Study On The Influence Mechanism Of Typical Microplastics On The Desulfurization Performance Of Desulfovibrio Vulgaris

Based on the serious damage to the water environment caused by sulfatecontaining wastewater,sulfate-reducing bacteria,as an important biological desulfurization treatment method,have become a research hotspot in the field of water pollution control in recent years.In addition,with the widespread detection of microplastics in natural water bodies,which will inevitably have an important impact on the survival and development of microorganisms in the environment.However,there are relatively few studies on the effects of microplastics on the survival and development of sulfate-reducing bacteria.In this paper,the Desulfovibrio vulgaris was used as a model strain,and polyamide(PA)and polystyrene(PS)were used as typical microplastics to study the changes in its growth and desulfurization performance under the stress of microplastics.And long-term microplastic acclimation was carried out on the Desulfovibrio vulgaris,and the change process of its desulfurization performance during the acclimation process was recorded.At the same time,from the perspectives of growth and proliferation,desulfurization performance,sludge concentration and performance,enzyme activity and gene expression level,the effect of microplastics on the desulfurization performance of the Desulfovibrio vulgaris was discussed.yields the following results:(1)Two typical microplastics PA and PS with different concentrations exist in their growth environment,which have inhibited the growth and reproduction of the Desulfovibrio vulgaris to varying degrees.After a long-term domestication of microplastics,the Desulfovibrio vulgaris has a certain adaptability and has recovered a certain level of growth and reproduction.(2)Microplastic stress reduced the desulfurization performance of the Desulfovibrio vulgaris.Although common Desulfovibrio had certain adaptability to this,it was still difficult to restore the original desulfurization performance level.(3)The presence of microplastics greatly reduces the concentration of activated sludge formed by the Desulfovibrio vulgaris,and its activated sludge performance is also greatly affected.The existence of microplastics can also cause the accumulation of SMP concentration,which has a toxic effect on the Desulfovibrio vulgaris.(4)The two microplastics also had a certain effect on the activity of the bacteria,which was reflected in the reduction of their enzymatic activities,After long-term domestication,its total enzyme activity gradually recovered to its original activity level,but whether the activity levels of various enzymes in the total enzyme activity are consistent with the original level remains to be further studied.(5)The expression level of the aps.A gene encoding APS reductase has been significantly decreased after long-term stress of microplastics,and the decrease in the expression level of this gene will directly lead to the reduction of the sulfur metabolism intensity of Desulfovibrio vulgaris.It has a serious impact on its desulfurization performance.At present,the research on the influence of microplastics on microorganisms mainly focuses on the accumulation of microplastics in microorganisms,the formation of biofilms on the surface of microplastics,and the degradation of microplastics by microorganisms.However,there are relatively few studies on the effects of microplastic stress on microbial life activities,especially on the desulfurization performance of SRB.SRB plays an important role not only in the sulfur cycle in nature,but also in the fields of biological desulfurization and biological corrosion.Due to the ubiquitous existence of microplastics in nature,the research on the effect of microplastic stress on the desulfurization performance of Vibrio desulfurization and its mechanism has important practical significance for the application of SRB in the treatment of sulfate-containing wastewater and the prevention and control of biological corrosion by SRB.