Characteristics Of Extracellular Sulfur Particles And Sulfur Oxidation Pathway From Thialkalivibrio Versutus D301

Gases containing toxic hydrogen sulfide(H₂S)must be effectively desulfurized before discharge or utilization.As the second generation of microbial desulfurization technology of sulfur oxidizing bacteria,the Thialkalivibrio has the advantages of high processing load,strong impact resistance and wide adaptability.In this study,Thialkalivibrio versutus D301,which was isolated from a saline-alkali lake in Inner Mongolia,was used to study its extracellular sulfur characteristics,regulation and sulfur metabolism by means of surfactant modification,electron microscopy,spectrum and transcriptome analysis.It will provide theoretical support for optimizing the biological desulfurization process,strengthening the desulfurization effect,and deepening people's understanding of the metabolism of sulfur oxidizing bacteria.The main research achievements of this paper are as follows:Firstly,the addition of surfactants Tween-80 and SDS can change the morphology and action characteristics of T.versutus D301 extracellular sulfur.The sulfur particles in the control group were regular and smooth spherical.After adding 0.01 g/L Tween-80,the sulfur particles were long rod-shaped,it's volume increased and the specific surface area decreased,which affected the contact between the sulfur particles and D301,and the utilization of sulfur particles was slow.When 0.3 g/L SDS was added,the sulfur particles were in short rod shape,the production amount was reduced,the utilization rate was fast,and the decay of D301 was also delayed.Secondly,analysis of extracellular sulfur characteristics of T.versutus D301.The characteristic of sulfur particles were characterized by shaking flask culture,electron microscope observation,spectral analysis and dye dyeing.The sulfur particles cultured in shaking flask were light yellow and regular,with a diameter of 0.05-10?m.The particles mainly existed in the form of?-S₈,and their outer membrane was covered with polysaccharides,proteins,nucleic acids and other macromolecules,among which polysaccharides were the main component.This slow down the ageing process of the amorphous sulfur and crystallization,speed up the degradation rate of sulfur,the biological sulfur has better hydrophilicity and utilization.Thirdly,the D301 transcriptome resolves sulfur oxidation pathways.By comparing the growth and metabolism of T.versutus D301 cultured with different sulfur sources,it was found that D301 had higher growth rate and sulfur oxidation activity when thiosulfate was used as sulfur source.Transcriptome analysis determined that polysulfides from thiosulfate and chemical sulfur were oxidized to sulfate in the periplasms by a truncated Sox system(Sox AXYZB).In addition,some of the polysulfides entering the cytoplasm were oxidized to sulfites using a Dsr like system,which were further oxidized to sulfites by Sox B or Soe ABC.Finally,the effect of Halomonas mongoliensis Js-01 on the sulfur metabolism of T.versutus D301.A strain was screened by plate crossing and named as Halomonas mongoliensis Js-01.The fluorescence quantitative PCR instrument was used to monitor the mixed bacterial system and the metabolic curve,it was found that the presence of Js-01significantly inhibited the growth of D301 and reduced the accumulation of extracellular sulfur particles.At the same time,it also slowed down the utilization of Na₂S₂O₃ by D301and sharply reduced the production of SO₄^2-,which ultimately led to the decline of the overall desulfurization efficiency.In conclusion,the whole sulfur oxidation process of Thialkalivibrio versutus can be explained by transcriptome analysis.The modification of biosulfide by surfactants and the characterization of biosulfide provide a theoretical basis for the analysis of the intermediate pathway and regulation of sulfur oxidation process.In industry,the study of mixed bacteria can provide a basis for solving the problem of mixed bacteria existing in the desulfurization application of Thialkalivibrio versutus.