Low-Cost Production of Green Microalga Botryococcus braunii Biomass with High Lipid Content Through Mixotrophic and Photoautotrophic Cultivation.

Yeesang, Chittra; Cheirsilp, Benjamas

Botryococcus braunii is a microalga that is regarded as a potential source of renewable fuel because of its ability to produce large amounts of lipid that can be converted into biodiesel. Agro-industrial by-products and wastes are of great interest as cultivation medium for microorganisms because of their low cost, renewable nature, and abundance. In this study, two strategies for low-cost production of B. braunii biomass with high lipid content were performed: (i) the mixotrophic cultivation using molasses, a cheap by-product from the sugar cane plant as a carbon source, and (ii) the photoautotrophic cultivation using nitrate-rich wastewater supplemented with CO as a carbon source. The mixotrophic cultivation added with 15 g L molasses produced a high amount of biomass of 3.05 g L with a high lipid content of 36.9 %. The photoautotrophic cultivation in nitrate-rich wastewater supplemented with 2.0 % CO produced a biomass of 2.26 g L and a lipid content of 30.3 %. The benefits of this photoautotrophic cultivation are that this cultivation would help to reduce accumulation of atmospheric carbon dioxide and more than 90 % of the nitrate could be removed from the wastewater. When this cultivation was scaled up in a stirred tank photobioreactor and run with semi-continuous cultivation regime, the highest microalgal biomass of 5.16 g L with a comparable lipid content of 32.2 % was achieved. These two strategies could be promising ways for producing cheap lipid-rich microalgal biomass that can be used as biofuel feedstocks and animal feeds.

BOTRYOCOCCUS braunii; MICROALGAE cultures & culture media; LIPIDS; SEWAGE purification; BIOMASS production; FISHERY processing plants

Applied Biochemistry & Biotechnology, 2014, Vol 174, Issue 1, p116

0273-2289

Academic Journal

10.1007/s12010-014-1041-9