Enhanced L-glutamic acid production by immobilized Corynebacterium glutamicum X680 using Response Surface Methodology

Abstract

L-glutamic acid is a non-essential amino acid largely used as flavor enhancer and food additive. It also has several therapeutic applications. Fermentation has gained superiority over its chemical synthesis as it produced stereo-specific isomer. Corynebacterium glutamicum is mostly used microorganism for Lglutamic acid fermentation. The study was dealing with optimization of L-glutamic acid production by immobilized mutant Corynebacterium glutamicum X680 in calcium alginate beads using response surface methodology as effective statistical tool. Among several parameters studied, pH, inoculums size, incubation time, concentration of sodium alginate, agitation and cell:alginate ration showed the most significant effect. Immobilized cells produced significantly (p<0.01) lower amount of L-glutamic acid (24.3mg/ml) compared to the production by free cells (27.6mg/ml). However, reusability of the beads minimized production cost and hence conferred benefit as far as the market economy is concerned.