Algal-biomass Production from Chlorella sp. Using Hot and Cold Water Infusions of Poultry Droppings

Abstract

Background: Microbial biomass is a valuable resource to the development of sustainable energy. However, the challenge of having an effective media for energy production have adversely affected biotechnological development. This study was aimed at comparing algal biomass produced by Chlorella sp. using hot and cold water extracts of poultry droppings. Methodology: Fifteen grams (15 g) of poultry droppings was infused into 500 mL (cold and hot water) and allowed to stand for 48 h prior. Algal growth was monitored by cell dry weight and optical density readings taken at 620 nm using a spectrophotometer. Results: Physicochemical composition of the poultry droppings for cold water infusion revealed the following: pH, 6.7; conductivity, 3404.1 µs/cm; phosphate, 25.3 ppm; nitrate,1.88 ppm; phosphate, 25.3 ppm; Mg2+, 27.20 ppm; TOC, 38.03 ppm and COD, 53.8 ppm after 48 h. Whereas, the values obtained for hot extractions were: pH, 6.28; conductivity, 3.82 µs/cm; nitrate, 1.24 ppm; phosphate, 28.0 ppm; Mg2+, 19.85 ppm; TOC, 64.03 ppm and COD, 553.3 ppm. The proximate composition of extract revealed crude fibre, 17.69%, ash content, 24.16%; crude fibre, 22.7%; crude protein, 21.02%; crude fat, 3.19% and crude carbohydrate 23.02%. Microflora obtained from the biostability test revealed the presence of Proteus sp, Vibrio sp. and Salmonella sp. in cold extract while hot extract had Bacillus sp. and Serratia sp. The Chlorella sp. was identified using colonial and microscopic features. Biomass yield of 3.1 g/L and 2.8 g/l wet weight of Chlorella biomass was recorded for the cold and hot aqueous extracts of the poultry droppings respectively. Conclusion: This study revealed that hot poultry droppings extract (PDE) could offer a better feedstock for biodiesel production.