Hemicellulose extraction by hot pressurized water pretreatment at 160 ºC for 10 different woods: Yield and molecular weight

Abstract

20A comprehensive study on the hemicellulose extraction from 10 different tree species was performed at 21 160 ºC using a novel cascade reactor. The aim was to identify which wood species were best candidates 22 to obtain a high concentration, yield and/or molecular weight of hemicelluloses. Hydrothermal 23 extractions at several times (from 5 to 80 min) were performed. We demonstrated that there is a relation 24 between extraction yield (between 9.7 and 40.3%), composition of the raw material and initial structure 25 determined via TGA data. Additionally, a new empirical equation able to estimate the hemicellulose 26 extraction yield from initial composition data was developed. The highest yield was obtained with 27 eucalyptus wood. Molecular weight of the oligomers varied from 3.4 to over 100 kDa. Three trends 28 were observed: molar mass decay with time, maximum and minimum of molar mass. In general, the 29 higher the extraction yield, the lower the molecular mass of the hemicelluloses. 30 31 32

Liquid Hot Water Pretreatment and Enzymatic Hydrolysis as a Valorization Route of Italian Green Pepper Waste to Delivery Free Sugars

“…The values decreased from 53.9% to 46.6% as temperature and time increased, mainly due to the progressive solubilization of some components of the raw material such as hemicellulosic sugars, extractives, and soluble ashes. These are the compounds that are most easily solubilized in this type of hydrothermal pretreatment, since their structure is less complex than that of other components of the vegetable waste [ 41 , 49 , 51 , 63 , 64 , 65 ]. The decrease in the solid recovery was well in agreement with the literature [ 35 , 66 , 67 , 68 , 69 ].…”

Poplar Hot Water Extract Enhances Barrier and Antioxidant Properties of Chitosan/Bentonite Composite Film for Packaging Applications

“…Hemicellulose is an amorphous branched heteropolysaccharide with various compositions in different raw material types. Xylan is the main component of hemicelluloses in hardwoods and grass-type biomass (like wheat straw or rice straw), while the main components of hemicellulose in softwoods is galactomannans [14]. Xylan extracted from corn cobs was co-heated with chitosan to prepare a polysaccharide-based food preservative in Li’s study [15].…”

Development of an integrated and green biorefinery from winery waste. Application to wine lees and grape stems

“…At higher temperatures, a slight increment in the oligomers was the result, whereas sugars started to decrease and degradation product linearly increased. These behaviors could be explained by the fact that the increase in temperature would not be severe enough to degrade the oligomers, since they would be shorter than the obtained at lower temperatures (Chen, Lawoko, & Heiningen, 2010;Gallina, Cabeza, et al, 2018). Unlike oligomers, sugars degradation would be promoted by higher temperatures.…”

“…The composition of GS was determined according to the Laboratory Analytical Procedure (LAP) for biomass analysis provided by the National Renewable Energy Laboratory (NREL) ( a Sluiter et al, 2008). This procedure has been previously described in prior works of our group (Gallina, Cabeza, et al, 2018;Sánchez-Bastardo et al, 2017).…”

“…Once the desired temperature was achieved the operating time started to run. The operating time was fixed at 20 min to maximize both, the oligomers length and the sugars extraction yield (Gallina, Cabeza, et al, 2018). At the end of the experiments, the extractor vessel was cooled in an ice bath.…”