Characterization of mucilage produced from the solid-state fermentation of soybean grit by Bacillus firmus

Mucilage containing gamma-polyglutamic acid (PGA) was efficiently generated by the solid-state fermentation (SSF) of soybean grit by Bacillus firmus NA-1. B. firmus NA-1 was shown to be a glutamate-dependent strain for PGA production. T e SSF of soybean grit was optimized in order to produce mucilage with a fortification of 5% glutamate, resulting in higher levels of mucilage production (6.14%) and a higher consistency index (1.1 Pa center dot seco(n)). The sticky mucilage was comprised of 38% PGA 7% levan. and some biopolymers. With regard to the viscoelastic properties of the mucilage solution, the viscous modulus (G") obtained from soybean grit fortified with 5% glutarnate was approximately 64 times higher than that of the mucilaLye solution obtained without -lutamate. Althou-h the addition of glutamate in the SSF of soybean grit influenced the rate of PGA production, the molecular weight of PGA remained unaltered, and was detected in a range between 1,400-1,440 kDa.