Escherichia coli and application thereof in tire rubber desulfurization

Abstract

The invention relates to Escherichia sp. And an application of the Escherichia sp. In tire rubber desulfurization, the name of the Escherichia sp. Is CSUFT-2024-Rubbr Desulfurization, the Escherichia sp. Is preserved in the General Microbiological Culture Collection Center of the China Committee for Culture Collection of Microorganisms on October 21, 2024, and the preservation number is CGMCC No.32280. The invention further discloses a preparation method of the Escherichia sp. According to the application, the Escherichia sp. Is used for desulfurization and degradation of tire rubber. The Escherichia coli disclosed by the invention is high in desulfurization and degradation capability, short in desulfurization and degradation time and high in desulfurization rate. The method is simple in application process, low in cost and suitable for industrial production.

Description

Technical Field

[0001] The present invention specifically relates to a strain of Escherichia and its application in the desulfurization of tire rubber. Background Art

[0002] In modern society, rubber (Tire Rubber, TR) is widely used and is one of the essential polymer materials in life. The amount of waste rubber generated in China has been increasing year by year, reaching more than 17 million tons, and about 65% of it is vehicle tire rubber. Due to the three-dimensional cross-linked structure of rubber and the presence of related additives contained therein, the degradation period of waste rubber is prolonged, posing a huge potential environmental risk. Therefore, the effective management of waste tire rubber has become an important issue of global concern. Currently, only a small part of waste rubber is successfully recycled and properly treated, while most waste rubber is disposed of by landfilling and incineration, which will undoubtedly harm human health and the environment.

[0003] Although rubber raw materials and raw rubber do not contain sulfur, due to the need for vulcanization treatment during the production process of rubber, sulfur elements are added to rubber as vulcanizing agents. Due to the stable three-dimensional network structure of waste rubber products, it is difficult to degrade naturally, resulting in a series of environmental and resource waste problems. Research has found that many microorganisms can not only use rubber as a source of carbon and energy but also consume sulfur, and the microbial desulfurization method has the advantages of mild reaction conditions, low energy consumption, environmental friendliness, and is conducive to the reuse or recycling of waste rubber as new products. Therefore, the microbial desulfurization of waste rubber has become a hot research direction.

[0004] CN103923945A discloses a method for desulfurizing and regenerating waste rubber using microbial bacteria, which utilizes the desulfurase produced during the co-cultivation and metabolism process of microbial bacteria and waste vulcanized rubber powder to catalytically break the sulfur-sulfur or sulfur-carbon cross-linking bonds on the surface of vulcanized rubber, so as to achieve the purpose of rubber desulfurization by de-crosslinking a certain depth range on the surface of waste vulcanized rubber particles. However, the desulfurization time used in this method is as long as 20 days, and the desulfurization rate is only 13.5%.

[0005] CN104962601A discloses a new method for biological desulfurization and regeneration of waste vulcanized rubber during the mixed growth process of two microbial bacteria, which utilizes the mixed growth of two microbial bacteria and co-cultivates with waste rubber for desulfurization. Specifically, it utilizes the desulfurase produced during the metabolism process of the mixed bacteria of Sphingomonas and Gordonia to catalytically break the sulfur cross-linking bonds in rubber, thereby achieving the purpose of desulfurizing and regenerating rubber. However, the desulfurization time used in this method is as long as 20 days, and the desulfurization rate is only 41.5%.

[0006] CN101456968A discloses a method for regenerating waste rubber using microorganisms, which utilizes the enzymes and sulfhydryl-containing metabolites produced by Saccharomyces cerevisiae cells during growth to react with waste rubber, breaking the sulfur cross-links of the rubber and desulfurizing and regenerating it to achieve the purpose of targeted desulfurization. However, this method does not specifically mention the changes in the surface structure of the rubber and the relevant data of desulfurization during the entire microbial desulfurization process.

