The gene encoding a cold-adapted phospholipase A(1) (PLA(1)) from a psychrotrophic, glacier soil bacterium Serratia sp. xjF1 was cloned by two-step PCR (general PCR and TAIL-PCR). The full-length fragment comprised two open reading frames plA and plS. The gene product of plA encoding 320 amino acids with a molecular weight of 33.8 kDa was identified as a phospholipase A(1). Its amino acid sequence exhibited the highest homology to PLA(1) of Serratia marcescens (71%). plS encoded a protein of 251 amino acids, which showed no enzymatic activity. The result of plA expression in Escherichia coli indicated that plS might improve the efficient expression of PLA(1) in E coli. Furthermore, PLA(1) was functionally expressed in Pichia pastoris, yielding 41.8 U/mL in a 3.7L fermentor. The purified recombinant phospholipase A(1) (rPLA(1)) had features typical of cold-adapted enzymes with a temperature optimum of 35 degrees C and a maximum activity of 70% at 10 degrees C. The rate of catalysis was optimal at pH 9.0 and the enzyme could be slightly activated by Ca2+. This is the first report on gene isolation and expression of cold-adapted PLA(1). (C) 2007 Elsevier Inc. All rights reserved.