Production and partial characterization of a crude cold-active cellulase (CMCase) from Bacillus mycoides AR20-61 isolate
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(2020) 70:67
SHORT COMMUNICATION
Annals of Microbiology
Open Access
Production and partial characterization of a crude cold-active cellulase (CMCase) from Bacillus mycoides AR20-61 isolated from an Alpine forest site Elisa Steiner and Rosa Margesin*
Abstract Purpose: To evaluate the production of a cold-active CMCase (endoglucanase) by Bacillus mycoides AR20-61 isolated from Alpine forest soil and to characterize the crude enzyme. Methods: After studying the effect of cultivation parameters (medium composition, temperature, NaCl concentration, pH) on bacterial growth and enzyme production, the crude enzyme was characterized with regard to the effect of pH, temperature, and inhibitors on enzyme activity and stability. Result: Optimum growth and enzyme production occurred at 20–25 °C, pH 7, and 1–1.5% (w/v) CMC. Despite high biomass production over the whole growth temperature range (10–35 °C), enzyme production was low at 10 and 35 °C. CMC concentration had a minor effect on growth, independent of the growth temperature, but a significant effect on CMCase production at temperatures ≥ 20 °C. The crude enzyme was active over a broad temperature range (0–60 °C); the apparent optimum temperature for activity was at 40–50 °C. The cultivation temperature influenced the effect of temperature on enzyme activity and stability. A significantly higher thermosensitivity of the enzyme produced at a cultivation temperature of 10 °C compared to that produced at 25 °C was noted at 50 and 65 °C. The enzyme was highly active over a pH range of 4–6 and showed optimum activity at pH 5. No activity was lost after 60 min of incubation at 30 °C and pH 4–9. The CMCase was resistant against a number of monovalent and divalent metal ions, metal-chelating agents, and phenol. Conclusion: The CMCase produced by the studied strain is characterized by high activities in the low temperature range (down to 0 °C) and acidic pH range, high stability over a broad pH range, and high resistance against a number of effectors. Our results also demonstrate the different, independent roles of temperature in bacterial growth, enzyme production, nutrient requirements during enzyme production, and enzyme characteristics regarding thermosensitivity, which has not yet been described for cellulases. Keywords: Alpine, Bacteria, Bacillus, Endoglucanase, CMC, Biopolymers
* Correspondence: [email protected] Institute of Microbiology, University of Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria © The Author(s). 2020 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If mat
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