[0007] Therefore, it is urgent to further find a desulfurizing bacterium with strong desulfurization and degradation ability, short desulfurization and degradation time, and high desulfurization rate, as well as an application in the desulfurization of tire rubber that has a simple process, low cost, and is suitable for industrial production. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to overcome the above-mentioned defects existing in the prior art and provide an Escherichia bacterium with strong desulfurization and degradation ability, short desulfurization and degradation time, and high desulfurization rate.

[0009] The further technical problem to be solved by the present invention is to overcome the above-mentioned defects existing in the prior art and provide an application of Escherichia bacterium in the desulfurization of tire rubber that has a simple process, low cost, and is suitable for industrial production.

[0010] The technical solution adopted by the present invention to solve its technical problems is as follows: An Escherichia bacterium ( Escherichia sp. ), the name of the Escherichia bacterium ( Escherichia sp. ) is CSUFT-2024-Rubbr desulfurization, which was deposited at the General Microbiological Center of the China Committee for Culture Collection of Microorganisms on October 21, 2024, with the deposit number CGMCC No. 32280. The deposit address is: No. 3, Beichen West Road, Chaoyang District, Beijing, Institute of Microbiology, Chinese Academy of Sciences.

[0011] Preferably, the 16S rRNA gene sequence of the Escherichia bacterium ( Escherichia sp. ) is as shown in SEQ ID No. 1.

[0012] The screening and purification method of the Escherichia bacterium ( Escherichia sp. ) strain includes the following steps: 1) Rinse the colonies growing on the waste tire rubber stacked in the outdoor environment with sterile water, and then inoculate them into a fermentation medium supplemented with tire rubber. After culturing and enriching, remove the residual tire rubber to obtain an enriched culture; in the fermentation medium, the addition amount of tire rubber is 4 - 6 g / 100 mL; the temperature for culturing and enriching is 28 - 32 °C, the rotation speed is 150 - 250 rpm, and the time is 140 - 300 h; 2) Use the standard dilution coating method to spread the enriched culture obtained in step 1) on LB agar medium, incubate it, randomly select single colonies, and spread them on fresh LB agar medium. Repeat the single colony streak isolation procedure 3 times to prove the culture purity, and finally successfully isolate multiple bacterial strains; the temperature for incubation is 28 - 32 °C, and the time is 60 - 180 h; the bacterial strains are routinely stored in a 40 - 60% (v / v) glycerol suspension at -15 °C to -25 °C; 3) Inoculate the multiple bacterial strains isolated in step 2) into the fermentation medium supplemented with tire rubber respectively, conduct fermentation, and measure the growth ability of the strains and the weight loss of the tire rubber. Screen out one strain that grows significantly in the fermentation medium supplemented with tire rubber and has the highest weight loss of the tire rubber as the screening strain for desulfurization and degradation of tire rubber; in the fermentation medium, the addition amount of tire rubber is 4 - 6 g / 100 mL; the temperature for fermentation is 28 - 32 °C, the rotation speed is 150 - 250 rpm, and the time is 140 - 300 h.

[0013] Identification of the screening strain: Identify the screened strain by sequencing the polymerase chain reaction (PCR) product of genomic DNA, including the following steps: 1) Isolate the genomic DNA of the screening strain, and use primers 27F (AGAGTTTGATCMTGGCTCAG) and 1492R (TACGGYTACCTTGTTACGACTT) to perform PCR amplification on the 16S rRNA gene sequence of the screening strain; 2) After sequencing the amplified 16S rRNA gene sequence obtained in step 1), compare the obtained 16S rRNA gene sequence with the bacterial type species recorded in the GenBank database. Based on the 16S rRNA gene sequence, construct a phylogenetic tree using the neighbor-joining (NJ) method to determine the closest phylogenetic neighbor and the corresponding similarity. Finally, according to the morphological characteristics of the strain and the sequencing results of the 16S rRNA gene sequence, identify that the screening strain belongs to Escherichia ( Escherichia sp. ).

[0014] The colony characteristics of the Escherichia ( Escherichia sp. ) are as follows: The colony morphology is milky white and opaque, with a smooth, moist, and shiny surface. Identified by the Gram staining reaction, the result shows that it is a Gram-negative bacterium.

