An alkali-resistant cellulase StrEgl and its applications

Abstract

The application provides an alkali-resistant cellulase StrEgl and an application thereof, and belongs to the technical field of bioengineering. The amino acid sequence of the cellulase StrEgl is shown as SEQ ID NO. 1, and the nucleotide sequence of a gene encoding the cellulase StrEgl is shown as SEQ ID NO. 2. The alkali-resistant cellulase StrEgl provided by the application has alkali-resistant performance and can degrade cellulose under an alkaline condition; the cellulase StrEgl still has good enzymolysis activity under an environment with a pH value of 9-10; meanwhile, the cellulase StrEgl has good tolerance to temperature, metal ions and chemical reagents, is very suitable for industrial application, and has a wide application prospect in the fields of papermaking, textile, detergent and the like.

Description

Technical Field

[0001] This invention belongs to the field of bioengineering technology, and in particular relates to an alkali-resistant cellulase StrEgl and its applications. Background Technology

[0002] Cellulase, as a highly active biocatalyst, has wide applications in the conversion and utilization of cellulose. Based on their substrates, sites of action, and products, cellulases can be divided into three main categories: endo-1,4-β-D-glucanase, exo-1,4-β-D-glucannase, and β-1,4-glucosidase. Endo-glucanases can randomly cleave the β-1,4-glycosidic bonds of cellulose molecules from within, producing shorter sugar chains or cellooligosaccharides, providing new sugar chain ends for subsequent degradation. Exo-glucanases act on the reducing or non-reducing ends of cellulose polysaccharide chains, while β-glucosidases can degrade cellobiose into glucose.

[0003] Cellulase has a wide range of applications and plays an important role in industries such as pulp and paper making, food brewing, feed production, and washing. Currently, most cellulases used in the market are derived from Trichoderma reesei or Aspergillus niger. They have low thermal stability and operate in acidic environments, making it difficult to meet the alkaline requirements of papermaking (pH between 7.5 and 9.5) and washing (pH around 7 to 10). Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide an alkali-resistant cellulase StrEgl and its application; the cellulase StrEgl has alkali resistance and thermal stability, and can efficiently exert its enzymatic activity under high temperature and alkaline environments, and can be used for the development and application of industrial products.

[0005] The present invention provides an alkali-resistant cellulase StrEgl, the amino acid sequence of which is shown in SEQ ID NO.1.

[0006] Preferably, the pH range for the cellulase StrEgl to perform its enzymatic hydrolysis function is 4–10.

[0007] Preferably, the cellulase StrEgl performs its enzymatic hydrolysis function in the temperature range of 40–100°C.

[0008] The present invention provides a gene encoding the cellulase StrEgl, the nucleotide sequence of which is shown in SEQ ID NO.2.

[0009] The present invention provides a recombinant vector for expressing the gene, comprising the gene and an initial vector.

[0010] Preferably, the initial vector is pET-28a, and the gene is cloned between the Nco I and Xho I restriction sites of the initial vector pET-28a.

[0011] The present invention provides a recombinant strain expressing the gene, which is obtained by transferring the recombinant vector into an empty vector.

[0012] Preferably, the empty carrier bacteria is Escherichia coli.

[0013] This invention provides the application of the cellulase StrEgl, the gene, the recombinant vector, and the recombinant strain in the decomposition of cellulose under alkaline conditions.

[0014] This invention provides the application of the cellulase StrEgl, the gene, the recombinant vector, and the recombinant strain in the fields of papermaking, textiles, or detergents.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] The alkali-resistant cellulase StrEgl provided by this invention has alkali resistance and can degrade cellulose under alkaline conditions; it has high relative enzyme activity in an environment with a pH of 4 to 8, all above 80%; and it still has good enzymatic activity in an environment with a pH of 9 to 10, with relative enzyme activities of 60% and 38%, respectively.

[0017] The cellulase StrEgl exhibits excellent enzyme activity stability within a pH range of 5–9. The residual enzyme activity did not decrease significantly after 1 hour of treatment, and 62.54% of the enzyme activity remained after treatment when the ambient pH was 10.

[0018] Meanwhile, the cellulase StrEgl has excellent thermal stability and can degrade cellulose under medium and high temperature conditions; its relative enzyme activity is higher than 90% at 40-60℃ and still has more than 40% relative enzyme activity at 80-100℃.

