title: 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.
authors.affiliation: Biotechnology Department, Iranian Research Organization for Science and Technology, Tehran, Iran.
authors.forename: Maryam
authors.initials: M
authors.lastname: Azizi
authors.affiliation: Biotechnology Department, Iranian Research Organization for Science and Technology, Tehran, Iran.
authors.forename: Jafar
authors.initials: J
authors.lastname: Hemmat
authors.affiliation: Ashkezar Branch, Department of Biology, Islamic Azad University, Ashkezar, Iran.
authors.forename: Seyed Morteza
authors.initials: SM
authors.lastname: Seifati
authors.affiliation: Biotechnology Department, Iranian Research Organization for Science and Technology, Tehran, Iran.
authors.forename: Ibrahim
authors.initials: I
authors.lastname: Torktaz
authors.affiliation: Biotechnology Department, Iranian Research Organization for Science and Technology, Tehran, Iran.
authors.forename: Soodabeh
authors.initials: S
authors.lastname: Karimi
mesh_terms: D039903:Actinobacteria / Q000201:enzymology* / Q000302:isolation & purification / Q000378:metabolism*; D000332:Aerobiosis; D002266:Carboxymethylcellulose Sodium / Q000378:metabolism*; D002480:Cellulase / Q000378:metabolism*; D003470:Culture Media / Q000737:chemistry; D004795:Enzyme Stability; D045482:Hot Springs / Q000382:microbiology; D006358:Hot Temperature; D007492:Iran; D012275:Oryza / Q000378:metabolism
chemical_list: D003470:Culture Media; D002480:Cellulase; D002266:Carboxymethylcellulose Sodium