Bioethanol Production from Areca Nut (Areca catechu L.) Husk as an Environmental Waste Management and Sustainable Energy

Abstract

Bioethanol from lignocellulosic biomass can be utilized for clean and renewable energy production. Determining optimal pre-treatment techniques for fermentation is essential for the success of lignocellulosic energy production process. The purpose of this study was to evaluate lignocellulosic ethanol production from areca nut husk. The study involved the acid pre-treatment and enzymatic hydrolysis using xylanase enzyme to degrade the complex lignocellulosic biomass to simple sugars. Sugars so formed in turn are converted to ethanol by employing suitable yeast strains and bacterium Zymomonas mobilis NCIM2915. Different fermentation process like separate hydrolysis and fermentation (SHF) process and simultaneous saccharification and fermentation (SSF) process have been evaluated for the biethanol production. In SHF process, it showed the higher ethanol production in Candida shehatae NCIM 3500 (45.76 ± 1.63 g l−1) and very low ethanol production in Saccharomyces uvarum NCIM3455 (22.09 ± 1.0 g l−1). In SSF process, it showed the higher ethanol production in Pichia stipitis NCIM 3498 (47.34 ± 1.86 g l-1) and very low ethanol production in C. shehatae NCIM 3500 (26.82 ± 1.23 g l-1) was monitored after the fermentation process. Structural changes of areca nut husk before and after acid pre-treatment were further investigated through scanning electron microscopy and Fourier transform-infrared analysis. Areca nut husk was revealed as a suitable substrate for ethanol production.