Production and partial characterization of a crude cold-active cellulase (CMCase) from Bacillus mycoides AR20-61 isolated from an Alpine forest site

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.

Screening and characterization of a low-temperature-resistant cellulose-degrading strain, Trichoderma harzianum L-8, from a primitive forest

“…It was seen that although there was a deviation in the optimal pHs of the two enzymes, their optimal activity conditions were the same, with both enzymes functioning at a neutral to acidic level as well as being well adapted to alkaline environments, with both enzymes being able to adapt to a wide pH range. This result was similar to Legodi et al (2019) and Steiner and Margesin (2020) regarding low-temperature tolerant cellulases. The effect of each metal ion on the enzyme reaction is shown in Fig.…”

The Isolation and Characterization of a Novel Psychrotolerant Cellulolytic Bacterium, Microbacterium sp. QXD-8T

“…In this study, reducing sugars could have accumulated in the extracellular environments under low temperatures, and the addition of cellobiose could have promoted the growth of cells. We speculated that the strain could not quickly transport reducing sugars into the intracellular space for growth under low-temperature conditions, although cellulase and transporter activity rates were reported to be inhibited by low temperatures [ 11 , 54 ]. The notion of whether the extracellular reducing sugars were accumulated or not depends on the cellulase and transporter activity rates at low temperatures.…”

“…Legodi et al isolated ten cellulose-degrading strains of bacteria from decomposed banana agro-waste and decomposed Strelitzia alba plant, which had high enzyme activity at 30–40 °C [ 10 ]. Generally, low-temperature-resistant and cellulose-degrading microorganisms can maintain considerable activity [ 11 ]. In particular, low-temperature-resistant microorganisms can expedite the process of composting [ 12 ].…”

Optimum Activity Temperatures of Fpases From Psychrotoelrent (Penicillium Canescens and Rhodotorula Mucilaginosa) and Psychrophylic (Pseudogymnoascus Roseus) Fungi

“…Although, cellulases from these sources are comparatively efficient ones but yet there is much scope to improve them, for example, T. reesei cellulases has below optimal cellobiase activity. Although, much advancement has been made to obtain and engineer cellulases from mesophilic sources for biofuel purposes, only a limited number of efforts have been made to obtain cold-active cellulases from either fungal [4][5][6][7][8] or bacterial [9][10][11] sources. Yet, there is hardly any report of prospecting cold-active cellulases for commercial uses.…”