The Effects Of Some Fungi And Bacteria On Physical And Chemical Nature Of Crude Oil

Microbial Enhanced Oil Recovery (MEOR) is also known as microbial enhanced oilrecovery, has been proved to have an good potential of application flowing the traditionalEOR technologies such as thermal flooding, chemical flooding and gas drive. The primaryobjective of this study is to separate and screen fungi and bacteria strains for MEOR and grindbran of fungi into powder, research them mainly from several aspects: strains screening andidentifying, the measurement of activity of dehydrogenase and the transformation of physicaland chemical properties of petroleum to sure the feasibility of enzymes and the good potentialof bacteria for MEOR. The main contributions of this research were summarized as follows:1Five fungi separated from oil-contaminated soils of Ansai oilfield have been identifiedas Aspergillus and Aspergillus oryzaeby morphology and the test chip. Grinding bran of fungiinto powder and then determining the TTC-dehydrogenase and catechol2,3-dioxygenaseactivity and studying the biodegradation efficiency for crude oil of crude enzyme. The resultsshowed that the dehydrogenase activities and catechol2,3-dioxygenase activities of all testedstrains displayed obvious difference, the dehydrogenase activities were in the range of8.5～12.4mg·L-1·h-1and the C23Oase activities were in the range of77～90μmol·h-1. All testedexoenzymes can degrade crude oil and the effect of enzymatic hydrolysis of16strain is thebest through the gas chromatogram analysis of processed petroleum and emulsibility of oil isimprove and the light component increased dramatically.2The effect of16strain′s exoenzyme to carbon source and temperature and petroleumsamples were researched. The results show that①It was found that both the biomass anddehydrogenase activities using white sugar as carbon source are highest whereas they are lowwhile using different concentration of oil as carbon source.②The emulsifing ability andremoval efficiency were better when exoenzyme was at1.0g/mL,0.6g/30mL,0.1g/30mL,but tow activities was lost when exoenzyme was at0.008g/30mL.③Along with theextending of time, the emulsifing ability and removal efficiency of crude oil increased.④Toexoenzyme,30℃is optimal and the degradation effect of oil is best, whereas the16strain′sexoenzyme is heat stable for60℃.⑤Exoenzyme can degrade different samples but theirdegradation differ in degree. 3Four bacteria6-1, P₁H₁₃₂, AP1H11and6-3Y were isolated from oil-contaminated soilsand crude oil of Ansai and Zhidan oilfield.4strains showed the higher ability to emulsify anddegrade petroleum hydrocarbons. The oil degradation test showed that34.0%～55.3%ofalkanes were thoroughly degraded by bacteria, the content of non-degrading alkanes decreasesignificantly via bacterial action. Four strains can produce biosurfactant in fermentation liquid,the biosurfactants produced by3strains (6-1,AP1H11,6-3Y) was primarily identified aslipopeptide and is that and they were identified as lipopeptide and the biosurfactants producedby1strain (P₁H₁₃₂) was primarily identified as glycolipid. Four bacterias have been identifiedas Rhizobium pusense (6-1), Zhihengliuella aestuarii (P₁H₁₃₂), Bacillus licheniformis(AP1H11), Bacillus aryabhattai (6-3Y) by morphological and physiological-biochemical testsand16S rDNA sequence analysis.