The Biological Pretreatment Of Brittle Rice Straw And Its Fermentation

With the exhaustion of oil resources, people spontaneously focus on alternative biofuel. Bioconversion of lignocellulosics to produce fuel-grade ethanol presents an attractive opportunity for the production of renewable, environmentally friendly biofuels. In this paper, a new type of brittle rice straw as the research object, biological pretreatment of rice straw degradation of fragile by white rot fungi, and the simultaneous saccharification and fermentation was done. The main results are as follows:1. Composition analysis by comparison with the traditional straw, brittle straw hemicellulose content is increased, cellulose content is decreased and lignin content is increased; By tensile testing showed that the stem part of the brittle straw pull smaller compared with the traditional straw, the part of the average tension was 39.42%of traditional straw, stretching the length was less than the traditional straw, the average was 56%of the traditional straw. From the crushing consumption experiment, the brittle straw was less energy waste. Microexamination observed:brittle straw rice crispy bar thin thick cell wall, cell lumen and lignin content increased slightly.2. The brittle rice straw and traditional rice straw was used as materials for screen 15 strains of white rot fungi on the degradation of rice straw. Pleurotus cornucopiae 6 on the growth rate in the fastest lap reached 90 mm (7D). The growth rate of Ganoderma Iucidum, Lentinus edodes, Pleurotus eryngii were slower; and the pretreatment experiments showed:Pleurotus cornucopiae 6 treatment of brittle rice straw and traditional rice straw lignin degradation ordinary high loss of cellulose and hemicellulose less. Lentinus edodes had no degradation of lignin virtually. Pleurotus ostreatus 115, Pleurotus ostreatus dongbai 1 and Pleurotus ostreatus huibai 1 showed apparently ability to depredate lignin, but cellulose and hemicellulose loss rate was also higher.3. Though the pretreatment processing, the composition of brittle straw and traditional straw were changed after 60 days in treatment. Traditional straw weight loss: 22.06±0.1%, lignin degradation was 28.92±1.8%, cellulose was 6.76±1.4%, hemicellulose:35.58±2.8%; Brittle straw were:27.28±2.1%,33.54±1.9%,5.71±2.5%,47.88±2.0%, respectively. The hydrolysis rate of the pretreated brittle straw and traditional straw were 2.82 times and 3.17 times increase. Brittle straw and the traditional increase in the initial adsorption rate of 5.55 times and 1.02 times. SEM also found: mycelium changed with processing time of traditional cellulose materials.4. Use of pretreatment materials to optimize SSF conditions, and found:5%of inoculum, fermentation temperature 40℃, cellulase dosage of 20 FPU/g, fermentation 48h were the best conditions. The yield of ethanol increased 1.51 times, while the traditional rice straw yield increased 0.81 times. Compared with microcrystalline cellulose fermentation, the ethanol production were 33.85%and 21.43%, respectively, which was produced by pretreatment of brittle straw and traditional straw.