L(+)-Lactic Acid Production by Immobilized Lactobacillus casei Using Low Cost Agro-Industrial Waste as Carbon and Nitrogen Sources

Abstract

Batch fermentation of molasses for l(+) lactic acid production using corn steep liquor (CSL) as nitrogen source by immobilized Lactobacillus (Lb.) casei MTCC 1423 has been studied. Among different tested immobilizing matrices, sodium alginate has been observed to be the best matrix for l(+)-lactic acid production. Significant reduction in cell release with double layer coated (chitosan and alginate, ACA) beads in comparison to uncoated alginate beads as well as with single layer of chitosan coated beads was observed. Stability of beads in reusability process as a function of l(+)-lactic acid production was tested and found that double layer coated alginate beads containing Lb. casei MTCC 1423 with chitosan and alginate was effective for reducing its porosity, effective l(+)-lactic acid production, enhancing stability and cell entrapment efficiency. Process conditions influence on the production of the l(+)-lactic acid production using immobilized cell system has been studied and maximum lactic acid was obtained with beads having diameter: 2.5 mm, biomass concentration: 40 g (cell dry weight, CDW)/L, shaking speed: 150 rpm, substrate concentration: 175 g/L, CSL concentration: 25 mL/L, at incubation temperature of 37 °C after incubation time of 72 h and pH 7.0.