Scaling-up and techno-economics of ethanol production from cassava starch via separate hydrolysis and fermentation

• Published in: IOP conference series. Earth and environmental science 2021-05, Vol.765 (1), p.12004
• Main Authors: Chong, C B, Ismail, K S K, Ma’Radzi, A H
• Format: Article
• Language: English
• Subjects: Biofuels; Bioprocessing; Cassava; Energy demand; Ethanol; Fermentation; Fuel production; Hydrolysis; Laboratories; Starch; Superhigh frequencies; Yeasts
• ISSN: 1755-1307; 1755-1315
• DOI: 10.1088/1755-1315/765/1/012004

Nowadays bioethanol is being used extensively in fuel production because of its technical feasibility, economically competitive, and environmentally friendly. It is expected that biofuel will contribute to 30% of the global energy demand by 2050. Therefore, it is very important to investigate any cost-effective bioprocessing that can improve the overall production yield. The study aims to produce bioethanol from cassava starch by Kluyveromyces marxianus at a laboratory scale and a 5L fermentation rig. A separate hydrolysis and fermentation (SHF) process of cassava starch was introduced due to high sugar content in starch, using a thermoanaerobe able to reduce the cooling time after hydrolysis. A combination of 0.35% v/w amylase and 0.20% v/w amyloglucosidase used in the hydrolysis of cassava starch produced 19.18 g/L of sugar. A 15 g/L of K. marxianus showed to be the best yeast concentration which could produce the highest bioethanol, 42.85 g/L. When the laboratory scale was scaled up to 5 L fermentation, the result was comparable at 42.33 g/L. The same SHF parameters in laboratory scale had been proven to be effective in a larger scale fermentation based on similar results obtained. Simulation using SuperPro software indicated that 50.13% of starch can be converted into ethanol.