Safe technological trend towards the production of bioethanol from algal biomass grown on rice straw (original) (raw)

As a result of rapid growth in the population and manufacturing, the demand for ethanol is increasing continuously in worldwide. Because, biofuels produced from first and second-generation became unable to meet the international demand of bioethanol because of their needed value for food and feed. So, algae are among the most important sources of potential biofuels in the future of renewable energy because of accumulating high cellulose and also algae are distributed widely in the natural environment. This paper shows the ability of algae for bioethanol production, by pretreatment, hydrolysis, and fermentation of algal biomass. Two types of algae, Chlorella vulgaris and Arthrospira platensis were cultured under pre-treated rice straw with advantages as crop residues, a low-cost and carbon-rich source for algal cultivation. The chemical hydrolysates of rice straw (RS) were used for heterotrophic cultivation of Chlorella vulgaris and Arthrospira platensis for bioethanol production. Algal biomasses of the two microalgae were treated chemically with 4% H 2 SO 4 at 121°C in autoclave for 90 min, followed by biological treatment with Bacillus subtilis for 72 hours at 30°C and pH 4.5 to increase the reducing sugars production. The fermentation by Saccharomyces cerevisiae for 72 hours and distillation of Chlorella vulgaris and Arthrospira platensis solutions were resulted in ethanol productivity of 8.7% and 2.5 % respectively after 24 hours at 30°C and pH 4.5.