固体发酵染菌的防控

发酵染菌是影响生产的首要因素。发酵过程稍有疏忽,杂菌就会"卷土重来",导致染菌的严重后果,本文从风系统、设备、空间灭菌等三方面着手,简明阐述发酵生产中染菌问题的防控。     

井冈霉素生产工艺优化研究

井冈霉素是一种农用抗生素,自工业化生产30多年来,生产工业条件和技术没有大的改变,笔者总结从事近20年的井冈霉素生产实践工作,提出从菌种选育、发酵培养基、发酵染菌控制等进行工艺优化,为工业生产提供可靠的依据。     

发酵染菌问题的研究

为查找抗生素染菌原因,预防染菌,从染菌的原因分析、处理措施、防止措施及列举案例进行发酵染菌问题的探讨。结果表明,在发酵生产过程中须做好培养基、发酵设备、管道与附件的灭菌及空气除菌,严格控制生产操作的各个环节,杜绝杂菌污染。     

伤寒沙门菌中试阶段发酵过程染菌建模预测

目的建立模型预测伤寒沙门菌中试阶段发酵过程染菌情况。方法通过对伤寒沙门菌中试阶段36批次发酵数据进行分析,选取特征和目标变量,利用GBDT(Gradient Boosting Decision Tree,GBDT)+LR(Logistic Regression,LR)混合机器学习算法建立染菌预测模型,并对所建立模型进行预测评估。结果选取特征为:培养基A600值,0、2、3、4 h发酵液A600值,2、3、4 h每升发酵液的累计葡萄糖消耗量,共8个特征;以发酵4 h是否染菌作为目标变量;建立染菌预测模型。利用预测样本对所建立染菌预测模型进行预测评估,其auc值为0. 83。结论利用所建立的伤寒沙门菌中试阶段发酵过程染菌预测模型可对发酵过程进行染菌预测。     

工业生产螺旋霉素发酵染菌罐批处理工艺

螺旋霉素(SPM)是一种大环内酯类抗生素,在医疗、农业、畜牧业都在广泛使用。SPM的工业化生产工艺已趋成熟,但对于工业生产中的异常罐批的工艺调整鲜见报道,本文介绍发酵过程染菌对抗生素生产的危害,其染菌原因也是多种多样[1]。而本文主要在于查找抗生素染菌原因,同时预防染菌,并从染菌的原因分析,采取有效的处理措施。结果表明,在发酵过程中做好培养基、发酵设备、管道及各个附件的灭菌及空气除菌,严格控制生产操作的各个环节,杜绝杂菌污染。     

提高种子罐灭菌质量的措施

在深层多级发酵过程中,种子罐染菌直接影响发酵生产,通过改进接种形式和操作方式,降低了种子罐染菌率,提高了发酵水平.     

发酵过程中净化压缩空气的设计

从在生物发酵过程中，造成染菌的主要原因是空气系统有菌谈起，阐述从空气净化流程和设备的设计，过滤介质的选用和装填等方面完善空气净化系统，杜绝无菌空气带菌。     

丙酮丁醇发酵的研究进展及其高产策略

从代谢机理的阐明、生产菌种的改良和发酵工艺的改进3个方面综述了丙酮丁醇发酵近年来的研究进展。针对丙酮丁醇发酵工艺中存在的问题,提出高丁醇耐受性菌种的选育、高丁醇比例菌种的选育、发酵细胞的高效利用、发酵与高效低能耗分离工艺的耦合等高产策略。     

玻璃钢制品在发酵行业中的应用

本文介绍了发酵行业对设备耐腐蚀，防染菌和强度等方面的要求，以及玻璃钢的诸多优点，论述了发酵行业用玻璃钢赃民制作 应注意的事项，并展望了玻璃钢在发酵行业的应用前景。     

-乳酸的研究

从所选取的产l-乳酸的4株菌中筛选出一株性能优良、糖利用率和乳酸产量较高的菌种作为试验用菌种。对影响乳酸菌发酵大豆秸秆酶解物制备l-乳酸的因素进行了研究,影响大豆秸秆酶解液发酵的主要因素是菌种类型、底物糖浓度、接种量、温度及pH值。结果表明:干酪乳酸菌是较适宜的发酵菌种,较适宜的发酵条件为:发酵温度30℃,接种量10%,pH值5.5。随着底物糖含量的增加,乳酸产率相应增大,在实验范围内,乳酸菌发酵所产乳酸的产率达到80%。     

