Identification of organic solvent-tolerant lipases from organic solvent-sensitive microorganisms

Organic solvent-tolerant (OST) lipases are becoming increasingly useful in organic synthesis, thereby raising the importance for the discovery of new OST lipases. Until now, the screening method has only focused on pre-selection of OST bacterial strains as microbial resource of OST lipases. With the aim of screening for novel OST lipases from organic solvent sensitive (OSS) microorganisms, we used an established fluorescence-based assay to develop a biphasic reaction for direct functional identification of OST lipases. Using this approach, we have isolated and identified nine OSS bacteria secreting lipases that showed the same level of solvent tolerance of lipases from another 11 OST bacterial strains. Among them, two OST lipases from the OSS bacteria, Bacillus subtilis ZJU003 and Xanthomonas oryzae ZJU548, showed remarkable stability in 50% (v/v) a variety of hydrophobic organic solvents over an incubation period of 7 days. These results show that OSS microorganisms are a rich microbial resource for OST lipases that can display excellent stability in organic solvents.