Enzymatic Hydrolysis of Hydrotropic Pulps at Different Substrate Loadings

Abstract

Enzymatic hydrolysis of cellulosic raw materials to produce nutrient broths for microbiological synthesis of ethanol and other valuable products is an important field of modern biotechnology. Biotechnological processing implies the selection of an effective pretreatment technique for raw materials. In this study, the hydrotropic treatment increased the reactivity of the obtained substrates toward enzymatic hydrolysis by 7.1 times for Miscanthus and by 7.3 times for oat hulls. The hydrotropic pulp from oat hulls was more reactive toward enzymatic hydrolysis compared to that from Miscanthus, despite that the substrates had similar compositions. As the initial substrate loadings were raised during enzymatic hydrolysis of the hydrotropic Miscanthus and oat hull pulps, the concentration of reducing sugars increased by 34 g/dm(3) and the yield of reducing sugars decreased by 31 %. The findings allow us to predict the efficiency of enzymatic hydrolysis of hydrotropic pulps from Miscanthus and oat hulls when scaling up the process by volume.

Production of Cellulose Materials from Oat Agricultural Wastes: A Review of Recent Approaches

“…It allows one to isolate cellulose and lignin without significant modifying their structure. This process is carried out using non-toxic and low cost reagents, at low pressures; chemicals can be reused [34,35,55,61,[137][138][139][140][141]. Denisova et al carried out cellulose separation from oat husks by several stages [34,35,137,138,141].…”

“…High cellulose content makes oat hulls (oat husks) very promising resource for the production of cellulose based materials (Figure 1). Along with the glucose polysaccharide, the waste under consideration contains hemicelluloses (24-35%) and lignin (13-25%) [9,11,34,35]. Hemicelluloses which are branched structures are mainly presented by the saccharide polymers xylose, arabinose, and galactose.…”

Current achievements in the mechanically pretreated conversion of plant biomass

“…In particular, the production of bioethanol is increasingly involving the replacement of edible raw materials with nonedible raw materials (Bai, Anderson, & Moo‐Young, ; Galbe & Zacchi, ; Lynd, Weimer, van Zyl, & Pretorius, ; Skiba, Mironova, Kukhlenko, & Orlov, ; Taherzadeh & Karimi, ; Zheng, Pan, & Zhang, ). In this context, the most promising raw material is the waste from agricultural processes (straw of cereals, oil‐palm bunches, sunflower husks) and plants with a high growth rate and abundant green mass, for example, miscanthus (silver grass; Denisova, Makarova, Pavlov, Budaeva, & Sakovich, ; Gaveau, Balzter, & Plummer, ; Ge, Burner, Xu, Phillips, & Sivakumar, ; Makarova, Budaeva, Skiba, & Sakovich, ; Skiba et al, , ; Sorensen, Teller, Hilstrom, & Ahring, ).…”

Pretreatments of Non-Woody Cellulosic Feedstocks for Bacterial Cellulose Synthesis

“…For Miscanthus , various pretreatment methods have been tested in order to obtain substrates. These methods employ sulfuric acid/ethanol/water, formic acid/acetic acid/water, formic acid/hydrogen peroxide/water, aqueous NaOH, ethylenediamine/DMSO, ethylenediamine/1-butyl-3-methylimidazolium dimethylphosphate, 1-ethyl-3-methylimidazolium acetate with ammonia and/or oxygen, autohydrolysis in water with and without 2-naphthol, ozone/ethanol and electrolyzed water with or without alkaline peroxide, as well as aqueous ammonia with or without hydrogen peroxide [35], various alkali and acids [34,36,37], concentrated sodium benzoate solution [38,39], and steam explosion [40].…”