Usage of thermophilic cyanobacterial biomass for bioethanol production

Abstract

Although the usage of microalgae biomass as a feedstock for bioethanol production has been extensively studied, very little attention has been given to the usage of cyanobacterial biomass for bioethanol production. In this study, a thermophilic cyanobacterial strain namely Phormidium sp. was used for producing bioethanol. Some important parameters for bioethanol production were optimized. When the initial sugar concentration was 8.69 at 40 g L−1 cyanobacteria loading, Pichia stipitis used 31.5% of the sugar and produced 1.64 g L−1 ethanol and Saccharomyces cerevisiae used 34.6% of the sugar and produced 1.97 g L−1 ethanol at the end of 72 h. The highest bioethanol concentration was obtained as 2.32 g L−1 for S. cerevisiae and 1.7 g L−1 for P. stipitis at 24 h of incubation time and substrate concentration of 40 g L−1 cyanobacterial biomass at pH 5. This study demonstrated that the biomass of a thermophilic cyanobacteria is a promising feedstock for bioethanol production. © 2014 American Institute of Chemical Engineers Environ Prog, 34: 903–907, 2015