总大肠菌群和大肠埃希氏菌检测方法的对比分析

为了探究酶底物法、多管发酵法用于水中总大肠菌群和大肠埃希氏菌的检测中的效果。通过加标试验检测和实际水样检测等方式,比较酶底物法和多管发酵法对水中总大肠菌群和大肠埃希氏菌的检测效果算,结果显示两种检测方式在不同菌株检测适用性方面存在一定差异。针对水中总大肠菌群和大肠埃希氏菌的检测选择酶底物法和多管发酵法结果一致,说明两种方式均可用于水质微生物检测中,均有较为理想的应用效果。     

水中粪大肠菌群检测方法的对比

文中进行了多管发酵法和酶底物法检测水中(耐热)粪大肠菌群结果的对比。首先,试验通过对认证的商售IDEXXQC大肠埃希氏菌和绿脓假单胞菌分别作为阳性和阴性控制菌株进行检测,其结果显示均在置信范围。其次,用较清洁的水样和污水进水水样分别进行多管发酵法和酶底物法平行检测,并进行配对t检验。较清洁的水样结果显示P=0.818(0.05)、相关系数r=0.947;污水进水水样结果显示P=0.712(0.05)、相关系数r=0.602,差异无统计学意义。相关系数均大于0.6,两种检测方法相关性均较强,说明多管发酵法和酶底物法检测水中(耐热)粪大肠菌群具有一致性。     

酶底物法测定水中耐热大肠菌群的方法验证

目的验证酶底物法可用于生活饮用水、地表水、地下水中耐热大肠菌群的测定。方法通过6家实验单位对生活饮用水、地表水、地下水各30组水样分别用酶底物法和多管发酵法来做比对。结论酶底物法与多管发酵法检测数据存在相关性,且相关程度很高,具有一致性和稳定性。结果酶底物法可应用于生活饮用水、地表水、地下水中耐热大肠菌群的测定。     

固定酶底物法与多管发酵法测定地表水耐热大肠菌群的综合效果比较

通过比较固定酶底物法与多管发酵法的检测效果,为监测站耐热大肠菌群的检测方法选择提供技术支持。2018年11月～2019年3月,选取广州市主要饮用水水源地和水源调查点采集的地表水为样本,用固定酶底物法与多管发酵法两种方法分别对51份水样中耐热大肠菌群进行比对试验检测。结果表明:固定酶底物法与多管发酵法相比,在检测一致性方面无统计学上的显著性差异,但固定酶底物法具有检测时间短、效率高、人力成本较低、结果更加精确、安全性较好等优势,既可作为地表水常规检测方法,又可用作应急、灾害时监测的快速筛查方法。     

多管发酵法和酶底物法检测总大肠菌群的结果差异性

多管发酵法和酶底物法检测总大肠菌群的结果差异大小与样品的细菌种类组成有关,而多管发酵法和酶底物法检测原理的不同导致检测的目标菌有一定的差异,也是两者结果差异的根本原因。酶底物法对肠杆菌属中的桑树肠杆菌Enterobacter mori(R18-2)、路氏肠杆菌Enterobacter ludwigii(EN-119)有特异性,而多管发酵法未表现出特异性。酶底物法对阴沟肠杆菌(CICC 21539)表现出一定的迟滞效应。酶底物法可作为生产企业检测控制手段,但用作产品合格检验或仲裁检测时应慎重,统一总大肠菌群的定义是当前亟需解决的问题。     

酶底物法在总大肠菌群、粪大肠菌群和大肠埃希氏菌检测的适用性研究

为探讨酶底物法在三峡库区水质检测中的适用性,用酶底物法对库区地表水、污水厂出水中的总大肠菌群、粪大肠菌群和大肠埃希氏菌进行检测,测定结果 RSD<4%,测定标准菌株结果符合要求,用酶底物法和多管发酵法对不同样品进行比对,结果无统计学意义上的显著性差异(P>0.05),满足水质监测技术要求。     

酶底物法检测粪大肠菌群

文章对检测水中粪大肠菌群的方法进行了探讨。通过采集50种地表水和污水厂水样,分别用酶底物法和多管发酵法进行比较,从检测结果发现,两种方法的数据无明显差异,相关性好。相比之下,酶底物法更加高效、简便、快速、准确、二次污染少,是取代传统方法的发展趋势。     

