A Novel GH7 Endo-β-1,4-Glucanase from Neosartorya fischeri P1 with Good Thermostability, Broad Substrate Specificity and Potential Application in the Brewing Industry

Abstract

An endo-β-1,4-glucanase gene, cel7A, was cloned from the thermophilic cellulase-producing fungus Neosartorya fischeri P1 and expressed in Pichia pastoris. The 1,410-bp full-length gene encodes a polypeptide of 469 amino acids consisting of a putative signal peptide at residues 1–20, a catalytic domain of glycoside hydrolase family 7 (GH7), a short Thr/Ser-rich linker and a family 1 carbohydrate-binding module (CBM 1). The purified recombinant Cel7A had pH and temperature optima of pH 5.0 and 60°C, respectively, and showed broad pH adaptability (pH 3.0–6.0) and excellent stability at pH3.0–8.0 and 60°C. Belonging to the group of nonspecific endoglucanases, Cel7A exhibited the highest activity on barley β-glucan (2020 ± 9 U mg–1), moderate on lichenan and CMC-Na, and weak on laminarin, locust bean galactomannan, Avicel, and filter paper. Under simulated mashing conditions, addition of Cel7A (99 μg) reduced the mash viscosity by 9.1% and filtration time by 24.6%. These favorable enzymatic properties make Cel7A as a good candidate for applications in the brewing industry.

Genome-wide characterization of cellulases from the hemi-biotrophic plant pathogen, Bipolaris sorokiniana, reveals the presence of a highly stable GH7 endoglucanase

“…To elucidate BsGH7-3 function, we characterized the substrate specificity and modelled the structure of BsGH7-3. BsGH7-3 shows higher specific activity towards lichenan (14172.7 U mg −1 ) and β- d -glucan (6739.4 U mg −1 ) and the lowest activity towards Avicel (Avicel being a substrate specific to cellobiohydrolases) following the trends reported for other endoglucanases [45, 49, 55]. The 25% reduction in activity observed on the substrate PASC has also been reported for other GH7 endoglucanases [45].…”

“…BsGH7-3 shows higher specific activity towards lichenan (14172.7 U mg −1 ) and β- d -glucan (6739.4 U mg −1 ) and the lowest activity towards Avicel (Avicel being a substrate specific to cellobiohydrolases) following the trends reported for other endoglucanases [45, 49, 55]. The 25% reduction in activity observed on the substrate PASC has also been reported for other GH7 endoglucanases [45]. This non-specific substrate specificity is a characteristic feature of the GH7 endoglucanase.…”

Identification and Characterization of a Novel Hyperthermostable Bifunctional Cellobiohydrolase- Xylanase Enzyme for Synergistic Effect With Commercial Cellulase on Pretreated Wheat Straw Degradation

“…Notably, EDTA and SDS severely compromised the efficiency of the bifunctional activities of CtCel7. Similar results were detected for a GH7 endo-β-1,4-glucanase (Cel7A) (Liu et al, 2015), a GH10 xylanase (Xyln-SH1) (Cheng et al, 2012) and a GH5 bifunctional cellulasexylanase (CbGH5) (Tan et al, 2018). The beneficial effect of Tween-20, Triton X-100 and PEG-600 on enzyme activity may be attributed to the effect of surfactant binding on enzyme secondary and tertiary structure that results in a more flexible conformation (Delorme et al, 2011;Holmberg, 2018).…”

A bifunctional cellulase–xylanase of a new Chryseobacterium strain isolated from the dung of a straw‐fed cattle

“…The activity levels of EG‐CMC and XYN‐bw are higher than many known cellulases and xylanases. To date, only a few cellulase or xylanase possess high activity level comparable with CbGH5 (Borges et al ., ; Lafond et al ., ; Liu et al ., ). Altogether, these characteristics make CbGH5 advantageous in cellulose and xylan catalysis.…”