Appropriate lignocellulosic biomass processing strategies for efficient 2,3-butanediol production from biomass-derived sugars using Bacillus licheniformis DSM 8785

Abstract

A nonpathogenic organism, Bacillus licheniformis DSM 8785, was evaluated for efficient 2,3- butanediol (BD) production from different sugar media. Productivities in glucose, xylose, and mixed-sugar (glucose:xylose=1:2) media were 2.23, 1.58, and 0.91gL−1h−1, respectively. These were almost two-fold more than use of a more common BD producer, albeit a pathogenic organism, Klebsiella oxytoca ATCC 8724. Fermentation efficiency in the biomass hydrolyzates with 40g/L of total sugar was as efficient as synthetic sugar with a similar sugar concentration, but not so in the hydrolyzates with 80g/L of total sugar. The optimum fed-batch process in a glucose medium produced 103g/L BD in the final fermentation broth, with yield and productivity of 0.47g/g and 0.81gL−1h−1, respectively. Our study concluded that an efficient BD fermentation is possible using a nonpathogenic culture in a single-sugar medium; however, appropriate biomass processing strategies must be developed to produce separate streams of glucose and xylose from lignocellulosic biomass for efficient BD production. We, therefore, proposed a novel biomass processing strategy using a three-step pretreatment process to obtain separate streams of biomass extractives, cellulose hydrolyzate, and hemicellulose hydrolyzate. This information is pertinent for efficient BD production from biomass-derived sugar.