Pretreatment of Wastepaper using Aqueous Glycerol to enhance Enzymatic Hydrolysis

Abstract

Pretreatment of wastepaper using aqueous glycerol was investigated to enhance the enzymatic hydrolysis. The effects of four factors (solid/liquid ratio, glycerol concentration, acid concentration, and reaction time) on the dissolution yield, the removal of cellulose, hemicellulose and lignin, and the enzymatic digestibility were examined at 150 o C. The 1/8 of solid/liquid was determined to perform the reaction uniformly, and the 93% of glycerol concentration was found to be a minimum concentration to conduct the reaction under atmospheric pressure. Also, it was found that the acid concentration and reaction time were strongly related to the dissolution yield and the removal of cellulose, hemicellulose and lignin, but moderately to the enzymatic digestibility. At an optimum condition of 150 o C, 1 h and 1% acid concentration, 56% and 49% of hemicellulose and lignin, respectively, were removed, while only 4% of cellulose was removed. The enzymatic digestibility at this condition was 86%, meaning that 83% of the glucan present in the initial substrate was converted to glucose. Compared to glycerol with ethylene glycol as a pretreatment solvent, glycerol is much cheaper than ethylene glycol, but ethylene glycol is superior to glycerol in delignification.

Pretreatment of Wastepaper using Aqueous Glycerol under High Pressure to Enhance Enzymatic Hydrolysis

“…메탄 올과 에탄올 같은 저비점 용매는 휘발성과 가연성이 높기 때 문에 폭발 위험이 있어 실제 공정에서는 사용하기 어렵다 [4]. 그래서 ethylene glycol과 glycerol 같은 고비점 유기용매 가 고려되는데 가장 큰 장점은 비점이 높아 고압장치 없이 대기압에서 전처리 반응이 가능하다는 점이나, 단점은 용매 비용이 상대적으로 비싸고 사용 후 용매를 회수할 경우 높은 비점으로 인해 에너지 비용이 많이 소요된다는 점이다 [5][6][7][8].…”