[0019] The cellulase StrEgl is also resistant to metal ions and chemical reagents; studies have found that the metal ion Mn 2+ and Co 2+ The chemical reagents 1% Tween 20 and 1% Tween 80 have a promoting effect on the activity of the cellulase StrEgl. However, EDTA, PMSF, Triton X-100, and Urea have no effect on the activity of the cellulase StrEgl.

[0020] In summary, the alkali-resistant cellulase StrEgl provided by this invention has excellent tolerance to pH, temperature, metal ions, and chemical reagents, making it very suitable for industrial applications and promising for use in papermaking, textiles, detergents, and other fields. Attached Figure Description

[0021] Figure 1 The results of SDS-PAGE electrophoresis of cellulase StrEgl are shown. Lane M is the protein marker, lane 1 is the lysate of BL21-StrEgl bacterial culture without IPTG induction, lane 2 is the total protein of the engineered strain BL21-StrEgl induced by IPTG, lane 3 is the flow-through buffer of crude cellulase StrEgl through the column, and lane 4 is the NTA-60 elution buffer.

[0022] Figure 2 A 3D structural simulation of the cellulase StrEgl;

[0023] Figure 3 The results of the enzymatic property analysis of cellulase StrEgl are shown, where A represents the relative enzyme activity of cellulase StrEgl at different pH values, and B represents the relative enzyme activity of cellulase StrEgl at different temperatures.

[0024] Figure 4 The results of pH stability analysis of cellulase StrEgl;

[0025] Figure 5 Results regarding the metal ion tolerance of cellulase StrEgl;

[0026] Figure 6 Results of chemical reagent tolerance of cellulase StrEgl. Detailed Implementation

[0027] This invention provides an alkali-resistant cellulase StrEgl, the amino acid sequence of which is shown in SEQ ID NO.1, and is as follows:

[0028] MDTTVCEQYGSTVIQGRYVVQNNRWGTGATQCVTATDTGFRVTRADGSVPTNGAPKSYPSVFNGCHYTNCSPGTSLPARLSTISGAPSSISYGYVSGAVYNASYDIWLDPTPRTDGVNRTEIMIWFNRVGPVQPIGSPVGTATVGGRSWEVWTGSNGSNDVISFVAPSAI SSWSFDVMDFVDQAVARGLAQSNWYLTSIQAGFEPWQNGAGLAVHSFSSTVDLGGGNPGDPGDPVTACRVTYATNVWQGGFTADVTVENTGSSAVDNWRLGFTLPSGQLVTNSWNTTLSGSSGAVTASAVAHNAQIAPGGSQTFGFQGTHSGTFAQPTGFSLNGTACTSA.

[0029] The alkali-resistant cellulase StrEgl described in this invention is derived from the cellulase gene of Streptomyces isolated and screened from metagenomic DNA of soil samples from the Taklamakan Desert in Yuli County, Xinjiang, and obtained by removing the signal peptide sequence.

[0030] In this invention, the cellulase StrEgl exerts its enzymatic hydrolysis function at a pH range of 4–10 and a temperature range of 40–100°C; the cellulase StrEgl is also tolerant to metal ions and chemical reagents.

[0031] This invention provides a gene encoding the cellulase StrEgl, the nucleotide sequence of which is shown in SEQ ID NO.2, and is as follows:

