Isolation and characterization of a novel native bacillus strain capable of degrading diesel fuel

The ability of native bacteria to utilize diesel fuel as the sole carbon and energy source was investigated in this research. Ten bacterial strains were isolated from the oil refinery field in Tehran, Iran. Two biodegradation experiments were performed in low and high [500 and 10000 ppm, respectively] concentration of diesel fuel for 15 days. Only two isolates were able to efficiently degrade the petroleum hydrocarbons in the first test and degraded 86.67% and, 80.60% of diesel fuel, respectively. The secondary experiment was performed to investigate the toxicity effect of diesel fuel at high concentration [10000 ppm]. Only one strain was capable to degrade 85.20% of diesel fuel at the same time [15 days]. Phenotype and phylogeny analysis of this strain was characterized and identified as dieseldegrading bacteria, based on gram staining, biochemical tests, 16S rRNA gene sequence analysis. These results indicate that this new strain was Bacillus sp. and could be considered as Bacillus Cereus with 98% 16 S rRNA gene sequence similarity. The results indicate that native strains have great potential for in situ remediation of diesel-contaminated soils in oil refinery sites

[Efficiency of advanced oxidation and hydroxyl technology in methyl terciary - butyl ether [MTBE]]

Advanced oxidation processes have been demonstrated as the rapid and effective methods for the treatment of a vast range of the refractory pollutants. The aim of this study was to use ozone in reaction with hydroxyl radicals [high-PH] as the reaction accelerator for MTBE degradation in industrial wastewater and polluted water. The effect of O3 with the hydroxyl radicals [high-PH] was experimented for MTBE degradation in an aqueous phase. All the reactions were performed in a semi-continuous bubbling column reactor. The effects of PH, reaction time and rate of O3 needed to attain complete MTBE degradation were examined. MTBE ozonation in five different PHs [10,10.5,11,11.5 and 12] during 100 minutes for each PH was performed. The study showed that the PH=11.5 is the fittest PH for MTBE degradation by the radical reactions. In this pH [intermediates] /[MTBE] ratio was 0.6v / mM that it is 20% more than its nearest ratio [related to PH=11]. The least time [70 minutes] and needed ozone [5.3 moles] for 90% degradation of each mole of MTBE occurred at PH=11.5. The test performed to determine the rate of removed MTBE as a result of air stripping showed that this rate was 11-19.5% at different PHs during 100 minutes. There was no significant relationship between the rate of removed MTBE as a result of air stripping and the aqueous PH at PHs=10-12 at level of 5% error. MTBE is relatively resistant to degradation even in advanced oxidation processes, but with continuous oxidation can be degraded completely and the best PH for that is11.5