近年来,我国不断提高对食品药品安全的重视程度,食品药品安全形势发展总体向好,但食品药品安全领域存在的问题仍不容忽视,各种食品药品安全问题对消费者的健康和生命安全构成了极大威胁.食品药品检测是保证食药安全的一种重要手段,近年来食品药品检测工作不断复杂化,这无疑加大了食品药品检测实验室管理的难度,传统管理模式已经过时.对此,需要引入更为先进、适用的管理手段,以提升食品药品检测实验室的管理水平,进而确保食品药品检测数据及结果的准确性、可靠性,进一步保障食品药品质量安全.

研究旨在改造株链球菌来源的α-半乳糖苷酶基因Gal27A,获得耐热性高的突变体.在常规PCR体系中加入不同水平的MnCl2,将基因克隆至载体pGAPZαA并成功构建表达酶产物的重组质粒pGAPZαA-Gal27A.将线性化的重组质粒电转至毕赤酵母GS115,在含有100 g/L博来霉素的YPDS平板上筛选耐热性提高的突变体,通过pNPG的方法测定重组酶的酶学性质为最适温度65℃,最适pH值6.5,Ag2+、Hg2+对重组酶的酶学活性具有明显的抑制作用,Cu2+对重组酶的酶活性具有促进作用.研究表明,试验成功构建耐热α-半乳糖苷酶高效表达菌株29和54,在55℃保温10 min与同等条件下的野生型进行对比,加热前后的保留酶活比的增幅大于45%.

畜禽除臭方法有多种,植物提取物作为添加剂应用是一种环保、经济、高效的畜禽除臭方法,其在畜牧业生产中较微生物菌剂等其他除臭方法应用少且除臭作用机理有待进一步深入研究.基于此,本文对植物提取物在畜禽生产中的除臭应用和除臭作用机理进行了系统梳理和分析,希望为畜牧行业相关生产人员和研究人员提供一些参考,助力于畜牧行业健康、持续、和谐发展.

The discharge of wastewater containing hexavalent chromium (Cr(VI)) into the environment is very harmful to living things. Therefore, before effluent that contains Cr(VI) can be discharged into the environment, this toxin should be removed from the contaminated water. In this study, corn stalk biochar was investigated to evaluate the Cr(VI) removal efficiency from an aqueous solution. The effects of pH (2–10), biochar concentration (0.5 to 10 g/L), Cr(VI) concentration (10–500 mg/L), and contact time (10–1440 min) were studied. The actual experimental value of the Cr(VI) removal efficiency was 28.67%, largely consistent with the predicted model value of 29.31%, under the optimal conditions of a Cr(VI) concentration of 60 g/L, pH 4, contact time of 270 min, and a biochar concentration of 4.5 g/L. A significant interaction between the Cr(VI) concentration and pH was observed, along with significance in the interaction between Cr(VI) concentration and biochar concentration, which had a greater impact on the removal of Cr(VI). Biosorption onto corn stalk biochar is an affordable and economical adsorption process to treat wastewater contaminated with Cr(VI). The aim of this study is to provide data to serve as a basis for future studies on the use of raw agricultural waste to remove Cr(VI).

Some microbial strains are ideal producers of extracellular enzymes that can be used in various industries. However, in many fields, especially in the pharmaceutical field, these enzymes need to be recovered and purified through multistep processes and tedious procedures before they can be used. The recovery process is difficult and increases the cost of enzyme production. Therefore, reducing purification steps will greatly benefit the utilization of microbial enzymes. The 35 M strain of Bacillus amyloliquefaciens, which has high extracellular protease production, was isolated from a phosphate mine. When cultured in a medium with soybean meal as the main component, the maximum activity of extracellular protease reached 16,992 U/mL. SDS-PAGE showed that there were two main proteins in the fermentation supernatant, with a paucity of other defined protein bands. Mass spectrometry and zymogram analysis showed that the two main bands were two proteases, corresponding to alkaline protease (AprM) and neutral protease (NprM), respectively. Gene cloning, sequencing, and further comparisons were used to confirm AprM and NprM correspond to these proteases from B. amyloliquefaciens. Notably, SDS-PAGE and zymogram analysis showed that NprM had obviously higher catalytic efficiency toward casein than did AprM. Strain 35 M is a promising protease producer with great potential for applications in industrial protease production. Additionally, this study demonstrates strain 35 M may be particularly well suited to use in degrading anti-nutritional factors in soybean meal, so as to improve the nutritional value of soybean meal.

