Small variations in food can result in unexpected evolution in microbes: IIT Bombay study

Mumbai, Aug 18 (PTI) Researchers at IIT Bombay discovered that even minute changes in feeding microbes can cause them to evolve in different ways, a finding that could help in better understanding of how evolution works, and how it can be controlled for industrial and medical purposes.

IIT Bombay conducted a study involving replicating evolution in the lab using microbes.

Researchers from the Department of Chemical Engineering used two microbes- common gut bacterium E.coli and baking ingredient yeast- to explore how they process and evolve when identical sugars are served differently.

The researchers gave a mix of sugars, glucose and galactose that is found in dairy products to one group of microbes and complex sugars made up of the same glucose and galactose to the other group, and allowed the microbes to multiply for several hundred generations.

"We picked sugars that are chemically related. Our goal was to see if microbes care about how the meal is served," says Prof Supreet Saini, who led the study from IIT Bombay.

Based on the sugar composition, each group of microbes adapts into two unpredictable evolutionary paths, the researchers found.

The genetic study revealed that several mutations led to this adaptation.

"We didn't expect these subtle differences in food and nutrients to create completely distinct adaptive paths. The findings suggest that the way a cell responds to a nutrient can influence which mutations are beneficial and what paths evolution can take," said Neetika Ahlawat, a post-doctoral researcher and author on both studies.

Surprisingly, when the researchers transferred these evolved populations of both E.coli and yeast to a new set of sugar sources, their growth showed a predictable pattern.

The study found that while the performance of the populations in the environments in which they were grown was unpredictable, the side effects of evolution could be predicted successfully.

"It's a nice reminder that evolution is both flexible and constrained. In identical environments, the outcome was unpredictable, demonstrating a possible flexibility in evolution, added Pavithra Venkataraman, a former PhD student at IIT Bombay, and an author of the study on E. coli.

The findings can be scaled to large-scale industrial applications, said the study.

Microbes with improved growth rate and better metabolite yields can be utilised for commercial applications such as food and beverages, pharmaceuticals, and the biofuels industry, it added. PTI SM NSK