Production and Purification of Lactic Acid from LactobacillusImmobilized onAgar-agar

Abstract

Cells of L. acidophilus and Lactobacillus sp. (25) were immobilized using entrapment method with two different supports . Results showed that agar – agar was more efficient in lactic acid production in compare with sodium alginate . Factors affect cells immobilization were studied and the results showed that (3)% agar – agar as a support with (1×109) cell / ml gave the highest production of lactic acid . Some of the optimal conditions for lactic acid production from the immobilized cells of L. acidophilus and Lactobacillus sp.(25) were studied . The results revealed that the best date juice concentration and yeast extract for lactic acid production were (4 and 0.3)% for both isolates , respectively .The optimal incubation periods for lactic acid production were (60 and 72) hours for L. acidophilus and Lactobacillus sp. (25), respectively.The immobilized cells for both isolates were stable during five repeated cycles and no acid production loss was observed during the studied periods. Lactic acid was isolated from culture filtrate of L. acidophilus and Lactobacillus sp.(25) . The isolation procedure included Clarification step, Ion exchange with anionic exchanger ( Amberlite IR- 400) and Ion exchange with cationic exchanger ]Amberlite IR 120- (H)[. Lactic acid yield obtained were (88.75 and 91.56)% for the above mentioned isolates , respectively .