Study the crude oil degrading bacteria from industrial effluents in Shiraz

Pollution of the environment with petroleum and its derivatives is a serious threat to human health and the environment, so treatment of these substances is of great importance. The bioremediation process is defined as the use of microorganisms to remove many industrial effluents, including petroleum products. The aim of this research is isolation and characterization of crude oil degrading bacteria from some industrial sewage at Shiraz province

This study was performed to isolate crude oil degrading bacteria from some industrial areas of Shiraz. To investigate the effect of crude oil on the frequency and variety of microbial populations of Soil and water sampling, identification and counting of crude-oil degrading bacteria and heterotrophic bacteria were performed by CFU and MPN methods. Preliminary identification of the strains was carried out based on gram staining, colony shape and microscopic characteristics. Then properties such as oil-spreading,emulsifying activity and growth and degradation rate of these bacteria were investigated.

After screening, it was found that 20 strains were capable of growing and decomposing crude oil The highest oil-spreading,bacterial adhesion to hydrocarbon, emulsifying activity were related to PE3, SN1, DS1, 23%, 16% and 22%, respectively. Using these results seven suitable strains were selected and crude oil removal rates were determined by spectrophotometric and gravimetric methods for each strain. One strain with the highest rate of crude oil degradation was identified molecularly. This strain belonged to the genus Cellulosimicrobium cellulans. The highest percentage of degradation by this strain was in the concentration of 1.5% at 67%. Percentage of oil degradation of this strain by analyzing the effects of mixture culture, excess carbon source, excess nitrogen source, excess carbon and nitrogen source, time was 75%, 71%, 100%, 81%, 100%, respectively.

The results of this study showed that the use of these microorganisms by creating optimal conditions can be an important step in the removal and control of oil pollution.