Dilute Acid Hydrolysis of Agro-Residues for the Depolymerization of Hemicellulose: State-of-the-Art

Ethanol fermentation characteristics of Pichia stipitis yeast from sugar beet pulp hydrolysate: Use of new detoxification methods

“…93 For hemicellulose conversion, dilute sulfuric acid hydrolysis is 94 known to be an efficient and industrially-applicable method. The 95 hydrolysate medium ingredients obtained from acidic hydrolysis 96 are xylose (the main component), arabinose, glucose, galactose 97 and mannose sugars and the inhibitory by-products include furan 98 derivatives (furfural and 5-hydroxymethyl furfural), phenolic 99 compounds and weak acids [13]. The efficiency of ethanol fermen-100 tation can be enhanced by detoxification of the hydrolysate and by 101 using microorganisms with high tolerance toward inhibitor 102 compounds [14].…”

Biotechnological Transformation of Lignocellulosic Biomass in to Industrial Products: An Overview

“…Carbohydrates (cellulose and hemicelluloses) are hydrolyzed by cellulases and xylanases to monomer sugars such as glucose, xylose, mannose, arabinose and galactose. These monomer sugars are utilized as carbon sources for the production of different industrial products such as ethanol, xylitol, biobutanol, bio-hydrogen, microbial polysaccharides, organic acids, and single cell proteins etc [93] [94]. Maximum laccase activity (416.4 U/ml) obtained by submerged fermentation of wheat bran by Cerrena unicolor C-139 [65] Amylase (327 IU/ml) produced by Aspergillus fumigatus NTCC1222 using wheat bran as substrate [66] Lipase activity (9.14 IU/g of dry substrate) obtained by Aspergillus niger under SSF using wheat bran as substrate [67] Lactic acid yield of 0.73 g/g substrate achieved by fermentation by Lactobacillus pentosus using wheat bran as substrate [59] Fumaric acid 20.2 g/l was achieved by fermentation by Rhizopus oryzae using wheat bran hydrolysate as substrate [58] The maximum hydrogen yield of 128.2 ml/g total volatile solid from pre-treated wheat bran by mixed anaerobic cultures [68] Wheat straw…”

Carbon Sources for Biomass, Food, Fossils, Biofuels and Biotechnology - Review Article

“…Efficiency of pretreated solid material for enzyme monomerization reached 81% for acid pretreatment, 77% for autohydrolysis and 57% for alkaline pretreatment after 72 h (Gurgel et al, 2012;Batalha et al, 2015). Pretreatment of agro-residues, acting mechanistically and disorganizing hemicellulose, is an inevitable process to depolymerize hemicellulosic fraction into xylose, whereby acid load, temperature, residence time and solid-to-liquid ratio as well as reactor design are pivotal parameters in kinetics of dilute acid hydrolysis of agro-residues and minimization of side (or by)-products (Chandel et al, 2012). Dilute sulfuric acid (acid hydrolysis with 2% of H2SO4 at 155°C for 10 min, 1:8 solid-liquid ratio) is most common and efficient separating process in pretreatment of agro-residues for obtaining cellulose, which is submitted to acid or enzymatic hydrolysis to release glucose after a delignification stage using sodium hydroxide as catalyst (Chandel et al, 2012;Dussan et al, 2014).…”