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Lake Meyghan is one of the largest and commercially most important salt lakes in Iran. Despite its inland location and high altitude, Lake Meyghan has a thalassohaline salt composition suggesting a marine origin. Inputs of fresh water by rivers and rainfall formed various basins characterized by different salinities. We analyzed the microbial community composition of three basins by isolation and culturing of microorganisms and by analysis of the metagenome. The basins that were investigated comprised a green ~50 g kg -1 salinity brine, a red ~180 g kg -1 salinity brine and a white ~300 g kg -1 salinity brine. Using different growth media, 57 strains of Bacteria and 48 strains of Archaea were isolated. Two bacterial isolates represent potential novel species with less than 96% 16S rRNA gene sequence identity to known species. Abundant isolates were also well represented in the metagenome. Bacteria dominated the low salinity brine, with Alteromonadales (Gammaproteobacteria) as a particularly important taxon, whereas the high salinity brines were dominated by haloarchaea. Although the brines of Lake Meyghan differ in geochemical composition, their ecosystem function appears largely conserved amongst each other while being driven by different microbial communities.

The purpose of the present study was to screen and identify the lipase-producing microorganisms from various regions of Iran. Samples collected from hot spring, Persian Gulf, desert area and oil-contaminated soil, were analyzed for thermophilic extracellular-lipase producing organisms. Six strains with high activity on rhodamine B plates were selected for chemical identification and further study. Among these isolated bacteria, four strains show higher activity in pH-Stat method at 55 °C. These strains were identified by PCR amplification of 16s rRNA genes using universal primers. Fermentation increased the activity up to 50%. The growth medium, designed for lipase production, increased the activity up to 4.55 folds. The crude supernatant of ZR-5 after fermentation and separation the cells, was lyophilized and the activity was measured. Total activity of this strain was 12 kU/g that shows its potential for industrial uses. Further study is required for purification of enzyme and calculation its specific activity. Immobilization is another approach should be considered.

A Gram-negative bacterium was isolated from corn root. This isolate is ellipsoidal to rod-shaped and slightly curved. The size of bacterium is 0.6×(1−4) nm and occurring singly, in pairs or in chains. The isolated strain reduces nitrate, oxidizes ethanol to acetic acid, and hydrolyses starch and cellulose. The maximum amylase and Cellulase activities are 20 and 5.5 u ml−1, respectively. In addition, the isolate fixes nitrogen and has a good growth on the media without any nitrogen sources. A nitrogen fixation negative strain (Nif−) was obtained from the isolate by UV mutation. This mutant strain Nif− dose not grow on the media without nitrogen sources, but it has cellulase activities. [Copyright &y& Elsevier]