Preliminary Study On The Genome Of Steroid Estrogen Degr Adation In Serratia(DH-S01)

At present,the World Health Organization has listed environmental estrogen as t he first carcinogen,and the pollution caused by it has become the third largest enviro nmental problem in the world,which seriously threatens human health and ecological security.The treatment of estrogen pollution is imminent,and it has increasingly beco me a hot issue of social concern.It is the most environmentally friendly and econom ic effective method to remove estrogen from the environment by using the process of microbial degradation and metabolism.It plays an important role in the treatment of estrogen pollution,and has been paid more and more attention.In this paper,a strain named DH-S01 was screened and isolated from soil sampl es near a pharmaceutical factory,which can effectively degrade steroid estrogen.Morp hological observation showed that the colony was round,with neat edge,shiny,orang e red or purple red,easy to pick up,rod-shaped,without flagella.Physiological and b iochemical experiments identified as Gram-negative bacteria,which can use glucose,maltose,sucrose and so on.Combined with molecular biological identification,DH-S01 was identified as Serratia.The results of degradation experiments showed that DHS01 could grow and subculture with steroid estrone and 17?-estradiol as the sole carb on source,and the biodegradation rates of estrone and 17?-estradiol were over 90% i n the experimental period.In order to understand the strain's genome structure and function information and its estrogen degradation mechanism in depth,based on the PacBio sequencing platfor m,the strain was sequenced and analyzed.The genome of the strain DH-S01 consists of a circular chromosome with a size of 5256558 bp,a GC content of 59.53%,and a coding region containing 4874 genes.In addition,the noncoding region contains 84 sporadic repeats,110 tandem repeats,140 noncoding RNA(ncRNA)and 12 gene isl ands.Based on the analysis of average nucleotide identity(ANI),strain DH-S01 was further identified as Serratia nematodiphila.Through functional annotation of the codi ng genes through the database,the results show that DH-S01 has abundant metabolic function genes,which can provide resources for further research on the mechanism of bacterial degradation and metabolism and the development of engineering bacteria wi th high application value.According to the annotation results of gene function and lit erature reports,a total of 13 genes involved in steroid estrogen degradation were iden tified,encoding 9 kinds of sterol estrogen degrading enzymes.It includes catechol 1,2-dioxygenase(cat A),one kind of sterol core degrading enzyme and seven kinds of sterol side chain degrading enzyme.Through PCR cloning technology and RT-PCR tec hnology,the existence of steroid estrogen degrading enzyme and the expression of rel ated genes were confirmed in strain DH-S01.Compared with the genomes of three known Serratia species,DH-S01 has higher colinearity with S.nematodiphila DZ0503SBS1 and S.marcescens Db11,and lower colinearity with S.fonticola DSM4576.In the pan genome,a total of 6471 genes wer e identified,including 3252 homologous genes,which constitute the core genome,incl uding 8 kinds of related coding genes of sterol estrogen degrading enzyme in strain DH-S01.In addition,there are 85 specific genes related to specific environmental ada ptability in DH-S01.The above research results confirmed that DH-S01 has a strong ability to degrad e steroid estrogen at the genetic level.This not only increases the genomic informatio n of Serratia,but also enriches the types of steroid estrogen degrading bacteria.In ad dition,the results of this paper provide further information for the study of steroid es trogen degradation mechanism and degradation-related enzymes,thus providing a theor etical basis for microbial remediation for steroid estrogen contaminated environments.