, vol. 10, issue 4, pp. 1823-1828, 2013.
Thirty soil samples from different six localities representing Wadi Araba, Egypt were collected for
isolation of alkaliphilic and alkaline-resistant microorganisms as a possible source of new antimicrobial compounds.
The climatic factors and soil analysis of the study area are given. The soil samples were sandy and varied from
slightly to moderate alkaline, and also from non-saline to slightly saline. The number of microbial colonies from the
different soil samples varied from 102 to 104 CFU/g of soil. It was obvious that the viable microbial counts were
affected by the organic matter content and the pH of the soil. A total of 117 alkaliphilic and alkaline-resistant
microorganisms were isolated. Among them, 73 isolates were bacteria, 40 isolates were actinomycetes and the
remaining 4 isolates were fungi. The purified alkaliphilic and alkaline-resistant microorganisms were investigated
for their antimicrobial activities and the results revealed that 23 isolates of bacteria, 22 isolates of actinomycetes and
two fungal isolates have antimicrobial activities. Therefore, the results recommended the screening of extremophiles
as possible source of new secondary metabolites.