[0015] The cell morphological characteristics of the Escherichia ( Escherichia sp. ) are as follows: The cells are rod-shaped, with a length of about 1 - 6 μm and a width of about 0.4 - 0.7 μm, without endospores, and with flagella.

[0016] The partial physiological and biochemical characteristics of the Escherichia bacteria ( Escherichia sp. ) are as follows: the growth temperature range is 20 - 35 °C, the pH value range is 6.0 - 7.5, it shows aerobic characteristics, and moves by flagella.

[0017] The technical solution adopted by the present invention to further solve its technical problems is as follows: an application of an Escherichia bacteria ( Escherichia sp. ) in the desulfurization of tire rubber, using the Escherichia bacteria ( Escherichia sp. ) for the desulfurization and degradation of tire rubber. During the biodegradation process of the tire rubber by the Escherichia bacteria of the present invention, not only can it grow using carbon in the tire rubber as a carbon source, but it can also simultaneously cut the C = C bonds in the main chain within the crosslinked network of the tire rubber and the sulfur bonds (S - S and C - S bonds) of the crosslinked vulcanization bridges, and through its metabolic pathway, it can convert the sulfur compounds in the vulcanized rubber into other forms, such as elemental sulfur or sulfates, thereby achieving the consumption of sulfur and causing the crosslinking breakage or main chain polymer breakage of the tire rubber, and converting inorganic sulfur into organic sulfur to enter the amino acid metabolism (cysteine synthesis), ultimately effectively reducing the sulfur content in the tire rubber.

[0018] Preferably, the method for desulfurizing and degrading the tire rubber includes the following steps: (1) After grinding the tire rubber, perform sterilization treatment to obtain sterilized tire rubber powder; (2) First, inoculate the Escherichia bacteria ( Escherichia sp. ) strains into the strain activation medium for activation, and then inoculate the obtained activated culture solution into the fermentation medium for fermentation to the stable stage to obtain a stable - phase fermentation broth; (3) Add the sterilized tire rubber powder obtained in step (1) to the stable - phase fermentation broth obtained in step (2) for desulfurization fermentation to obtain desulfurized tire rubber powder.

[0019] Preferably, in step (1), the sulfur content of the tire rubber is 2 - 4%.

[0020] Preferably, in step (1), after grinding, it passes through an 80 - mesh sieve.

[0021] Preferably, in step (1), the sterilization treatment means: first soak the ground tire rubber powder with ethanol, then place the soaked tire rubber powder in a ventilated place to volatilize the ethanol, and finally perform high - pressure sterilization. The purpose of the sterilization treatment is to reduce the interference of other miscellaneous bacteria.

[0022] Preferably, the soaking time is 36 - 48 h.

[0023] Preferably, the volatilization time is 3 - 4 h.

[0024] Preferably, the temperature for autoclaving is 115 - 125 °C, the pressure is 0.10 - 0.12 MPa, and the time is 0.8 - 1.2 h.

[0025] Preferably, in step (2), the inoculation amount of the Escherichia coli ( Escherichia sp. ) strain is 0.08 - 0.12% (v / v).

[0026] Preferably, in step (2), the activation temperature is 28 - 32 °C, the rotation speed is 150 - 250 rpm, and the activation time is 18 - 30 h.

[0027] Preferably, in step (2), the OD 600 of the activated culture medium is 0.6 - 1.0.

[0028] Preferably, in step (2), the inoculation amount of the activated culture medium is 8 - 12% (v / v).

[0029] Preferably, in step (2), the fermentation temperature is 28 - 32 °C, the rotation speed is 150 - 250 rpm, and the time is 10 - 14 h.

[0030] Preferably, in step (2), the OD 600 of the fermentation broth in the stationary phase after fermentation is 0.6 - 1.0.

[0031] Preferably, in step (2), the formula of the strain activation medium is: in every 1000 mL of deionized water, it contains 8 - 12 g of polypeptone, 1.5 - 2.5 g of yeast powder, and 0.5 - 1.5 g of MgSO4·H2O.

