Microalgae Chlorella as a Sustainable Feedstock for Bioethanol Production

Microlgae can serve as an excellent feedstock for bioethanol production. The microalgae cells of Chlorella were cultivated and acid hydrolyzed to extract the glucose content in the cells. Production of bioethanol was achieved by fermentation process with the use of yeast Saccharomyces cerevisiae. The bioethanol content was determined by gas chromatography–mass spectrometry (GC-MS). The effect of different parameters such as sulphuric acid concentration, temperature and time on acid hydrolysis was studied. The maximum glucose concentration of 5.382 ± 0.063 g/l was obtained with the conditions of 2.0 M sulphuric acid, 30 °C and 30 min of incubation time. On the other hand, the highest ethanol concentration of 1.126 g/l was obtained with 15% v/v yeast inoculum concentration. Meanwhile, the bioethanol production reached its maximum after 24 h with ethanol concentration and yield of 1.020 g/l and 0.190 g/g glucose, respectively.