Increased enzymatic hydrolysis of sugarcane bagasse by a novel glucose- and xylose-stimulated β-glucosidase from Anoxybacillus flavithermus subsp. yunnanensis E13T

Abstract

Backgroundβ-Glucosidase is claimed as a key enzyme in cellulose hydrolysis. The cellulosic fibers are usually entrapped with hemicelluloses containing xylose. So there is ongoing interest in searching for glucose- and xylose-stimulated β-glucosidases to increase the efficiency of hydrolysis of cellulosic biomass.ResultsA thermostable β-glucosidase gene (Bglp) was cloned from Anoxybacillus flavithermus subsp. yunnanensis E13T and characterized. Optimal enzyme activity was observed at 60 °C and pH 7.0. Bglp was relatively stable at 60 °C with a 10-h half-life. The kinetic parameters V max and K m for p-nitrophenyl-β-D-glucopyranoside (pNPG) were 771 ± 39 μmol/min/mg and 0.29 ± 0.01 mM, respectively. The activity of Bglp is dramatically stimulated by glucose or xylose at concentrations up to 1.4 M. After Bglp was added to Celluclast® 1.5 L, the conversion of sugarcane bagasse was 48.4 ± 0.8%, which was much higher than of Celluclast® 1.5 L alone. Furthermore, Bglp showed obvious advantages in the hydrolysis when initial concentrations of glucose and xylose are high.ConclusionsThe supplementation of BglP significantly enhanced the glucose yield from sugarcane bagasse, especially in the presence of high concentrations of glucose or xylose. Bglp should be a promising candidate for industrial applications.Electronic supplementary materialThe online version of this article (doi:10.1186/s12858-017-0079-z) contains supplementary material, which is available to authorized users.

Highly Efficient Biotransformation of Astragaloside IV to Cycloastragenol by Sugar-Stimulated ¥ é-Glucosidase and é é-Xylosidase from Dictyoglomus thermophilum

“…With the increasing of glucose, the enzyme activity of Dth3 was gradually inhibited, with a K i of over 3 M glucose, which was higher than that from Anoxybacillus flavithermus subsp. yunnanensis, Thermotoga thermarum, and other reported β- glucosidases [31,44,45]. In addition, the activity of xylose has not been reported yet.…”

“…Recently, most β-glucosidases and β-xylosidases are sensitive to glucose and xylose, and few β-glucosidases and β-xylosidases are tolerant and stimulated by both glucose and xylose [30,31]. As we all know, in most industries, application of β-glucosidases and β-xylosidases with glucose and xylose tolerance and stimulation can improve the efficiency of substrate hydrolyzation [32][33][34].…”

Revisiting the scope and applications of food enzymes from extremophiles

“…shown that a thermostable β-glucosidase produced by Anoxybacillus flavithermus isolated from Tengchong hot spring in Yunnan, China was highly effective in hydrolyzing cellulose when used with a commercial cellulase product (Celluclast®, Novozymes) (Liu et al, 2017). The authors found that the cellulose content of sugarcane bagasse decreased by 25% when only Celluclast® was used, but when β-glucosidase (50 µg/g sugarcane bagasse) was used synergistically with Celluclast®, a 48% decrease was observed (Liu et al, 2017 & Dijkhuizen, 2002;Whitehurst & Van Oort, 2009). Thermostable α-glucosidase from Thermococcus hydrothermalis has been used with α-amylase and pullulanase for starch processing into glucose syrup (Legin, Copinet, & Duchiron, 1998).…”

“…β‐glucosidase is an important enzyme for the processing of sugarcane bagasse, the dry pulpy fibrous residue after juice extraction. It has been shown that a thermostable β‐glucosidase produced by Anoxybacillus flavithermus isolated from Tengchong hot spring in Yunnan, China was highly effective in hydrolyzing cellulose when used with a commercial cellulase product (Celluclast®, Novozymes) (Liu et al., 2017). The authors found that the cellulose content of sugarcane bagasse decreased by 25% when only Celluclast® was used, but when β‐glucosidase (50 µg/g sugarcane bagasse) was used synergistically with Celluclast®, a 48% decrease was observed (Liu et al., 2017).…”

Microbial Beta Glucosidase Enzymes: Recent Advances in Biomass Conversation for Biofuels Application

“…For achieving the goal of economic biofuel production, many researchers have been working on different fungal and bacterial strains so as to obtain an effective cellulolytic fungal or bacterial β-glucosidase [73]. Liu et al [74] reported on the increased hydrolysis of sugarcane bagasse with the help of BGL produced from Anoxybacillus flavithermus subsp. yunnanensis E13 T .…”