Comparison of Bacterial Biodiversity and Enzyme Production in Three Hypersaline Lakes; Urmia, Howz-Soltan and Aran-Bidgol

Abstract

This research is a comparative study on the diversity of halophilic bacteria with hydrolytic activities in three significant hypersaline lakes; Urmia in the northwest and Howz-Soltan and Aran-Bidgol in the central desert in Iran. Isolated strains from these saline lakes were found to be halotolerant, moderately and extremely halophilic bacteria. The bacteria in each saline lake were able to produce different hydrolytic enzymes including amylase, protease, lipase, DNase, inulinase, xylanase, carboxy methyl cellulase, pectinase and pullulanase. 188, 302, 91 halophilic strains were isolated from Urmia Lake, Howz-Soltan and Aran-Bidgol playa, respectively. The numbers of Grampositive strains were more than Gram-negatives, and among Gram-positive bacteria; spore-forming bacilli were most abundant. Due to the unique physico-chemical conditions of the lake environments, the hydrolytic activities of isolated strains were significantly different. For instance, isolated strains from Howz-Soltan playa did not produce pectinase, DNase, amylase, lipase and inulinase, while the isolates from Aran-Bidgol playa had a great ability to produce pectinase and DNase. The strains from Urmia Lake were also good producers of DNase but failed to show any chitinase activity. The diversity of halophilic bacteria from the mentioned three saline lakes was also determined using PCR-amplified 16S rRNA followed by phylogenetic analysis of the partial 16S rRNA sequences.

Isolation, Identification and Extracellular Enzymatic Activity of Culturable Extremely Halophilic Archaea and Bacteria of IncheBoroun Wetland

“…In surveys performed in Aran-Bigol salt lake in Iran the archaeal isolates were similar to members of Halorubrum, Haloarcula, Natrinema, Halogeometricum, Natronomonas, Halobacterium, Halovivax, Halolamina and Halorientalis [9]. Also in surveys performed in west coasts of Urmia salt lake, the investigated isolates were similar to members of Halorubrum, Haloarcula, Natrinema, Natronococcus, Natronomonas, Halobacterium, Halovivax, Halosimplex, Haloterrigenaand Halobiforma, Halomicrobium and Haloplagius [2]. Unlike Inche-Broun wetland, most of the isolates of Urmia and Aran-Bidgol salt lakes were similar to a member of Halorubrum and Haloarcula (in order) and no isolate similar to genus Haloferaxhas been obtained from these salt lakes.…”

“…In such ecosystems, fundamental questions like biodiversity, natural selection, biogeography and evolution can be investigated more conveniently. The sediments of these waters often consist of diverse microbial populations that have not been investigated completely [1,2]. Different types of halophiles have confronted the problem of salinity stress (and other forms of stress) in different ways, so the study of microbial life in high salinity can be the answer to a vast majority of fundamental questions about the compatibility of microorganisms with their environments [3].…”

“…For instance, bacteriorhodopsins have some applications in holography, optical modulators, calculators and optical memories [8]. Production of biopolymers like biosurfactants and exopolysaccharides are considered as other applications of halophilic microorganisms [1,2]. Iran has a great variety of hypersaline environments particularly hypersaline lakes.…”

Regionalization of precipitation characteristics in Iran’s Lake Urmia basin

“…Due to the socio-ecological importance of the Lake Urmia in the region, a great amount of research has dealt with Lake Urmia shrinkage addressing different aspects of it such as biodiversity, climate, hydrology and water resources, and environmental management (Abatzopoulos et al 2006;Zarghami 2011;Babavalian et al 2014;Alipour and Olya 2015;Hamzekhani et al 2016). Climate change and variability, recognized as drivers of the lake's desiccation, have been the focus of many studies over the past decades.…”

Hydrolytic Enzymes in Halophilic Bacteria, Properties and Biotechnological Potential

“…Diversity of halobacteria from different hypersaline habitats has been studied. In some cases, alongside exploring biodiversity and taxonomy of halobacteria, biotechnological potential of halobacteria has been examined (Babavalian et al 2014 ).…”