Application of fishmeal wastewater as a potential low-cost medium for lipid production by Lipomyces starkeyi HL

Abstract

Due to the high organic compounds and high salinity of fishmeal wastewater (FW), it was firstly used as a novel medium to produce microbial lipid in this paper. Fermentation of FW without any additives adding showed that the broth was appropriate for the growth of strain Lipomyces starkeyi HL; however, production of 5.34 g l⁻¹ of biomass containing 20.8% of lipid was not satisfied. In order to enhance the accumulation of lipid and cell growth, FW was supplemented with various concentrations of glucose; meanwhile, the influence of initial pH was investigated. Biomass and lipid yield on FW were markedly affected by glucose concentration and initial pH. The addition of 20 g l⁻¹ glucose at initial pH 4.0 got the best results: 17.6 g l⁻¹ of biomass, 2.7 g l⁻¹ of lipid yield, 91.2% of protein removal and 43.4% of the chemical oxygen demand removal. The variation of fatty acid composition upon time course in the cellular lipid on FW or a mixture of glucose and FW was further studied.

Keywords:

• fermentation
• fishmeal wastewater
• Lipomyces starkeyi HL
• microbial lipid
• chemical oxygen demand removal

Acknowledgements

The authors gratefully acknowledge the financial support from Rongcheng Mingyuan Aquatic Food Co., Ltd in Weihai of Shandong Province, China. We also thank Dr. Hui-Jun Xie, Dr. Li Li and Guang-Bin Yin for their valuable advice and Yu-Mei Liu for her help in the laboratory.