肺炎链球菌dnaJ基因缺陷对小鼠肺炎感染模型天然免疫应答的影响

目的探讨肺炎链球菌(Streptococcus pneumonia,S.pn)dnaJ基因缺陷对肺炎感染模型小鼠天然免疫应答的影响。方法将BALB/c小鼠随机分为空白对照组、D39感染组和△dnaJ感染组,分别经鼻腔滴注30μl无菌PBS、30μl含2×107cfu的S.pn D39和△dnaJ(dnaJ基因缺陷株)菌液,复制小鼠肺炎感染模型。于感染后6、12、24、36和48 h处死小鼠,取肺组织,匀浆后分离上清,ELISA检测促炎因子TNF-α、IL-1β、IL-6和IFNγ的表达水平,HE染色观察感染12 h的小鼠肺组织炎症反应变化;将小鼠巨噬细胞株RAW264.7体外感染S.pn D39和△dnaJ,细菌与细胞的比例为100∶1,感染1、2、3 h后分离细胞培养上清液,ELISA检测TNF-α和IL-6的表达水平。实时定量PCR和Western blot分别检测感染12 h的小鼠肺组织中模式识别受体TLRs基因mRNA的转录水平和炎症相关信号p38MAPK的磷酸化水平。结果与D39感染组相比,△dnaJ感染组小鼠肺组织炎症反应强度下降,TNF-α、IL-6和IL-1β等促炎因子水平达峰时间延迟,且峰值降低,RAW264.7细胞感染3 h分泌TNF-α和IL-6显著减少(P<0.01或P<0.05);小鼠肺组织Tlr2和Tlr13基因mRNA转录水平显著降低(P<0.05),p38MAPK的磷酸化水平也明显下降。结论肺炎链球菌dnaJ基因缺陷可下调肺炎感染模型小鼠的炎症反应、促炎因子分泌及胞内信号分子的激活,也可影响小鼠感染后肺组织中Trl2和Tlr13基因mRNA的表达,为进一步研究机体对肺炎链球菌DnaJ蛋白的天然免疫应答分子机制奠定了基础。     

新城疫病毒致Hep-2肿瘤细胞死亡方式的研究

目的研究新城疫病毒弱毒株致Hep-2肿瘤细胞死亡方式及其作用机制。方法应用AO/EB染色、电子显微镜观察、DCFA染色测定细胞内活性氧水平及罗丹明123染色法测定细胞线粒体膜电位等方法分析新城疫病毒弱毒株致Hep-2肿瘤细胞的死亡方式及途径。结果新城疫病毒弱毒株感染能够导致Hep-2肿瘤细胞浓缩,被AO/EB浓染,细胞核缩小,染色质边集。FACS细胞周期分析显示,感染后的Hep-2肿瘤细胞72 h出现二倍体亚峰,G1期细胞凋亡率为8.59%,电子显微镜观察显示,肿瘤细胞核染色质边集、浓缩,细胞核呈固缩状,呈现典型的凋亡形态。另外,细胞内活性氧水平上升,线粒体膜电位下降。结论新城疫病毒弱毒株主要通过细胞内线粒体途径诱导肿瘤细胞凋亡,从而发挥其抑瘤作用。     

微生物起泡剂及其煤泥浮选应用的研究

分离一株能产生微生物起泡剂的假单胞菌(Pseudomonas sp.).考察了该菌株产生起泡剂的特性、起泡剂的成分以及起泡剂在煤泥浮选中的应用.结果表明,添加还原糖为20g/L,在第3d起泡剂达最高量.通过薄层层析分析,表明该起泡剂为脂肽类化合物,具有较高的起泡稳定性.通过微生物起泡剂进行煤泥浮选实验,其浮选效果与杂醇油相当.     

柯萨奇病毒A组16型G20分离株在不同培养条件下的增殖动力学

目的探讨柯萨奇病毒A组16型(Coxsackievirus A16,CA16)G20分离株在不同培养条件下的增殖动力学。方法常规培养Vero和人二倍体KMB-17细胞,待细胞长至单层,接种G20株病毒,进行病毒蚀斑试验,以0.1 MOI的感染复数分别感染此两种细胞,置不同温度和pH维持液中进行培养,每2 h收样1次至第24 h,以48 h收样作为对照样,微量滴定法检测病毒滴度,并绘制增殖动力学曲线。结果 G20株病毒在Vero及KMB-17细胞中传代适应后,均可导致细胞病变。G20株病毒在此两种细胞中培养,pH 6.0、pH 6.5时,不同培养温度下,病毒基本不增殖;pH 7.5与pH 7.0的病毒增殖基本一致,增殖速度随温度呈现37℃>35℃>33℃的趋势;在33℃～37℃、pH 7.0～8.0时,病毒均有不同程度的增殖;在41℃、各pH条件下,病毒增殖均明显受到限制。结论病毒在此两种细胞中,37℃,pH 7.5培养条件下,增殖速度及滴度均较理想。     

活性微生物絮凝剂的应用研究

从活性污泥中筛选得到一株活性微生物絮凝剂产生菌(127#),培养得到微生物絮凝剂,与聚丙烯酰胺(PAM)进行了絮凝效果对比试验。结果表明,该微生物絮凝剂处理面食废水、乳品废水、啤酒废水、石料废水及磨料废水,絮凝效果显著,对剩余活性污泥脱水性能有明显改善。     

Antimicrobial Face Shield: Next Generation of Facial Protective Equipment against SARS-CoV-2 and Multidrug-Resistant Bacteria

