【作者】 强郁荣；

【导师】 来航线；

【作者基本信息】 西北农林科技大学 ， 植物营养， 2006， 硕士

【摘要】 本研究以黄河中上游半干旱区典型盐渍土这种特殊生态环境中分离出的细菌和放线菌为供试菌株,采用平板筛选法对细菌产淀粉酶、脂肪酶、蛋白酶、纤维素酶的能力进行初步研究;采用经典分类方法对供试放线菌进行了初步的分类鉴定,获得供试放线菌的类群组成,并以作物栽培和动物养殖中危害较大的几种病原菌为靶标菌,采用固体和液体两种筛选方法,对放线菌拮抗性进行研究,从中筛选出对病原菌有较好拮抗作用或优良的抑菌物质产生菌;对筛选出的3株优良拮抗放线菌进行分类鉴定;通过生物试验筛选出一株优良的拮抗菌株,并对其产生抑菌活性物质的最佳培养基和培养条件进行了研究。得到如下结论:1.供试放线菌中以链霉菌属为主占到90.73%。链霉菌属中以球孢类群,粉红孢类群,灰褐类群,黄色类群为主,占到放线菌总数的55.62%。2.供试的706株放线菌中有拮抗活性的占到76.44%,但广谱性拮抗菌较少;拮抗性放线菌以粉红孢类群、灰褐类群和球孢类群为优势类群。对动物病原菌拮抗能力普遍比对植物病原菌强;通过初筛和复筛试验得到3株优良的广谱拮抗放线菌02D01、43A04和13H06。3.供试细菌能产生纤维素酶和蛋白酶的菌株都达到50%以上,且产酶能力较强的菌株所占比例也较大;而淀粉酶和脂肪酶的产生能力较弱,其中脂肪酶的产生能力最弱。产酶能力较好的菌株均为革兰氏阳性菌。4.通过经典的形态、培养特征观察,生理生化、生态条件试验以及胞壁组分、分子生物学鉴定,最后确定菌株02D01、13H06和43A04为链霉菌（Streptomyces）。其中02D01和43A04是同一种,为戈壁三素链霉菌（Streptomyces gobitricini）;菌株13H06与Streptomyces sparsus亲缘关系最近,序列相似数为99.69%。5.通过生物试验确定出一株发酵液对于引发鱼细菌性肠炎的肠型点状气单胞菌有良好抑制作用的菌株02D01。用药量在2mg/kg?d就能达到很好的治疗效果,其发酵液对生物无急性毒性,具有较好的温度和酸稳定性。6.液体发酵培养时,02D01菌株在种龄为48h,发酵时间120h发酵液的抑菌活性为最大。通过二次正交旋转组合设计试验,获得产生抑菌活性物质的最佳培养基配方为,可溶性淀粉2%,鱼粉2%,NaCl 2%, K₂HPO₄ 0.05%,MgSO₄·7H₂O 0.05%,CaCO₃ 0.1%。均匀设计对发酵工艺进行优化,结果显示,02D01菌株接种在优化的培养基中,接种量5%,25℃,装液量50mL/250mL,初始pH 9时发酵液效价可达到34197.94μg/mL,比更多还原

【Abstract】 Ability of bacteria produce enzyme was measured and actinomycetes with high antagonism activity or high bacteriostatics productivity were screened, identified and classified. Biologic test was used on the selected actinomycetes to determine the optimum substrate and its optimum fermentation technology. The obtained result was listed following:1 All actinomycetes of typical saline soil in middle-up Yellow River semi-arid area belong to streptomyces, with 9.27% of it except. And 55.62% of the actinomycetes belongs to Globosporus Roseosporus, Griseofuscus and Aureus.2. In all 706 individual actinomycetes, 76.44% of the test strains had antagonistic activity, but few broadspectrum. Dominant group of the antagonistic are Roseosporus, Globosporus, Griseofuscus . These strains had stronger antagonistic ability to animal pathogenic microbe compare to plant pathogenic microbe. Via two times screen, get three eximious board range antagonistic actinomycetes 02D01、43A04 and 13H06.3 Bacteria of typical saline soil in middle-up Yellow River semi-arid area has high capacity of cellulose and protease, productivity of amylase and lipase by the bacteria is lower than cellulose, which is the highest, and productivity of lipase by the bacteria is the lowest. Bacteria with better enzyme productivity belongs to Gram-positive bacteria.4. Use classic classify method combine cell wall compose analyze and molecule biology method ensure these 3 strains are belong to Streptomyces. 02D01、13H06 are Streptomyces gobitricini, 13H06 is most alike Streptomyces sparsus.5. Screen one strain that had outstanding effect to bacterial enteritis, 2mg/kg·d dose can play good curative effect, fermenting liquor had no toxicity, stabilization to temperature and can store under acidic condition.6. Cultivation condition test showed that when the cell age reach 48h and fermentation time reach 120h, bacteriostasis activity of 02D01 reaches the maximum. The optimum更多还原