Native hydrocarbonoclastic bacteria and hydrocarbon mineralization processes

• Hydrocarbon contaminated soil are the source hydrocarboncalstic bacteria.
• Hydrocarboncalstic bacteria from soil contaminated with crude oil were isolated.
• Bacillus spp., Alcaligenes spp., Enterobacter Spp. and Pseudomonas spp were seen to be dominant in Assam crude oil contaminated soil.
• Enterobacter sp RC4 and Bacillus aryabhattai RC6 were found to be the most potent degraders.

In the present study we have isolated fourteen hydrocarbonoclastic bacterial strains, from the crude oil contaminated soil of Assam, India. Each of these strain utilized crude oil as sole carbon source. The samples were found to produce crude oil deposition in a range of 0.04%–89.36% and moisture content 1.25%–66.6%. The isolated strains were designated as RC1-RC14 that includes Alcaligenes, Bacillus, Enterobacter, and Pseudomonas species; which were able to metabolize crude oil to different extents. Interestingly, we have found that Enterobacter sp. RC4 and Bacillus aryabhattai RC6 were capable of reducing crude oil content by 80% and 64%, respectively. Further by using different techniques such as GC-MS, FT-IR, NMR and viscosity analysis altogether had confirmed the mineralization of crude oil by the isolated strains. Furthermore, we have found that these strains were distinctively utilized polar fraction, resin by 78% and 64% respectively. Catechol dioxygenase gene was detected in RC4 genome indicating its potential catabolic capabilities for degrading aromatic oil fraction. From the investigation, it was concluded that utilization/mineralization process of crude oil by the investigated HCB was achieved by five independent ways. Our findings of the present study clearly indicate the prospect to develop an environment friendly mitigation technology against crude oil pollution using indigenous HCB.