Enabling the synthesis of medium chain alkanes and 1-alkenes in yeast

•Medium chain fatty acids were obtained by engineering fungal fatty acid synthases.•Medium chain alkanes were produced by expressing an alkane biosynthesis pathway.•Among 13 candidates, the ADO from Thermosynechococcus elongatus showed superior activity.•Targeting of the alkane-forming pathway into peroxisomes improved alkane production.•Medium chain 1-alkenes were synthesized by expressing UndA decarboxylase.

Microbial synthesis of medium chain aliphatic hydrocarbons, attractive drop-in molecules to gasoline and jet fuels, is a promising way to reduce our reliance on petroleum-based fuels. In this study, we enabled the synthesis of straight chain hydrocarbons (C7-C13) by yeast Saccharomyces cerevisiae through engineering fatty acid synthases to control the chain length of fatty acids and introducing heterologous pathways for alkane or 1-alkene synthesis. We carried out enzyme engineering/screening of the fatty aldehyde deformylating oxygenase (ADO), and compartmentalization of the alkane biosynthesis pathway into peroxisomes to improve alkane production. The two-step synthesis of alkanes was found to be inefficient due to the formation of alcohols derived from aldehyde intermediates. Alternatively, the drain of aldehyde intermediates could be circumvented by introducing a one-step decarboxylation of fatty acids to 1-alkenes, which could be synthesized at a level of 3 mg/L, 25-fold higher than that of alkanes produced via aldehydes.

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