Characterization of a glucose tolerant β-glucosidase from Aspergillus unguis with high potential as a blend-in for biomass hydrolyzing enzyme cocktails
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Characterization of glucose tolerant beta glucosidase (GT-BGL) secreted by Aspergillus unguis NII 08123, determination of the gene and protein sequences of the enzyme and establishing its performance in blends for lignocellulose hydrolysis.
Supplementation of A. unguis beta glucosidase (BGL) to cellulase released 1.6 times more sugar within 12 h during the hydrolysis of lignocellulosic biomass. The enzyme was determined to be similar to BGL-F from Emericella nidulans by MALDI-TOF analysis, and was found to be a GH3 family protein. Molecular Docking simulation studies showed that the enzyme has lesser affinity for glucose (− 5.7 kcal/mol) compared to its substrate cellobiose (− 7.5 kcal/mol). The residues present in the N-terminal domain are mostly involved in bond formation with both the substrate and the product, while the C-terminal domain contains the catalytic region. In-silico studies showed that its predicted structure is unlike that of previously reported BGLs, which might provide a clue to its exceptional catalytic activity.
The GT-BGL from A. unguis NII 08123 was proven effective as a blend in for biomass hydrolyzing enzyme cocktails and the possible reasons for its glucose tolerance was determined through studies on its modeled structure.
Keywordsβ-glucosidase Glucose tolerant Aspergillus unguis Biomass hydrolysis Genome Homology model
PKV wishes to thank CSIR for providing research fellowship to pursue his PhD studies at NIIST. We are thankful to Department of Biotechnology, Govt. of India for R&D funding to RKS under the project BT/PR20695/BBE/117/211/2016. The P. janthinellum strain is a kind gift from Dr. D. V. Gokhale, from the CSIR-National Chemical Laboratory, Pune, India. We thank Dr. N Ramesh Kumar, MPTD, CSIR-NIIST for sequencing services and Mass Spectrometry and Proteomic Core Facility, Rajiv Gandhi Centre for Biotechnology (RGCB), Thiruvananthapuram for the MALDI-TOF analysis.
Compliance with ethical standards
This study was partially funded by Department of Biotechnology Govt. of India (BT/PR20695/BBE/117/211/2016). RKS, the corresponding author declare on behalf of all authors that we do not have any conflict of interest. This article does not contain any studies with human participants or animals performed by any of the authors.
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