Growth and wax ester production of an Acinetobacter baylyi ADP1 mutant deficient in exopolysaccharide capsule synthesis.

Acinetobacter baylyi ADP1 naturally produces wax esters that could be used as a raw material in industrial applications. We attempted to improve wax ester yield of A. baylyi ADP1 by removing rmlA, a gene involved in exopolysaccharide production. Growth rate, biomass formation and wax ester yield on 4-hydroxybenzoate were not affected, but the rmlA strain grew slower on acetate, while reaching similar biomass and wax ester yield. The rmlA cells had malformed shape and large size and grew poorly on glucose without expression of the gene for pyruvate kinase (pykF) from Escherichia coli. The pykF-expressing rmlA strain had similar growth rate, lowered biomass formation and improved wax ester production on glucose as compared to the wild-type strain expressing pykF. Cultivation of the pykF-expressing rmlA strain on an elevated glucose concentration in a medium supplemented with amino acids resulted in doubled molar wax ester yield and acetate production.