Increasing carbohydrate and lipid productivity in tropical microalgae biomass as a sustainable biofuel feed stock

Research has been conducted to increase carbohydrate and lipid content in tropical microalgae biomass which can further be processed into biofuel. Three species of tropical microalgae, Chlorella vulgaris, Scenedesmus obliquus and Ankistrodesmus sp. were grown under controlled conditions in a photobioreactor which is fed with pure CO2 of 5%, 10%, 15% and 18% (v/v) concentrations. The addition of 10% pure CO2 that is continuously flowed at a flow rate of 5L/min into the photobioreactor increased the production of carbohydrates and lipids in biomass. Biomass C. vulgaris harvested by bioflocculation method yields lipid and carbohydrate contents of 23.57% and 18.35% respectively, while C. vulgaris harvested by centrifugation has a lipid content of about 30% lower. Biofloculation harvesting also increased the productivity of carbohydrates and lipids in the dried biomass of mixculture microalgae. High productivity and high carbohydrate and lipid content make algae a potentially important future source of biofuel. (C) 2019 The Authors. Published by Elsevier Ltd.