build nearly all cellular components.

In addition to these major elements, elements like iron, selenium, calcium, sodium, and several others are required to build specific structures and perform specific processes.

E. coli, along with all other living organisms, requires environmental sources of all of these elements in order to survive. Most of these elements come from food sources, like carbohydrates, proteins, and fats. 

In addition to these building blocks are growth factors, which are essential metabolites an organism needs but is unable to synthesize. Growth factors can include amino acids, nucleotides, fatty acids, or vitamins. 

The naturally occurring strains of E. coli don’t require any growth factors. If given the appropriate elements and an energy source, E. coli can synthesize all 20 amino acids, all vitamins, all nucleotides, and all fatty acids that it uses during growth and metabolism.

Despite E. coli‘s ability to make its own growth factors, there is an advantage to supplying them.  It takes a lot of energy to produce every single growth factor needed. E. coli are able to grow and reproduce much faster if these compounds are provided.  

Faster growth allows a scientist working with E. coli to conduct more experiments and collect more data. 

With the right conditions and a complete mix of growth factors, an E. coli population can double in size about every 20 minutes.

In the colon, where E. coli has to compete for growth factors with other intestinal bacteria and the host, it can take around 12 hours for the population to double. 

Environmental and host niches of E. coli 

Because the gastrointestinal tract (GIT) has long been considered the primary niche of E. coli,  strains isolated from natural sources were originally thought to be derived from feces discharged into the environment.

Despite this, there is a growing body of evidence for distinct subpopulations of E. coli, which are specifically adapted to external environments. It is estimated that half of the total E. coli population can reside and transit in non-host, natural environments as secondary habitats. 

Among the potential host species that E. coli can colonize, there is a great deal of variation in body size, gastrointestinal, physiological, and biochemical conditions, microbiome composition, and diets. 

How long does E. coli survive outside the body? 

E. coli can survive outside the body for a few hours to several months. They can live in soil for about 130 days, in river water for about 27 days, and in cattle slurry for about 10 days.

On stainless steel, E. coli was shown to survive for more than 60 days. On wooden cutting boards, they can survive for a minimum of 12 hours. 

Factors such as temperature, the presence of water, the availability of nutrients, pH, and solar radiation affect how long E. coli can survive outside the body.

These factors are especially important when one considers the fact that E. coli has to spend plenty of time outside its host’s body before gaining access.  

What Next?

Exploring what E. coli eats provides valuable insights into its role in the gut microbiome and its potential impact on human health.

While many strains of E. coli are benign and even beneficial, understanding their nutritional requirements can shed light on the factors that contribute to their survival and proliferation.

Beyond satisfying our curiosity about E. coli’s diet, this knowledge has broader implications. It can inform research on probiotics and the manipulation of gut microbiota for health benefits.

Additionally, understanding how E. coli obtains nutrients can aid in the development of strategies to control pathogenic strains and mitigate their impact on human health.

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Last Updated on July 12, 2023 by Our Editorial Team