Research Progress on Detection Methods of Fecal Coliform

粪大肠菌群是水体粪便污染的指示菌。详细介绍了多管发酵法、滤膜法、纸片法、酶底物法及分子生物学方法检测粪大肠菌群的优缺点及主要应用实例。     

粪大肠菌群检测方法研究进展

粪大肠菌群是水体粪便污染的指示菌。详细介绍了多管发酵法、滤膜法、纸片法、酶底物法及分子生物学方法检测粪大肠菌群的优缺点及主要应用实例。     

滤膜法与固定底物酶底物法测定地表水中粪大肠菌群的比较研究

通过比较滤膜法与固定底物酶底物法测定地表水中粪大肠菌群(耐热大肠菌群)的结果和方法,讨论固定底物酶底物法用于监测地表水中粪大肠菌群的可行性。     

Different process configurations for bioethanol production from pretreated olive pruning biomass

BACKGROUND: In Mediterranean countries, olive tree pruning provides a widely available renewable agricultural residue with, currently, no industrial application. This residue could provide feedstock for the bioethanol industry. In the present study, olive tree pruning biomass pretreated with both ‘liquid hot water’ and ‘dilute‐sulfuric acid’ was tested as a substrate for ethanol production. Three different process configurations, separate hydrolysis and fermentation (SHF), simultaneous saccharification, fermentation and prehydrolysis (PSSF), and simultaneous saccharification and fermentation (SSF), were compared at different water‐insoluble solids concentrations. RESULTS: High ethanol concentration of about 3.7% (v/v) was obtained by separate hydrolysis and fermentation or prehydrolysis and simultaneous saccharification and fermentation of liquid hot water pretreated at 23% (w/w) substrate loading. CONCLUSION: The nature of the pretreated residue allows high substrate concentration (≥17% w/w) to be used in the enzymatic hydrolysis step. Substrate loading of 17% DM has been shown to provide a compromise between hydrolysis efficiency and glucose concentrations for the same enzyme/substrate ratio. Prehydrolysis prior to simultaneous saccharification and fermentation facilitated SSF performance at high substrate loading on liquid hot water pretreated olive pruning residue. This effect was not observed with dilute‐acid pretreated substrate. Copyright © 2011 Society of Chemical Industry     

污泥中粪大肠菌群菌值检测方法的改进

对污泥中粪大肠菌群菌值目前通用的多管发酵法进行优化。将污泥接种到乳糖胆盐发酵管,(44.5±0.5)℃培养24 h,阳性发酵管转种到EC培养液,(44.5±0.5)℃培养24 h,查MPN检索表,求倒数算出粪大肠菌群菌值,并与优化前的国标方法进行比对。结果表明,改进后的方法比国标方法减少了平板分离和染色镜检过程,缩短了检测时间,提高了检测结果的重现性,但两者在结果上无统计学意义上的差异。改进后的多管发酵法可以用于污泥中粪大肠菌群菌值的检测。     

Application and automation of flow injection analysis (FIA) using fast responding enzyme glass electrodes to detect penicillin in fermentation broth and urea in human serum

An enzyme immobilization technique has been developed to determine the concentration of biological compounds. This technique has been applied to penicillinase and urease, which are crosslinked as very fine films directly onto the sensitive ends of pH glass electrodes, thereby dispensing with the need of an on-line enzyme reactor. The biosensor is incorporated in an FIA system within a magnetically stirred detection cell. Penicillin-V in fermentation broth and urea in human serum samples were detected and the results were compared with HPLC and spectrophotometric methods. On-line measurement is achieved through the automation of this FIA system.     

High-throughput enzyme kinetics using microarrays

We report a microanalytical method to study enzyme kinetics. The technique involves immobilizing horseradish peroxidase on a poly-L-lysine (PLL)-coated glass slide in a microarray format, followed by applying substrate solution onto the enzyme microarray. Enzyme molecules are immobilized on the PLL-coated glass slide through electrostatic interactions, and no further modification of the enzyme or glass slide is needed. In situ detection of the products generated on the enzyme spots is made possible by monitoring the light intensity of each spot using a scientific-grade charged-coupled device (CCD). Reactions of substrate solutions of various types and concentrations can be carried out sequentially on one enzyme microarray. To account for the loss of enzyme from washing in between runs, a standard substrate solution is used for calibration. Substantially reduced amounts of substrate solution are consumed for each reaction on each enzyme spot. The Michaelis constant K_m obtained by using this method is comparable to the result for homogeneous solutions. Absorbance detection allows universal monitoring, and no chemical modification of the substrate is needed. High-throughput studies of native enzyme kinetics for multiple enzymes are therefore possible in a simple, rapid, and low-cost manner.     

