Glutamic acid independent production of poly(γ-glutamic acid) by bacillus subtilis TAM-4

Abstract

A bacterium that produced a large amount of poly(γ-glutamic acid) (PGA) when it was grown aerobically in a culture medium containing ammonium salt and sugar as sources of nitrogen and carbon, respectively, was isolated from soil. The bacterium, strain TAM-4, was classified as Bacillus subtilis. The maximum PGA production (22.1 mg/ml) was obtained when it was grown in a medium containing 1.8% ammonium chloride and 7.5% fructose at 30°C for 96 h with shaking. Some properties of the PGA obtained at different times of cultivation were investigated by gel permeation chromatography, SDS–PAGE, and measurement of viscosity, and calculation of the d/l ratio of glutamic acid constituting PGA. The results suggested that PGA was elongated with no changes in the diastereoisomer ratio in the molecule. © 1996, Taylor & Francis Group, LLC. All rights reserved.