Biochemical and genomic identification of novel thermophilic Bacillus licheniformis strains YNP1-TSU, YNP2-TSU, and YNP3-TSU with potential in 2,3-butanediol production from non-sterile food waste fermentation

Abstract

In the U.S., 30–40% of all food produced ends up as waste. By taking advantage of biological processes this waste nutrients can be converted into value-added 2,3-butanediol (2,3-BDO). However, food waste contains live bacteria and fungi which must first be inactivated, a process typically done with autoclaving under high pressure steam. If contaminants are not removed they can out-compete added industrial microbes for nutrients, resulting in lower yields of bio-products. Unfortunately, sterilization methods such as autoclaving greatly increase production time, and increase energy consumption. This creates a demand for novel microorganisms that can out-compete food waste microbiota by natural means without the need for sterilization of food waste. For this study, several Bacillus licheniformis isolates from Yellowstone National Park were investigated for their potential use in the 2,3-BDO industry. B. licheniformis species are a strain of industrial importance as of late, due to the wide metabolic functions and sustainable growth conditions above 45 °C. Whole genomic sequencing data and biochemical classification of B. licheniformis YNP1-TSU, B. licheniformis YNP2-TSU, and B. licheniformis YNP3-TSU were assessed and revealed a wide assortment of anti-microbial peptides and antibodies as well as catabolic genes for assimilation of glucose, fructose, galactose, xylose, arabinose, mannose, starch and sucrose, and linoleic acid. All three B. licheniformis strains had an optimal growth temperature of 50 °C, and were identified as high 2,3-BDO producers. Each strain YNP1-TSU, YNP2-TSU, and YNP3-TSU yielded 0.44 g/g, 0.45 g/g, and 0.43 g/g from mixed sugars found in non-sterilized food waste, respectively.