Effect of surfactants on α‐amylase production in a solid substrate fermentation process

Solid substrate fermentation (SSF) is a process where the substrate is a moist solid, which is insoluble in water but not suspended in water. In this study SSF of Bacillus subtilis (ATCC 21556) was used to produce an enzyme of commercial importance, α‐amylase, using as a substrate potato peel. To enhance the production of this enzyme, two nonionic synthetic surfactants were used, Tween 80 and Tween 20, one anionic surfactant, SDS at concentrations of 0.05% and 0.10% (v/w) and a biosurfactant produced by Bacillus subtilis (ATCC 21332), known as surfactin, at concentrations of 0.003%, 0.007%, 0.013% and 0.03% (w/w). The results have shown that surfactants significantly increase the production of α‐amylase. Tween 80 at 0.10% and surfactin at 0.013% provided the highest enzyme activity when compared with the control. © 1999 Society of Chemical Industry     

蒸汽爆破麦草同步糖化发酵转化乙醇的研究

近年来对木质生物资源同步糖化发酵转化乙醇的研究较多,但是,麦草同步糖化发酵转化乙醇的最佳工艺条件还未确定。文中采用正交试验设计的方法,对在混合酶(纤维素酶Celluclast 1.5 1,β-葡萄糖苷酶Novozym 188)与酿酒酵母菌作用下,稀硫酸催化的蒸汽爆破麦草原料同步糖化发酵转化乙醇的工艺条件进行研究,详细讨论了反应温度、底物质量浓度、发酵液pH值、纤维素酶浓度对乙醇质量浓度和得率的影响。结果表明,工艺条件对乙醇质量浓度和得率的影响程度由高到低依次为:底物质量浓度、纤维素酶浓度、发酵液pH值、反应温度。最佳工艺条件为反应温度35℃,底物质量浓度100 g/L,发酵液pH值5.0,纤维素酶浓度30 FPU/g。在此条件下,随着反应时间的延长,乙醇质量浓度持续上升。反应72 h后,乙醇质量浓度和得率分别达到22.7 g/L和65.8%。     

Study of simultaneous saccharification and fermentation for steam exploded wheat straw to ethanol

Although simultaneous saccharification and fermentation (SSF) has been investigated extensively, the optimum condition for SSF of wheat straw has not yet been determined. Dilute sulfuric acid impregnated and steam explosion pretreated wheat straw was used as a substrate for the production of ethanol by SSF through orthogonal experiment design in this study. Cellulase mixture (Celluclast 1.5 l and ?-glucosidase Novozym 188) were adopted in combination with the yeast Saccharomyces cerevisiae AS2.1. The effects of reaction temperature, substrate concentration, initial fermentation liquid pH value and enzyme loading were evaluated and the SSF conditions were optimized. The ranking, from high to low, of influential extent of the SSF affecting factors to ethanol concentration and yield was substrate concentration, enzyme loading, initial fermentation liquid pH value and reaction temperature, respectively. The optimal SSF conditions were: reaction temperature, 35°C; substrate concentration, 100 g·L^-1; initial fermentation liquid pH, 5.0; enzyme loading, 30 FPU·g^-1. Under these conditions, the ethanol concentration increased with reaction time, and after 72 h, ethanol was obtained in 65.8% yield with a concentration of 22.7 g·L^-1.     

黑曲霉生产柠檬酸的控制论模型

黑曲霉发酵是工业生产柠檬酸的主要途径,研究该过程的动力学模型对更好地理解这一工业微生物的代谢机理有重要意义。基于黑曲霉(Aspergillus niger)柠檬酸发酵过程主要代谢途径的分析,构建了简化的碳代谢网络,建立了胞内物质和酶浓度的平衡模型。引入一阶闭环调节器模型描述发酵初期微生物酶系的建立过程。结合生物反应器模型,给出了重要宏观状态变量(如细胞物质浓度、基质浓度、产物浓度)和胞内酶浓度的动态仿真结果与实验值的对比。