An acidophilic GH12 xyloglucanase from Trichoderma asperellum produces prebiotic oligosaccharides that promote probiotic growth

Enzymatic transformation of lignocellulosic biomass offers an eco-friendly pathway to produce valuable β -oligoglucosides. In this study, an acidophilic GH12 xyloglucanase (TaXEG12) from Trichoderma asperellum ND-1 was overexpressed in Komagataella phaffii . TaXEG12 displayed maximum activity at 40 °C and a pH of 4.0, while retaining >80% activity in the presence of 1.71 M NaCl and 10% ethanol. Glu 140 and Glu 227 are important catalytic residues, while Asp 126 plays an auxiliary role in xyloglucan degradation. The enzyme showed strict substrate specificity toward tamarind xyloglucan. Through fed-batch fermentation, the enzyme production of TaXEG12 improved by 28.5-fold (2914.5 ± 65.7 U/mL). Interestingly, TLC and ESI-MS analyses revealed that TaXEG12 could hydrolyze xyloglucan into xyloglucan oligosaccharides (XXXG, XXLG/XLXG, and XLLG). These xyloglucan oligosaccharides can promote the growth of Lactobacillus bulgaricus . Additionally, the synergy degrees of corn bran and apple pulp in the degradation by TaXEG12 and TrCel were 1.34 and 1.32, respectively. TaXEG12 displayed unique properties and could be a desirable catalyst for the more sustainable production of high-value oligosaccharides, which are significantly beneficial for human intestinal health.