Submitted to: Biotechnology for Fuels and Chemicals Symposium Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: January 8, 2006
Publication Date: April 30, 2006
Citation: Mulbry Iii, W.W., Wen, Z. 2006. Effect of loading rate on lipid production from microalgae grown on dairy manure effluent. Biotechnology for Fuels and Chemicals Symposium Proceedings.
Microalgae are a potential source for renewable oil production. Although this research area has been the focus of numerous studies over nearly 50 years, microalgal bioenergy production has been limited largely because of the difficulty of harvesting and drying biomass from suspended microalgal culture systems. However, as the quest for renewable energy sources intensifies, there is renewed interest in microalgal production for bioenergy, especially in regard to oil production from microalgal systems designed to treat agricultural wastewater or animal manure. Our research has focused on the use of filamentous freshwater algae for manure treatment because the resulting biomass is relatively easy to harvest and dewater. The objective of this study was to determine the effect of manure loading rates on the lipid content of freshwater filamentous algae grown in algal turf scrubbers (ATS) with and without carbon dioxide supplementation. Algal biomass was harvested weekly from laboratory scale ATS units using three loading rates of anaerobically digested dairy manure effluent corresponding to daily loading rates of 0.37-1.8 g total N per sq. meter. The harvested algal biomass was air-dried, ground, and stored at 20 C prior to lipid analysis. The total lipid content of the dried biomass from ATS grown with CO2 supplementation was roughly 7% of dry weight and did not change with increased loading rate. In contrast,the total lipid content of dried biomass from ATS grown without CO2 supplementation increased with loading rate from 7 to 11% of dry weight. Further experiments will focus on manipulation of algal growth conditions and algal inocula to enrich for species with increased lipid content.