3-Methylindole is a major component of organic pollutants in livestock compost, which can contribute to the deterioration of the environment in livestock farms and their surrounding areas. This study demonstrates that using microorganisms to degrade 3-methylindole is an effective method for energy conservation and environmental protection. The microbe capable of efficiently degrading 3-methylindole was isolated and screened from fecal samples. The isolated bacteria were identified as Acinetobacter oleivorans after morphological characterization and 16S rRNA sequencing. This project demonstrated that 3-methylindole was completely degraded under optimal conditions (initial concentration of 3MI: 100 mg/L, 30°C, pH8.0, and shaking at 160 rpm for 48 h). N2-Acetyl-L-ornithine, Phenylacetaldehyde, Phenylacetic acid, Indole-3-carboxylic acid, and Indole-3-carboxaldehyde were the primary metabolites of this degradation process. This study provides a theoretical foundation for other microbe-mediated environmental remediation approaches as well as a basis for future work to apply bacteria that degrade 3-methylindole for the purification of polluted environments. It has a promising application in the control of malodorous gas pollution in the large-scale livestock and poultry breeding industries.

微生物谷氨酰胺转氨酶(MTGase)是一种通过异肽键来催化蛋白质或多肽链之间的酰基发生转移反应的重要酶制剂,在食品、生物医药、化妆品、纺织等领域有着广泛的应用前景.该文综述了MTGase的国内外研究现状,MTGase基因、MTGase工程菌株的构建和表达,以及MTGase的分子改造技术研究进展,并对生物工程技术应用于MTGase的产品生产进行了展望,为高效和低成本MT-Gase的产品开发及应用提供新的思路和方法.

试验旨在探讨不同日粮添加组合蛋白酶对育肥猪生长性能、营养物质表观消化率和氮利用率的影响.选取120头体重约60 kg"杜×长×大"三元猪,按照公母各半的原则随机分为3组,每组4个重复,每个重复10头猪.各组猪分别饲喂玉米-豆粕型、玉米-杂粕型和小麦-杂粕型日粮.每组2个重复设为对照,不添加组合蛋白酶;2个重复设为试验,添加0.1％的组合蛋白酶.试验期40 d.结果 显示,与对照猪相比,饲喂添加组合蛋白酶不同日粮的试验猪的末重和平均日增重极显著增加(P＜0.01);平均日采食量增加,料重比降低,但差异不显著(P＞0.05).添加组合蛋白酶日粮的试验猪对干物质、有机物、粗蛋白、粗脂肪和粗纤维的表观消化率极显著提高(P＜0.01),氮摄入量显著提高(P＜0.05),粪便和尿中氮排放量极显著降低(P＜0.01),氮利用量和氮利用率极显著提高(P＜0.01).玉米-豆粕型日粮的试验猪平均日增重显著低于玉米-杂粕型和小麦-杂粕型日粮(P＜0.05).研究表明,饲喂添加组合蛋白酶的不同的日粮可以提高育肥猪的生长性能,提高饲料中的营养物质表观消化率,降低粪尿中氮的排放量.

该研究旨在从非传统环境(磷矿)中分离、筛选高产胞外蛋白酶菌株,对菌株进行形态学观察、生理生化和分子生物学鉴定,并研究其蛋白酶的酶学性质.结果表明,分离筛选到一株蛋白酶高产菌株,编号为PB5,该菌株被鉴定为贝莱斯芽孢杆菌(Bacillus velezensis),该菌株产胞外蛋白酶活力为562.3 U/mL,胞外蛋白酶的最适pH值为10,在pH 7～10有较好的pH稳定性;最适温度为60℃,20～50℃时有较好的稳定性;Na+、Mg2+、Mn2+、K+对蛋白酶活力有明显的促进作用;Fe2+、Ag+、乙二胺四乙酸(EDTA)、苯甲基磺酰氟(PMSF)、十二烷基硫酸钠(SDS)对蛋白酶活力有明显抑制效果.

试验利用高效液相法(HPLC)从发酵制品中筛选高产D-苯乳酸的LB2366,对其进行系统发育分析、菌落形态观察及生理生化试验研究,确定菌株LB2366为短乳杆菌.试验通过正交试验研究菌株LB2366产D-苯乳酸的发酵条件,确定4个因素的主次关系为:葡萄糖浓度＞酵母粉浓度＞苯丙氨酸浓度＞培养时间.最佳反应条件为葡萄糖15 g/L、酵母粉5 g/L、苯丙氨酸浓度20 g/L、培养时间72 h.经过发酵培养,得到最高D-苯乳酸产量为194.27mg/L.研究表明,优化后的D-苯乳酸产量比优化前的76.16mg/L提高1.55倍.

