文摘
This study evaluated growth and lipid productivity of Nannochloropsis salina under sparging with carbon dioxide-enriched air. Carbon dioxide enrichments ranging from 0.5 to 9.5 % and gas-to-culture volume ratios ranging from 0.02 to 1.0?min?1 were tested in 900?mL bubble column batch reactors. An energy-based approach is proposed to optimize CO2 enrichment. Cultures sparged with CO2-enrichments of 0.5-4 % grew at nearly double the rate of those sparged with ambient air, accumulating 64 % or more lipids. Based on energy efficiency, CO2-enrichment of 0.5 % was found to be optimal while CO2-enrichments of 6.5 % and greater were observed to cause inhibition. At this optimal CO2-enrichment of 0.5 % , no significant changes were noted in the lipid content over the range of gas-to-culture volume ratios tested. These studies indicated that optimal energy recovery from N. salina can be achieved with CO2-enrichment of 0.5 % sparged at a gas-to-culture volume ratio 0.18?min?1. Under this optimal condition, biomass growth rate was 0.161?g?L?1?d?1, and the lipid content was 67.8 % , yielding total lipid production of 0.771?g?L?1 over 10 days at a net energy yield of 25?W?m?3.
