Bioconversion of Lignocellulosic Materials with the Contribution of a Multifunctional GH78 Glycoside Hydrolase from Xylaria polymorpha to Release Aromatic Fragments and Carbohydrates

Abstract

A bifunctional glycoside hydrolase GH78 from the ascomycete Xylaria polymorpha (XpoGH78) possesses catalytic versatility towards both glycosides and esters, which may be advantageous for the efficient degradation of the plant cell-wall complex that contains both diverse sugar residues and esterified structures. The contribution of XpoGH78 to the conversion of lignocellulosic materials without any chemical pretreatment to release the water-soluble aromatic fragments, carbohydrates, and methanol was studied. The disintegrating effect of enzymatic lignocellulose treatment can be significantly improved by using different kinds of hydrolases and phenoloxidases. The considerable changes in low (3 kDa), medium (30 kDa), and high (> 200 kDa) aromatic fragments were observed after the treatment with XpoGH78 alone or with this potent cocktail. Synergistic conversion of rape straw also resulted in a release of 17.3 mg of total carbohydrates (e.g., arabinose, galactose, glucose, mannose, xylose) per gram of substrate after incubating for 72 h. Moreover, the treatment of rape straw with XpoGH78 led to a marginal methanol release of approximately 17 μg/g and improved to 270 μg/g by cooperation with the above accessory enzymes. In the case of beech wood conversion, the combined catalysis by XpoGH78 and laccase caused an effect comparable with that of fungal strain X. polymorpha in woody cultures concerning the liberation of aromatic lignocellulose fragments.

A gene catalogue of Rhinopithecus gut microbiome provides new insights into dietary adaptation of foregut fermenting animals

“…Although the genera and GHs that were significantly enriched in SNMs and ruminants were different, these genera and GHs were mainly associated with the digestion of structural carbohydrates. For example, Ruminococcus ,Clostridium and Butyrivibrio belong to Firmicutes and are related to the degradation of cellulose (Canfora et al, 2019), and GH5 and GH78 both have cellulase activity (Christiane Liers, 2021). However, the genera and GHs that were significantly enriched in monogastric animals were related to the degradation of fat and protein and oligosaccharides, such as Bacteroides (Naofumi Yoshida, 2021) (Figure 4a and 4b).…”