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High-solid pretreatment of rice straw at cold temperature using NaOH/Urea for enhanced enzymatic conversion and hydrogen production

Dong, Lili, Cao, Guangli, Wu, Jiwen, Liu, Bingfeng, Xing, Defeng, Zhao, Lei, Zhou, Chunshuang, Feng, Liping, Ren, Nanqi
Bioresource technology 2019 v.287 pp. 121399
Fourier transform infrared spectroscopy, X-ray diffraction, cellulose, cold, crystal structure, fermentation, hydrogen, hydrogen production, hydrolysates, lignin, lignocellulose, reducing sugars, rice straw, sodium hydroxide, temperature, urea
A high-solid loading pretreatment using NaOH/Urea solution at −12 °C was proposed to pretreat rice straw (RS) for enhanced saccharify and hydrogen production. Results shown NaOH/Urea pretreatment exhibited excellent pretreatment performance at solid loading ranged from 10% to 100% (w/v) with an average reducing sugar conversion of 80.22% was obtained which was 31.89% higher than that untreated RS. Upon fermentation of 100% solid loading pretreated hydrolysate, the H2 yield of 72.5 mL/g-pretreated RS was calculated based on substrate consumption, which enabled 49.5% higher reducing sugar transfer to H2 through material balance. FTIR and XRD analysis further demonstrated that the cold NaOH/Urea pretreatment at 100% (w/v) could effectively disrupt the lignin structure and decrease the cellulose crystallinity. The present study suggested a high solid loading pretreatment with NaOH/Urea at cold temperature could be a valuable alternative for better techno-economic of the lignocelluloses – to – sugars – to H2 routes.