一株产抗菌脂肽芽孢杆菌筛选鉴定、产酶特性及其脂肽初步鉴定

为筛选可用于动物生产的优良枯草芽孢杆菌,试验通过抑菌性能筛选,从200余株分离自土壤、枯叶等材料的芽孢杆菌中筛选得到菌种S21,经分子生物学鉴定菌种S21为枯草芽孢杆菌(Bacillus subtilis);通过产酶定性分析,枯草芽孢杆菌S21产蛋白酶、脂肪酶、淀粉酶和纤维素酶;采用酸沉、醇提和半制备色谱对S21产抗菌脂肽纯化,利用ESI-TOF-MS对纯化出的抗菌脂肽进行鉴定,鉴定抗菌脂肽为surfactin家族抗菌脂肽;抑菌试验分析显示枯草芽孢杆菌S21产抗菌脂肽对革兰氏阳性、革兰氏阴性和霉菌都有抑制效果,热耐受性和酸碱耐受性好。综上所述,枯草芽孢杆菌S21有用于动物生产的潜力。

激光参数对果胶酶产生菌变株产酶特性的影响

采用Ｋｒ＋、Ａｒ＋、Ｈｅ—Ｎｅ、ＬＤ、ＹＡＧ倍频等多种激光辐照果胶酶产生菌—黑曲霉。在同一波长、同一照射剂量下，不同辐照功率与时间的组合将产生变株产酶特性的不同变化，实验中存在着一个最佳辐照时间与功率的组合。在同一照射剂量、同一辐照功率与时间组合的条件下，变株果胶酶活变异率随波长变化基本呈线性关系。紫外光、可见光产生的酶活正变率与最大增幅高于红外光。激光的连续或不同调制频率的输出方式可能影响黑曲霉变株的产酶特性。

加州鲈肠道芽孢杆菌的筛选及其功能研究

为筛选对加州鲈(Micropterus salmoides)有益生效果的芽孢杆菌,从加州鲈肠道分离芽孢杆菌,检测其溶血性、产酶能力、生物被膜形成能力、对多种常见抗生素的敏感性、耐受人工胃肠液及体外拮抗诺卡氏菌的能力等,并将菌株拌料饲喂加州鲈后测定加州鲈体质量增长和炎症因子的表达。结果显示,从鉴定到的94株芽孢杆菌中筛选出无溶血性且产酶能力广的4株枯草芽孢杆菌K-3、K-12、K-13、K-22,4株菌均是强生物被膜形成株,对多种常见抗生素敏感,其中K-3、K-13菌株能在体外拮抗诺卡氏菌。4株菌在人工胃液(pH 4)和人工肠液中2 h的存活率达到80%以上。K-13试验组的体质量增长率显著高于对照组,K-12、K-13试验组肠道蛋白酶、脂肪酶活性显著高于对照组。此外,与对照组相比,K-13试验组头肾、脾、后肠中的促炎因子表达水平下调,抑炎因子表达水平上调,表明K-13菌株具有减轻加州鲈肠道炎症发生的潜力。综合分析,本研究分离筛选的枯草芽孢杆菌K-13株具有安全性高、产酶能力强、拮抗诺卡氏菌、促进加州鲈生长的特性,可作为加州鲈饲料添加的益生菌制剂。

枯草芽孢杆菌的特性及其在养鸡业中的应用研究进展

枯草芽孢杆菌是一种益生菌,具有耐温度变化、快速复活、快速生长和较强分泌酶等特性,文章综述了枯草芽孢杆菌的产酶、调节消化道微生态平衡、增强免疫力的性能及在养鸡产业中的应用。

一株虹鳟源枯草芽孢杆菌的分离鉴定及生物学特性研究

为筛选对虹鳟(Oncorhynchus mykiss)有潜在益生效果的菌株,本研究从健康虹鳟幼鱼肠道中分离到1株潜在益生菌株RT-BS07,采用形态学观察和分子特征分析对该菌株进行了鉴定,并评价了该菌株的抑菌性、耐受性、黏附性和安全性。形态学观察显示,菌株RT-BS07为革兰氏阳性杆菌,有圆形或椭圆形芽孢。16S rRNA比对结果显示,该菌株与枯草芽孢杆菌(Bacillus subtilis)NCBI3610株的同源性为99.86%。结合16S rRNA基因序列分析和形态学观察结果,确定菌株RT-BS07为枯草芽孢杆菌。菌株RT-BS07具备产蛋白酶和纤维素酶能力,其酶活力分别为(0.039±0.002)和(0.393±0.002)U/mg;该菌株可有效抑制温和气单胞菌(Aeromonas sobria)、杀鲑气单胞菌(A.salmonicida)和鲁氏耶尔森氏菌(Yersinia ruckeri)等致病菌。菌株RT-BS07在pH为2~10 LB液体培养基中均可存活;在盐度为2%~8%条件下存活率为5.70%~93.28%,其存活率随盐度升高而降低。体外黏附试验结果表明,菌株RT-BS07可大量黏附在虹鳟前肠黏膜,不破坏肠道组织完整性,对左氟沙星、环丙沙星、氧氟沙星和链霉素等18种抗菌药物敏感。本研究分离筛选得到的枯草芽孢杆菌RT-BS07株具有产消化酶性能,其抗逆性能强,对虹鳟无毒害作用,可作为虹鳟健康养殖及益生菌制剂研发源益生菌候选株。