[0032] ATGGACACCACGGTCTGCGAGCAGTACGGCTCGACCGTCATCCAGGGGCGCTACGTCGTCCAGAACAACCGCTGGGGCACCGGCGCCACCCAGTGCGTCACCGCCACCGACACCGGCTTCCGGGTCACCCGGGCCGACGGCTCGGTACCCACCAACGGCGCCCCGAAGTCGTACCCGTCCGTCTTCAACGGCTGCCACTACACGAACTGTTCGCCGGGCACCAGCCTTCCGGCCCGGCTCAGCACCATCTCCGGTGCGCCCAGCAGCATCTCCTACGGCTATGTCTCGGGCGCCGTGTACAACGCCTCGTACGACATCTGGCTGGACCCGACGCCCCGCACCGACGGCGTCAACCGGACCGAGATCATGATCTGGTTCAACCGGGTGGGCCCGGTCCAGCCGATCGGCTCGCCGGTGGGCACCGCCACCGTCGGTGGCCGCAGCTGGGAGGTGTGGACCGGCAGCAACGGCTCCAACGACGTGATCTCCTTCGTCGCCCCCTCGGCGATCAGCAGCTGGAGCTTCGACGTCATGGACTTCGTCGACCAGGCCGTCGCCCGGGGCCTGGCGCAGAGCAACTGGTATCTGACGAGTATCCAGGCCGGGTTCGAGCCGTGGCAGAACGGCGCCGGGCTCGCGGTGCACTCCTTCTCCTCCACCGTCGATCTCGGCGGCGGCAACCCCGGTGACCCCGGCGACCCGGTGACGGCCTGCCGGGTGACCTACGCGACCAACGTCTGGCAGGGCGGCTTCACCGCCGACGTCACGGTCGAGAACACCGGTTCCAGCGCCGTCGACAACTGGCGGCTCGGCTTCACCCTGCCCTCCGGGCAGCTCGTCACCAACTCCTGGAACACCACCCTGTCCGGCTCCTCGGGCGCGGTCACGGCGAGCGCCGTGGCGCACAACGCGCAGATCGCCCCCGGCGGCAGCCAGACCTTCGGCTTCCAGGGCACCCACAGCGGCACGTTCGCGCAGCCGACCGGGTTCAGCCTGAACGGAACGGCCTGCACCAGCGCGTGA。

[0033] This invention describes the isolation and screening of cellulase genes from Streptomyces in metagenomic DNA samples from soil samples in the Taklamakan Desert of Yuli County, Xinjiang. After removing the signal peptide sequence, the genes were synthesized by Suzhou Genewiz Biotechnology Co., Ltd.

[0034] This invention also provides a recombinant vector expressing the gene, comprising the gene and an initial vector. The initial vector is preferably pET-28a, and the gene is preferably cloned between the Nco I and Xho I restriction sites of the initial vector pET-28a. This invention does not specifically limit the preparation method of the recombinant vector; any method known in the art for preparing recombinant vectors may be used.

[0035] This invention provides a recombinant bacterial strain expressing the aforementioned gene, obtained by transferring the recombinant vector into an empty vector bacterial strain. In this invention, the empty vector bacterial strain is preferably *Escherichia coli*, and more preferably *Escherichia coli* BL21(DE3) strain. This invention does not specify a particular method for preparing the recombinant bacterial strain; any method known in the art can be used.

[0036] This invention provides the application of the cellulase StrEgl, the gene, the recombinant vector, and the recombinant strain in the decomposition of cellulose under alkaline conditions.

[0037] The present invention also provides the application of the cellulase StrEgl, the gene, the recombinant vector, and the recombinant strain in the fields of papermaking, textiles, or detergents.

[0038] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0039] Example 1

[0040] (1) The cellulase gene from Streptomyces in the metagenomic DNA of soil samples from the Taklamakan Desert in Yuli County, Xinjiang, was deciphered by removing the signal peptide sequence. The StrEgl gene sequence was then synthesized by Suzhou Genewise Biotechnology Co., Ltd. The sequence information is shown in SEQ ID NO.2.

[0041] Primer design: Using the nucleotide sequence of the synthesized cellulase gene StrEgl as a DNA template, primers StrEgl-F / R for amplifying the cellulase gene StrEgl were designed and synthesized by Suzhou Genewiz Biotechnology Co., Ltd. The nucleotide sequence of primers StrEgl-F / R is shown in Table 1.

[0042] Table 1. Nucleotide sequence of primer StrEgl-F / R

[0043] name Sequence (5'~3') StrEgl-F GAAGGAGATATACCATGGGCATGGACACCACGGTCTG(SEQ ID NO.3) StrEgl-R TGGTGGTGGTGGTGCTCGAGCGCGCTGGTGCAG(SEQ ID NO.4)

[0044] (2) PCR amplification: The PCR amplification system was 20 μL, including 10 μL 2×PhantaMax Master Mix, 1 μL DNA template (synthesized cellulase gene StrEgl), 1 μL upstream primer StrEgl-F with an initial concentration of 10 μmol / L, 1 μL downstream primer StrEgl-R with an initial concentration of 10 μmol / L, and 7 μL ddH2O. The PCR amplification program was 95℃ denaturation for 3 min → (95℃ denaturation for 30 s → 60℃ annealing for 30 s → 72℃ extension for 1 min) × 35 cycles → 72℃ extension for 5 min → storage at 4℃ to obtain the cellulase gene StrEgl, the sequence of which is shown in SEQ ID NO.2.

