Characteristics and applications of a recombinant alkaline serine protease from a novel bacterium Bacillus lehensis

Abstract

A highly alkaline protease (BLAP) from a novel psychrotolerant and alkaliphilic bacterium, Bacillus lehensis was cloned and expressed in Escherichia coli. BLAP belongs to subtilase S8 family of proteases, comprising 27 aa secretion signal, 83 aa prosequence and 269 aa mature BLAP. The amino acids Asp 141, His 171 and Ser 324 form catalytic triad, while Ile 214, Leu 233 and Asn 267 are other active site moieties. Recombinant alkaline protease (rBLAP) is a monomeric protein of 39.0±1.0kDa, and it is active over broad pH (8-12) and temperature (30-60°C) ranges, with optima at pH 12.8 and 50°C. rBLAP is stimulated by SDS, Co(2+), Ca(2+), β-ME, and inhibited by Hg(2+) and PMSF. The rBLAP is compatible with commercial detergents, useful in silk degumming and silver recovery from the used photographic films and a potent biocontrol agent for arresting the development of eggs of the nematode Meloidogyne incognita.