Anaerobic Bioconversion of Heavy Hydrocarbons Using Native Consortia

This research work is concerned with the bioconversion of a heavy hydrocarbon cut from a petroleum refinery using native anaerobic consortia. The heavy cut is taken from one of the end-cuts of the vacuum distillation column of Tehran refinery which is normally fed into Isomax unit (a catalytic cracking process) called Isofeed. The consortia for this study were prepared from the petroleum-contaminated sludge and soils from Abadan, Shiraz, Isfahan and Tehran petroleum refineries of Iran. Nine microbial samples were collected (A, B, C,…and I) and examined. Microorganisms were cultivated in an anaerobic medium to which Isofeed from Tehran refinery was added under anaerobic conditions. After twice sub-culturing the samples, the oil was separated from the liquid and examined to identify its bioconversion extent. For this purpose, a column chromatograph method was used to separate saturates, aromatics and resins content of the oil. The results demonstrate that consortia A and C were able to increase the saturated and aromatics fractions of the oil and reduce the resins content of the oil. The saturated fractions of the bio-treated oil were also analyzed by a GC-MS analytical instrument. The GC-MS results revealed that the amount of normal chain hydrocarbons are reduced and the branched and cyclic hydrocarbons are increased.