Vol. 7(36), pp. 4483-4490, 6 September, 2013 DOI: 10.5897/AJMR12.1690 ISSN 1996-0808 ©2013 Academic Journals http://www.academicjournals.org/AJMR African Journal of Microbiology Research Full Length Research Paper Isolation, characterization and identification of amylase producing halothermophilic isolates from Howz Soltan Lake, Iran Mahmoudnia Fahimeh 1* , Bahador Nima 1 and Baserisalehi Majid 2 1 Department of Microbiology, Science and Research Branch, Islamic Azad University, Fars, Iran. 2 Department of Microbiology, Kazeroun Branch, Islamic Azad University, Kazeroun, Iran. Accepted 2 January, 2013 Halophilic bacteria are a group of salt tolerant microorganisms; the production of enzymes by halophilic bacteria, due to their activities in harsh environments, is considered as a major field of investigation. Hence, the present study was conducted for the isolation of halothermophilic bacteria from Howz Soltan salt lake. For this purpose 40 samples were collected from five regions of the Howz Soltan lake. The samples were diluted and cultivated on Molten haloid agar (MH) with different salt concentrations (5-35%). Then the plates were incubated at 35-70°C in aerobic conditions for 7-10 days. The strains were screened for amylase production based on differences in enzyme production. In total 205 strains were grown on media including 5-15% salt concentrations. Of all, 18 strains were hyperhalophilic and could grow on media including 20-35% salt concentrations at 40-70°С. Three (3) isolates were identified as best amylase producers. In addition, the results indicated that maximum enzyme activity was observed at 48 h (18.145 U/ml). The optimal pH, temperature and NaCl concentration for amylase production were 7.0-7.5, 40°C and 15% (2.5 M), respectively. Taxonomic and phylogenetic analysis using 16SrRNA gene sequencing revealed that they belonged to Bacillus licheniformis and Gracilibacillus while the third isolate was closer to β proteobacterium. Key words: Halothermophilic bacteria, amylase, Howz Soltan Lake. INTRODUCTION Halophilic bacteria are a group of salt tolerant micro- organisms. These bacteria are divided into three groups: Slightly, moderately and extremely halophiles (Larsen, 2001). However, survival of halophilic bacteria in the environment depends on concentration of Na + and K + , but compatible solutes in their cells culminate their survival in ocean, salt lakes and salt fields (Fukushima et al., 2007). Although production of energy in some halophilic bacteria depends on their red pigment (bacteriorhodopsin), non pigmented halophilic bacteria could obtain energy in the environment with high salt concentrations (Dave et al., 2006). Nowadays, production of enzymes such as amylases, proteases and nucleases by halophilic bacteria due to their activities in harsh environments is considered as a major field of investigation (Alqueres et al., 2007). Several reports confirmed that the activity of halophilic bacterial enzymes remained stable at high salt concentrations and temperatures (Parakesh and Jaiswal, 2009). However, α- amylase is produced by different microorganisms viz., Bacillus subtilis, Bacillus stearothermophilus, Bacillus licheniformis, and Bacillus amyloliquefaciens, Pseudomonas (Devi et al., 2012; Bassabrani et al., 2012), Halobacillus sp. (Amoozegar et al., 2003), Chromohalobacter sp. (Prakesh et al., 2009), Haloarcula hispanica (Hutcheon et al., 2005), Halomonas meridiana (Coronado et al., 2000), and Bacillus *Corresponding author. Email: f_mn_1981@yahoo.com.