Isolation and characterization of psychrophile and psycrotolerant microorganisms from polar fresh water and sea water samples

Despite challenging environmental conditions of Antarctic continent, prokaryotes have managed to become the dominant biomass component. They play an important role in biogeochemical cycles and in mineralization of pollutants. It is very important to screen microorganisms living in Antarctica for potential biotechnological applications such as extremozyme production and bioremediation ability. We aimed at isolation of microorganisms from fresh lake and sea water samples of Antarctica's Galindez Island, Horse Shoe Island, Bryde Island and King George Island-(Arctowski Base), their morphological, biochemical and molecular characterizations and evaluation of their biotechnological potential. In our study, 23 microorganisms consisted of 22 bacteria and 1 fungus were isolated. Based on 16S-5.8S rRNA sequence results obtained using universal BactF/AIIR and ITS1/ITS4 primers, 10 isolates of Psychrobacter sp. (97.44-99.93%), 3 isolates of Pedobacter sp. (87.73- 99.57%) and Flavobacterium sp. (91.15-99.71%), 1 isolate each from Pseudomonas sp. (99.65), Pseudoalteromonas sp. (99.65%), Planococcus sp. (100%), Chryseobacterium sp. (99.69%), and Aspergillus sp. (99.83%) showed nucleotide similarity. Strains were psychrotolerant and maximum growth temperature for Pedobacter sp. FO2, Flavobacterium sp. FN1, Flavobacterium sp. FN3 and Pseudoalteromonas sp. F1 was 20 C. Planococcus sp. FG1 and Psychrobacter sp. FUL12 grew in the widest pH range (pH 5.0-12.0). The best NaCl tolerants were Psychrobacter sp. FUL1 and Planococcus sp. FG1 (moderately halophilic). Additionally, the best protease producer strain was Flavobacterium sp. The toxicity status of the tested heavy metals was Ni+2=Cd+2>Cu+2>Cr+3>Zn+2>Pb+2. Various levels of antibiotic resistance profiles were consistent with heavy metal resistance. Pseudomonas sp. FG1, Flavobacterium sp. FN2 and Psychrobacter sp. FUL3 could degrade 5-10% diesel while Psychrobacter sp. FUL5 and FUL6 could decompose 10% kerosene. The prominent PHA and siderophore producer was Pseudoalteromonas sp. F1, while maximum IAA production was recorded in Pseudomonas sp. FH1. Next, we will focus our study on the most outstanding potential of each strain.