A Novel Neutral Endoglucanase from Streptomyces sp. H31 with Wide-pH-range Stability

Abstract

An endoglucanase-producing strain Streptomyces sp. H31 was isolated from mangrove soil in Shenzhen, P.R.China, and the endoglucanase gene egH31 was cloned. The open reading frame (ORF) of this gene is 762bp and it encodes 253 amino acid residues, which showed the highest similarity (84%) with the endoglucanase from Streptomyces davawensis. The endoglucanase gene egH31 was successfully expressed in E. coli. We purified the recombinant EgH31 to homogeneity by affinity chromatography. Molecular mass of the recombinant EgH31 is about 31 kDa. The maximum activity of EG-H31 was determined at pH 7.0 and 45°C and shown high stability within a wide pH range (3.0-11.0). EgH31 had good resistibility to SDS, EDTA, EGTA and most of metal ions examined. Most interestingly, EgH31 was stable in commercial laundry detergents, indicating that this enzyme is useful in textile and detergent industry.