[0045] The amino acid sequence of cellulase StrEgl, encoded by the cellulase gene StrEgl, is shown in SEQ ID NO.1.

[0046] (3) Vector construction and transformation: The cellulase gene StrEgl was ligated into the pET-28a vector containing the T7 promoter obtained after double digestion with Nco I and Xho I using C115-01 recombinase to construct the expression vector pET28a-StrEgl. For specific steps, please refer to the pET-28a vector instruction manual. Then, Escherichia coli BL21(DE3) strain was transformed. For specific steps, please refer to the Escherichia coli BL21(DE3) strain instruction manual to obtain the engineered strain BL21-StrEgl.

[0047] (4) Protein induction expression and purification: 5 mL of the seed culture (OD) of engineered strain BL21-StrEgl was added. 600 =5) Inoculate into 500 mL LB medium (50 μg / mL Kan) and incubate at 37 °C until OD. 600=0.8, to obtain BL21-StrEgl bacterial culture; add IPTG to the culture to a final concentration of 0.5 mmol / L, induce protein expression at 16℃ for 20 h, centrifuge at 5000 rpm for 10 min to collect bacterial cells, resuspend in NTA-0 buffer, and sonicate for 10 min, setting the sonication power to 400W, with a 5-s interval between every 3 s of sonication; after sonication, centrifuge at 5000 rpm for 30 min to collect the supernatant to obtain crude enzyme solution; wash a 70666-3 nickel column with crude enzyme solution, and co-wash... Wash twice at a flow rate of 1 mL / min, followed by gradient elution with NTA-10, NTA-20, NTA-40, NTA-60, NTA-80, and NTA-100 buffers at a flow rate of 1 mL / min. Simultaneously, E112-01 protein detection solution was used for detection, and the elution peaks were collected. After ultrafiltration and centrifugation to remove imidazole, purified StrEgl enzyme solution was obtained. SDS-PAGE electrophoresis was performed on the StrEgl enzyme solution, and the results are shown below. Figure 1 As shown. The NTA buffer was purchased from Sangon Biotech (Shanghai) Co., Ltd., product number C600304-0500.

[0048] (5) Protein structure analysis: The structure of cellulase StrEgl was analyzed using Swiss-Model (https: / / swissmodel.expasy.org / ), and the results are as follows. Figure 2 As shown.

[0049] PCR amplification results showed that the full-length cellulase gene StrEgl is 1020 bp (after removing the stop codon), encoding a cellulase StrEgl containing 340 amino acids. Protein induction expression and purification results showed that the cellulase StrEgl with the His-Tag was successfully purified using the *E. coli* expression system. SDS-PAGE electrophoresis results showed a single protein band at approximately 35 kDa, consistent with predictions, indicating high protein purity and a high expression level in the StrEgl enzyme solution.

[0050] Example 2

[0051] The optimal pH for cellulase StrEgl

[0052] Prepare 0.1 mol / L citrate-sodium citrate buffer solutions (pH 3, 4, 5, 6), 0.2 mol / L disodium hydrogen phosphate-sodium dihydrogen phosphate buffer solutions (pH 7, 8), and 0.2 mol / L glycine-sodium hydroxide buffer solutions (pH 9, 10, 11, 12). Using 1% carboxymethyl cellulose sodium solution (CMC-Na) as a substrate, mix 100 μL of 1% CMC-Na solution, 80 μL of buffer solutions at different pH values, and 20 μL of StrEgl enzyme solution with a final concentration of 400 mg / L to obtain a reaction system. Incubate at 50°C for 30 min. Determine the specific enzyme activity of cellulase StrEgl at different pH values ​​using the DNS method. Specifically, add 300 μL of DNS reagent to each reaction system to terminate the reaction, then incubate in a boiling water bath for 5 min for color development. After cooling to room temperature, add distilled water to a final volume of 1 mL. Transfer 200 μL of each solution to a 96-well microplate and measure the OD using a microplate reader. 540 The reducing sugar content in each reaction system was calculated using the glucose standard curve formula, and the specific enzyme activity of cellulase StrEgl at different pH values ​​was calculated using the specific enzyme activity formula. Taking the highest enzyme activity as 100%, the optimal pH for cellulase StrEgl was determined. The results are shown in Table 2 and... Figure 3 As shown.

