Optimization of limonene biotransformation to limonene-1,2-diol by Colletotrichum nymphaeae CBMAI 0864

Abstract

Abstract This study aimed to optimize the conditions of the biotransformation of limonene to limonene-1,2-diol by C. nymphaeae. In the initial modeling, in shake flasks, the use of 13.2 g.L−1 biomass, 27 °C, 250 rpm, and pH of 6.0 could maximize the production of limonene-1,2-diol (6.75 g.L−1). Subsequently, optimal conditions were transposed to a bioreactor, where agitation and aeration were also evaluated. A minimum 60% of dissolved oxygen was defined for this process. The limonene volatilization could be reduced almost three times when a larger condenser is used. Finally, when the bioreactor was operated at 27 °C, 300 rpm, 1 vvm, and with 13.2 g.L−1 biomass, limonene-1,2-diol production reached 7.1, 7.8, and 5.6 g.L−1 after 72 h when using 20 g.L−1 of R-(+)-, S-(−)-limonene or citrus terpene as substrate, respectively. This is approximately the same maximum product concentration found for the shake flasks, but it represents an almost three times higher productivity.