从市售豆豉和保藏的固体发酵产纳豆激酶(NK)高活性的菌株中,筛选出5株诱变育种出发菌株.经紫外-亚硝基胍-Co60复合诱变后,获得5株液体发酵产NK高活性的菌株LJJ-1-13-12-4、PXDBJ-13-9-7-18、DNS-17-3-15-7、CBL-2-7-10-6和L-5-8-15,其产NK活性,分别为1846.15、1956.48、2184.32、1865.38和2095.23 U/mL,分别是诱变前出发菌株的1.62、1.81、1.98、1.61和1.62倍.高产纳豆激酶菌株的选育为纳豆激酶液体发酵的进一步工业化奠定了良好的基础.

用实验室复合诱变选育的5株产纳豆激酶正向突变菌株,通过随机组合混菌发酵试验,确定了混菌发酵产NK活性最高的菌株组合为CBL-2-7-10-6、DNS-17-3-15-7和L-5-8-15.随后经过一系列正交试验和单因素试验,确定了这3个突变菌株混合发酵的最佳发酵工艺:发酵培养基中葡萄糖质量分数为4％、大豆蛋白胨4％、MgSO40.04％、CaCl20.06％、K2HPO40.2％、KH2PO40.1％;CBL-2-7-10-6、DNS-17-3-15-7和L-5-8-15这3个突变株接种量分别为670、670和1000μL/100 mL;初始pH 7.0,发酵温度31℃,摇床转速160 r/min,发酵时间50 h.在该条件下,发酵NK酶活性可以达到4952.33 IU/mL,是本研究单菌株发酵最高酶活(DNS-17-3-15-7的NK活性2096.57 IU/mL)的2.36倍.

试验旨在研究乳酸菌发酵液体饲料对仔猪生长性能、粪样菌群和血液生化指标的影响.选用体重相近的150头体重20 kg左右的三元杂交仔猪,对照组(Ⅰ组)饲喂基础日粮,试验组(Ⅱ组)饲喂含抗生素的基础饲料日粮,试验组(Ⅲ组)饲喂乳酸菌液体发酵饲料.结果表明,与对照组相比,饲喂乳酸菌发酵液体饲料仔猪的平均日增重和平均日采食量明显增加(P<0.05),显著降低了仔猪的发病率(P<0.05);鲜粪中大肠杆菌和沙门氏菌的数量显著降低,乳酸菌的数量显著增加(P<0.05);显著提高了血液中总蛋白、白蛋白、免疫球蛋白G、葡萄糖的含量(P<0.05),显著降低了血液中尿素氮的含量(P<0.05).

The purpose of this experiment was to investigate the effects of lactobacillus liquid fermented feed on apparent digestibility of nutrients, fecal microflora, blood biochemical indicators and production performance of fattening pigs. A total of 200 Duroc × Large White × Landrace pigs with average body weight of 60 kg were selected and randomly assigned into 4 groups with 5 replicates of 10 pigs per group. The control group was fed with basic diet, while the experimental group was fed with 10%, 30% or 50% lactobacillus liquid fermented feed replaced by the corresponding proportion of full-price formu?la feed in the basic diet. The results showed that the apparent digestibility of crude protein, crude fiber, crude fat, calcium, total phosphorus and nitrogen was increased significantly (P<0.05), the number of Escherichia coli and Salmonella in fresh manure was decreased significantly, and the number of lactoba?cillus was increased significantly (P<0.05) in the experimental groups. The contents of total protein, al?bumin,immunoglobulin A, immunoglobulin G and glucose in the solution (P<0.05) were also increased and the content of urea nitrogen in the blood was decreased (P<0.05), but there was no significant differ? ence in the contents of total cholesterol, triglycer?ide and immunoglobulin M; the average daily gain and average daily feed intake were increased significantly (P<0.05), and the ratio of feed to meat was also increased significantly (P<0.05). Results from feed-to-meat ratio showed that addi?tion of 10% lactobacillus liquid fermented feed had the best feed reward rate.The disease incidence of fattening pigs was significantly reduced (P<0.05).

