Evaluation of Sugarcane Bagasse Acid Hydrolyzate Treatments for Xylitol Production

Abstract

Acid sugarcane bagasse hydrolyzate was submitted to pH shifts in order to remove toxic compounds from the medium. The hydrolyzate was treated with bases containing mono-, di- or tri-valent cations and H2SO4, and its performance as a fermentation medium was evaluated by the production of xylitol by Candida guilliermondii FTI 20037. The use of bases containing mono-valent cations was not an efficient method of detoxification, and the use of a tri-valent cation did not show any detectable improvement in detoxification. The treated hydrolyzate recovery (in volume) is greatly affected by the utilized base. Treatment using Al(OH)3 and NaOH showed the best hydrolyzate recovery (87.5%), while the others presented a recovery of about 45% of the original hydrolyzate volume. Considering the whole process, best results were achieved by treatment using Al(OH)3 and NaOH which allowed 0.55 g of xylitol produced from each gram of xylose in the raw hydrolyzate

Xylitol from rice husks by acid hydrolysis and Candida yeast fermentation

“…The use of low solubility calcium hydroxide increases the reaction time and reduces the amount of fermentable sugar. 25 …”

Second Generation Ethanol from Residual Biomass: Research and Perspectives in Ecuador

“…The pentose fraction, composed of D-xylose (usually not less than 95%) and L-arabinose is much higher in hardwoods (19 to 33%) than in softwoods (10 to 12%) [17] Hemicellulose is a branched polymer, which is composed of both linear and branched heteropolymers of D-xylose, L-arabinose, D-mannose, D-glucose, D-galactose and Dglucuronic acid with a high content of xylans, that consist essentially in -1,4 links with branching variables; due to it heterogeneous structure and low degree of polymerization, it is easily hydrolyzed to xylose [15,16]. Xylan accounts for 11-35% (dry weight basis) of lignocellulosic materials such as hardwoods and agricultural residues, such as sugarcane bagasse [14,18], rice straw [19], and soy hulls [20,21] which are xylan-rich substrates and have been satisfactorily used as alternative media for xylitol production through different treatments [22] and cultivation conditions [23], aimed at increasing process yield and productivity.…”

Lignocellulosics as a Renewable Feedstock for Chemical Industry: Chemical Hydrolysis and Pretreatment Processes

“…Strategies for detoxification of hydrolysates include overliming [233,234], laccase treatment [233], pH adjustment [235], activated carbon adsorption [236], and electrodialysis [237]. Mechanisms of inhibition and detoxification have been reviewed generally for lignocellulosic materials [102,238,239].…”