[0053] The formula for the glucose standard curve is: y = 1.67x - 0.0349(R²). 2 =0.998); Formula I;

[0054] In Formula I, x is the glucose concentration in mg / mL, and y is the OD value. 540 value

[0055] The specific enzyme activity formula is:

[0056] In Formula II: specific enzyme activity (U / mg) is the amount of enzyme required for StrEgl enzyme solution to decompose the substrate and release 1 μg of glucose in 1 min, G is the reducing sugar content (mg / mL), M is the dilution factor of StrEgl enzyme solution, V is the volume of StrEgl enzyme solution (mL), T is the reaction time (min), and N is the cellulase concentration (mg / mL).

[0057] Table 2. Specific enzyme activities of cellulase StrEgl at different pH values.

[0058] pH Enzyme activity (U / mg) pH Enzyme activity (U / mg) 3 885.39±43.46 8 3876.67±58.75 4 4438.39±53.57 9 3017.74±50.43 5 4861.04±43.92 10 1850.67±7.71 6 4552.91±61.17 11 495.46±13.90 7 4326.59±34.71 12 451.83±26.99

[0059] The results showed that the optimal pH for cellulase StrEgl to exert its enzymatic hydrolytic function was 5. Based on the highest enzyme activity of 100%, it exhibited high relative enzyme activity (above 80%) at pH 4–8. It also maintained good enzymatic activity at pH 9–10, with relative enzyme activities of 62% and 38%, respectively. This indicates that cellulase StrEgl is a highly active cellulase with alkali tolerance, capable of degrading cellulose under alkaline conditions.

[0060] Example 3

[0061] The optimal temperature for cellulase StrEgl

[0062] Using 1% CMC-Na solution as a substrate, 100 μL of 1% CMC-Na solution, 80 μL of 0.1 mol / L citrate-sodium citrate buffer solution (pH=5), and 20 μL of BvEgl enzyme solution with a final concentration of 400 mg / L were mixed thoroughly to obtain a reaction system. The reaction was carried out in a water bath at 20℃, 30℃, 40℃, 50℃, 60℃, 70℃, 80℃, 90℃, and 100℃ for 30 min, respectively. The specific enzyme activity of cellulase StrEgl at different temperatures was determined and calculated according to the DNS method described in Example 2. The optimal temperature for cellulase StrEgl was determined with the highest enzyme activity as 100%. The results are shown in Table 3 and... Figure 3 As shown.

[0063] Table 3. Specific enzyme activity of cellulase BvEgl at different temperatures.

[0064] Temperature (°C) Enzyme activity (U / mg) Temperature (°C) Enzyme activity (U / mg) 20 2837.76±11.57 70 3312.23±87.01 30 36.31.26±58.23 80 2537.82±23.36 40 4454.75±60.23 90 2134.26±54.67 50 4855.59±59.72 100 1965.19±17.72 60 4801.05±58.23

[0065] The results showed that the optimal temperature for cellulase StrEgl to exert its enzymatic hydrolytic function was 50℃; its relative enzyme activity was above 90% at 40–60℃, and it still retained more than 40% relative enzyme activity at 80–100℃. This indicates that cellulase StrEgl is a highly active cellulase with thermostable properties, capable of degrading cellulose under medium to high temperature conditions.

[0066] Example 4

[0067] pH stability of cellulase StrEgl

[0068] Cellulase StrEgl was diluted to 400 mg / L in prepared buffer solutions of different pH (4-10) (citric acid-sodium citrate buffer solution). The specific reaction system was as follows: 100 μL 1% CMC-Na solution, 80 μL buffer solution, and 20 μL StrEgl enzyme with a final concentration of 400 mg / L. After incubation at 50°C for 1 h, the specific enzyme activity of cellulase StrEgl under different pH buffer treatments was determined and calculated according to the method described in Example 2. The results are as follows. Figure 4 As shown.

[0069] The results showed that cellulase StrEgl exhibited good enzyme activity stability within a pH range of 5–9, with virtually no decrease in residual enzyme activity after 1 hour of treatment. At an ambient pH of 10, 62.54% of the enzyme activity remained after treatment. This indicates that cellulase StrEgl is a highly active cellulase with alkali resistance.

