Valorization of crude glycerol as carbon source for the bioconversion of L-phenylamine to 2-phenylethanol by Yarrowia species

Abstract

BACKGROUND 2-Phenylethanol (2-PE) is an aromatic alcohol with delicate fragrance of rose petals, widely used in perfumes, cosmetics, foods, beverages, and pharmaceutical industries. The yeast Yarrowia can produce 2-PE through L-Phenylalanine (L-Phe) biotransformation. However, it is poorly explored in this field, despite its interesting characteristics for this process, such as the Crabtree negative trait. RESULTS This study explored the potential of different Yarrowia species (Y. lipolytica W29, CH 1/5 and CH 3/4 and Y. divulgata M 445/4) for 2-PE production. It was observed that all strains were inhibited by 2-PE concentrations above 2gL1, but only Y. lipolytica W29 was inhibited by 15gL1 L-Phe. It was also confirmed that all strains were able to produce 2-PE, with concentrations ranging from 1 to 2.2gL1. Afterwards, crude glycerol was used as an alternative carbon source for 2-PE production. All strains grew and produce 2-PE on this carbon source, but CH 1/5 strain was selected for further studies since it allowed the highest 2-PE throughput. The production of 2-PE with CH 1/5 was further studied in bioreactor batch cultures, where a low accumulation of 2-PE was observed. However, a step-wise fed-batch culture allowed to increase the production of 2-PE to 3.2gL1. CONCLUSION To the best of the author's knowledge, this value corresponds to the highest titer of 2-PE obtained to date with Y. lipolytica. In this study, Y. lipolytica CH 1/5 is for the first time described as a good natural producer for 2-PE.