A lipase with broad solvent stability from Burkholderia cepacia RQ3: isolation, characteristics and application for chiral resolution of 1-phenylethanol

Using both polar and low polar organic solvents (DMSO and toluene) as screening stress, a solvent-stable bacterium Burkholderia cepacia RQ3 was newly isolated. An organic solvent-stable lipase from strain RQ3 was purified in a single step with 50.1 % recovery by hydrophobic chromatography. The purified lipase was homogenous on SDS-PAGE and had an apparent molecular mass of 33 kDa. The gene of lipase RQ3 with an open reading frame of 1095 bp encoding 364-amino acid residues was cloned. The optimal pH and temperature for lipase activity were 9.0 and 40 A degrees C. The lipase was stable in a wide pH range of 6.0-10.0 and at temperature below 50 A degrees C. Strikingly, all the tested hydrophilic and hydrophobic organic solvents significantly extended the half-life of lipase RQ3 compared with that in a solvent-free system, which indicated that lipase RQ3 showed a broad solvent tolerance to various organic solvents. The lipase demonstrated excellent enantioselective transesterification toward the (S)-1-phenylethanol with a theoretical conversion yield of 50 % and ee (p) of 99.9 %, which made it an exploitable biocatalyst for organic synthesis and pharmaceutical industries.