Affiliation:
1. Department of Botany, Hansraj College University of Delhi New Delhi India
2. National Chemical Laboratory (NCL) National Collection of Industrial Microorganisms (NCIM), Biochemical Sciences Division Pune India
3. Applied Microbiology and Biotechnology Laboratory, Department of Botany University of Delhi New Delhi India
Abstract
AbstractCellulolytic actinobacterium, Promicromonospora sp. VP111 concomitantly produced cellulases (CELs), xylanase and pectinase when grown on commercial cellulose and untreated agricultural lignocellulosic residues (wheat straw and sugarcane bagasse). Secreted CELs hydrolyzed (enhanced with Co2+ ion) multiple cellulosic substrates, including sodium carboxymethyl cellulose (Na‐CMC), Whatman filter paper no. 1, microcrystalline cellulose (avicel), p‐nitrophenyl‐β‐D‐glucopyranoside (pNPG), laminarin, and cellulose powder. The CELs showed stabilities in the presence of various chemicals, including glucose (0.2 M), detergents (1%, w/v or v/v), denaturants (1%, w/v or v/v), and sodium chloride (NaCl, 30%, w/v). The CELs were fractionated using ammonium sulfate precipitation and dialysis. Activities (%) of fractionated CELs were retained at 60°C for endoglucanase/carboxymethyl cellulase (CMCase) (88.38), filter paper cellulase (FPase) (77.55), and β‐glucosidase (90.52), which indicated of thermo‐stability. Similarly, the activities (%) for CMCase (85.79), FPase (82.48), and β‐glucosidase (85.92) at pH 8.5 indicated of alkaline‐stability. Kinetic factors, Km and Vmax for endoglucanase component of fractionated CELs were 0.014 g/l and 158.23 µM glucose/min/mL, respectively. Fractionated CELs yielded activation energies (kJ/mol) of 17.933, 6.294, and 4.207 for CMCase, FPase, and β‐glucosidase activities, respectively in linear thermostable Arrhenius plots. Thus, this study reports on the multipurpose CELs from an untreated agricultural residue utilizing Promicromonospora in relation to broad substrate specificity, halo‐tolerance, alkaline‐tolerance, detergent‐tolerance, thermo‐tolerance, organic solvent‐tolerance, and end product‐tolerance.
Funder
University Grants Commission
Subject
Applied Microbiology and Biotechnology,General Medicine