Screening, identifying and medium optimization of a lipase-producing filamentous fungus from soil for high chiral resolution of 1-phenylethanol

Abstract

The kinetic resolution of racemates by biocatalysis is one of the major routes to manufacture optically pure compounds. Lipase-producing microorganisms were screened from soil for chiral resolution of 1-phenylethanol in the study. One microorganism with high chiral resolution ability was isolated and identified as Rhizopusstolonifer by the sequence similarity analysis and construction of phylogenetic tree. The media for the microorganism were optimized using Plackeet-Burman, Steepest Ascent and Box-Benhnken experiments. After optimization, the composition of the optimized medium used for lipase production was as follows: soluble starch (7.60 g/L), yeast extract (22.59 g/L), K2HPO4 (5.55 g/)L, NH4Cl (1.80 g/L), MgSO4·7H2O (2.40 g/L), NaCl (1.00 g/L), olive oil (25.00 mL/L), Tween-80 8.00 (mL/L), pH 4.59, and the lipase activity increased nearly by 2.04-fold, from 0.46 to 1.40 U/mL. The optimization was significant for the isolation and purification of the lipase and for the research of enzymatic characteristics. Key words: Screening, lipase, identification, Rhizopus stolonifer; optimization, 1-phenylethanol.