Screening heterotrophic microalgal strains by using the Biolog method for biofuel production from organic wastewater

Heterotrophic cultivation of microalgae based on organic wastewater is a promising way to improve the feasibility of large-scale microalgal biofuel production and thus has received much attention recently. Biolog-ECO plates, which has been widely applied to analyze the ability of different bacteria to oxidize or utilize organic compounds, was firstly used in this study to evaluate the heterotrophic metabolic properties of five wastewater-borne microalgal strains (Scenedesmus sp. ZTY1, ZTY2 and ZTY3, Chlorella sp. ZTY4 and ZTY5). The results revealed that the microalgal strains could use a wide range of organic substrates. Scenedesmus sp. ZTY1 and Chlorella sp. ZTY4 could utilize 23 and 20 kinds of substrates among all 31 kinds of organic substrates in Biolog-ECO plate, respectively. The other three microalgal strains could also assimilate half the total kinds of the substrates. Furthermore, the metabolic patterns of the microalgal strains on different substrates were summarized according to the biochemical categories of the substrates. This study provides a new and rapid method to screen heterotrophic microalgal strains for microalgal biofuel production, and presents an evidence that some wastewater-borne microalgal strains could assimilate a wide range of organic substrates.