Significantly enhancing enzymatic hydrolysis of rice straw after pretreatment using renewable ionic liquid–water mixtures

• Published in: Bioresource technology 2013-05, Vol.136, p.469-474
• Main Authors: Hou, Xue-Dan, Li, Ning, Zong, Min-Hua
• Format: Article
• Language: English
• Subjects: Basicity; Biological and medical sciences; Biotechnology; Cellulase - metabolism; Cholinium amino acids ionic liquids; Delignification; energy; enzymatic hydrolysis; Enzymatic saccharification; enzymes; Food industries; Fundamental and applied biological sciences. Psychology; glucose; Hydrolysis - drug effects; industrial applications; Ionic Liquids - pharmacology; Lignin - isolation & purification; Lignocellulosic biomass; lysine; Oryza - drug effects; rice straw; solvents; surface area; Temperature; Time Factors; Trichoderma - enzymology; Use and upgrading of agricultural and food by-products. Biotechnology; Waste Products - analysis; Water - pharmacology; xylan; xylose
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2013.02.118

•[Ch][Lys]-water mixtures as highly effective solvents for rice straw pretreatment.•A clear correlation between the medium basicity and its delignification capacity.•Substantial increase in surface area and pore volume of rice straw after pretreatment.•Good sugar yields in the enzymatic digestion of the biomass upon pretreatment.•Great application potential of this pretreatment process due to a lot of advantages. Pretreatment of rice straw by using renewable cholinium lysine ionic liquid ([Ch][Lys] IL)-water mixtures and subsequent enzymatic hydrolysis of the residues were conducted in this work. There is a clear correlation between the delignification capacity of the pretreatment solvent and its basicity. After pretreatment, surface area and pore volume of rice straw increased significantly, which substantially improved polysaccharides accessibility to enzymes and thus enhanced polysaccharides digestion. By carefully controlling the pretreatment severity (IL content, temperature and duration), loss of readily extractable xylan could be minimized. The sugar yields of 81% for glucose and 48% for xylose were achieved in the enzymatic hydrolysis of rice straw after pretreatment with 20% [Ch][Lys]-water mixture at 90°C for 1h. This pretreatment process is highly promising for industrial application because of high sugar yields, low energy input, short pretreatment time, and being environmentally benign and highly tolerant to moisture.