Hydrolysis Of Abandoned Cellulosic Materials

The main purpose of this paper is about the utilization of renewable materials, which includes waste cotton from textile factory, corncob and corn stalk. Hydrolysis of abandoned cellulose was studied. Three techniques were used, concentrated sulfuric acid hydrolysis, dilute sulfuric 'acid hydrolysis and enzymatic hydrolysis. Lactic acid fermentation of hydrolyzate of cellulosic materials had also been studied.At first, the concentrated sulfuric acid hydrolysis was studied. The influential factors, the concentration of sulfuric acid, hydrolyzing temperature, the granularity of corn stalk, solid content, were investigated. From the experimental result, concentration of sulfuric acid and hydrolyzing temperature were the main factors among them. As for corn stalk, the hydrolysis rate was accelerated as hydrolyzing temperature and the concentration of sulfuric acid rising. But when hydrolyzing temperature was higher than 60 癈 and the concentration was larger than 70%, the rate of hydrolysis dropped. According to the mechanism of the concentrated sulfuric acid hydrolysis, the kinetic equation of hydrolysis had been deduced, the calculation value was coincide well with experimental result.The hydrolysis of concentrated sulfuric acid can be carried out at low temperature, atmospheric pressure, and the reducing sugar concentration is large. However, it needs a large quantity of sulfuric acid to hydrolysis, and difficult to reuse the waste sulfuric acid, so it may pollute the environment. In order to overcome the shortcoming, dilute sulfuric acid hydrolysis had been studied.The dilute sulfuric acid (05%-3%) hydrolysis was carried out at atmospheric pressure, and the influential factors are the same as mentionedabove. According to the results, the hydrolysis rate was accelerated as hydrolyzing temperature and the concentration of sulfuric acid rising. When hydrolysis concentration reached to 1%, both hydrolysis rate and reducing sugar concentration were high. While hydrolysis concentration was lager than 2%, reducing sugar concentration began dropping. Hydrolyzing waste cotton and corncob on the same condition. It was found that the hydrolysis rate of corn core was the highest, while the hydrolysis rate of waste cotton was the lowest. Through research, the most suitable hydrolyzing conditions were found.Dilute sulfuric acid hydrolysis needs high temperature, and obtains lowreducing sugar concentration, which will be difficult to ferment. So enzymatic hydrolysis was studied next.Most enzymatic hydrolysis researches using Trichoderma reesi and Trichoderma viride, these cellulases are researching in laboratory. In this experiment we use Cellusoft L and Suhong Cellish L as hydrolysis enzymes, which were widely used in textile industry. It was the first time that was applied to cellulosic materials enzymatic hydrolysis. The results of enzymatic hydrolysis were very good: high hydrolysis rate (almost reached to balance within twenty-four hours). The cellulases we used can adapt to industrialization producing, when enzymatic hydrolysis conditions becomes maturity, it can be put into producing immediately, so it will save the capital and time of research on cellulose enzyme.The main influential factors of enzymatic hydrolysis were temperature, pH, microelement and solid content. In consideration of the factors, we designed four factors and three levels orthogonal experiment. The impacts of time and different materials on enzymatic hydrolysis were also studied. The notable effects are temperature and pH. Hydrolyzing waste cotton and corncob were on the same condition. The hydrolysis rate of corncob was the highest. The advantages of enzymatic hydrolysis are large sugar concentration, highquality of sugar, and moderate reaction conditions.At last, lactic acid fermentation of hydrolyzate of cellulosic materials by Rhizopus oryzae had been studied briefly.YangXiaohan(Environment Engineering) Supervised by: Prof. Zhou Meihua...