Outdoor cultivation of microalgae in a medium enriched with poultry droppings for biomass production

Microalgae require nutrients and optimal pH for good growth and metabolite production. Microalgae biomass has various applications in food and feed, pharmaceuticals, bio-energy, aquaculture, cosmetics and other related industries. However, the cost of media represents a significant percentage of the total production cost. The aim of this work was therefore, to develop a cheap medium for efficient outdoor cultivation of microalgae and to find the optimum pH for biomass production. Three Chlorella species designated A, B and C were isolated from three stagnant water bodies at Amoke Lane, University market road in Nsukka town by using BG-11 enriched with poultry droppings. Poultry droppings medium was prepared by drying under the sunlight for 5 days. The dried poultry droppings were crushed into a fine powder and 200 g was weighed and soaked in 1000 ml of distilled water for 3 days and filtered using a muslin cloth. A mixture of the poultry droppings medium and the conventional BG-11 medium was prepared by mixing equal volume of each medium. The growth and biomass productivity of the three local isolates in BG-11 medium were compared with those in poultry medium, and a mixture of poultry and BG-11 media. The results showed that the growth of the three isolates in poultry medium alone were significantly higher than the values obtained in BG-11 and a mixture of BG-11 and poultry medium (p< 0.05). With poultry medium, the maximum optical densities of the cultures were 2.10± 0.07, 2.56± 0.09 and 3.35± 0.11 for isolates A, B, and C respectively. However, with a mixture of BG-11 and poultry medium, the maximum optical densities were 0.83± 0.01, 1.67± 0.05 and 0.57± 0.02 respectively. BG-11 supported the least growth of the three isolates, giving maximum optical densities of 0.38± 0.01, 0.42± 0.03 and 0.52± 0.02 respectively. All the three isolates had their best growth in poultry medium at pH of 5.0. The results show that poultry medium, which is cheap and can be easily prepared from poultry droppings, is very good for cultivation of some species of microalgae.

 Ezea Ifeanyi Boniface and Ogbonna James Chukwuma