Efficient and practical bioconversion strategy of xylose-rich corncob for prebiotic Bacillus subtilis production

The probiotic of Bacillus subtilis ( B.subtilis ) is widely used in animal husbandry as a promising alternative to antibiotics, and a high value-added bioproduct from abundant and low-cost agricultural straws. For efficient fermentation of xylose-rich corncob slurry to B. subtilis cells, the step-by-step fermentation process (SSFP) and one-step fermentation process (OSFP) were proposed and compared by the combined technology of sulfuric acid pretreatment and enzymatic hydrolysis with cellulase . Xylose and glucose were fermented separately and sequentially in the SSFP route, while they were co-fermented in OSFP route. Here, B. subtilis performed an efficient bioconversion and almost fermented simultaneously glucose, xylose and arabinose in corncob slurry. We could obtain 326.8 g of B. subtilis in SSFP and 323.7 g probiotic cells in OSFP from 1000 g of corncob, respectively. In general, the OSFP route was preferable by virtue of a straightforward process and simple operation.