Isolation of halophilic bacteria from Balıkesir/Ayvalık saltern and determination theirs biotechnological enzyme potential

Microorganisms that grow at high salt concentrations (10% and above) are included in halophiles group. Halophiles include a diverse microorganisms with ability to survive in highly saline conditions, including major life domains Archaea as well as Bacteria. Some important biotechnological and ecological features of halophiles grabbing the the attention of scientists to further examine the halophilic biology. This study presents isolation and identification of halophilic bacteria from Ayvalık Saltern by focusing on some biotechnologically important enzymes. Water and sediment samples were be sampled at different time intervals, and halophilic bacteria were isolated. Determination of some ions (fluoride, chloride, nitrite, bromide, sulphate etc.) by ion chromatography and some metals (Na, Ca, Mg, Cd, Cu, Fe, Mn etc.) by ICP-OES metal analyses of saline samples, it is tried to determine whether there is a relationship between the frequency and the types of halophilic bacteria. As a result of isolations, approximately 1.2 x 103 cfu/mL culturable halophilic bacteria were determined in the water samples taken from the saltern. Representative 55 different halophilic bacteria for isolated microorganisms were selected and ability of the producing different enzymes (xylanase, amylase, cellulase, pectinase, protease and lipase) were determined in both solid and liquid medium. Tests in solid media showed that 34 of the 55 halophilic bacteria had the capacity to produce at least one of the enzymes investigated, while 14 of the bacteria produced high amounts of enzyme. As a result of liquid medium fermentation, the enzyme yields of the selected halophilic bacteria were 2-21.9 for xylanase, 2.2-22.2 for cellulase, 2.4-18.2 for amylase and 1.2-9.8 U/mL for pectinase. Although the temperature tolerance of the produced enzymes is around 40 oC, their activity at higher (alkaline) pHs is much more stable and higher. 11 of the 14 selected bacteria were identified by morphological, cultural characteristics and 16S rRNA sequence data. The species identified are Halobacillus karajensis, Halobacillus alkaliphilus, Salegentibacter salarius, Halomonas alimentaria, Halomonas denitrificans, Actinopolyspora erythraea, Chromohalobacter beijerinckii and Marinobacter algicola. In addition, 3 halophilic bacteria producing the enzymes were determined on genus level (2 Haloferax sp. and 1 Saccharopolyspora sp.). Halophilic bacteria identified in this study were able to produce much higher amounts of different enzymes than some halophilic bacteria studied in the literature. However, in later studies, to determine the usability of these enzymes in different fields of biotechnology, it is important to complete some more tests such as optimization of enzyme production and purification.