[0032] Preferably, in step (2), the formula of the fermentation medium is: in every 1000 mL of deionized water, it contains 3 - 5 g of KH2PO4, 3 - 5 g of K2HPO4·H2O, 0.6 - 1.0 g of MgSO4·7H2O, 0.2 - 0.6 g of NH4Cl, 8 - 12 g of Na2S2O3·5H2O, 0.005 - 0.015 g of CaCl2, 1.5 - 2.5 g of glucose, 0.8 - 1.2 g of peptone, and 0.08 - 0.12 g of yeast powder.

[0033] Preferably, in step (3), the addition amount of the sterilized tire rubber powder is 4 - 6 g / 100 mL of fermentation medium.

[0034] Preferably, in step (3), the temperature for desulfurization fermentation is 28 - 32 °C, the rotation speed is 150 - 250 rpm, and the time is 140 - 300 h (more preferably 150 - 250 h).

[0035] The beneficial effects of the present invention are as follows: (1) The Escherichia bacterium of the present invention has strong desulfurization and degradation ability and short desulfurization and degradation time. Within 168 hours of desulfurization time, the desulfurization rate of organic elemental analysis can reach as high as 37.61%, and the desulfurization rate of surface analysis can reach 17.23%, showing high desulfurization ability. It can effectively reduce the sulfur content in rubber, has excellent characteristics of industrial application strains, and has broad industrial application potential. (2) The application process of the present invention is simple and has low cost, which is suitable for industrial production. The Escherichia bacterium of the present invention can be widely applied in the rubber industry, environmental protection industry and other related industries. Description of the Drawings

[0036] Figure 1 is the optical microscope morphology diagram of the Escherichia bacterium ( Escherichia sp. ) of Example 1 of the present invention; Figure 2 is the growth curve diagram of the strain in the culture medium with TR added and the control culture medium without TR added in the Escherichia bacterium ( Escherichia sp. ) of Example 1 of the present invention (calculated from the inoculation of the activated culture solution into the fermentation medium); Figure 3 is the dry weight diagram of TR before and after fermentation of the screened strain in step 3) of screening and purification of the Escherichia bacterium ( Escherichia sp. ) of Example 1 of the present invention; Figure 4 is the phylogenetic evolution tree constructed based on the 16S rDNA gene sequence of the Escherichia bacterium ( Escherichia sp. ) of Example 1 of the present invention; Figure 5 is the scanning electron microscope diagram of the surface of TR before and after desulfurization fermentation of the Escherichia bacterium ( Escherichia sp. ) in Application Example 1 of the present invention ((a) 300 times before desulfurization fermentation, (b) 1000 times before desulfurization fermentation, (c) 300 times after desulfurization fermentation, (d) 1000 times after desulfurization fermentation); Figure 6 is the Fourier infrared spectrum diagram of the surface of TR before and after desulfurization fermentation of the Escherichia bacterium ( Escherichia sp. ) in Application Example 1 of the present invention; Figure 7 is the relative sulfur content comparison diagram of TR before and after desulfurization fermentation of the Escherichia bacterium ( Escherichia sp. ) in Application Example 1 of the present invention; Figure 8 is the scanning electron energy spectrum diagram of TR before and after desulfurization fermentation of the Escherichia bacterium ( Escherichia sp. ) in Application Example 1 of the present invention. Detailed Embodiments

[0037] The present invention will be further described below in conjunction with embodiments and the accompanying drawings.

