A Serratia marcescens and its application

Abstract

The present invention discloses a Serratia marcescens and its application. The Serratia marcescens HZ-XW2 has a preservation number of CCTCC NO: M 20221375, a preservation time of September 5, 2022, and a preservation unit of China Center for Type Culture Collection, located at School of Life Sciences, Wuhan University, Luojia Mountain, Wuchang District, Wuhan City, Hubei Province. It is screened from farmland soil, and the Serratia marcescens HZ-XW2 of the present invention has high degradation ability for various PAEs.

Description

Technical Field

[0001] The invention belongs to the technical field of bioengineering, and particularly relates to Serratia marcescens and application thereof. Background Art

[0002] Phthalate esters (PAEs) are a class of organic compounds generated by esterification of phthalic anhydride and corresponding alcohols under the action of acid catalysts. They are usually colorless, transparent, oily, viscous liquids that are insoluble in water but soluble in organic reagents such as methanol and ether. PAEs can be divided into long-side chain PAEs (DEHP, DnOP, DiNP, etc.) and short-side chain PAEs (DEP, DBP, etc.) according to the length of the side chain. PAEs are mainly added to polyvinyl chloride as plasticizers to make it elastic. They are widely used in materials such as plastic products, medical supplies, home appliances and toys. Statistics from the International Agency for Research on Cancer (IARC) show that the content of PAEs in finished plastics is usually 10% to 60%, and there are reports that the content of mixed PAEs in plastics can be as high as 70%. As a plasticizer, the bond between PAEs and polymers is not a strong chemical bond, but a physical bond (hydrogen bond or van der Waals force). Therefore, slight changes in environmental factors will accelerate the separation of PAEs from polymers into the environment. PAEs are a typical environmental endocrine disruptor, which has hepatotoxicity, reproductive toxicity and "three-hazard" toxicity to humans. PAEs are stable in the environment, difficult to degrade naturally, have a long retention time, and have been detected in soil, atmosphere, and water bodies. Among them, PAEs in the environment are mainly enriched in soil. With the extensive use of plastic products, the problem of soil contamination by PAEs has attracted more and more attention. Among them, DBP, BBP, DEHP, DnOP, etc. are listed as priority controlled pollutants by the US Environmental Protection Agency (EPA). In my country, DEHP and DBP are the PAEs with the highest detected content in soil.

[0003] At present, domestic research on microbial degradation of PAEs mainly focuses on the degradation of single or short side chain PAEs, while the environment is usually polluted by a combination of multiple PAEs, and PAEs with long side chains are more difficult to degrade. Summary of the invention

[0004] In view of the problems existing in the prior art, the object of the present invention is to provide a Serratia marcescens and application thereof.

[0005] In order to achieve the above objectives, the following technical solutions are proposed:

[0006] A strain of Serratia marcescens HZ-XW2, preservation number: CCTCC NO: M20221375, preservation date: September 5, 2022, preservation unit: China Center for Type Culture Collection, address: School of Life Sciences, Wuhan University, Luojia Mountain, Wuchang District, Wuhan, Hubei Province.

[0007] Sample source: Isolated from farmland soil in Baimao Town, Jiujiang District, Wuhu City, Anhui Province (118°46′35″E, 31°1′42″N), preserved in a sterile sampling tube.

[0008] Screening method: Take 5 g of soil sample and add 25 ml of water. After shaking and mixing evenly, let it settle naturally for 30 min. Then, respectively pipette 2 ml of the supernatant into 50 ml of LB and culture in LB. After 3 days of culture, take 2 mL of the upper liquid and add it to 100 mL of BSM medium (added with 100 mg / L DEP, 100 mg / L DBP, 100 mg / L DEHP, 100 mg / L DnOP), and culture at 30 °C and 180 r / min for 4 days; then take 2 mL of the culture and transfer it to a new 100 mL of BSM medium (added with 100 mg / L DEP, 100 mg / L DBP, 100 mg / L DEHP, 100 mg / L DnOP) and repeat the above culture process. After several transfers, dilute the final culture solution and spread it on an LB plate to obtain colonies.

[0009] Application of a strain of Serratia marcescens in degrading phthalic acid esters, the phthalic acid esters include DMP, DEP, DPrP, DBP, BBP, DEHP, DnOP, DiNP. Verify growth with DMP, DEP, DPrP, DBP, BBP, DEHP, DnOP, DiNP as the sole carbon source; test the degradation of 100 mg / L DMP, DEP, DPrP, DBP, BBP, DEHP, DnOP, DiNP by the test strain respectively.