[0070] Example 5

[0071] Substrate specificity of cellulase StrEgl

[0072] Prepare 1% CMC-Na solution, crystalline cellulose solution (Avicel), beechwood xylan solution, barley glucan solution, β-mannan solution, sucrose solution, laminarin solution, and amylopetin solution, 100 μL of each as substrate. Mix each substrate with 80 μL of 0.1 mol / L citrate-sodium citrate buffer solution (pH=5) and 20 μL of StrEgl enzyme solution with a final concentration of 400 mg / L to obtain a reaction system. Incubate at 40°C for 30 min. Measure and calculate the specific enzyme activity of cellulase StrEgl in each reaction system according to the DNS method described in Example 2. The results are shown in Table 4.

[0073] Table 4. Specific enzyme activities of cellulase StrEgl on different substrates.

[0074] Substrate Enzyme activity (U / mg) CMC-Na solution 4861.04±43.92 microcrystalline cellulose solution 1077.79±54.41 Beech polysaccharide solution 892.91±4.67 Barley beta-glucan solution —— β-Mannan solution —— sucrose solution —— Kelp polysaccharide solution —— amylopectin solution ——

[0075] The results showed that cellulase StrEgl exhibits a superior degradation ability for cellulose substrates containing β-1,4 glycosidic bonds, with a specific enzyme activity reaching 4861.04 ± 43.92 U / mg. This indicates that cellulase StrEgl is a highly active cellulase.

[0076] Example 5

[0077] Metal ion and chemical reagent tolerance of cellulase StrEgl

[0078] K was diluted in 80 μL of 1 mM and 10 mM solutions with 0.1 M Tris-HCl pH 5 buffer. 1+ Mg 2+ Cu 2+ Mn 2+ Ni 2+ Ca 2+ Co 2+ Zn2+ Fe 3+ Nine metal ion solutions, 80 μL of 5 mM SDS, EDTA, PMSF, β-ME, and Urea diluted in 0.1 M Tris-HCl pH 5 buffer, or 80 μL of 1% Tween20, Tween80, and Triton X-100 diluted in 0.1 M Tris-HCl pH 5 buffer, were mixed with 20 μL of StrEgl enzyme solution to a final concentration of 400 mg / L to obtain 100 mg / L cellulase StrEgl diluted solutions with different metal ion and chemical reagent concentrations. The specific enzyme activity of cellulase StrEgl in each reaction system was determined and calculated using the DNS method described in Example 2, and the results are as follows: Figure 5 and Figure 6 As shown.

[0079] according to Figure 5 and Figure 6 It can be seen that the metal ion Mn 2+ and Co 2+ The chemical reagents 1% Tween 20 and 1% Tween 80 promoted the activity of cellulase StrEgl. EDTA, PMSF, Triton X-100, and Urea had no effect on the activity of cellulase StrEgl, indicating that cellulase StrEgl has great commercial development potential.

[0080] As can be seen from the above embodiments, the alkali-resistant cellulase StrEgl provided by the present invention has excellent tolerance to pH, temperature, metal ions and chemical reagents, and is very suitable for industrial applications, with broad application prospects in papermaking, textiles, detergents and other fields.

[0081] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An alkaline-tolerant cellulase StrEgl, characterized in that, The amino acid sequence of the cellulase StrEgl is shown as SEQ ID NO.

1.

2. The cellulase StrEgl according to claim 1, characterized in that, The cellulase StrEgl has enzymatic function in the pH range of 4-10.

3. The cellulase StrEgl according to claim 1 or 2, characterized in that, The cellulase StrEgl has enzymatic function in the temperature range of 40-100℃.

4. A gene encoding the cellulase StrEgl according to any one of claims 1 to 3, characterized in that, The nucleotide sequence of the gene is shown as SEQ ID NO.

2.

5. A recombinant vector expressing the gene of claim 4, characterized in that, The gene and the initial carrier of claim 4 are included.

6. The recombinant vector of claim 5, wherein, The initial vector is pET-28a, the gene is cloned between the Nco I and Xho I restriction sites.

7. A recombinant strain expressing the gene of claim 4, characterized in that, The recombinant strain is obtained by transferring the recombinant carrier of claim 5 or 6 into an empty carrier.

8. The recombinant bacterial strain of claim 7, wherein, The empty carrier is Escherichia coli.

9. Use of the cellulase StrEgl of any one of claims 1-3, the gene of claim 4, the recombinant carrier of claim 5 or 6, or the recombinant strain of claim 7 or 8 in decomposing cellulose under alkaline conditions.

Images