[0038] The waste tire rubber used in the embodiments of the present invention (sulfur content in surface analysis is 2.67%, sulfur content in organic elemental analysis is 2.34%) was purchased from Huayi Rubber Factory; the formula of the strain activation medium used in the embodiments of the present invention is: in every 1000 mL of deionized water, it contains 10 g of polypeptone, 2 g of yeast powder and 1 g of MgSO4·H2O; the formula of the fermentation medium used in the embodiments of the present invention is: in every 1000 mL of deionized water, it contains 4 g of KH2PO4, 4 g of K2HPO4·H2O, 0.8 g of MgSO4·7H2O, 0.4 g of NH4Cl, 10 g of Na2S2O3·5H2O, 0.01 g of CaCl2, 2 g of glucose, 1 g of peptone and 0.1 g of yeast powder; the LB (Luria-Bertani) agar medium used in the embodiments of the present invention is a general nutrient medium and is prepared according to the standard formula; before use, all the media in the embodiments of the present invention are first autoclaved at 121°C and 0.1 MPa for 20 min; the raw materials or chemical and biological reagents used in the embodiments of the present invention, unless otherwise specified, are all obtained through conventional commercial channels.

[0039] An Escherichia bacterium ( Escherichia sp. ) Example 1 The Escherichia bacterium ( Escherichia sp. ) is named CSUFT-2024-Rubbrdesulfurization and was deposited on October 21, 2024 at the General Microbiological Center of the China Committee for Culture Collection of Microorganisms, with the deposit number CGMCC No. 32280. The deposit address is: No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing, Institute of Microbiology, Chinese Academy of Sciences; the 16S rRNA gene sequence of the Escherichia bacterium ( Escherichia sp. ) is as shown in SEQ ID No. 1.

[0040] The screening and purification method of the Escherichia bacterium ( Escherichia sp. ) strain includes the following steps: 1) Rinse the colonies growing on the waste tire rubber (TR) stacked in the outdoor environment with sterile water, and then inoculate them into 100 mL of fermentation medium supplemented with 5 g of TR. In an incubator shaker at 30°C with a rotation speed of 200 rpm, cultivate and enrich for 168 h, and then remove the residual TR to obtain the enriched culture. 2) Spread the enriched culture obtained in step 1) on LB agar medium by the standard dilution coating method, place it in an incubator, and culture it at 30 °C for 120 h. Randomly select single colonies and spread them on fresh LB agar medium. Repeat the single colony streak isolation procedure 3 times to prove the culture purity. Finally, successfully isolate multiple bacterial strains and store them routinely in 50% (v / v) glycerol suspension at -20 °C; 3) Inoculate the multiple bacterial strains isolated in step 2) into 100 mL fermentation medium supplemented with 5 g of TR respectively, and ferment them in a constant temperature shaker at 30 °C and a rotation speed of 200 rpm for 168 h. Measure the growth ability of the strains and the weight loss of TR, and screen out one strain with significant growth in the fermentation medium supplemented with TR and the highest TR weight loss as the screening strain for desulfurizing and degrading TR; The morphological appearance of the screening strain under an optical microscope is as Figure 1 shown; The growth curves of the screening strain in 100 mL fermentation medium supplemented with 5 g of TR and in a control medium without TR are as Figure 2 shown; The dry weight of TR before and after fermentation of the screening strain is as Figure 3 shown, and the weight loss rate of TR is 2.08%.

[0041] Identification of the screening strain: Identify the screened strain by sequencing the PCR products of genomic DNA, including the following steps: 1) Isolate the genomic DNA of the screening strain using the TIANamp Bacteria DNA Kit (Tiangen, China), and perform PCR amplification of the 16S rRNA gene sequence of the screening strain using primers 27F (AGAGTTTGATCMTGGCTCAG) and 1492R (TACGGYTACCTTGTTACGACTT); 2) After sending the amplified 16S rRNA gene sequence obtained in step 1) to Qingdao Biotechnology Co., Ltd. (Beijing, China) for sequencing, compare the obtained 16S rRNA gene sequence (as shown in SEQ ID No.1) with the bacterial species recorded in the GenBank database of the National Center for Biotechnology Information (NCBI). Based on the 16S rRNA gene sequence, construct a phylogenetic tree using NJ (as Figure 4 shown) to determine the closest phylogenetic neighbors and the corresponding similarities. Finally, according to the morphological characteristics of the strain and the sequencing results of the 16S rRNA gene sequence, it is found that the 16S rRNA gene sequence of the screening strain is related to the genus Escherichia ( Escherichia sp.The similarity with ( Escherichia sp. ).

