Conversion of β‐1,6‐Glucans to Gentiobiose using an endo‐β‐1,6‐Glucanase PsGly30A from Paenibacillus sp. GKG

Abstract

A plethora of di‐ and oligosaccharides isolated from the natural sources are used in food and pharmaceutical industry. An enzymatic hydrolysis of fungal cell wall β‐glucans is a good alternative to produce the desired oligosaccharides with different functionalities, such as the flavour enhancer gentiobiose. We have previously identified PsGly30A as a potential yeast cell wall degrading β‐1,6‐glycosidase. The aim of this study is to characterise the PsGly30A enzyme, a member of the GH30 family, and to evaluate its suitability for the production of gentiobiose from β‐1,6‐glucans. An endo‐β‐1,6‐glucanase PsGly30A encoding gene from Paenibacillus sp. GKG has been cloned and overexpressed in Escherichia coli. The recombinant enzyme has been active towards pustulan and yeast β‐glucan, but not on laminarin from the Laminaria digitata, confirming the endo‐β‐1,6‐glucanase mode of action. The PsGly30A shows the highest activity at pH 5.5 and 50°C. The specific activity of PsGly30A on pustulan (1262±82 U/mg) is among the highest reported for GH30 β‐1,6‐glycosidases. Moreover, gentiobiose is the major reaction product when pustulan, yeast β‐glucan or yeast cell walls has been used as a substrate. Therefore, PsGly30A is a promising catalyst for valorisation of the yeast‐related by‐products.

Functional analysis of a novel endo-β-1,6-glucanase MoGlu16 and its application in detecting cell wall β-1,6-glucan of Magnaporthe oryzae

“…On the basis of the amino acid sequences of Mo Glu16 and other reported β-1,6-glucanases in which contained six representative members from GH30 family and GH5 family, respectively ( Plakys et al, 2024 ), a phylogenetic tree of Mo Glu16 was constructed using the neighbor-joining method in MEGA v.6.06 software with 1,000 bootstrap iterations. The amino acid sequences of the above thirteen proteins extracted from GH30 and GH5 family were from NCBI.…”

“…By contrast, only a few β-1,6-glucanase were found in bacteria, such as PsGly30A from Paenibacillus sp. GKG ( Plakys et al, 2024 ), CpGlu30A from Chitinophaga pinensis ( Lu Z. et al, 2023 ) and Gly30B from Saccharophagus degradans 2–40 T ( Wang et al, 2017 ). In addition, β-1,6-glucanases were reported to be involved in mycoparasitism, autolysis and extensibility of fungal cell wall.…”