Biomass of a Psychrophilic Fungus as a Biocatalyst for Efficient Direct Esterification of Citronellol

Abstract

A biomass-bound lipase from psychrophilic Chrysosporium pannorum A-1 is an efficient biocatalyst for direct esterification of β-citronellol and acetic acid in an organic solvent. The biomass is effectively produced by fungal submerged culture at 20 ℃, which results in lower energy consumption during the production of biocatalyst. Supplementation of the culture medium with calcium carbonate together with olive oil contributed to a significant increase in the active biomass of mycelium in one batch culture and increased the efficiency of the biocatalyst. Biomass-bound lipase showed high catalytic activity in a broad temperature range of 30–60 °C and stability up to 70 °C. A maximum molar conversion value of 98% was obtained at 30 °C in n-hexane using a 2:1 alcohol-to-acid molar ratio and 3% w/v of the biocatalyst within 24 h. The high equimolar concentration of the substrates (200 mM) did not have an adverse effect on mycelial biomass activity. Dry mycelium of C. pannorum is a promising biocatalyst for large-scale biosynthesis of citronellyl acetate, given its low-cost production, high activity at low temperatures, and reusability in a minimum of seven 24-h biocatalytic cycles.