[0042] In order to further study the microbial identification characteristics of this strain, the identified screened strain Escherichia coli ( Escherichia sp. ) was inoculated on LB medium and cultured at a pH value of 7.0 and a culture temperature of 30 °C for 12 h; its colony characteristics, cell morphological characteristics and some physiological and biochemical characteristics were observed.

[0043] The colony characteristics of the Escherichia coli ( Escherichia sp. ) are as follows: The colony morphology is milky white and opaque, with a smooth, moist and shiny surface. Identified by Gram staining reaction, the result shows that it is a Gram-negative bacterium, as Figure 1 shown.

[0044] The cell morphological characteristics of the Escherichia coli ( Escherichia sp. ) are as follows: The cells are rod-shaped, about 1 - 6 μm in length and about 0.4 - 0.7 μm in width, without spores and with flagella, as Figure 1 shown.

[0045] Some physiological and biochemical characteristics of the Escherichia coli ( Escherichia sp. ) are as follows: The growth temperature range is 20 - 35 °C, the pH value range is 6.0 - 7.5, showing aerobic characteristics and moving by flagella.

[0046] Example 1 of the application of an Escherichia coli ( Escherichia sp. ) in the desulfurization of tire rubber The Escherichia coli ( Escherichia sp. ) was used for the desulfurization and degradation of waste tire rubber; the desulfurization and degradation method of the waste tire rubber includes the following steps: (1) After grinding the waste tire rubber and passing it through an 80-mesh sieve, it was sterilized: First, the ground waste tire rubber powder was soaked in ethanol for 42 h, then the soaked waste tire rubber powder was placed in a ventilated place to volatilize ethanol for 3.5 h, and finally, it was autoclaved at 121 °C and 0.1 MPa for 1 h to obtain sterilized tire rubber powder; (2) First, the Escherichia coli strain of Example 1 of the present invention ( Escherichia sp. ) was inoculated into the strain activation medium at an inoculation amount of 0.1% (v / v), and activated at 30 °C and a rotation speed of 200 rpm for 24 h until OD 600 reached 0.80. Then, the obtained activated culture solution was inoculated into 100 mL of fermentation medium at an inoculation amount of 10% (v / v), placed in a constant temperature shaking incubator, and fermented at 30 °C and a rotation speed of 200 rpm for 12 h until the stable stage OD 600 reached 0.75 to obtain a stable-phase fermentation broth; (3) Add 5 g of the sterilized tire rubber powder obtained in step (1) to the fermentation broth in the stationary phase obtained in step (2), place it in a constant temperature shaking incubator, and carry out desulfurization fermentation at 30 °C and a rotation speed of 200 rpm for 168 h to obtain desulfurized tire rubber powder.

[0047] To further verify the desulfurization ability of the strain on TR, TR before and after desulfurization fermentation was analyzed by scanning electron microscopy, Fourier transform infrared spectroscopy, organic elemental analysis, and scanning electron energy spectrometer analysis.

[0048] (1) Scanning electron microscopy analysis of TR: Using a scanning electron microscope (EVO MA25, Zeiss), the morphological changes on the surface of TR after 168 h of desulfurization fermentation in Example 1 of Escherichia coli ( Escherichia sp. ) of the present invention were evaluated at magnifications of 300 times and 1000 times.

[0049] As Figure 5 shown in (a) and (b), the surface of TR without desulfurization fermentation is relatively smooth and flat, and the structure is dense; as Figure 5 shown in (c) and (d), the dense structure on the surface of TR after desulfurization fermentation in Example 1 of Escherichia coli ( Escherichia sp. ) of the present invention is damaged, and small holes appear.

[0050] (2) Fourier transform infrared spectroscopy analysis of TR: Using FTIR spectroscopy to further determine the breakage of the main chain and sulfur bridges of the TR polymer during desulfurization, so as to monitor the change of the surface structure of TR during the whole desulfurization fermentation process in Example 1 of Escherichia coli ( Escherichia sp. ) of the present invention, that is, the modification of functional groups.

