Simultaneous cultivation of Chlorella protothecoides and treatment of anaerobic treated brewery wastewater for biodiesel production

Abstract

The deficiency of petroleum based fuel to fulfill the Earth’s energy demands has driven researches to look for other energy sources. Recently, microalgal biodiesel has been considered as an alternative energy source due to its sustainability and environmentally-friendly nature. Furthermore, microalgae are known for their ability to mitigate the global warming by capturing CO2 in the atmosphere through photosynthesis. Nevertheless, the industrial development of microalgal biodiesel still faces major obstacles such as (1) high cost for water and nutrients supply for microalgal cultivation, (2) low lipid content of microalgal biomass, (3) high cost and energy demands for microalgal harvesting, (4) and high cost for extraction of oil from microalgae. This research aimed at evaluating the performance of microalga Chlorella protothecodies cultivated in anaerobic-treated brewery wastewater (ABWW) for biodiesel production. Simultaneously, C. protothecoides was tested for its ability as a biological wastewater treatment agent that can remove nitrogen and phosphorus in ABWW. In addition, the auto-flocculation of the microalgal strain cultivated in ABWW was investigated in order to develop a harvest process that is suitable for C. protothecoides. Finally, the effect of glucose and glycerol as organic carbon sources to improve the lipid content in microalgal cells was also studied. Based on the author’s knowledge, this was the first study to deliberate these issues concomitantly Cultivation of C. protothecoides in ABWW produced 1.88±0.09 g/L and 0.23±0.11 g.L-1.day-1 of biomass production and productivity, respectively. Concomitantly, the microalgae could uptake 95.73±0.59 and 89.61±1.8 % of total nitrogen and phosphorus from ABWW. Furthermore, cultivation of C. protothecoides in ABWW produced large and floc of microalgae, that appears to be due to the low N:P ratio predisposed by ABWW and pH fluctuation during cultivation period. C. protothecoides was recovered as much ...