Author(s)

Nisa Saelee^1,2, Klanarong Sriroth¹

¹Department of Biotechnology, Faculty of Agro-Industry, Kasetsart University, Bangkok, Thailand.
²Department of Biotechnology, Institute of Agricultural Technology, Walailak University, Nakhon Si Thammarat, Thailand.

Complex nutrients e.g. carbon, nitrogen, peptides, vitamin and salts significantly play important roles in lactic acid production efficiency depending on types of microorganism and sources of raw material. In this study oil palm trunk juice and Lactobacillus rhamnosus TISTR 108 (ATTC 10863) were utilized for lactic acid production. Additional nutrients including peptone, yeast extract and mixed salts were tested. Response surface methodology involving Box Behkhen Design (BBD) was applied to examine the optimal condition. Prediction of optimization was performed using full quadratic regression equation. The predicted maximum lactic acid concentration was obtained at 64.05 g·l^-1 within a period of 48 h under an optimal condition of 10 g·l^-1 peptone with mixed salts containing 0.4 g·l^-1 MgSO₄·7H₂O, 0.1 g·l^-1 MnSO₄·4H₂O, 3 g·l^-1 K₂HPO₄, 3 g·l^-1 KH₂PO₄ and 3 g·l^-1 CH₃COONa·3H₂O in 250 ml shake flask using CaCO₃ as a titrant. Verification of optimization condition was performed in 2 l fermenter using Ca(OH)₂ as neutralizing agent. Increase in lactic acid fermentation was achieved at 92.81 g·l^-1 at 48 h cultivation. The lactic acid yield and volumetric productivity were 0.94 g·g^-1 and 1.91 g l^-1·h^-1, respectively. This suggests that OPT juice is potentially used as carbon and nutrient sources for lactic acid production.

Lactic Acid, Oil Palm, Oil Palm Trunk Juice, OPT, Lactobacillus rhamnosus, Box Behkhen Design, BBD

Saelee, N. and Sriroth, K. (2014) Optimization of Nutrients in Fermentative Lactic Acid Production Using Oil Palm Trunk Juice as Substrate. Advances in Bioscience and Biotechnology, 5, 957-965. doi: 10.4236/abb.2014.512109.