Isolation, and identification of haloalkalotolerant /haloalkalophilic fungi and their biotechnological potentials

In this study, Acıgöl (Çardak/Denizli/Turkey), which is a hypersaline and alkaline tectonic lake dominated by extreme conditions, was chosen for fungus isolation. A total of 8 water samples were taken from two stations seasonally and microfungi were isolated using the membrane filtration method. The isolates, which were determined to be moderate halophiles based on the halotolerance and alkalotolerance tests, were screened for antimicrobial and antioxidant activities and exopolysaccharide production. Antimicrobial activity of isolates was determined by the agar block method using E. coli, S. aureus, C. albicans as test microorganizms. DPPH method was used for antioxidant activity. In exopolysaccharide production studies, the EPS formed in the medium was precipitated with ethyl alcohol and the amount of carbohydrates was determined by the phenol-sulfuric acid method. A total of 199 microfungi were isolated from water samples and were identified by traditional and molecular methods. It was determined that 31%, 28%, 11% and 6% of the isolates belonged to the genera Penicillium, Aspergillus, Cladosporium, and Alternaria respectively. Among the isolates, A. alternata (8), A. flavus (19), A. tubingensis (10), C. cladosporioides (12), P. chrysogenum (15), P. allii (10) have evaluated as the leading species. Aspergillus urmiensis, Cladosporium limoniforme and Neocamarosporium obiones are new records for Türkiye. Compared to amphotericin B, Aspergillus dimorphicus AG2B-4-1 isolate showed activity against C. albicans. Compared to ampicillin, Aspergillus tubingensis AG1X1-6 and Penicillium heteringtonii AG1-50-3 isolates showed the highest activity against E. coli and S. aureus with an inhibition zone diameter of 10 mm and 21 mm respectively. In the antioxidant activity evaluation accompanied by BHT control, it was determined that Penicillium chrysogenum AG2X2-7 isolate showed the highest activity with 77%. Aspergillus tubingensis AG1X1-3 isolate produced the highest amount of (7.79 mg) EPS. The unique properties of fungi hold great promise for applications in biotechnology and industry. Keywords: Acıgöl, Moderate halophiles, Halotolerance, Alkalotolerance, Penicillium, Aspergillus