Effect of major and minor nutrients on lactic acid production using biodiesel waste-derived crude glycerol as a carbon source by Lactobacillus casei NCIM 2125

ABSTRACT

Significant growth of the biodiesel industry has lead to an increased availability of its principal by-product crude glycerol. This study deals with the production of lactic acid, using biodiesel waste-derived crude glycerol as a sole carbon source and ammonium sulphate as the nitrogen source. It was observed that 15 g/L of semipurified glycerol, 2 g/L NH₄SO₄, 0.03 g/L FeSO₄.7H₂O, 0.04 g/L MgSO₄.H₂O, 0.3 g/L MnSO₄.H₂O and 1 g/L Sodium acetate were the optimum concentrations for the production of lactic acid. Similarly, an incubation period of 40 h, pH of 6.5 and a temperature of 37°C were found to be optimum. The results suggested that crude glycerol and ammonium sulphate could serve as a good cheap alternative, for the existing resources.

KEYWORDS:

• Biodiesel waste- derived crude glycerol
• carbon source
• Lactic acid production
• Lactobacillus casei NCIM 2125
• nitrogen source

Acknowledgments

The authors wish to thank the Management, Sri Venkateswara College of Engineering, Sriperumbudur (Tk.) for their support and National chemical laboratories, Pune for providing the microbial culture.