Use of thixotropic biopolymers as an alternative to agar for the cultivation of microorganisms on solid media
Use of thixotropic biopolymers as an alternative to agar for the cultivation of microorganisms on solid media
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DOI：
10.1016/s0141-3910(97)00150-x
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发表时间：
1998-01-01
影响因子：
5.9
通讯作者：
Hill, EC
中科院分区：
文献类型：
--
作者：
Hill, EC
在石油和相关行业，对燃料样品的可靠活菌计数的需求不断增加，膜过滤程序IP385/95和乳化程序AFNOR MO7070/92已经标准化。前者不适合现场使用，虽然后者可以与倾斜滑动试验相结合，但它继承了这一程序的局限性。所描述的方法是对燃料进行灵敏的、定量的现场微生物测试的需要的直接反应，但该技术可以应用于任何水和非水样品。一种营养溶液，如果需要的话，可能是有选择性的，用触变性和/或假性塑化剂代替琼脂制成凝胶。可以通过摇动将样品分散在凝胶中，并允许凝胶重新设定为平坦的水平层。在孵化过程中，菌落的发展类似于摇板中的菌落形成。在燃料测试的首选配置中，大约16毫升的凝胶被分配到容量约为65毫升的有螺丝盖的矩形玻璃容器中。在孵化过程中，一个灵敏的氧化还原指示器提供了菌落生长的早期指示。其精度类似于振动板。大量的微生物在几个小时内就会产生一种有色的福尔马赞--这是一种实时测试。所述凝胶组合物的配方使非水样品乳化并完全分散。该配方已用于柴油和航空煤油的测试，结果与IP385/95和AFNOR M07070/92方法相当。对水、牛奶、乳剂等的初步测试结果表明，该方法在实验室特别是现场将有广泛的应用。(C)1998年爱思唯尔科学有限公司。版权所有。
In the petroleum and allied industries, there has been an increasing demand for reliable viable counts on fuel samples, and a membrane filtration procedure, IP385/95, and an emulsification procedure AFNOR MO7070/92, have been standardised. The former is unsuitable for on site use, and although the latter can be coupled to a Dip-slide test, it inherits the limitations of this procedure. The methodology described was a direct response to the need for a sensitive, quantitative on-site microbiological test for fuel, but the technology can be applied to any aqueous and non-aqueous sample. A nutritive solution, which may, if required, be selective, is gelled with thixotropic and/or pseudo-plastic agents instead of agar. A sample can be dispersed in the gel by shaking, and the gel is allowed to re-set as a flat horizontal layer. During incubation, colonies develop comparable to colony formation in 'shake' plates. In the preferred configuration for fuel-testing, ca. 16 ml of gel is dispensed into screw-capped rectangular glass containers ca. 65 ml capacity. During incubation, a sensitive redox indicator gives an early indication of colony growth. The accuracy is similar to a shake plate. Very large numbers of microbes produce a coloured formazan within a few hours-a real time test. The gel composition described has been formulated so that non-aqueous samples emulsify and completely disperse. The formulation has been used to test diesel fuel and aviation kerosene; the results are comparable to the methods IP385/95 and AFNOR M07070/92. Preliminary results of tests on water, milk, emulsions, etc, suggest that the methodology will have wide applications in the laboratory but particularly on-site. (C) 1998 Elsevier Science Limited. All rights reserved.