Growth of Chlorella sp. on Flue Gas

Abstract

Aims: To use the ubiquitous dirt scavenger, Chlorella sp. as an affordable, low tech transducing device in the interplay between energy utilization and extreme climatic and ecological impacts which is a key to sustainable development. Methodology: Chlorella sp. was isolated from effluent samples of a fertilizer company in the Niger Delta. The Chlorella sp. was cultured using a mixture of effluent and river water and supplied with 2%, 5%, 10% and 15% flue gas from a 3.0 kW TEC gasoline powered generator. The cultures, in triplicate, were aerated with an aquarium pump and the growth conditions were monitored as cell density (OD 600nm), cell number (cells/ml), lipid (mg/g), dry matter (mg/l) and CO2 utilization (g/l) for 14 days at an ambient temperature of 29±2ºC. Results: The flue gas solution supported the growth of the Chlorella sp. with no lag phase. The CO2 removal in the culture was quantitatively measured as 0.0428g/l, 0.1214g/l, 0.2094g/l and 0.3219g/l for the 2%, 5%, 10% and 15% flue gas concentrations respectively. The highest increase in cell number was recorded with the 15% flue gas concentration. Dry cell weight of 3.30mg/ml, 4.40mg/ml, 5.40mg/ml and 5.60mg/ml were obtained for the 2%, 5% 10% and 15% flue gas concentrations respectively. Lipid yields of 45mg/g, 47.5mg/g, 52.5mg/g, and 57.5mg/g of cell dry weight were obtained on the 14th day for the respective flue gas concentrations. Conclusion: The results demonstrate that an inexpensive growth medium can be realized from the flue gas, the effluent and river water for cultivation of the Chlorella sp. for biomass and lipids. The biomass can be used as food supplements (nutriceuticals) and biochemicals while the lipid can be converted into biofuel as biodiesel. The flue gas is sequestered reducing environmental pollution (a clean development methodology) which could mitigate the effects of global warming in an environmentally friendly way.