ISOLATION AND CHARACTERIZATION OF OIL UTILIZING BACTERIA ISOLATED FROM DRILLING OILY BASE MUD WASTE IN THE EGYPTIAN WESTERN DESERT

Abstract

The main aim of this study is to isolate, screen and identify the most potent oil degrading bacteria (ODB) isolated from oil base mud (OBM) waste resulted from group of selected oil and gas drilling and exploration wells. Another aim is to determine the metabolic fingerprint of the most potent ODB. To achieve these aims, eleven samples from the waste of oily base mud were collected from different drilling sites at western desert. Total bacterial counts at 22 oC and 30 oC were determined for giving a full picture about the presence of natural bacterial flora in the collected samples. Moreover, ODB were determined on oil agar media containing 0.1% oil (V/V) using spread plate method. The results showed that, the average of total bacterial counts at 22 oC and 30 oC were 1.4x104 and 1.6x104 CFU/g, respectively. Moreover, the oil degrading bacteria (ODB) counts were fluctuated between 1.0×102 and 6.1x103 CFU/g in all collected samples. After six screening steps, the most potent oil degrading bacteria were identified using BIOLOG as follows Enterobacter hormaechei, Enterobacter cloacae and Bacillus subtilis. The only difference in the metabolic fingerprints view between two bacterial strains that, Enterobacter hormaechei (H17) are able to utilize D-serine while and Enterobacter cloacae (H32) not. It can be concluded that, metabolic fingerprints of the most potent oil degrading bacteria provide full information about the microbial metabolic activities that may be helpful in determination of favorable conditions which aid in biodegradation experiments.