【作者】 石伟；

【导师】 陈五岭；

【作者基本信息】 西北大学 ， 应用微生物学， 2008， 硕士

【摘要】 纤维素是地球上最廉价、最丰富的可再生资源,全世界每年的纤维素及半纤维素的生成量为850亿吨,由于纤维素具有水不溶性的高结晶结构,再把它水解成可利用的葡萄糖相当困难。利用微生物产生的纤维素酶来分解和转化纤维素则是其利用的有效途径。目前人们对纤维素酶的研究多集中于霉菌,但霉菌多为好氧性微生物,而青贮饲料发酵是在少氧或缺氧环境中进行的,故筛选产纤维素酶活高的厌氧及兼性厌氧细菌更具有应用上的现实意义。本研究从自然界野牦牛粪中分离出三株高产纤维素酶细菌菌株YMN8、YMN30、YMN41,经鉴定结果三株菌为芽孢杆菌属细菌,YMN8为短小芽孢杆菌(Bacillus pumilus)、YMN30为多粘芽孢杆菌(Bacillus polymyxa)、YMN41为凝结芽孢杆菌(Bacillus coagulans)。DNS法测纤维素酶活,单一培养后的纤维素酶活分别为3752U/ml、3910U/ml和3975U/ml;经拮抗试验证明这三株细菌菌株间无拮抗作用,组合培养后纤维素酶活有明显提高,最后确定三组合培养其纤维素酶活达到最高为4210U/ml。通过正交试验结果得知,接种量对产酶的影响较大,氮的含量和水的含量影响较小,从而确定了三组合细菌菌剂接种量在0.1%时产纤维素酶活最高。同时,实验确定了将筛选出来的高产纤维素酶细菌与乳酸菌、酵母菌的微生物固体菌剂按1:2:2的混合配比,加入0.5%的尿素,添加到全株玉米青贮原料中,发酵30天后,感官评定为1级优良;与对照组相比,其中干物质(DM)含量提高了11.67%,粗蛋白(CP)含量提高了16.2%,中性洗涤纤维(NDF)和酸性洗涤纤维(ADF)的含量分别降低了16.63%和15.85%,PH为3.54。通过奶牛喂养试验,对30头中国荷斯坦泌乳牛在相同的饲养条件下进行了30天饲养对比试验。与对照组相比试验组平均日产奶量增加了3.85%。此外,试验组所产牛奶的各种乳指标也均有提高,与对照组相比乳脂含量增加2.51%、乳蛋白含量增加6.40%、乳糖含量增加2.93%,同时提高了试验组奶牛的免疫抗疾病能力。更多还原

【Abstract】 Cellulose is the cheapest and the most abundant regeneration resource on the earth.the create capacity of the cellulose and hemicellulose is reach to 85 billion ton. Because of the cellulose has the high crystal structural which have water insolubility, it is very difficult to translate for available Glucose. Using the cellulase which produced by the microbiology to decompound and translate the cellulose is an efficacious way. at present people on the research of cellulase are mostly concentrated on the Mildew, but the most of Mildew is the microbiology which need the oxygen and the silage fermentation is going on the condition of little or no oxygen, so screening the high producing cellulase bacteria which the growing course is not need or little need the oxygen have the big practical significance on the application.The study have screened three bacteria strains YMN8 YMN30 YMN41 from the feces of wild yak on the nature, after the identify the result was that the three stains were belonged to the bacillus bacteria, YMN8 was Bacillus pumilus, YMN30 was Bacillus polymyxa and YMN41 was Bacillus coagulans. Using the way of DNS measure the activity of the cellulase, the single bacteria stain incubate the CMCase activity were reach to 3752U/ml, 3910U/ml and 3975U/ml respectively. The antagonism test proved that between of the bacteria strains hadn’t the antagonism action. Two of the strains mixed could improve the cellulase produce, and the three bacteria stains mixed made the highest cellulase activity amounted to 4210U/ml. The orthogonal experiment showed that the inoculation capacity of the mixed strains was the primary element to affect the cellulase activity, the compound of the nirtrogenous and the water was weaker. So the highest cellulase activity produced with the 0.1 percent inoculated. At the same time, the experiment was made the culture proportion of the screened bacteria stains, lactobacillus culture and microzyme culture 1:2:2, the recruitment of urea was 0.5 percent, add to the whole-corn silage with the processing of the micro-fermentation for 30 days. After the fermentation the sensory of the silage was 1 degree best. Compared with the contrast groups, the dry matter (DM) increased by 11.67 percent, the crude protein (CP) increased by 16.2 percent, the neutral detergent fiber (NDF) and the acid detergent fiber (ADF) decreased by 16.63 percent and 15.85 percent, PH was 3.54.Through the cow feed test with the corn silage, in which the 30 Holstein dairy cattle were conducted with feed comparison trial for 30 days. Compared with the contrast groups, the per day per dairy cow milk production of the test groups increase 3.85 percent, in addition, the every milk containing guideline of test groups were all better than the contrast groups, the milk fat content was increased by 2.51 percent, milk protein was increased by 6.40 percent, lactose was increased by 2.93 percent,at the same time, the test crow’s immunity and the ability of resist to illness would be improved.更多还原