Growth and exopolysaccharide production by Azotobacter vinelandii in media containing phenolic acids

Azotobacter vinelandii was cultured in chemically defined, nitrogen‐free media supplemented with either 4‐hydroxyphenylacetic, 4‐hydroxybenzoic or protocatechuic acids at different concentrations. Under these conditions, biomass, exopolysaccharide production and consumption of the carbon sources were investigated. Results obtained throughout this study showed that 4‐hydroxyphenylacetic acid yielded the highest growth levels measured as biomass, and exopolysaccharide production, independently of the concentration of the carbon source tested. 4‐Hydroxybenzoic acid also supported appreciable growth and exopolysaccharide recovery by A. vinelandii. Protocatechuic acid, however, only allowed a very small production of biomass and exopolysaccharide by the strain investigated. Under given conditions, more than 26% of the carbon source supplied was converted to exopolysaccharide in cultures of A. vinelandii.