Test using Pseudomonas fluorescens

Dissolved toxic substances contained in sewage inhibit the ability of the bacterium Pseudomonas fluorescens to produce organic acids from glucose. 

Inhibition of acid production can be quantitatively determined by measuring the pH. For this purpose the pH and acid consumption of the sewage must be adjusted to match the corresponding values for the receiving water before testing begins. 

The ratio of volume of sewage to total volume of receiving water plus sewage must then be found for the level of dilution which produces the smallest deviation from the pH of the receiving water sample by the end of the test period. This ratio provides a measure of the biological damage caused by a particular toxic sewage. 

The method can be used with all types of industrial effluent. 

Incubator, steam bath, vibrator, pressure-filtering device for membrane filters, membrane-filters pore size 0.2 pm (1 pm = 0.001 mm), photometer with nephelometer attachment, filter Hg 436 nm, cuvettes (path length 10 mm), electric pH gauge, culture tubes with caps, Erlenmeyer flasks (300 ml), graduated pipettes (1 ml), graduated pipettes (10 ml), measuring cylinders (100 ml), glass beads (diameter approx. 2 mm), inoculation loop, aqueous sodium hydroxide, hydrochloric acid. 

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Mott and Bott [1991] compared the accumulation of biofilm on simulated heat exchanger tubes. The equilibiium or plateau value of biofilm deposit, has the highest for 316 stmnless steel tubes with lower amounts on electropolished stainless steel, glass and fluorinated ethylene propylene. Table 15.7 summarises their data. The tests were carried out using Pseudomonas fluorescens under identical conditions. The velocity of flow through the tubes was 1 m/s. 

The antibacterial activity of the secoiridoids 14,15, 17-19, 20a, b, 28a and 38, and the caffeoyl esters of phenylethanoid glycosides 22 -27 has also been tested using the direct bioautographic TLC assay as published by Hamburger and Cordell [39]. Bacillus subtilis spp. and Pseudomonas fluorescens were the representatives of the gram-positive and gramnegative bacteria, respectively. The minimum inhibition amount (MIA) was determined. Cefotaxime was used as a positive control. 

Pseudomonas fluorescens lipase and Burkholderia cepacia lipase were the enzymes tested. In the case of phosphonate 146, the reverse procedure, i.e. the hydrolysis of the acetyl group, provides better results. Good yields (usually limited to 50% due to the kinetic conditions used) and ee values up to 92% were obtained for 144 and 145. 

PEG-lipase from C, cylindracea catalyzes esterification in water-saturated benzene and its substrate specificity was compared with that of PEG-lipase from P. fluorescens [81] and P. fragi [80]. First, esterification from a normal alcohol and a fatty acid with different carbon chain length was tested using three kinds of PEG-lipase, as shown in Fig. 9. Although PEG-lipases from Pseudomonas preferentially catalyzed the esterification reactions from n-alcohol and fatty acid with longer carbon chains, PEG-lipase from C. 

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