Potential Antimicrobials Against Contaminating Bacteria in Ethanol Fermentation

The February 7 issue of the journal Biotechnology for Biofuels reports the study conducted by researchers from the US Department of Agriculture that seeks to address the low ethanol yield from fermentation systems contaminated by lactic acid bacteria or LAB.

The study embarks on the exploitation of antimicrobial proteins called lysins produced by bacteriophages or viruses that typically infect bacteria. Lysins exert their lethal effects on target bacteria by degrading the bacterial cell wall component called peptidoglycan. Initially the researchers isolated and screened a number of lysins for their ability to kill Lactobacillus strains from fuel ethanol fermentation. Using knowledge from bacteriophage genome databases, four lysin molecules identified from the preliminary screening were produced in vitro, purified and rigorously assayed against a variety of LAB including the notorious L. fermentum under laboratory conditions that simulated industrial fermentation environments.

Overall, results suggest that potent bacteriophage lysins can be used to control unwanted lactobacilli contamination in ethanol fermentation systems without the pitfall of bacterial resistance associated with conventional antibiotics.