Growth and Acid Lactic Production of Lactobacillus delbrueckii sp bulgaricus Isolated from Mother’s

Author

NORZALINA OTHMAN
Tang Chun Huan, Nor Zalina Othman, Hesham A. El Enshasy, Yahya Jalal, Ahmad Farid Adnan, Mohamad Roji Sarmidi and Ramlan Abdul Aziz

Language

English

Title

Growth and Acid Lactic Production of Lactobacillus delbrueckii sp bulgaricus  Isolated from Mother’s Milk in  Defined Medium

Proceeding

7th INTRACOM – 2nd ICBWI 2009

Date

7/25/2009

Place Held

PWTC, Kuala Lumpur

Abstract

Lactobacillus delbrueckii sp bulgaricus isolated from healthy breast milk was studied as potential probiotic bacteria. For Lactobacillus delbrueckii sp bulgaricus to be used in functional food industries; the strain should have the capability to produce high cell density in the low cost medium. However, the productivity of the cell growth was influenced by inhibition activity of the production of lactic acid during cultivation. Therefore, the optimization of the growth medium with high cell density and very low production of lactic acid was studied in shake flask followed by the study of the cell growth kinetics in the controlled and uncontrolled pH in the bioreactor. In the chemical defined medium before optimization studied, the maximal cell growth was only 2.97 g/L and the lactic acid production was 1.30 g/L after 10 hours of cultivation. After the medium optimization studied, the kinetic growth in the shake flask studied shown that the maximal cell growth was increased up to 3.15 g/L and lactic acid production was decreased 0.84 g/L after 10 hours of cultivation. There was only 21.5% increased in the cell biomass (4.88 g/L) and lactic acid production was 1.94g/L after 14 hours cultivation in uncontrolled pH of bioreactor when compared to shake flask studied. The comparison study between the growth of Lactobacillus delbrueckii sp bulgaricus in the shake flask and in the bioreactor had shown more valuable results by increasing the percentage of the biomass up to 35.25% (6.58 g/L) and constant value of lactic acid production that was maintained at 0.9 g/L under controlled pH for only 8 hours of cultivation. In conclusion, the medium composition may effect the cell growth because of  inhibition activity of lactic acid on the cell growth during cultivation

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