[0051] As Figure 6 shown, the characteristic peak at 650 cm -1 corresponds to the C=C bond, which is a characteristic of the rubber main chain. After the desulfurization fermentation treatment in Example 1 of Escherichia coli ( Escherichia sp. ) of the present invention, the intensity of the C=C bond peak decreases relative to that of TR without desulfurization fermentation, indicating that its surface structure is broken; the characteristic peak at 1401 cm -1 corresponds to the C=O bond. When the C=C bond breaks, the C=O bond will be generated. After the desulfurization fermentation treatment in Example 1 of Escherichia coli ( Escherichia sp. ) of the present invention, the peak intensity increases. The C=O bond appears in the range of 1401 cm -1 , indicating that the bacteria have undergone an oxidation reaction; in addition, the characteristic peak at 1641 cm -1 corresponds to the C-S bond, which is a sign of the rubber cross-linking sulfur bridge. After the desulfurization fermentation treatment in Example 1 of Escherichia coli ( Escherichia sp.)After the desulfurization fermentation treatment in Example 1, the peak intensity decreased, indicating that the C-S bond was cleaved; the characteristic peak at 1074 cm -1 corresponded to the S=O bond and O=S=O, indicating the formation of intermediate products. After the desulfurization fermentation treatment in Example 1 of Escherichia coli ( Escherichia sp. ), the peak intensity increased. In summary, it shows that Escherichia coli ( Escherichia sp. in Example 1 of the present invention can not only oxidatively cleave the C=C bond on the main chain of TR, but also oxidatively cleave the C-S bond on the crosslinked thioether bridge to generate new carbonyl bonds C=O, sulfone bonds O=S=O and sulfoxide bonds S=O.

[0052] (3) Organic elemental analysis: The desulfurized tire rubber powder after the desulfurization fermentation treatment was fully combusted in a high-temperature pure oxygen environment, and the sulfur content in the desulfurized tire rubber powder before and after the desulfurization fermentation in Example 1 of Escherichia coli ( Escherichia sp. ) of the present invention was determined by organic elemental analysis (Vario MACRO cube, Elementar).

[0053] As Figure 7 shown, in step (3) of the application example of the present invention, when the fermentation time was 0 h, the relative sulfur content of TR without desulfurization fermentation was 2.34%. When the desulfurization fermentation time was 168 h, Escherichia coli ( Escherichia sp. ) in Example 1 of the present invention showed a high desulfurization ability for TR. The relative sulfur content of TR was only 1.46%, and the desulfurization rate was 37.61%, indicating that Escherichia coli ( Escherichia sp. ) in Example 1 of the present invention could effectively reduce the sulfur content in TR.

[0054] (4) Scanning electron energy spectrometer analysis: SEM-EDS (Aztec X-Max 80, oxford) was used to analyze the surface element distribution of TR before and after the desulfurization fermentation in Example 1 of Escherichia coli ( Escherichia sp. ). The surface of TR before and after the desulfurization fermentation was scanned using an EDS spectrometer to measure the distribution of S on the surface of TR, the corresponding surface spectrum, and the weight percentage.

[0055] As Figure 8 shown, after 168 h of desulfurization fermentation in Example 1 of Escherichia coli ( Escherichia sp. ), the surface element content of TR changed significantly. The sulfur content on the surface of TR decreased from 2.67% to 2.21%, and the desulfurization rate was 17.23%, indicating that Escherichia coli ( Escherichia sp. ) in Example 1 of the present invention could effectively reduce the sulfur content in TR.

Claims

1. An Escherichia bacterium ( Escherichia sp. ), characterized in that: The Escherichia bacterium ( Escherichia sp. ) is named CSUFT-2024-Rubbr desulfurization and was deposited at the General Microbiology Center of the China Microbial Culture Collection Center on October 21, 2024, with the deposit number CGMCC No. 32280.

2. The Escherichia bacterium according to claim 1 ( Escherichia sp. ), characterized in that: The 16S rRNA gene sequence of the Escherichia coli ( Escherichia sp. ) is shown in SEQ ID No.

