玉米秸秆浓硫酸糖化工艺优化及酸糖分离树脂评价

Optimization of concentrated sulfuric acid saccharification process of corn straw and evaluation of ion-exchange resin for acid/sugar separation

可发酵糖生产是制约从木质纤维素生物质经济性生产燃料乙醇的瓶颈环节.基于浓硫酸糖化生产可发酵糖具有高糖回收率和无需纤维素酶投入的优点,本研究探究了玉米秸秆浓酸糖化工艺的优化条件并评价市售树脂分离酸糖的潜力.本文采用浓硫酸溶化-水解两步工艺,考察了关键操作参数酸料比(A/F)、水解温度以及秸秆含水率对糖化效率的影响,获得优化条件(A/F比1.25、水解温度80℃、含水率5%~10%),总糖浓度达到180.4~183.16 g/L,总糖回收率达到79.06%~81.83%;乙酸和色度物质是糖化过程中形成的主要副产物,常见发酵抑制物糠醛和羟甲基糠醛低于抑制发酵临界浓度.糖化液中色度物质可被活性炭吸附有效脱除,脱色糖化液利用筛选的国产市售强基阴离子交换树脂Monojet S4850进行酸糖分离,糖和硫酸之间的分离度约0.59,显示其较好地分离糖化液中的硫酸和糖的潜力.研究结果将为开发面向工业应用的浓硫酸糖化工艺生产可发酵糖提供数据和技术支撑.

Fermentable sugar production is the bottleneck that restricts the economical production of fuel ethanol from lignocellulosic biomass.The production of fermentable sugars based on concentrated sulfuric acid saccharification has the advantages of high sugar recovery efficiency and no cellulase input;In this study,the optimization conditions for the production of fermentable sugars from corn straw by concentrated sulfuric acid saccharification process were explored,and the potential of commercially available resins for acid/sugar separation was evaluated.For concentrated sulfuric acid saccharification,the effects of key operating parameters such as acid/feedstock ratio(A/F ratio),hydrolysis temperature and straw moisture content on saccharification efficiency were investigated by using a two-step solubilization and hydrolysis process,and the optimized conditions(A/F ratio 1.25,hydrolysis temperature 80°C,moisture content 5%~10%)were achieved,in which the total sugar concentration reached 180.4~183.16 g/L,and the sugar recovery efficiency reached 79.06%~81.83%;acetic acid and colored substances were the main by-products formed during the saccharification process,and the common fermentation inhibitors furfural and 5-HMF were below the critical concentration of fermentation inhibition.The colored substances in the saccharified liquid can be effectively removed by activated carbon adsorption and the decolored saccharified liquid was subjected to acid/sugar separation by using the commercially available strong anion exchange resin Monojet S4850 and its utilization potential was evaluated;The separation degree between sugar and sulfuric acid was about 0.59,indicating good separation capacity of sulfuric acid and sugar in the saccharified liquid.These results provide data and technical support for the development of industrial applications of concentrated sulfuric acid saccharification process to produce fermentable sugars.