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8342077 
Journal Article 
Studying the influence of nitrogen source on lactic acid production from whey permeate by immobilized Lactobacillus bulgaricus Lb-12 
Mawgoud, YA; Ibrahim, GA; El-Ssayad, MF 
2016 
0 
Research Journal of Pharmaceutical, Biological and Chemical Sciences
ISSN: 0975-8585 
7 
1 
693-705 
English 
Aiming to enhance the lactic acid production (g/l) and lactose utilization from whey permeate in a step toward eco-friendly management of this serious dairy waste and cost-effective production of very important chemical, several nitrogen sources including yeast extract, casein hydrolysate and other two cheaper sources the ground corn and the defatted soybean were used. Fermentations were performed as batch fermentations in 100 ml static flasks. Yeast extract and casein hydrolysate were added separately by the ratios 0.5-2 % to whey permeate and then flasks were inoculated with free and Ca alginate immobilized Lactobacillus bulgaricus Lb-12. Corn and soy were extracted separately in permeate in the ratio of 10 % and the clear supernatants were fermented by free and immobilized cells. Mineral salts (0.2 g/l MgSO4 and 0.05 g/l MnSO4) were added. Control experiment contain only whey permeate. Lactic acid yield increased with increase in yeast extract concentration in immobilized cells than free ones. Mineral salts appeared to enhance production. The increase in lactic acid yield and productivity was greater in case of casein hydrolysate by 42% and 0.062 g/l.h respectively. Soy and corn extracts showed promising results when partially replaced yeast extract (150 gram replaced 17.5 gram yeast extract) thus lactic acid yield increased by 42% and 82% for soy and corn respectively. Due to its high potential, corn was chosen for further combinations in different ratios with yeast extract. The highest of lactic acid 26g/l was obtained for 20% corn and 0.5% yeast extract. Under full controlled (pH, temperature, agitation) fermentor system, the yield reached 44 g/l with productivity of 0.88 g/l.h and 88% efficiency, achieving complete lactose utilization. For lactic acid production, corn successfully replaced yeast extract resulting incomplete lactose exhaustion and enhancing the acid production by 322%, and saving time and energy by 27.7%. 
Immobilization; Lactic acid production; Lactobacillus; Nitrogen source; Whey permeate