Sunday, October 28, 2012: 2:00 PM
The biofuel ethanol fermentation process is subject to bacterial contamination, resulting in diminished fermentation performance and ethanol yield loss. Reducing bacterial contamination by even one or two colony forming unit (cfu) log orders has been found to profitably increase ethanol product. The most commonly implicated group of bacteria at reducing ethanol production are lactic acid bacteria (LAB), primarily members of the Gram-positive genera Lactobacillus, Pediococcus, Leuconostoc and Weissella. LAB contamination is frequently controlled by routine antibiotic application, a practice that can affect down stream utilization of the dried distillers grain co-product. An alternative product for controlling LAB is one based on the application of natural bacteriolytic agents bacteriophage. The development of phage based formulations is confounded by the high strain diversity of bacteria and the typically extremely limited host range of phage. We have isolated novel phages active against across multiple ethanol fermentation plant derived Lactobacillus isolates. Phage application in a model corn ethanol fermentation system resulted in recovery of ethanol yields. Genomic analysis of two of the new phages indicates broad genetic diversity, with phage Sau1 closely related to previously described LAB phages, and phage Inf representing a novel phage only distantly related to known phages. Developing phage-based industrial bacterial control products requires an improved understanding of the true extent of target bacterial diversity, and overcoming the limitations conferred by narrow host range.