Harnessing the Power of Bacillus subtilis MR42: Direct Production of Defined Xylo-Oligosaccharides (XOS) from Corn Stalks with Enhanced Prebiotic Properties

Abstract

Abstract The production of value-added bioproducts from renewable carbon sources has gained increasing attention in recent years. Bacillus subtilis MR42 was used to produce specific xylooligosaccharides (XOS) from corn stalks. This strain, through a genetic modification targeting the xynC gene, can convert arabinoxylan into specific XOS without generating xylose as a byproduct. Under optimal conditions, a high yield of XOS (703.4 mg/g xylan) was obtained. The purified XOS were further characterized using various techniques including TLC, HPLC, ESI-MS and 1HNMR spectroscopy. The analysis revealed that the XOS primarily consisted of xylotriose (289 ± 0.03 mg/g), xylotetraose (237 ± 0.05 mg/g) and xylopentaose (267 ± 0.03 mg/g), accounting for approximately 80% of the total XOS. The prebiotic effect of XOS was evaluated by examining its impact on the growth of Lactobacillus, the production of short-chain fatty acids, and its antioxidant activity. B. subtilis MR42 showed a promising ability to produce short DP of XOS without xylose.