The Bio-Uptaking and Fermenting Characteristics of Various Lignocellulose-Digested Mono- and Oligo-Saccharides by Bacillus subtilis

Bacillus subtilis (B. subtilis) has booming application prospects in the feed industry as a value-added probiotic. Considering the intermediate and end saccharides of glucan and xylan digestion during lignocellulose biorefinery processing, the various digested saccharides were detected to disclose the bio-uptake and fermenting characteristics by solo or co-fermentation, especially with respect to five monosaccharides, cellobiose, and functional food additive—xylo-oligosaccharides (XOS). B. subtilis can directly ferment XOS without xylose, achieving a cell yield of 0.71 g/g, while it hardly utilizes cellobiose except glucose co-fermentation. With a 5 g/L glucose addition and co-fermentation, bacterial cell yield was improved to 0.70 g/g. In total, B. subtilis had a 0.56–0.90 g/g cell yield from corncob-digested saccharides and the highest saccharide-uptaking rate of 98%. This study provides critical insights and experimental data to advance lignocellulosic biorefinery technologies, particularly for probiotics production and simplification of enzymatic hydrolysis, as well as the potential application in high value-added XOS biopurification.