Process intensification strategies for enhanced holocellulose solubilization: Beneficiation of pineapple peel waste for cleaner butanol production

TL;DR

This study develops an effective pretreatment process using binary acid to enhance hemicellulose solubilization from pineapple peel waste, leading to improved butanol production via fermentation, promoting sustainable bioenergy from low-cost feedstock.

Contribution

It introduces an optimized binary acid pretreatment method for pineapple peel waste that significantly improves hemicellulose solubilization and biofuel yield.

Findings

Binary acid pretreatment achieved 81.17% hemicellulose solubilization.

Enzymatic hydrolysis of solid residue yielded 24.50% cellulose breakdown.

Fermentation produced 5.18 g/L butanol with a yield of 0.13 g/g sugar.

Abstract

Biorefinery sector has become a serious dispute for cleaner and sustainable development in recent years. In the present study, pretreatment of pineapple peel waste was carried out in high pressure reactor using various pretreatment-enhancers. The type and concentration effect of each enhancer on hemicellulose solubilization was systematically investigated. The binary acid (phenol + sulfuric acid) at 180 {\deg}C was found to be superior amongst other studied enhancers, giving 81.17% (w/v) hemicellulose solubilization in liquid-fraction under optimized conditions. Solid residue thus obtained was subjected to enzymatic hydrolysis that resulted into 24.50% (w/v) cellulose breakdown. Treated solid residue was further characterized by scanning electron microscopy and Fourier transform infrared spectroscopy to elucidate structural changes. The pooled fractions (acid treated and enzymatically hydrolyzed) were fermented using Clostridium acetobutylicum NRRL B 527 which resulted in butanol production of 5.18 g/L with yield of 0.13 g butanol/g sugar consumed. Therefore, pretreatment of pineapple peel waste evaluated in this study can be considered as milestone in utilization of low cost feedstock, for bioenergy production.