Biodegradation Of Crude Oil And Its Fractions By Mixed Culture

Petroleum is a complex mixture of hydrocarbons. Various fractions can be obtained after atmospheric and vacuum distillation. In the process of crude oil processing all countries attempt to improve the yield of the light oil. Large numbers of researches show that many microorganisms have the ability to utilize hydrocarbons as sole sources of energy and such microorganisms are widely distributed in nature. This study was designed to degrade long-chain hydrocarbons to short-chain hydrocarbons and heavy oil to light oil based on the characteristics of microbial degradation of crude oil.In this paper, 62 oil-degrading microorganisms were screened using oil-plate method from the soil and water contaminated by crude oil and other oil for long time. Morphological and physiological and biochemical identification of some strains were carried on. The identification results show that they belong to Pseudomonas, Bacillus, Enterobacter, Acetobacter, Brachybacterium, and Aeromonas. And crude oil degradation by Hafnia has been reported rarely. The crude oil and fractions degradation experiments by single culture showed that different microorganisms broke down the components of crude oil or its fractions selectively. It was proved that there were two different relationships: synergistic effects and inhibitive effects between microorganisms in the experiment of degradation of crude oil and its fractions. This research provides a reference for the feasibility of crude oil and its fractions degradation by mixed culture.