High value lipid production in Acinetobacter baylyi ADP1 with acetate as a carbon source

Abstract

Bacteria are able to produce different lipids which could be utilized in industrial and commercial products. In this thesis the wax ester production in Acinetobacter baylyi ADP1 was studied in different temperatures and with either glucose or acetate supplementation. The effects of overexpressing a thioesterase ('tesA) and aldehyde reduction (Acr1) genes were also studied. Overexpression of the Acr1 gene was monitored with a biosensor. The optimum growth range for A. baylyi was observed between 20-30 °C, the highest lipid accumulation at 20 °C and the highest wax ester accumulation at 25 °C. 100 mM acetate supplementation produced wax esters 49 μmol/g CDW whereas glucose produced wax esters 62-92 μmol/g CDW. The overexpression of the Acr1 gene was observed with glucose-grown batches whereas the acetate-grown batches showed inconclusive results. Also, the glucose-grown batches showed increased accumulation of fatty acids with 'tesA overexpression, although wax ester accumulation was not enhanced. In future experiments the fatty acids might be steered towards other metabolites using fatty acids as precursors. Even though lower wax ester yields were obtained on acetate-grown cultures, these results show promise in utilizing a sustainable carbon source for high value lipid production.