Studies on the bacterial flora of Nasser's Lake: the distribution of some strains of bacillus stearothermophilus in the lake water

ABSTRACT

An attempt has been trade to study the bacterial flora of Nasser-s lake along at out 1 50 km at various depths and localities. Thermophilic isolates from nutrient agar plates were purified and identified down to the species level. The results have shown that all the bacterial isolates [9 strains] belong to Bacillus stearothermophilus, 2 of these were occasionally facultative thermophiles, and 7 could not grow within the limits of the study below 50 §C, with vigorous growth at 55§C and over 65§C [one strain grew at 77-78°C and one grew at as high as 80 §C]. Temperature-conditioned lipases production has been reported in sore of these obligate thermophiles [no growth on nutrient and some other media below 50 §C and one strain grows at up to 80§C]