Potential applications of some moderate halophilic bacteria

Abstract

The characteristics of halophiles made them a target for employing in several industrial processes. In this study, four moderate halophilic bacteria isolates have been isolated from the northern coast of Mediterranean sea in Egypt. These isolates have been identified according to their 16S rRNA sequence analysis and submission on Genbank-NCBI as Piscibacillus Ish and Piscibacillus Pink with close relevance to Piscibacillus halophilus, Bacillus Cs with close relevance to Bacillus aquimaris and Halomonas Cb with close relevance to Halomonas merediana. The isolates Piscibacillus Ish and Halomonas Cb showed remarkable potential to produce lipase in addition to their ability to degrade the used engine oil. The isolate Piscibacillus Ish showed the higher growth on the oil and the lower weight of residual oil than the isolate Halomonas Cb and the GC-MS analysis of the digested oil sample showed that the amount of certain hydrocarbons such as C 19 , C 21 , C 27 , C 28 and C 39 have been reduced drastically on day 20 by a percentage of 71.83%, 78.67%, 62.21%, 74.60% and 91.95% respectively.The disappearance of hydrocarbon fractions; C 7 , C 15 and C 35 on day 20 suggests that these may be saturated linear alkanes, so they are easily degraded or fragmented into shorter fractions. All the isolates also were capable of degrading an industrial textile dye called Indigo dye with different degrees and the highest isolate was Halomonas Cb. The obtained results in this study indicated the ability of the studied moderate halophile Piscibacillus Ish to be used in petroleum and used engine oil degradation and the ability of the studied moderate halophile Halomonas Cb to be used in bioremediation of effluents produced from textile industries contaminated with Indigo dye.