Bacillus subtilis GB Shows High Polyglutamic Acid Bioconversion Efficiency in Low-Glutamic-Acid Monosodium Glutamate Wastewater
TL;DR
The low-cost L-MSGW can be used for the high-value γ-PGA by B. subtilis GB, providing a novel technical approach and theoretical basis for low-cost treatment and high-value resource utilization of L-MSGW and provides a sustainable and economically viable solution for industrial wastewater treatment.
Abstract
Low-glutamic-acid monosodium glutamate wastewater (L-MSGW), characterized by high (NH4)2SO4 concentrations, presents significant challenges for conventional treatment. γ-Polyglutamic acid (γ-PGA) production using industrial wastewater is an economical and environmentally friendly strategy. In the current study, we isolated and identified Bacillus subtilis GB, which exhibited exceptional tolerance to (NH4)2SO4, and capability for the high-efficiency biosynthesis of γ-PGA using untreated L-MSGW. Fermentation conditions were optimized using single-factor experiments coupled with response surface methodology, followed by scale-up validation in a 5 L fermenter. Under optimal conditions, the maximum γ-PGA yield reached 16.57 g/L with a minimal glutamate consumption of only 4.9 g/L. The study validated the feasibility of efficient γ-PGA production from L-MSGW by B. subtilis GB, providing a novel technical approach and theoretical basis for low-cost treatment and high-value resource utilization of L-MSGW. This study not only demonstrates the low-cost L-MSGW can be used for the high-value γ-PGA by B. subtilis GB but also provides a sustainable and economically viable solution for industrial wastewater treatment.