Keywords : Lactic acid production
Preparation of local structural media for lactic acid production from commercial isolate Lactobacillus delbrueckii
journal of kerbala university,
Volume 13, Issue 1, Pages 178-184
Lactic acid discovered at 1780 and its had many application in food industries such as acidulant ,preservative and material for organic synthesis. Commercial Lactobacillus delbrueckii isolate of has been used in the production of lactic acid from sweet bovine whey supplemented with local renewable resources The study used cane sugar molasses and date waste juice (5,10,15,20,25)% (w/v) as carbon sources and yeast extract ,urea ,ammonium salphate percentage as nitrogen sources (0.2 , 0.4 , 0.6 , 0.8 ) % (w/v) . the study showed:
* The commercial isolate was ferment the un supplemented whey during 48 hr . at 45c and pH 6 , its lactic acid production as 3.5 gm/100 ml whey with conversion efficiency 18.6%.
* When the molasses was added (5, 10, 15, 20, 25)% (w/v) the study showed increased lactic acid amount to (4.7, 5.8, 6.9, 18.5, 33.9)gm/100 ml whey with conversion efficiency (44.7, 19.3, 22.5, 28.3, 81.5) % respectively.
*On the other hand our study showed the addition of date waste juice (5,10,15,20,25) % (w/v) increased lactic acid amount as (4.8, 6.7, 10.7, 20.7, 29.5) gm /100 ml whey with conversion efficiency (43.7, 22.8, 20.8, 44.7, 52.8) % respectively.
*The generally treatment (whey and 25% molasses) was selected as a fermentation medium for the production of lactic acid it is also supplemented by different nitrogen sources, the results showed:
*The addition of ammonium salphate (0.2, 0.4, 0.6, 0.8) % (w/v) increased lactic acid amount to (4.8, 5.3, 5.5, 5) gm /100 ml whey with conversion efficiency (28.3, 75.73, 66.5, 71.42) % respectively. and The addition of urea as nitrogen source did not exert any change in the amount of lactic acid product. While The addition of yeast extract (0.2, 0.4, 0.6, 0.8) % (w/v) the result illustrated increased lactic acid amount was (4.9, 6.5, 21.7, 31.9) gm /100 ml whey with conversion efficiency (71.22, 66.77, 86.55, 89.65) % respectively. On the other hand molasses 25% and whey +0.8%yeast extract was selected as best medium for lactic acid production.