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

Abstract

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 °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 β-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.