利用大肠杆菌(Escherichia coli)表达系统,经异丙基-β-D-硫代半乳糖苷(IPTG)诱导,成功异源表达了一株链球菌(Streptococcus)S1的α-半乳糖苷酶基因,重组α-半乳糖苷酶经镍柱纯化后,测定其酶学性质.重组α-半乳糖苷酶最适pH值为6.5,最适温度为50℃,在碱性环境中(pH 7.5～10.0)及在40℃以下温度条件下该酶较为稳定;酶催化动力学结果显示,该酶在最适条件下水解硝基苯-α-D-半乳糖苷(pNPG)的最大水解速率(Vmax)为508.38μmol/(min·mg),米氏常数(Km)值为1.2 mmol/L;通过薄层层析(TLC)法检测到该重组α-半乳糖苷酶可以高效地水解天然底物蜜二糖、棉籽糖和水苏糖中的α-半乳糖苷键.

试验选择断奶分窝的新西兰肉兔幼兔1 000只,随机分为对照组和试验组各500只,采用由使君子、常山、仙鹤草、陈皮、白头翁、板蓝根、大青叶、金银花、黄芪、当归和甘草11种中草药组成的复方中药制剂与地克珠利进行对比试验.结果 表明,复方中药制剂可使幼兔平均末重和平均日增重分别增加8.05％、9.94％(P＜0.05);日均耗料量和料重比分别降低0.75％、10.52％(P＞0.05);幼兔干物质、总能、粗蛋白质的表观消化率分别提高5.73％、5.00％、6.71％(P＜0.05),粗纤维的表观消化率提高5.75％(P＞0.05);幼兔血清中球蛋白、免疫球蛋白G分别提高19.53％、44.71％(P＜0.05),免疫球蛋白A、免疫球蛋白M分别提高22.03％、17.78％(P＞0.05);幼兔球虫发病率降低70.79％(P＜0.05),死亡数降低72.73％(P＜0.05),成活率提高8.99％(P＜0.05).

纳豆红曲胶囊是以保健红曲和纳豆冻干粉为原料制成的保健食品,不仅含有红曲的活性物质,如红曲色素、Monacolin K、麦角甾醇、γ-氨基丁酸等,还含有纳豆的活性成分如纳豆激酶、纳豆菌、维生素K2、异黄酮等,因此纳豆红曲胶囊具有传统红曲和纳豆的双重保健功效,具有降血脂、溶栓、抗心脑血管疾病、抗菌、抗癌等功能.本文对红曲和纳豆的主要活性成分及其保健功效作了简单的介绍,并对其发展前景进行了展望.

为了优化绣球菌液体菌种制备和栽培方法,对绣球菌液体菌种的发酵培养基pH和发酵时间进行了优化,并比较了不同接种量对发酵时间的影响.结果表明:绣球菌液体菌种发酵培养基的最佳pH为3.5,发酵13 d时生物量达到最大值,最佳接种比例为30 mL菌液/550 g固体栽培湿料,液体菌种接种至栽培袋4个月后每袋可收获鲜重100 g左右的绣球菌子实体.

To further ameliorate the cultivation characteristics and improve the yield of Sparassis crispa,the condition for preparation and regeneration of protoplasts from Sparassis crispa were preliminary studied.Factors including isotonic solutions,enzyme temperature,pH,enzymolysis time were optimized based on the regeneration amount.Results showed that 2％ lysozyme was used to dissolve the mycelium cell wall of mycelium of S.crispa,and the optimal condition for preparing protoplasts were 0.6 M sucrose as isotonic solution,30 ℃,pH 6.0,3 h.Under this condition,the regeneration amount was 11 850 per mL.

Vectors pGAPZαA and pPICZαA were utilized to construct the multi-copies expression plasmid that can be linearized to maintain the transformation rate at a high level and have a higher yield of interesting protein than the single-copy plasmid.The gene of the interesting protein was originally constructed in the constitutiveexpression vector pGAPZαA,then the expression cassette is digested out with the isocaudamers Bgl Ⅱ and BamH Ⅰ and constructed in the methanol inducible expression vector pPICZαA at BamH Ⅰ site.The multi-copies expression plasmid was constructed after several times repeating.The LZ8 which is a fungal immunomodulatory protein from Lingzhi is used as an example.Its multi-copies expression plasmid pPICZαA-[GAPZαA-LZ8] 4 is constructed after repeating 4 times.Then the plasmid is linearized at the unique Sac Ⅰ site of pPICZαA and transformed in GS115.The yield of LZ8 expressed in the clones is transformed with pPICZαA-[GAPZαA-LZ8]4 reaches 2 or 3 times of that in the clones which is transformed with pGAPZαA-LZ8.We find the linearizable multi-copies expression plasmid bases on combination utilization of pGAPZαA and pPICZαA can express the interesting protein in GS115 at a higher level than the single-copy plasmid.