Enhanced Biofuel Production from High-Concentration Bioethanol Wastewater by a Newly Isolated Heterotrophic Microalga, Chlorella vulgaris LAM-Q
2013
Xie, T.H., Sichuan University, Chengdu, China | Liu, J., Sichuan University, Chengdu, China | Du, K., Sichuan University, Chengdu, China | Liang,, Sichuan University, Chengdu, China
Microalgal biofuel production from wastewater has economic and environmental advantages. This article investigates the lipid production from high chemical oxygen demand (COD) bioethanol wastewater without dilution or additional nutrients, using a newly isolated heterotrophic microalga, Chlorella vulgaris LAM-Q. To enhance lipid accumulation, the combined effects of important operational parameters were studied via response surface methodology. The optimal conditions were found to be temperature of 22.8oC, initial pH of 6.7, and inoculum density of 1.2 × 108 cells/ml. Under these conditions, the lipid productivity reached 195.96 mg/l/d, which was markedly higher than previously reported values in similar systems. According to the fatty acid composition, the obtained lipids were suitable feedstock for biodiesel production. Meanwhile, 61.40% of COD, 51.24% of total nitrogen, and 58.76% of total phosphorus were removed from the bioethanol wastewater during microalgal growth. In addition, 19.17% of the energy contained in the wastewater was transferred to the microalgal biomass in the fermentation process. These findings suggest that C. vulgaris LAMQ can efficiently produce lipids from high-concentration bioethanol wastewater, and simultaneously performs wastewater treatment.
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