Improvement of xylo-oligosaccharides dissolution from Caragana korshinskii through liquid hot water pretreatment with tiny choline chloride

Xylo-oligosaccharides (XOS) is a kind of high-value substance with bioactivity, extracted from plants with liquid hot water (LHW) treatment that is usually applied for biorefinery. Herein, we reported a system of LHW with tiny choline chloride (ChCl) to treat a shrub Caragana korshinskii to improve XOS extraction. It is found that the ChCl acted as a buffer in LHW pretreatment promotes the XOS extraction with a yield of 36.59% at 160 degrees C for 120 min. Compared with LHW/NaOH pretreatment, it also showed that the content of xylan in the residue was decreased by about 14% after LHW/ChCl pretreatment. The concentrations of furfural and 5-HMF in the hydrolysate were decreased after LHW/ChCl pretreatment. Moreover, the cellulose conversion rate of the residue treated with ChCl was 41.30% when using 25 FPU/g-substrate cellulase and 25 CBU/g-substrate beta-glucosidase, an increase of 38% compared with the untreated one. The LHW/ChCl pretreatment provided a strategy to utilize the sandy growth biomass for high value products.

Automated summary

This study found that adding a tiny amount of choline chloride during liquid hot water treatment for XOS extraction can increase the extraction yield, decrease xylan content in the residue, and reduce the concentrations of certain compounds in the hydrolysate. Additionally, the cellulose conversion rate of the treated residue was significantly improved.