Researchers have found a way to make biofuel production more environmentally-friendly. By using a special strain of bacteria, the team was able to eliminate microbial contamination, reducing the need for antibiotics. The findings are in a paper just published in the journal Science.
Biofuels provide an alternative to fossil fuels and can help reduce carbon emissions and other types of pollution. One common way to accomplish this is to use microbes to break down sugars into fuel. For example, microbes can convert sugars from corn into ethanol. The technology isn’t perfect, however, and it’s not always cost-effective. One problem is contamination; as microbes ferment sugars, other microorganisms can show up. These unwanted microbes, usually bacteria, can outcompete yeasts and other beneficial microbes. Biofuel companies can use special sterilization techniques but these tend to require expensive equipment. The other option is the use of antibiotics. Overuse of antibiotics is an environmental and human health threat, however, and contributes to the development of antibiotic-resistant strains of bacteria.
Researchers from the Massachusetts Institute of Technology developed a unique strain of E.coli bacteria. The bacterial strain could only absorb nitrogen and phosphorous, both required for growth, from novel sources. Rather than using the standard ammonium in biofuel vessels, for example, the researchers used melamine. Contaminating bacteria can’t extract nitrogen from melamine and so only the special bacteria could grow. The team was also able to manipulate yeast species to utilize unusual food sources, including cyanamide and potassium phosphite. They tested these genetically-modified strains and found that they were just as productive as their naturally-occurring counterparts.
By using unique bacteria and yeast strains, the researchers were able to eliminate microbial contamination in biofuel vessels without affecting productivity. This would allow biofuel production to be more practical on an industrial scale by reducing the need for antibiotics and expensive sterilization methods.
Joe Shaw et al. Metabolic engineering of microbial competitive advantage for industrial fermentation processes. Science (2016).