Selection Of Microbial Consortium And Research On Methane Production From Petroleum Hydrocarbon

The key task is to deeply exploit the maturing oil well so as to enhance oil recovery.The other significant task,however,is how to take advantage of a large number of petroleum remaining in the reservoir because of existence of a large amount of residual oil.It becomes an effective way to make the most of residual oil through microbe degradation oil and aerogenesis.The oilwell produced liquid from six wells in an oil field was sampled and investigated.Oilwell produced fluid in anaerobic conditions for cultivating?YH?,while the oily sludge in anaerobic conditions for cultivating?TH?,and the number was the sampling number.After enrichment culture,the result showed that the YH5 microbes reached the highest methane production and the TH2 microbes reached the highest methane production.The HYH5microbes was obtained by compounding of YH5 and TH2 and after 30^oC,260days,6g oil enrichment culture,the highest methane production of HYH5 microbes was up to 283.8?mol.And in the same enrichment culture conditions the methane production of YH5 microbes was173.2?mol.The methane production of TH2 microbes was 269.4?mol.The infrared spectrum analysis of oil sample,before and after HYH5 degradation oil to produce methane,could be found that the vibration peak of 3380cm^-11 appears after degradation.This suggests that the hydroxyl compounds would be produced in the process of anaerobic degradation and aerogenesis.The analysis result of GC-MS and HTSD showed that the saturated hydrocarbon in oil can be degraded by microbial action.And the ion chromatographic analysis to HYH5 degradation products could be seen that high carbon acid such as palmitic acid,octadecanoic acid,arachidic acid and Behenic Acid exists.When the HYH5 microbial consortium were study by temperature and pressure.It showed that the highest methane production was 280.6?mol and 163.2?mol respectively when the temperature was 30^oC and 60^oC accordingly.Stress had a significant influence on degradation oil and methane-producing as well.The methane yield ranged from 279.4?mol to145.7?mol when the pressure was from ordinary to high 15MPa.Three strains of petroleum hydrocarbon degradation bacteria was obtained though isolation and purification to mixed anaerobic microbes HYH5 and named HYH5-1,HYH5-2and HYH5-3 respectively.Through extracting DNA from HYH5-1,HYH5-2 and HYH5-3,amplifying V3 region of bacterial 16s rDNA and comparing the partial sequence of 16s rRNA which was obtained,it could be identified that the strain HYH5-1,of all the bacteria,had the highest similarities with Thermodesulfobiaceae bacterium enrichment culture clone.However,the strain HYH5-2 was most similar to a strain which can degrade petroleum in anaerobic and produce methane.And the similarity was 97%.The strain HYH5-3 was most similar to Uncultured Methanomethylovorans sp.Clone which was methanogenic archaea in high temperature reservoir and belonged to Sarcina.This article study showed that the biosurfactant had an obvious influence on methanogenesis of HYH5,and bicarbonate had an obvious influence on methanogenesis of HYH5.Molybdenum ions and zinc ions could collectively promote the function of methane production.Relative to zinc ions,however,the promoting effect of molybdenum ion was more obvious.Meanwhile,the combined action also played an important role on HYH5methane production.The analysis of HPLC-MS showed that the enrichment product can promote methanogenesis efficiency of HYH5.The enrichment product may be peptide.The degrading-toluene microbes from HYH5 were studied by using the method¹³C-Tluene.Toluene degradation mainly generated benzoic acid,fumaric acid and benzoyl succinic acid,etc.It was fumaric acid addition reaction.Long chain alkane n-hexadecane degradation products mainly included ten alkanes dicarboxylic acid,tetradecyl dicarboxylic acid,pentadecane acid and hexadecanoic acid,which could be found that the carboxyl reaction was carried on.