Abstract

Agwa, O. K., Ibe, S. N and Abu, G. O

Heterotrophic growth of Chlorella sp. using glucose as carbon source was investigated using different animal waste extracts. The Chlorella cells were obtained from a fresh water pond by blooming and cultured under different growth conditions. Artificial illumination with forced aeration resulted in 2.30 mg/ml (pig); 2.39 mg/ml (goat); 1.43 mg/ml (cow dung); 2.12 mg/ml (grass cutter) and 2.52 mg/ml (poultry) and lipid content of 4.25%; 4.49%; 10.16%; 8.15% and 8.66% respectively. Artificial illumination with unaerated growth condition gave 1.74 mg/ml; 1.71 mg/ml; 1.16 mg/ml; 1.64 mg/ml and 2.06 mg/ml of dry matter and lipid content of 2.40%; 2.13%; 9.92%; 4.97% and 8.39% respectively. The natural condition showed 1.99 mg/ml; 1.64 mg/ml; 2.30 mg/ml; 2.58 mg/ml and 2.77 mg/ml of dry matter with 7.78%; 4.03% 12.99%; 19.56% and 22.71% lipid content respectively. There were significant difference (P<0.05) between the different cultural conditions and the waste extracts. The proximate composition of the Chlorella cells under the heterotrophic growth conditions revealed about 38.30% of crude fat content compared to 13.20% from an autotrophic Chlorella cell. This result shows that heterotrophic cultivation of Chlorella cells using poultry waste extracts under natural condition is feasible as a potential waste utilization, management and pollution control alternative.