[0010] The beneficial effect of the present invention is that a strain with degradation efficiency for multiple PAEs is screened out. So far, there is no literature report on the degradation of multiple PAEs by Serratia marcescens. Description of the Drawings

[0011] Figure 1 It is the colony morphology of Serratia marcescens HZ-XW2 on an LB plate;

[0012] Figure 2 It is the transmission electron microscope picture of Serratia marcescens HZ-XW2;

[0013] Figure 3 It is the Gram staining result diagram;

[0014] Figure 4 is a phylogenetic tree;

[0015] Figure 5 shows the degradation and production of various PAEs by Serratia marcescens HZ-XW2. Detailed implementation manners

[0016] The present invention will be further described below in conjunction with the accompanying drawings of the specification and embodiments, but the protection scope of the present invention is not limited thereto.

[0017] Example 1

[0018] Sample source: Isolated from farmland soil in Baimao Town, Jiujiang District, Wuhu City, Anhui Province (118°46′35″E, 31°1′42″N), and stored in a sterile sampling tube.

[0019] Take 5 g of soil sample and add 25 ml of water. After shaking and mixing evenly, let it settle naturally for 30 min. Then, respectively pipette 2 ml of the supernatant into 50 ml of LB and culture in LB. After 3 days of culture, take 2 mL of the upper liquid and add it to 100 mL of BSM medium (added with 100 mg / L DEP, 100 mg / L DBP, 100 mg / L DEHP, 100 mg / L DnOP), and culture at 30 °C and 180 r / min for 4 days; then take 2 mL of the culture and transfer it to a new 100 mL of BSM medium (added with 100 mg / L DEP, 100 mg / L DBP, 100 mg / L DEHP, 100 mg / L DnOP) and repeat the above culture process. After several transfers, dilute the final culture solution and spread it on an LB plate. The colony morphology is as Figure 1 shown. The colonies are purplish-red, with a smooth and round surface, neat edges, and relatively large colonies. The transmission electron micrograph ([[]]END]] Figure 2 ) shows that the cells are short rod-shaped, with a single flagellum at the end, and the Gram staining result is negative ([[]]END]] Figure 3 ).

[0020] The obtained strain was identified by physiological and biochemical experiments and 16S rDNA sequence sequencing comparison with reference to Bergey's Manual of Systematic Bacteriology (2012) to determine the genus of the obtained strain.

[0021] Physiological and biochemical experiments and the utilization characteristics of the sole carbon source: The strain HZ-XW2 was identified by some physiological and biochemical experiments. The results are shown in Table 1; in addition, its utilization characteristics for 10 sole carbon sources were also detected. The results are shown in Table 2. In Table 1 and Table 2, "+" indicates a positive test result, and "-" indicates a negative test result.

[0022] Table 1 Physiological and biochemical experimental results of strain HZ-XW2

[0023] Biochemical experiment HZ-XW2 Catalase + Casein hydrolysis + Urease - V-P + Methyl red -

[0024] Table 2 The characteristics of the sole carbon source utilization of strain HZ-XW2

[0025] Single carbon source experiment HZ-XW2 Glucose + Fructose + Sucrose + Lactose + Starch + Acetate - Citrate + Mannose + Sorbitol + Maltose +

[0026] Based on the 16S rDNA sequencing alignment results, phylogenetic analysis was carried out, showing that it has the closest genetic relationship with Serratia marcescens( Figure 4 ). Therefore, combining the physiological and biochemical and 16S rDNA identification results, the strain was identified as Serratiamarcescens HZ-XW2.

[0027] Through 16S rDNA sequence detection, it was found that the sequence results of the strain are shown in SEQ ID NO:1.

[0028] Degradation ability test:

[0029] Using 200 mg / L DMP, DEP, DPrP, DBP, BBP, DEHP, DnOP, DiNP as the sole carbon source to verify growth; testing the degradation of the strain on 200 mg / L DMP, DEP, DPrP, DBP, BBP, DEHP, DnOP, DiNP respectively within 6 days, and the test results are as Figure 5 shown. It can be seen from the figure that after 6 days of cultivation, HZ-XW2 degraded PAEs at 200 mg / L to varying degrees, among which the degradation rate of BBP reached more than 50%. Degradation rate = (initial concentration - residual concentration) / initial concentration * 100%.

Claims

1. A Serratia marcescens Serratia marcescens strain HZ-XW2, deposit number: CCTCC NO: M20221375, deposit date: September 5, 2022, depository: China Center for Type Culture Collection, address: Wuhan University, Wuhan, China.

2. Use of Serratia marcescens as claimed in claim 1 in the degradation of phthalates, wherein the phthalates are DMP, DEP, DPrP, DBP, BBP, DEHP, DnOP and DiNP.

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