Abstract

Utilization of whey as a substrate for lactic acid producion by lactobacillus cells using immobilization technique

Author(s): R.C.Dev Goswami, S.Dulakakhoria, A.K.Dolui, E.Malakar

Whey is the liquid remaining after the separation ofmilk fat and casein from whole milk, its disposal, is a major problem for the dairy industry, which demands simple and economical solutions. The bioconversion of lactose present in whey to valuable products has been actively explored. Production of lactic acid through lactic acid bacteria could be a processing route for whey lactose and various attempts have been made in this direction. Immobilized cell technology has also been applied to whey fermentation processes, to improve the economics of the process. A fermentative means of lactic acid production has advantages over chemical synthesis, as desirable optically pure lactic acid could be produced, and the demand for optically pure lactic acid has increased considerably because of its use in the production of poly(lactic acid), a biodegradable polymer, and other industrial applications. In our experiment lactic acid production by immobilized Lactobacillus cells has been studied for that the cells were immobilized in alginate beads and the effect of variations in different parameters on product formation and productivity was investigated. Repeated batch fermentations were performed with lactobacillus cells (L. acidophilus) cells immobilized in 2.4-2.9 mm alginate beads to investigate the possibility of reusing the gel beads. The fermentation was carried out for 48 hours in four batches in normal mediumas well as whey medium.At the end of each run, the beads were washed with sterile physiological saline and transferred to freshmedium.Alginate immobilized cells were reused successfully for 3 continuous runs without marked activity loss. The highest lactic acid (31.605 g/l) was obtained using whey as substrate in the third run.