MIT Researchers Engineer Microbes that Feed on Artificial Nutrient Sources

Biofuel production is prone to contamination with unwanted microbes. These invaders can outcompete the producer microbes for nutrients, reducing yield and productivity. Researchers at MIT and Novogy, a startup company, now describe a technique that gives producer microbes the upper hand against unwanted microbes.

Researchers engineered Escherichia coli with a synthetic pathway that allows it to convert melamine to ammonia and carbon dioxide. While contaminating organisms can extract nutrients from natural sources such as ammonia, they do not have the genetic pathways needed to use melamine as a nitrogen source. They tested the engineered E. coli strain against a wildtype strain and found that the engineered type rapidly outcompeted the control, when fed with melamine.

They were also successful in engineering Saccharomyces cerevisiae that uses cyanamide as a nitrogen source as well as a Yarrowia lipolytica that consumes potassium phosphite as a source of phosphorous. Like the engineered E. coli strain, both the engineered yeasts were able to outcompete naturally occurring strains when fed on these chemicals.

Since these engineered strains possess this ability when they are fed unconventional chemicals, the chances of them growing uncontrollably in a natural environment are extremely low.