Two-step production of gamma-aminobutyric acid from cassava powder using Corynebacterium glutamicum and Lactobacillus plantarum

Production of gamma-aminobutyric acid (GABA) from crop biomass such as cassava in high concentration is desirable, but difficult to achieve. A safe biotechnological route was investigated to produce GABA from cassava powder by C. glutamicum G01 and L. plantarum GB01-21. Liquefied cassava powder was first transformed to glutamic acid by simultaneous saccharification and fermentation with C. glutamicum G01, followed by biotransformation of glutamic acid to GABA with resting cells of L. plantarum GB01-21 in the reaction medium. After optimizing the reaction conditions, the maximum concentration of GABA reached 80.5 g/L with a GABA productivity of 2.68 g/L/h. This is the highest yield ever reported of GABA production from cassava-derived glucose. The bioprocess provides the added advantage of employing nonpathogenic microorganisms, C. glutamicum and L. plantarum, in microbial production of GABA from cassava biomass, which can be used in the food and pharmaceutical industries.