Bringing Ethyl Acetate Production into the Biobased Economy

Aleksander Kruis¹, Astrid Mars², Mark Levisson¹, Servé Kengen¹, John van der Oost¹, Ruud Weusthuis³

¹Laboratory of Microbiology, Wageningen UR, Dreijenplein 10, 6703 HB, Wageningen

²Biobased Products, Wageningen UR, Bornse Weilanden 9, 6708 WG Wageningen

³Bioprocess Engineering, Wageningen UR, Droevendaalsesteeg 1, 6708PB, Wageningen

Ethyl acetate is used extensively as a food additive or as a bulk industrial chemical. However, like most bulk chemicals, they are traditionally produced from petrochemical resources. The use of petrochemical resources has various negative environmental and social impacts, which is why sustainable, biobased alternatives are being researched. One such alternative is the production of ethyl acetate from biomass through microbial fermentations. The biggest challenge of microbial fermentations is often the design of an efficient production organism. The most commonly used production organisms are E. coli and S. cerevisiae, due to their well-researched metabolism and genetic accessibility. However, they naturally produce only trace amounts of ethyl acetate because they lack the necessary enzymes.

Several non-Saccharomyces yeasts are able to produce large amounts of ethyl acetate and could be used as enzyme sources to transfer this trait to other organisms. However, the metabolic pathways and enzymes involved in ethyl acetate synthesis are poorly understood, posing a major bottleneck in engineering more efficient ways of producing biobased ethyl acetate. To understand the biochemistry behind the ethyl acetate synthesis, we have studied the yeast Wickerhamomyces anomalus. We performed an RNAseq analysis in an attempt to identify the genes involved in ethyl acetate synthesis.