Bioethanol production from mixed culture microalgae biomass with temperature hydrolysis variation

Universitas Trisakti, Environmental Engineering Department, Faculty of Landscape Architecture and Environmental Technology, Jakarta, Indonesia.

^* Corresponding author: rositayanti@trisakti.ac.id

Abstract

This preliminary study aims to exploit the biomass of microalgae Chlorella vulgaris; Scenedesmus obliquus; and Chlorococcum sp. in the form of a mixed culture as raw material of alternative fuels. Microalgae were cultivated in the artificial growth medium of PHM (Provasoli Haematococcus Media) for 9 days to reach the exponential phase. Hydrolysis was carried out at a temperature variation of (oC) 25; 80; 100; 120; 140; 160 within 30 minutes by adding hydrochloric acid. Biomass fermentation by adding 50% (v/v) Saccharomyces cerevisiae for 5 day to produce alcohol compounds. The last stage is separation of the alcohol compounds from another compounds by distillation. The result showed that carbohydrate levels with color change indicator in luff schoorl solution at hydrolysis and fermentation stages severely were 12.20 mg/L. Carbohydrate levels in fermentation stage produced 17% (v/v) alcohol compounds while in the distillation stage, 98% (v/v) alcohol will be separated into intermediate compounds such as linoleic acid and methyl alcohol as a characteristic of bioethanol. At 80oC of hydrolysis temperature, 58% bioethanol was produced. Further research is needed, since the preliminary study proves the mixed culture of microalgae is potentially to be utilized in producing bioethanol.