Characterization of a thermostable endoglucanase produced by Isoptericola variabilis sp. IDAH9

Abstract

This study aimed to isolate and evaluate the cellulase activity of cellulolytic bacteria in hot springs of Dehloran, Ilam province, Iran. Water and sludge samples were collected from the hot springs and the bacterial enrichment was performed in a medium containing rice barn and carboxymethyl cellulose (CMC). The cultures were incubated at 50 °C in aerobic conditions. The bacteria were isolated on CMC agar (1%) medium. Cellulase assay of the isolates was measured by the evaluation of endoglucanase enzyme activity, which is also called as carboxymethyl cellulase (CMCase). The isolated thermotolerant bacteria were then identified and optimized for the production of CMCase. Moreover, stabilizing elements of the enzyme were identified with in silico approach. The chosen isolate was identified as Isoptericola variabilis sp. IDAH9. The identified strain produced the most thermostable CMCase at a concentration of 5.6 g/L of ammonium sulfate, 9 g/L CMCase or 12 g/L rice bran, 0/6% Tween-80, and 0.2% sucrose. The produced enzyme showed 80% of the residual activity after 1 h of incubation at 65 °C. In silico data indicated that the remaining residual activity was due to the redundant stabilizing elements in the protein structure. Consequently, I. variabilis can be isolated from the extreme environment and has a thermostable endoglucanase which may be used for various applications after studying them.

A Thermostable Aspergillus fumigatus GH7 Endoglucanase Over-Expressed in Pichia pastoris Stimulates Lignocellulosic Biomass Hydrolysis

“…In fact, Af-EGL7 exhibited higher thermal stability than many previously reported thermostable glucanases. Given the numerous advantages of carrying out processes at temperatures above 50 °C, thermostability is one of the most desirable enzymatic properties in the industry [13,28,29]. Steam pre-treatment has been the most frequently employed treatment to make biomass suitable for enzymatic saccharification.…”

“…Steam pre-treatment has been the most frequently employed treatment to make biomass suitable for enzymatic saccharification. Thermostable enzymes can be directly used after this heating step, saving time, expenses, and as well as providing better reaction yields [11,29,30,31].…”

Thermophiles: A Bio-Gadget towards Waste Reclamation through Cellulase Production

“…IDAH9, showed CMCase i.e. endoglucanase activity using rice bran & CMC as substrate at 65°C [19]. Bacillus subtilis, a faecal thermophile exhibited better cellulolytic activity i.e.…”

Optimization of Food-Waste Based Culture Medium for Cellulase Production by Thermophilic Bacillus sp SMIA-2 and effect of Divalent Metal Ions on Activity and Stability of the Enzyme at Higher Temperatures

“…Therefore, being rich in polysaccharides, sugarcane bagasse and yellow passion fruit peel have been studied as a potential media component for the production of various industrially important enzymes, in particular, cellulose-degrading enzymes [6,7].Cellulases are the third most abundant industrial enzyme [8]. Thermophilic cellulases are ideal biocatalysts for modern biotechnology because of their thermostability and better yields under extreme operational conditions [9,10]. The wide range of applications of thermophilic cellulases include the food, textile, chemical, pulp and paper industries, laundry detergents, and second generation ethanol production [11][12][13][14][15][16].…”