| At present,heavy metal pollution of water in some regions of China is serious,it affects the health of local residents.The treatments of heavy metals wastewater include the physical,chemical and biological methods.The first two methods are suitable for treatment of the high-concentration heavy metals wastewater.However,the biological method plays an important role in the treatment of low concentration heavy metal sewage.Copper poisoning can cause damage to multiple tissues and organs such as the nervous system,cardiovascular system,digestive system,etc.But copper toxicity is easily neglected by residents.The purpose of this research is to screen out copper-resistant bacteria,and insight into its copper resistance mechanism,excepting of their application in the sewage treatment.There were 98 strains of copper-resistant bacteria isolated from intertidal zone sediments,which were affiliated to 12 genera in total.The three dominant species were Shewanella,Vibrio,Bacillus,and the sum of the three strains accounted for 69.39% of the total;16S rRNA sequence alignment during the screening process revealed a suspected new species Y2-5 with a sequence similarity of 98.5% to its closest strain.Y2-5 was finally determined as a new species through molecular taxonomy;morphology,physiology and biochemical indicators and chemistry taxonomy.Five strains of copper-resistant bacteria including YLB-01,YLB-06,YLB-07,YLB-08,and YLB-09 were screened from 81 strains of deep-sea-derived bacteria.YLB-06,07,08,and 09 belonged to Shewanella,YLB-01 belongs to the genus Microbacterium,and the number of copper-resistant strains accounts for 6% of the total.Microbacterium YLB-01 is the strongest copper resistance which was used to investigate its ability to remove copper ions under different reaction conditions.The results showed that the optimal reaction time was 30 minutes,the optimal pH was 6,and the optimal initial inoculation volume was 4 g/L.It was found to follow the second-order kinetic equation.through the establishment of a kinetic model during the reaction process;which indicates that the process of copper ion removal may be a composite effect of multiple adsorption mechanisms.The specific action mechanism needs to be further analyzed.The copper resistance mechanism was initially explored through a genome analysis of YLB-01,A total of 2919864 bp was obtained by whole genome sequencing,and A total of 2819 genes were annotated.We found more than 40 genes related to copper resistance including copABCZ,pcoC,csoR,ricR,etc.It is speculated that it has a P-type ATPase-mediated efflux system and a plasmid-coded copper resistance system CopABCD.It can be concluded that the distribution of copper-resistant bacteria between species is different in the intertidal zone.In the deep sea,the number of copper-resistant bacteria is small,and the distribution of the genus and species is relatively single.The copper ion removal experiment made the preliminary laboratory data for YLB-01,which was used as a microbial adsorbent to treat copper-containing heavy metal wastewater.And initially explored the copper resistance mechanism of YLB-01. |
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