An organic solvent and thermally stable lipase from Burkholderia ambifaria YCJ01: Purification, characteristics and application for chiral resolution of mandelic acid

A solvent-tolerant bacterium Burkholderia ambifaria YCJ01 was newly isolated by DMSO enrichment of the medium. The lipase from the strain YCJ01 was purified to homogeneity with apparent molecular mass of 34 kDa determined by SOS-PAGE. The purified lipase exhibited maximal activity at a temperature of 60 degrees C and a pH of 7.5. The lipase was very stable below 55 degrees C for 7 days (remaining 80.3% initial activity) or at 30 degrees C for 60 days. PMSF significantly inhibited the lipase activity, while EDTA had no effect on the activity. Strikingly, the lipase showed distinct super-stability to the most tested hydrophilic and hydrophobic solvents (25%, v/v) for 60 days, and different optimal pH in contrast with the alkaline lipase from B. cepacia S31. The lipase demonstrated excellent enantioselective transesterification toward the S-isomer of mandelic acid with a theoretical conversion yield of 50%. ee(p) of 99.9% and ee(s) of 99.9%, which made it an exploitable biocatalyst for organic synthesis and pharmaceutical industries. (C) 2012 Elsevier B.V. All rights reserved.

通过二甲基亚砜（DMSO）富集培养基，新分离出一株耐溶剂细菌——伯克霍尔德氏菌YCJ01。通过SDS - PAGE测定，来自菌株YCJ01的脂肪酶纯化至均一，表观分子量为34 kDa。纯化后的脂肪酶在60℃和pH 7.5时表现出最大活性。该脂肪酶在55℃以下稳定7天（剩余80.3%的初始活性），或在30℃稳定60天。苯甲基磺酰氟（PMSF）显著抑制脂肪酶活性，而乙二胺四乙酸（EDTA）对其活性无影响。引人注目的是，与洋葱伯克霍尔德氏菌S31的碱性脂肪酶相比，该脂肪酶对大多数测试的亲水性和疏水性溶剂（25%，v/v）在60天内表现出明显的超稳定性，且最适pH不同。该脂肪酶对扁桃酸的S - 异构体表现出优异的对映选择性酯交换反应，理论转化率为50%，对映体过量值（ee）：产物为99.9%，底物为99.9%，这使其成为有机合成和制药工业中一种可开发的生物催化剂。（C）2012爱思唯尔公司。版权所有。