Transparent materials used for facial protection equipment provide protection against microbial infections caused by viruses and bacteria, including multidrug-resistant strains. However, transparent materials used for this type of application are made of materials that do not possess antimicrobial activity. They just avoid direct contact between the person and the biological agent. Therefore, healthy people can become infected through contact of the contaminated material surfaces and this equipment constitute an increasing source of infectious biological waste. Furthermore, infected people can transmit microbial infections easily because the protective equipment do not inactivate the microbial load generated while breathing, sneezing or coughing. In this regard, the goal of this work consisted of fabricating a transparent face shield with intrinsic antimicrobial activity that could provide extra-protection against infectious agents and reduce the generation of infectious waste. Thus, a single-use transparent antimicrobial face shield composed of polyethylene terephthalate and an antimicrobial coating of benzalkonium chloride has been developed for the next generation of facial protective equipment. The antimicrobial coating was analyzed by atomic force microscopy and field emission scanning electron microscopy with elemental analysis. This is the first facial transparent protective material capable of inactivating enveloped viruses such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in less than one minute of contact, and the methicillin-resistant Staphylococcus aureus and Staphylococcus epidermidis. Bacterial infections contribute to severe pneumonia associated with the SARS-CoV-2 infection, and their resistance to antibiotics is increasing. Our extra protective broad-spectrum antimicrobial composite material could also be applied for the fabrication of other facial protective tools such as such as goggles, helmets, plastic masks and space separation screens used for counters or vehicles. This low-cost technology would be very useful to combat the current pandemic and protect health care workers from multidrug-resistant infections in developed and underdeveloped countries.     

Phytohormones Mediate Volatile Emissions During The Interaction Of Compatible and Incompatible Pathogens: The Role Of Ethylene In <Emphasis Type="Italic">Pseudomonas syringae</Emphasis> Infected Tobacco

Interactions between the phytohormones ethylene, salicylic acid (SA), and jasmonic acid (JA) are thought to regulate the specificity of induced plant defenses against microbial pathogens and herbivores. However, the nature of these interactions leading to induced plant volatile emissions during pathogen infection is unclear. We previously demonstrated that a complex volatile blend including (E)--ocimene, methyl salicylate (MeSA), and numerous sesquiterpenes was released by tobacco plants, Nicotiana tabacum K326, infected with an avirulent/incompatible strain of Pseudomonas syringae pv. tomato (Pst DC3000). In contrast, a volatile blend, mainly consisting of MeSA and two unidentified sesquiterpenes, was released by plants infected with P. syringae pv.tabaci (Pstb) in a virulent/compatible interaction. In this study, we examined the interaction of multiple pathogen stresses, phytohormone signaling, and induced volatile emissions in tobacco. Combined pathogen infection involved the inoculation of one leaf with Pst DC 3000 and of a second leaf, from the same plant, with Pstb. Combined infection reduced emissions of ocimene and MeSA compared to plants infected with Pst DC 3000 alone, but with no significant changes in total sesquiterpene emissions. In the compatible interaction, Pstb elicited a large ethylene burst with a peak emission occurring 3 days after inoculation. In contrast, the incompatible interaction involving Pst DC3000 displayed no such ethylene induction. Pstb-induced ethylene production was not significantly altered by Pst DC3000 in the combined infection. We postulated that Pstb-induced ethylene production may play a regulatory role in altering the typical volatile emission in tobacco in response to Pst DC3000 infection. To clarify the role of ethylene, we dynamically applied ethylene to the headspace of tobacco plants following infection with Pst DC3000. Consistent with Pstb-induced ethylene, exogenous ethylene reduced both ocimene and MeSA emissions, and selectively altered the ratios and amounts of induced sesquiterpene emissions. Our findings suggest that ethylene can regulate the magnitude and blend of induced volatile emissions during pathogen infection.The use of trade, firm, or corporation names in this publication (or page) is for the information and convenience of the reader. Such use does not constitute an official endorsement or approval by the United States Department of Agriculture or the Agricultural Research Service of any product or service to the exclusion of others that may be suitable.     

系统生物学技术在微生物菌种改良中的应用

生物工业不断探索新方法来改良微生物菌株.系统生物学技术的重要目标是通过大量的组学数据分析来阐明细胞功能,已经为菌种改进提供了新技术.作者综述了基因组、转录组、蛋白组、代谢物组以及代谢流组等系统生物学技术在微生物菌种改良中的应用,进而展望了基于系统水平改进微生物菌种的发展方向.     

A novel compound, 12,13,17-trihydroxy-9(Z)-Octadecenoic acid,from linoleic acid by a new microbial isolateClavibacter sp. ALA2

A novel compound, 12,13,17-trihydroxy-9(Z)-octadecenoic acid (THOA), was produced from linoleic acid by microbial transformation at 25% yield. The newly isolated microbial strain that catalyzed this transformation was identified asClavibacter sp. ALA2. The product was purified by high-pressure liquid chromatography, and its structure was determined by¹H and¹³C nuclear magnetic resonance, Fourier transform infrared, and mass spectroscopy. Maximum production of THOA was reached after 85 h of reaction. THOA was not further metabolized by strain ALA2. This is the first report on 12,13,17-trihydroxy unsaturated fatty acid and its production by microbial transformation.