A Novel Digestive GH16 β-1,3 (4) -Glucanase from the Fungus-Growing Termite Macrotermes barneyi
Li, J.; Cao, C.; Jiang, Y.; Huang, Q.; Shen, Y.; Ni, J.
Applied Biochemistry and Biotechnology 192(4): 1284-1297
ISSN/ISBN: 1559-0291 PMID: 32725373 DOI: 10.1007/s12010-020-03368-w
β-1,3-glucanases are the main digestive enzymes of plant and fungal cell wall. Transcriptomic analysis of the fungus-growing termite Macrotermes barneyi revealed a high expression of a predicted β-1,3(4)-glucanase (Mbbgl) transcript in termite gut. Here, we described the cDNA cloning, heterologous expression, and enzyme characterization of Mbbgl. Sequence analysis and RT-PCR results showed that Mbbgl is a termite-origin GH16 β-1,3(4)-glucanase. The recombinant enzyme showed the highest activity towards laminarin and was active optimally at 50 °C, pH 5.5. The enzyme displayed endo/exo β-1,3(4)-glucanase activities. Moreover, Mbbgl had weak transglycosylation activity. The results indicate that Mbbgl is an endogenous digestive β-1,3(4)-glucanase, which contributes to the decomposition of plant biomass and fungal hyphae. Additionally, the multiple activities, pH, and ion stabilities make Mbbgl a potential candidate for application in the food industry.