发酵血粉菌株的优化选育

从霉变猪血中筛选到产蛋白酶菌株 16株 ,研究了各菌株产复合酶的性能 ,并对其进行组合优化 ,从中筛选出一组兼产蛋白酶、淀粉酶、糖化酶、羧甲基纤维素酶、植酸酶及果胶酶的优化菌株 ,初步鉴定并命名为米曲霉 (AspergillusOryzae )AS10 0、AS10 2 ,酿酒酵母 (Sac charomycescerevisiae)Y113 ,芽孢杆菌 (Bacillussp .)Asp0 0 7。经血粉发酵试验 ,发酵产品香味浓郁 ,营养丰富 ,蛋白质含量高达 69% ,且富含游离氨基酸和无机元素 ,证实了该组合菌株是发酵血粉的优化菌种。

复合益生菌发酵液的功能特性及对对虾诱食效果

为探求复合菌发酵液的多种功能,该试验选择具有脱氮、产酶、抑菌等优良性能的酵母菌、乳酸菌及芽孢杆菌各1株,利用已优化的HJ培养基进行共培养,实时监测发酵过程,分时段取样,对复合菌发酵液的脱氮、产酶、抑菌、培藻及诱食等功能进行研究。结果表明,酿酒酵母菌NJ-02、屎肠球菌SC-01及枯草芽孢杆菌M7-1能够在HJ培养基中进行共发酵,连续培养24 h后3株微生物活菌数量分别达到3.88×108、2.41×10^10 、5.38×10^9 CFU/mL。复合菌发酵液的脱氮、培藻性能同复合菌中枯草芽孢杆菌M7-1的活菌数相关较大,发酵至16h其降解亚硝态氮和培藻性能最为理想,亚硝态氮降解率为89%,并使小球藻叶绿素a质量分数提升49.6%。复合菌发酵液具有同枯草芽孢杆菌M7-1相当的产酶(蛋白酶、淀粉酶、纤维素酶)活性及同屎肠球菌SC-01相当的抑菌(副溶血弧菌)活性。复合菌发酵液饲喂对虾,诱食效果明显好于对照组(P<0.05),同化学诱食剂二甲基-β-丙酸噻亭(dimethyl-beta-propiothetin hydrochloride, DMPT)差异不显著,其肠道中乳酸菌、酵母菌数目显著高于对照组及化学诱食剂组(P <0.05)。该研究所制备的脱氮、培藻、抑菌及诱食功能复合菌发酵液,为可持续生态水产养殖提供了新的微生物资源和技术方法。

Effects of Feed-grade Proteinase on the Production Performance of Piglets

In this study, feed-grade proteinase was added into conventional diets of three-line crossbred （Duroc x Landrace x Large White） piglets, to investigate the effects of feed-grade proteinase on anti-diarrhea capacity, daily weight gain, feed intake and feed conversion ratio of piglets. The results showed that adding feed-grade proteinase in diets enhanced anti-diarrhea capacity of piglets and improved signifi- cantly production performance and breeding efficiency of piglets. This study provided the reference for rational utilization of feed-grade proteinase in actual production.

Study on the Correlation between Blood Enzyme Activity and Production Performance in Tibetan Yaks

Yak ( Bos grunniens ) is classified as Bovine genus,they live in Qingzang Plateau with elevation more than 3500m and it's neighbor highland,where the weather is high chilly,short of oxygen and large difference of temperature between day and night.But yak have adapted that circumstance after thousands of years' artificial and natural selection and has great anti adversity capacity.Yak is an important sustenance and means of production to Tibetan.China is a country with the largest number of yak,whose amount of livestock on hand accounts for 95% of the world and Tibet region takes the second place next to Qinghai in the number of yak.Tibetan yak has formed some groups for Tibetan's large area,complicated geological ecosystem conditions,geological isolation.The typical better groups are Yadong yak,Jiali yak and Sibu yak. Study about yak fell behind other animals due to the restriction of inconvenient transportation,difficult sampling and poor experimental technology.Study about the relationship between yak blood enzyme activities and milk production was little,only Jing (1992) studied correlation of milk production with serum amylase,esterase in Gansu Jiulong yak,Maiwa yak and no report was found in other groups.This study discussed six Jiali yak blood enzyme activities lactate dehydrogenase (LDH),alkaline phosphatases (AKP),acid phosphatase (ACP),catalase (CAT),amylase (Amy) and superoxide dismutase (SOD),and explored their relationship with milk production in Jiali yak,so as to supply with theoretical evidence by using blood enzyme activity as biochemical assisted selection marker in the breeding of Tibetan yak milk yield. This experiment investigated activity of six blood enzymes from 28 Tibetan yaks and explored its relationship to production performance.The results showed a extremely positive significant difference ( P <0.01) between activity of LDH and milk yield,CAT activity and length of belly hair respectively,while a positive significant difference ( P <0.05) was observed between AKP activity and body weight,Amy activity and body weight and a negative significant difference ( P <0.05) for SOD activity and body weight.Stepwise Regression Analysis showed that activity of LDH could be used for the prediction of milk yield,AKP,CAT,Amy for body weight,CAT,Amy for length of belly hair.So it is expected to use activity of LDH,AKP,CAT,Amy as biochemical genetic marker in the selection of milk yield,body weight and length of belly hair.