ABSTRACT: A total of 218 halophilic bacterial isolates were obtained from Lake Razazah, west of Karbala, Iraq. Optimum pH and temperature were 7.5 and 37 °C, respectively. According to optimal growth at different salt concentration, the slightly halophilic bacteria were the most abundant isolates with the frequency of 68%. The isolated bacteria were screened for the production of extracellular amylase, alkaline amylase, protease, alkaline protease, lipase, alkaline lipase, pectinase and cellulase. The production of pectinase (55.8%), amylase (52.6%) and lipase (50.0%) were observed in almost half of the halophilic bacteria. Alkaline amylase and alkaline lipase production were reported in less than one third (30%) of isolates. Phylogenetic analysis16S rRNA sequences indicated that all isolates were members of eight genera of the domain Bacteria, including Bacillus, Halobacillus, Virgibacillus, Oceanobacillus, Staphylococcus, Pseudomonas, Idiomarina and Halomonas. The predominant commercial enzymes producers in current study were Halobacillus sp. K51 and Halomonas sp. K46 with the ability to produce 7 out of 8 exoenzymes. The presented data shows that despite drought, dehydration, increased concentrations of salt and contaminants, Lake Razazah represents an untapped source of halophilic bacteria biodiversity.
Isolation and characterization of denitrifying halophilic bacteria from Bahr Al-Milh Salt Lake, Karbala, Iraq
