粘质沙雷氏菌高产发酵灵菌红素的工艺优化及抗病毒活性

为提高粘质沙雷氏菌S3菌株的灵菌红素产率,本研究对粘质沙雷氏菌S3发酵过程中重要的发酵条件参数和关键组分进行逐项优化,并验证了发酵液灵菌红素提取物对本氏烟草病毒的抑制效果。结果表明,最佳培养基配方为：丙三醇0.5%,蛋白胨1.5%,氯化钠0.5%,氯化钾0.25%;最佳发酵条件为：接种量为10%,装液量为60%~70%,pH恒定为6.0,培养温度为28℃,振摇速度160r/min,发酵周期为60h。在该发酵条件下,既有利于粘质沙雷氏菌菌体生长,又能够使灵菌红素的产量达到最大化。按照该优化条件进行发酵后,其灵菌红素提取物溶液喷施于接种TMV、CMV和PVY的本氏烟,烟叶中TMV、CMV和PVY病毒量分别为空白对照的12.61%、29.41%和17.69%,对病毒的抑制效果优于氨基寡糖素。试验所得的发酵制备条件能够提高灵菌红素产量,提取物具备显著抗病毒特性,具有产业化开发潜力和经济应用价值。     

产毒金葡菌和粘质沙雷氏菌在蘑菇罐头中的生长及产毒、产TECRA阳性物质的规律

本文研究了产毒金葡菌(Staphylococcus aureus)、粘质沙雷氏菌(Serrolia marcescens)的纯培养物,以及pH条件变化时,它们各自与其它细菌共存时,在蘑菇罐头中的生长及产葡萄球菌肠毒素、产TECRA阳性物质的规律。并了解热处理对肠毒素和阳性物质的效应。结果表明,金葡菌和粘质沙雷氏菌均能在蘑菇罐头中生长,并产毒/产阳性物质,但罐头汤汁的pH较有利于后者的生长和产阳性物质。在混合菌相中,金葡菌是虚弱竞争者,生长及产毒均受抑制。粘质沙雷氏菌所产阳性物质与肠毒素一样,具有一定的热抗性。     

Serratia marcescens非特异性核酸内切酶的原核表达及其应用

目的在大肠杆菌中表达Serratia marcescens非特异性核酸内切酶(SMNE),并进行纯化、活性检测及应用。方法合成smne基因,应用PCR技术在基因的5′端引入6个组氨酸标签序列,将其插入分泌表达载体pET-20b(+)中,转化大肠杆菌BL21(DE3)pLysS,IPTG诱导表达。表达产物经镍离子螯合琼脂糖凝胶一步纯化后,检测其活性并计算比活。将纯化的SMNE用于重组腺病毒的制备,对外源性核酸进行降解,并采用Southern blot对外源性DNA残留量进行测定。结果重组表达质粒pET-20b-smne经PCR、双酶切和测序证明构建正确。重组蛋白的表达量为8.0 mg/L,纯化后纯度达95%,比活达1.1×106 U/mg。在重组腺病毒制备过程中使用后,成品中的外源性DNA残留量≤10 ng/5.0×1011 VP。结论已成功地在大肠杆菌中表达了SMNE,纯化的SMNE活性高,有望应用于重组生物制品制备过程中外源性核酸的去除。     

一株从腐烂蓝藻中分离的细菌的鉴定及其发酵产蛋白酶研究

应用形态学、生理生化和16S rRNA基因序列分析方法,鉴定了从腐烂蓝藻中分离得到的一株细菌,利用液态发酵法探讨了碳、氮源等对其发酵产蛋白酶的影响并研究了其部分酶学性质.结果表明,该菌可归入沙雷氏菌属,定名为Serratia marcescens SYBC YH,其最适碳源为果糖、葡萄糖、羽毛粉或玉米粉,最适氮源为玉米浆粉、酵母膏和牛肉膏;该菌还可以蓝藻为唯一氮源发酵产耐有机溶剂蛋白酶.该酶的最适温度为40℃,最适pH为7.0.     

