Weak base pretreatment on coconut coir fibers for ethanol production using a simultaneous saccharification and fermentation process

ABSTRACT

In this work, coconut coir fibers, which are a good source of lignocellulosic biomass with a composition of 34.80% glucan, 18.30% xylan, 35.80% lignin and 8.70% extractives, were successfully pretreated with ammonium carbonate solution (20 and 25 wt.%) at 80°C for 4, 8 and 12 h working time at laboratory scale. The maximum yield of enzymatic hydrolysis (glucan digestibility) after 8 h was 77.03% and 71.43% after the 20% and 25% ammonium carbonate pretreatment, respectively. The simple simultaneous saccharification and fermentation (SSF) process was anaerobically carried out in order to produce second-generation bioethanol from coconut coir fibers at 37°C. The SSF slurry contained Saccharomyces cerevisiae yeast, 5% w/v glucan (untreated and pretreated samples), and 10 FPU/g glucan of cellulase. Subsequently, the maximum ethanol concentration was 8.65 g/L, after 72 h incubation, from 20% ammonium carbonate pretreated biomass for 8 h.

KEYWORDS:

• Coconut coir fibers
• ammonium carbonate solution
• glucan digestibility
• SSF
• bioethanol

Acknowledgements

The authors gratefully acknowledge the laboratories of Mapúa University for facilitating the present research. This research did not receive any specific grant from funding agencies in the public, commercial or not-for-profit sectors.

Disclosure statement

The authors declare that there is no conflict of interests regarding the publication of this paper.