Enhanced 2-phenylethanol production by newly isolated Meyerozyma sp. strain YLG18 and characterization of its synthetic pathways

Abstract

Background2-Phenylethanol (2-PE) is an aromatic alcohol which has been widely used in cosmetics, perfume and food industries owning to its delicate rose scent. The newly isolated yeast Meyerozyma guilliermondii YLG18 was able to tolerate high exogenous 2-PE and produce 2-PE with two different pathways.ResultsA unique Meyerozyma sp. strain YLG18 was obtained in this study, which was capable of tolerating 4.0 g/L exogenous 2-PE. Response surface methodology (RSM) was implemented to improve the maximum 2-PE production. At optimized conditions: temperature, 24.7℃; initial glucose, 63.54 g/L; initial L-phe, 10.70 g/L, 2-PE production was increased to 2.55 g/L, leading to 104% increase compared to the pre-optimized one. In situ product recovery (ISPR) could further help improve the final 2-PE production to 3.20 g/L with fatty acid methyl ester as the extractant, representing the highest 2-PE production by using Meyerozyma sp.. Furthermore, genes involved in 2-PE synthesis were identified and their expression levels between Shikimate pathway and Ehrlich pathway were compared. Based on the genomic and transcriptional analysis, a penta-functional enzyme AroM in Shikimate pathway and an aspartate aminotransferase (AAT) with the potential to convert phenylalanine into phenylpyruvate in Ehrlich pathway were identified.ConclusionsThese findings would help broaden our knowledge and add to the pool of known 2-PE generating microbes and genes. Moreover, this study describes a potential, new 2-PE producer that lays foundation for the industrial-scale production of 2-PE and its derivatives in the future. Key words: 2-phenylethanol; Meyerozyma guilliermondii; RSM; ISPR; gene analysis