Isolation of cold-active, acidic endocellulase from Ladakh soil by functional metagenomics.
Mining of soil sample from cold desert of Ladakh by functional metagenomics led to the isolation of cold-adapted endocellulase (CEL8M) that hydrolyses carboxymethyl cellulose (CMC). Mature CEL8M, a 347-residue polypeptide with a molecular mass of 38.9 kDa showed similarity to β-1,3-1,4 D-glucanase from Klebsiella sp. The enzyme contains the catalytic module of glycosyl hydrolase family 8 but does not possess a carbohydrate-binding domain. 3D structural model of the enzyme built by homology modeling showed an architecture of (α/α)6-barrel fold. The purified enzyme was found to be active against CMC, xylan, colloidal chitosan and lichenan but not active against avicel. Glucose was not among the initial hydrolysis products, indicating an endo mode of action. CEL8M displayed maximal activity at pH 4.5 and remained significantly active (~28 %) when the temperature decreased to 10 °C. Cold-active endocellulase CEL8M may find applications in textile industry at low temperature which can result in energy savings.
Microbial Biotechnology Division, Indian Institute of Integrative Medicine, Canal Road, Jammu Tawi, Jammu, India. archanabhatbiotech@gmail.com
Archana
A
Bhat
Syed
S
Riyaz-Ul-Hassan
Nasier
N
Ahmad
Nidhi
N
Srivastava
Sarojini
S
Johri
D000220:Adaptation, Biological / Q000235:genetics; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D001665:Binding Sites; D050260:Carbohydrate Metabolism; D020134:Catalytic Domain; D044602:Cellulases / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D003080:Cold Temperature; D003889:Desert Climate; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007194:India; D007709:Klebsiella / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D056186:Metagenomics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010802:Phylogeny; D012988:Soil Microbiology
D001426:Bacterial Proteins; D044602:Cellulases