1.

3. Use of Escherichia bacteria as described in claim 1 or 2 Escherichia sp. in the desulfurization of tire rubber, characterized in that: Use the Escherichia bacterium according to claim 1 or 2 ( Escherichia sp. ) for desulfurization degradation of tire rubber.

4. Use of the Escherichia bacterium according to claim 3 ( Escherichia sp. ) in the desulfurization of tire rubber, characterized in that: The method for desulfurizing and degrading tire rubber comprises the following steps: (1) After grinding the tire rubber, perform a sterilization treatment to obtain sterilized tire rubber powder; (2) First, inoculate the Escherichia coli strain described in claim 1 or 2 ( Escherichia sp. ) into a strain activation medium for activation, and then inoculate the obtained activated culture solution into a fermentation medium and ferment it to the stable stage to obtain a fermentation broth in the stationary phase; (3) Add the sterilized tire rubber powder obtained in step (1) to the fermentation broth in the stationary phase obtained in step (2), and carry out desulfurization fermentation to obtain desulfurized tire rubber powder.

5. The application of the Escherichia coli according to claim 4 Escherichia sp. in the desulfurization of tire rubber, characterized in that: In step (1), the sulfur content of the tire rubber is 2-4%; after grinding, it is sieved through a 80-mesh sieve; the sterilization treatment means: first soak the ground tire rubber powder with ethanol, then place the soaked tire rubber powder in a ventilated place to volatilize the ethanol, and finally perform high-pressure sterilization; the soaking time is 36-48 h; the volatilization time is 3-4 h; the temperature of the high-pressure sterilization is 115-125 °C, the pressure is 0.10-0.12 MPa, and the time is 0.8-1.2 h.

6. Use of the Escherichia bacterium according to claim 4 or 5 ( Escherichia sp. ) in the desulfurization of tire rubber, characterized in that: In step (2), the inoculation amount of the Escherichia coli ( Escherichia sp. ) strain is 0.08 - 0.12% (v / v); the activation temperature is 28 - 32 °C, the rotation speed is 150 - 250 rpm, and the activation time is 18 - 30 h; the OD 600 of the activated culture solution is 0.6 - 1.0; the inoculation amount of the activated culture solution is 8 - 12% (v / v); the fermentation temperature is 28 - 32 °C, the rotation speed is 150 - 250 rpm, and the time is 10 - 14 h; the OD 600 of the fermentation broth in the stationary phase after fermentation is 0.6 - 1.0; the formula of the strain activation medium is: in every 1000 mL of deionized water, it contains 8 - 12 g of polypeptone, 1.5 - 2.5 g of yeast powder, and 0.5 - 1.5 g of MgSO4·H2O; the formula of the fermentation medium is: in every 1000 mL of deionized water, it contains 3 - 5 g of KH2PO4, 3 - 5 g of K2HPO4·H2O, 0.6 - 1.0 g of MgSO4·7H2O, 0.2 - 0.6 g of NH4Cl, 8 - 12 g of Na2S2O3·5H2O, 0.005 - 0.015 g of CaCl2, 1.5 - 2.5 g of glucose, 0.8 - 1.2 g of peptone, and 0.08 - 0.12 g of yeast powder.

7. Use of the Escherichia bacterium according to claim 4 or 5 Escherichia sp. in the desulfurization of tire rubber, characterized in that: In step (3), the addition amount of the sterilized tire rubber powder is 4-6 g / 100 mL of fermentation medium; the temperature of the desulfurization fermentation is 28-32 °C, the rotation speed is 150-250 rpm, and the time is 140-300 h.

8. The application of the Escherichia coli according to claim 6 ( Escherichia sp. ) in the desulfurization of tire rubber, characterized in that: In step (3), the addition amount of the sterilized tire rubber powder is 4-6 g / 100 mL of fermentation medium; the temperature of the desulfurization fermentation is 28-32 °C, the rotation speed is 150-250 rpm, and the time is 140-300 h.

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