Ethanol production from alkali-pretreated oil palm empty fruit bunch by simultaneous saccharification and fermentation with mucor indicus

ABSTRACT

Oil palm empty fruit bunch (OPEFB) is a potential raw material for production of lignocellulosic bioethanol. The OPEFB was pretreated with 8% sodium hydroxide (NaOH) solution at 100°C for 10 to 90 min. Enzymatic digestion was carried out using cellulase and β-glucosidase at 45°C for 24 h. It was then inoculated with Mucor indicus spores suspension and fermented under anaerobic conditions at 37°C for 96 h. Sodium hydroxide pretreatment effectively removed 51–57% of lignin in the OPEFB and also its hemicellulose (40–84%). The highest glucan digestibility (0.75 g/g theoretical glucose) was achieved in 40-min NaOH pretreatment. Fermentation by M. indicus resulted in 68.4% of the theoretical ethanol yield, while glycerol (16.2–83.2 mg/g), succinic acid (0–0.4 mg/g), and acetic acid (0–0.9 mg/g) were its by-products. According to these results, 11.75 million tons of dry OPEFB in Indonesia can be converted into 1.5 billion liters of ethanol per year.

KEYWORDS:

• Ethanol
• Mucor indicus
• oil palm empty fruit bunch (OPEFB)
• pretreatment
• sodium hydroxide
• simultaneous saccharification and fermentation

Funding

The International Program Office of Sweden and Swedish International Development Cooperation Agency (SIDA) are gratefully acknowledged for the financial support for this research.

Additional information

Funding

The International Program Office of Sweden and Swedish International Development Cooperation Agency (SIDA) are gratefully acknowledged for the financial support for this research.