Characterization of Some Extremely Halophilic Bacteria Isolated from Salt Marshes of Gamasa Egypt

Abstract

Halophiles can be classified as extreme, moderate and slight halophiles. Many extremophiles produce unique biotechnological and commercial materials. Salinity stress is one of the major factors negatively affecting bacterial growth. Cellular biochemical changes could be monitored via protein pattern in response to different NaCl concentrations. So our work aimed to do a comparison among salt-tolerant bacteria in their response to different NaCl concentrations via halotolerance test, antimicrobial susceptibility, amino acid profile and protein banding pattern. From haloterance test of eleven bacterial isolates, STB5, STB8 and Shigella dysenteriae were more tolerance to NaCl. From 16S rRNA gene sequencing, the two isolates STB5 and STB8 were identified as Halomonas caseinilytica and Paraliobacillus quinghaiensis. From 32used antibiotics only 5 antibiotics, cefotaxime, ampicillin, penicillin G, ceftazidime and aztreonam, showed resistance. From SDS PAGE, the appearance or absence of high or low molecular weight bands may be directly associated with the bacterial response to salt. Protein profile of tested halophilic bacteria under different concentrations of NaCl% (0, 5% and 20%) showed variable polymorphism in Halomonas caseinilytica MG199079, Paraliobacillus quinghaiensis MG250199and Shigella dysenteriae. Environment-specific patterns of amino acids profile were observed. Based on the obtained results, it could be concluded that the three organisms Halomonas caseinilytica MG199079, Paraliobacillus quinghaiensis MG250199and Shigella dysenteriae, are extreme halophilic bacteria, they were different in of amino acids accumulation protein profile and in different concentration of NaCl.