Identification and characterization of a novel β-glucosidase via metagenomic analysis of Bursaphelenchus xylophilus and its microbial flora

Abstract

β-glucosidases catalyze the final step of cellulose hydrolysis and are essential in cellulose degradation. A β-glucosidase gene, cen502, was identified and isolated from a metagenomic library from Bursaphelenchus xylophilus via functional screening. Analyses indicated that cen502 encodes a 465 amino acid polypeptide that contains a catalytic domain belonging to the glycoside hydrolase family 1 (GH1). Cen502 was heterologously expressed, purified, and biochemically characterized. Recombinant Cen502 displayed optimum enzymatic activity at pH 8.0 and 38 °C. The enzyme had highest specific activity to p-nitrophenyl-β-D-glucopyranoside (pNPG; 180.3 U/mg) and had K m and V max values of 2.334 mol/ml and 9.017 μmol/min/mg, respectively. The addition of Fe2+ and Mn2+ significantly increased Cen502 β-glucosidase activity by 60% and 50%, respectively, while 10% and 25% loss of β-glucosidase activity was induced by addition of Pb2+ and K+, respectively. Cen502 exhibited activity against a broad array of substrates, including cellobiose, lactose, salicin, lichenan, laminarin, and sophorose. However, Cen502 displayed a preference for the hydrolysis of β-1,4 glycosidic bonds rather than β-1,3, β-1,6, or β-1,2 bonds. Our results indicate that Cen502 is a novel β-glucosidase derived from bacteria associated with B. xylophilus and may represent a promising target to enhance the efficiency of cellulose bio-degradation in industrial applications.

Cellulase Addition and Pre-hydrolysis Effect of High Solid Fed-Batch Simultaneous Saccharification and Ethanol Fermentation from a Combined Pretreated Oil Palm Trunk

“…cerevisiae SC90 was obtained with the pre-hydrolysis step. Glucose as the end product of cellulose hydrolysis is released by β-glucosidase through eliminating the effect of cellobiose inhibition on endoglucanase and cellobiohydrolase, consequently letting more efficient cellulolytic enzyme activity . The overall fermentation was swift and initiated as soon as S.…”

“…Glucose as the end product of cellulose hydrolysis is released by β-glucosidase through eliminating the effect of cellobiose inhibition on endoglucanase and cellobiohydrolase, consequently letting more efficient cellulolytic enzyme activity. 49 The overall fermentation was swift and initiated as soon as S. cerevisiae SC90 was added to the reactor. The maximum ethanol was observed in the first 36 h of fermentation; however, a reduction in the ethanol quantity rate occurred owing to the rapid consumption of S. cerevisiae SC90.…”

Transcriptomic analysis of stress response to novel antimicrobial coatings in a clinical MRSA strain

“…Cellulose is a linear chain of β-1, 4-glucose monomers linked by β-1, 4-glycosidic bonds [42,43]. Bacteria degrade it using three types of enzymes: endoglucanases and cellobiohydrolases, which synergistically depolymerize cellulose to cellobiose, followed by β-glucosidases, which hydrolyse cellobiose to glucose [42,44,45]. The action of the β-glucosidases is the rate-limiting factor in cellulose degradation, making the study of the expression of these genes imperative to understand cellulose degradation [44].…”

Metatranscriptomic dynamics after Verticillium dahliae infection and root damage in Olea europaea

“…The genus Bursaphelenchus involves a group of predominantly obligate mycophagous nematodes [46]. Generally, Bursaphelenchus nematodes feed on fungi or plant cells by using stylets that pierce cell walls thanks to industrially useful β-glucosidases degrading enzymes, causing pests in palms and trees [47]. Figure 7, the rank dynamics and stability plot for species, shows that the damage of the roots had a substantial effect on the rhizospheric microbiota but less severe than in the case of the infection with V. dahliae above.…”