biologia - Studia

MICROBIOLOGICAL AND ENZYMOLOGICAL STUDY ON RIVER SEDIMENTS AND WATER
10000
1000
Faecal coliforms/l
100
10
1
P1 P2 P3 P4 P5
Sampling site
Spring Summer Autumn Winter
Fig. 2. The number of faecal coliforms (logarithmic expression).
Results of the biochemical tests for differentiation of the coliform species.
Table 1.
Test
Bacterial strain tested
S1 S2 S3 S4
Indole production + - - +
Methyl red test + + - +
Voges-Proskauer test - - + -
Citrate utilization - + + +
Malonate utilization - - + +
Urea hydrolysis - + + +
H 2 S production on TSI medium - - - +
Genus to whom belong the strains Escherichia Klebsiella Enterobacter Citrobacter
The three enzymatic activities studied in autumn have been detected in all
the sediments analysed. On the base of the absolute values of each enzymatic activity,
the enzymatic indicator of sediment quality (EISQ) was calculated, according with
Muntean et al. (1996). The values of the EISQ follow an increasing curve along the
five sampling sites: the lowest value (EISQ = 0.159) in P1 and the highest value
(EISQ = 0.286) in P5 (fig. 2). We mention that the minimal theoretical value of the
EISQ is 0, and the maximal one is 1.
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