| Publisher DOI: | 10.1007/s00253-019-10218-1 | Title: | Characterization of an extremely thermo-active archaeal β-glucosidase and its activity towards glucan and mannan in concert with an endoglucanase | Language: | English | Authors: | Schröder, Carola Eixenberger, Daniela Suleiman, Marcel Schäfers, Christian Antranikian, Garabed |
Keywords: | Extremozymes;Glucose-tolerant;Heat-active;Synergism;β-Glucosidase | Issue Date: | 1-Dec-2019 | Source: | Applied Microbiology and Biotechnology 23-24 (103): 9505-9514 (2019-12-01) | Journal or Series Name: | Applied microbiology and biotechnology | Abstract (english): | A metagenome from an enrichment culture of a hydrothermal vent sample taken at Vulcano Island (Italy) was sequenced and an endoglucanase-encoding gene (vulcel5A) was identified in a previous work. VulCel5A with maximal activity at 115 °C was characterized as the most heat-active endoglucanase to date. Based on metagenome sequences, genomes were binned and bin4 included vulcel5A as well as a putative GH1 β-glycosidase-encoding gene (vulbgl1A) with highest identities to sequences from the archaeal genus Thermococcus. The recombinant β-glucosidase VulBgl1A produced in E. coli BL21 pQE-80L exhibited highest activity at 105 °C and pH 7.0 (76.12 ± 5.4 U/mg, 100%) using 4NP β-D-glucopyranoside as substrate and 61% relative activity at 120 °C. Accordingly, VulBgl1A represents one of the most heat-active β-glucosidases to date. The enzyme has a broad substrate specificity with 155% activity towards 4NP β-D-mannopyranoside in comparison with 4NP β-D-glucopyranoside. Moreover, nearly complete hydrolysis of cellobiose was demonstrated. The enzyme exhibited a high glucose tolerance with 26% residual activity in presence of 2 M glucose and was furthermore activated at glucose concentrations of up to 0.5 M. When the endoglucanase VulCel5A and the β-glucosidase VulBgl1A were applied simultaneously at 99 °C, 158% activity towards barley β-glucan and 215% towards mannan were achieved compared with the activity of VulCel5A alone (100%). Consequently, a significant increase in glucose formation was observed when both enzymes were incubated with β-glucan and mannan suggesting a synergistic effect. Hence, the two archaeal extremozymes are ideal candidates for complete glucan and mannan saccharification at temperatures above the boiling point of water. | URI: | http://hdl.handle.net/11420/3933 | ISSN: | 0175-7598 | Institute: | Technische Mikrobiologie V-7 | Type: | (wissenschaftlicher) Artikel |
| Appears in Collections: | Publications without fulltext |
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