Analysis of the optimum pH and salinity conditions for the cultivation and biomass production of Chlorella vulgaris from cassava waste

Biofuel serves as an alternative energy to the common fossil fuels currently in use globally and are drawing increasing attention worldwide as substitutes for petroleum-derived transportation fuels to help address challenges associated with petroleum derived fuels. Third generation biofuels, also termed advanced biofuels, are produced from fast growing microalgae and are potential replacements for conventional fuels. The growth and biomass production of these microalgae is dependent on the conditions they are cultivated such as pH and Salinity. Cassava waste mixtures were cultivated on Chlorella vulgaris stock culture at different concentration ratio at ambient temperature, natural light and dark conditions at 670nm absorbance for 14 days. Optimum growth was obtained at 160:40 for cassava peel water to cassava waste water CP:CW. pH variations 6.0, 6.5, 7.0, 7.5, 8.0, 8.5 and 9.0 were checked to determine the optimum pH for the growth and biomass production of Chlorella vulgaris on the optimum cassava waste mixture concentration. It revealed that at pH 6.5, optimal growth and biomass production was achieved, minimal growth was observed at pH 8.0 while minimal biomass was produced at pH 9.0. Salinity variations of 5, 10, 15, 20, 25, 30, 35 and 40 mg/l were used to determine the growth response and biomass production of Chlorella vulgaris. It revealed that salinity variation at 10ppm will be necessary for highest growth on the cassava waste as well as in biomass production. The use of optimal pH and salinity can significantly increase biomass production thus enhancing biofuel production.