Wu Xiaolei

Characteristics of Removal of Cr (VI) by Rhodococcus sp. Chr-9 and Exiguobacterium sp. Chr-43

For understanding the effect of environment factors on the removal of chromate by bacterial strains and to provide chromate-removing strains for the bioremediation of environments contaminated by chromate,two Gram-positive bacterial strains designated as Chr-9 and Chr-43 respectively,capable of removing Cr(VI) in LB medium,were isolated from sludge collected from one tannery plant in Binzhou,Shandong,China.Based on 16S rRNA genes and phenotype characteristics,strain Chr-9 and Chr-43 were identified as Rhodococcus and Exiguobacterium strains,respectively.The optimal temperature and pH for Cr(VI)-removal by the two strains were 35 ℃ and pH 7.0,respectively.The removal of Cr(VI) was enhanced by supplementation of 0.1~0.5 mol/L NO3-,SO42-,and Cl-for strain Chr-9 and by supplementation of 0.1~0.2 mol/L NO3-,SO42,and Cl-for strain Chr-43.The growth and Cr(VI)-removal rate of strain Chr-43 were both enhanced by co-cultivation with strain Chr-9.These results indicated that the removal of chromate by bacterial strains could be affected by temperature,pH,negative ions,and other co-cultured microbes.

Methanogenesis from Anaerobic Crude Oil Degradation Amended with CO_2

Carbon capture and sequestration(CCS) is nowadays regarded as a strategic approach to reduce atmospheric CO2,among which CO2storage in oil reservoir is one of the reliable technologies.However,it is yet not clear whether the stored CO2 can be reduced to CH4 via methanogenesis in oil reservoir.An investigation was thus conducted with a oil production mixture sampled from Qinghai Oilfield in which HCO3-was added to mimic CO2storage in oil reservoir.The result revealed that HCO3addition led to the detection of more relative contents of methanogenic archaea and CH4,along with degradation of aromatic hydrocarbons and asphaltenes,suggesting sequestrated CO2 in Qinghai Oilfield could be transformed to CH4,and resulting in enhanced oil recovery.