饮用天然矿泉水中疑似粪链球菌的鉴定与分析

目的 检测某品牌饮用天然矿泉水样品中是否含有粪链球菌,并对出现的疑似菌落进行分析。方法 按照GB 8538-2016《食品安全国家标准 饮用天然矿泉水检验方法》中规定的检测方法对样品进行检测,对疑似菌落进行确证性试验,并通过VITEK 2 COMPACT全自动微生物鉴定系统对疑似菌进行鉴定。结果 滤膜上出现典型红色菌落,经确证性试验确认为非粪链球菌;经VITEK 2 COMPACT鉴定,该菌为粘质沙雷氏菌。结论 样品中的疑似菌落非粪链球菌而是粘质沙雷菌,该菌作为干扰菌对滤膜法检测粪链球菌具有参考意义。     

Degradation of phenolic compounds with hydrogen peroxide catalyzed by enzyme from Serratia marcescens AB 90027

In this paper, the degradation of phenolic compounds using hydrogen peroxide as oxidizer and the enzyme extract from Serratia marcescens AB 90027 as catalyst was reported. With such an enzyme/H2O2 combination treatment, a high chemical oxygen demand (COD) removal efficiency was achieved, e.g., degradation of hydroquinone exceeded 96%. From UV-visible and IR spectra, the degradation mechanisms were judged as a process of phenyl ring cleavage. HPLC analysis shows that in the degradation p-benzoquinone, maleic acid and oxalic acid were formed as intermediates and that they were ultimately converted to CO2 and H2O. With the enzyme/H2O2 treatment, vanillin, hydroquinone, catechol, o-aminophenol, p-aminophenol, phloroglucinol and p-hydroxybenzaldehyde were readily degraded, whereas the degradation of phenol, salicylic acid, resorcinol, p-cholorophenol and p-nitrophenol were limited. Their degradability was closely related to the properties and positions of their side chain groups. Electron-donating groups, such as -OH, -NH2 and -OCH3 enhanced the degradation, whereas electron-withdrawing groups, such as -NO2, -Cl and -COOH, had a negative effect on the degradation of these compounds in the presence of enzyme/H2O2. Compounds with -OH at ortho and para positions were more readily degraded than those with -OH at meta positions.     

Production of chitinolytic enzymes by Serratia marcescens QMB1466 using various chitinous substrates

The chitinolytic activity of submerged cultures of Serratia marcescens QMB1466 in media containing four forms of chitin as the main substrate was investigated via a full factorial design experiment with pH, temperature and substrate concentration as the main parameters. At the optimum conditions (pH 7.0, 32.5 °C and 1.0% (w/v) substrate), bioprocessed chitin (BP), isolated by lactic acid fermentation of prawn shell (Nephrops sp), induced a higher level of enzyme activity than untreated prawn shell and colloidal chitin but not that of a chemically isolated chitin (CP). The optimal conditions of pH and temperature were then applied in a bench‐top bioreactor and the chitinolytic activity monitored temporally under the influence of higher concentrations of BP and CP. Increasing the concentration of substrate in the bioreactor (>1.0% w/v) was found to inhibit the enzyme activity of the bacteria. The enzyme mixtures in selected 120‐h culture supernatants were separated by sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE) and the main proteins characterised by molecular weight. The electrophoretic patterns obtained from cultures from different experiments and by the different chitin substrates showed marked similarity and the main proteins isolated were largely homologous to well‐documented chitinases found in the literature. BP chitin was found to be an efficient elicitor of chitinolytic activity from this bacterium and hence is a suitable substrate to employ in an integrated biotechnological process, whereby several commercially applicable products can be obtained from a waste product of the fishing industry. Copyright © 2004 Society of Chemical Industry     

粘质沙雷氏菌测量方法研究

粘质沙雷氏菌是生物防护评价的指示菌。对粘质沙雷氏菌营养琼脂平板涂布法进行了方法验证和协同实验验证以及不确定度分析。结果显示,该方法重复性和复现性均较好,室内重复性相对标准偏差为8.93%,室间相对标准偏差为14.95%。经统计分析,营养琼脂平板涂布法相对扩展不确定度为12.60%（k=2）,适用于粘质沙雷氏菌定量测量。     

粘质沙雷氏菌代谢产物灵菌红素的鉴定

从柠檬酸厂糖化车间酸性土壤中筛选得到一株产红色素的粘质沙雷氏菌（Serratia marcescens）ZSG,菌株发酵液经酸性甲醇萃取、浓缩、硅胶柱层析、薄层色谱和柱色谱等分离纯化后,得到灵菌红素纯品,并采用紫外可见吸收光谱、红外光谱、液质联用分析对其结构进行了表征。