Eco-friendly consolidated process for co-production of xylooligosaccharides and fermentable sugars using self-providing xylonic acid as key pretreatment catalyst

Abstract

BackgroundObtaining high-value products from lignocellulosic biomass is central for the realization of industrial biorefinery. Acid pretreatment has been reported to yield xylooligosaccharides (XOS) and improve enzymatic hydrolysis. Moreover, xylose, an inevitable byproduct, can be upgraded to xylonic acid (XA). The aim of this study was to valorize sugarcane bagasse (SB) by starting with XA pretreatment for XOS and glucose production within a multi-product biorefinery framework.ResultsSB was primarily subjected to XA pretreatment to maximize the XOS yield by the response surface method (RSM). A maximum XOS yield of 44.5% was achieved by acid pretreatment using 0.64 M XA for 42 min at 154 °C. Furthermore, XA pretreatment can efficiently improve enzymatic digestibility, and achieved a 90.8% cellulose conversion. In addition, xylose, the inevitable byproduct of the acid-hydrolysis of xylan, can be completely converted to XA via bio-oxidation of Gluconobacter oxydans (G. oxydans). Subsequently, XA and XOS can be simultaneously separated by electrodialysis.ConclusionsXA pretreatment was explored and exhibited a promising ability to depolymerize xylan into XOS. Mass balance analysis showed that the maximum XOS and fermentable sugars yields reached 10.5 g and 30.9 g per 100 g raw SB, respectively. In summary, by concurrently producing XOS and fermentable sugars with high yields, SB was thus valorized as a promising feedstock of lignocellulosic biorefinery for value-added products.

Isolation and Identification of a Novel Anti-protein Aggregation Activity of Lignin-Carbohydrate Complex From Chionanthus retusus Leaves

“…The chemical compositions (carbohydrates and lignin) of raw C. retusus tender leaf, hot water extracted C. retusus tender leaf, LCC and lignin preparations were analyzed according to the procedures developed by the National Renewable Energy Laboratory (Sluiter et al, 2011). The monosaccharides in all samples were analyzed by high-performance anion exchange chromatography system (Dionex ISC 5000, Sunnyvale, CA, United States), which was equipped with the PA10 (2 × 250 mm) column and pulsed amperometric detector (Zhou and Xu, 2019). The amount of polyphenols in the LCC and lignin preparations was determined according to Folin-Ciocalteu method using gallic acid as a calibration standard by UV-vis spectrophotometer at 745 nm (Singleton and Rossi, 1965).…”

A novel recyclable furoic acid-assisted pretreatment for sugarcane bagasse biorefinery in co-production of xylooligosaccharides and glucose

“…Hydrolysis of sugarcane bagasse by furoic acid SCB (3.0 ± 0.03 g) was mixed with 30 mL of 1-3% FA solution and loaded in a 50-mL stainless steel tube reactor, which was then immersed in preheated oil baths at 130-170 o C for 15-60 min; after the hydrolysis reaction was completed, the reactor was immediately got out from the oil bath and cooled down to room temperature. The resultant solid and liquid fractions were separated by ltration; and the solids was then subjected to enzymatic hydrolysis process [32].…”

Removal of fermentation inhibitors from pre-hydrolysis liquor using polystyrene divinylbenzene resin

“…After treatment with PS-DVB, the bioconversion e ciency reached 61.8% for ethanol production from feedstock containing 30 g/L xylose and 96.6% for XA production from feedstock containing 40 g/L xylose. Regarding the nal products ethanol and XA, both are important industrial products that can be applied in different areas [11,13,14]. Importantly, the used resin can be reused by regenerating it with ethanol, which can be obtained sugars that remained unadsorbed within the column.…”

“…Developing bioethanol has been regarded as one of the approaches towards reducing CO 2 emissions from fossil fuel consumption [12]. Recently, xylonic acid (XA), one of the top 30 high-value chemicals in National Renewable Energy Laboratory (NREL) and Paci c Northwest National Laboratory (PNNL) reports, can also be produced from xylose by chemical, electrochemical, or fermentative methods [13,14]. Due to the potential applications and great demand for xylose, various types of biomass have been explored at different scales for producing xylose via an acid hydrolysis process [15][16].…”