A 2b 2c

Alcaligenes faecalis 2A Alcaligenes faecalis 2B Alcaligenes faecalis 2C

The most promising pure cultures were identified in Czech Collection of Micro-oganisms on the basis of traditional biochemical and physiological tests.

The isolates N3H and NIC obtained from DHSS enrichments gave the following positive tests: catalase, tyrosine hydrolysis, nitrate reduction, growth on MacConkey agar, growth at 37°C. Negative tests included: acid from glucose, glucose fermentation, production of fluorescent pigment, growth at 42°C, growth on Simmons citrate, arginine dihydrolase, urease, nitrate reduction with gas formation, nitrite reduction, lysine decarboxylation, hemolysis; hydrolysis of gelatin, starch, Tween 80, esculin, casein, o-nitrophenyl galactoside and lecithin; acidogenesis from manitol, fructose, xylose, lactose, maltose and sucrose. The isolate NIC grew on Simmons citrate, the other tests gave the same results as in the case of N3H strain. Both strains (Gram-negative motile rods forming circular, entire, convex, shiny colonies 2-4 mm in diameter) were identified as Comamonas terrigena.

The isolate 9B, purified from the mixed culture enriched in the presence of di-n-tridecyl sulfosuccinate, was identified as Pseudomonas sp. on the basis of the following results. Morphology on nutrient agar plates: circular, entire, smooth, shiny umbonate colonies 2-4 mm in diameter. Positive tests: catalase, acid from glucose; growth at 37°C, on MacConkey agar, phenylalanine deamination, hemolysis, oxidase, phosphatase, tyrosine hydrolysis. Negative tests: glucose fermentation, fluorescent pigment, growth at 42°C and on Simmons citrate, arginine dihydrolase, acetamid, malonate, reduction of nitrite and nitrate; hydrolysis of gelatin, starch, Tween 80, esculin, casein, ONPG and lecithin; acid from mannitol, fructose, xylose, lactose, maltose and sucrose; lysine decarboxylation, urease, production of indole and hydrogen sulfide; growth in the presence of 6.5% NaCl.

The strains 2A, 2B and 2C were isolated on the basis of their capabilies to growth on mono-n-dodecyl sulfosuccinate. The following tests were positive for all three strains (gramnegative coccal rods; circular, entire, shiny colonies 1-2 mm in diameter): growth at 37°C, at 42°C (with the exception of 2B isolate), on MacConkey agar, on Simmons citrate, in the presence of 6.5% NaCl; catalase, oxidase, nitrite reduction. Negative tests included acid from glucose, glucose fermentation, fluorescent pigment, arginine dihydrolase, acetamid, malonate, nitrate reduction; hydrolysis of gelatin, esculin, starch, casein, tyrosine and ONPG; acid from mannitol, fructose, xylose; lysine decarboxylation, urease. All three isolates were identified as Alcaligenes faecalis.

The rates of DHSS primary biodégradation vary among isolated pure cultures (Figure 2), and are generally much higher than those observed among culture collection strains (Figure 1).

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