81 results about "Laccase activity" patented technology

The invention discloses a copper-based nano-enzyme, a preparation method thereof and application of the copper-based nano-enzyme in organophosphorus pesticide detection, and belongs to the technical field of pesticide residue detection. The copper-based nano-enzyme has a netted-like structure, a high specific surface area and many active sites, the valence state of a copper element is zero-valence Cu, Cu < + > and Cu < 2 + >, the copper-based nano-enzyme has high peroxidase-like activity and laccase-like activity, the detection limit is low, and glyphosate can be sensitively detected; and glyphosate, glufosinate-ammonium and isazofos can be well distinguished from six organophosphorus pesticides with medium concentration, and the method has high selectivity. The nano enzyme provided by the invention is prepared from ammonium citrate and copper nitrate in an N, N-dimethylformamide (DMF) solution by using a solvothermal method; the preparation process of the nano enzyme is simple.

The invention belongs to the technical field of chemical analysis and detection, and relates to a method for rapidly detecting sodium ions in cigarette paper by nano-enzyme laccase. According to the method, 2-aminoterephthalic acid, copper nitrate and cerous nitrate are taken as precursors, polyvinylpyrrolidone is taken as a stabilizer, and a solvothermal method is adopted to synthesize the copper-cerium-containing MOF-based nano-enzyme with laccase-like activity, namely Cu / Ce-BDC-NH2 nano-enzyme; cu / Ce-BDC-NH2 nano-enzyme oxidizes 2, 4-dichlorophenol and 4-aminoantipyrine to obtain a red product, the potassium pyroantimonate ligand is adsorbed on the surface of Cu / Ce-BDC-NH2 to inhibit catalytic action, so that laccase-like activity is reduced, Na < + > is introduced to react with potassium pyroantimonate to generate a stable complex, the activity of Cu / Ce-BDC-NH2 laccase is recovered, and the red color of a solution is deepened. The invention establishes a novel colorimetric rapid detection method for sodium ions.

The invention discloses an application of a self-cascade cerium-based MOF (Metal Organic Framework) nano-enzyme in detection of profenofos, the cerium-based MOF nano-enzyme is a cerium-based metal organic framework material HMUiO-66 (Ce) nano-enzyme, and the organophosphorus-like hydrolase activity and laccase-like activity of the HMUiO-66 (Ce) nano-enzyme can be sequentially exerted by adjusting the pH value. The method comprises the following steps: firstly, hydrolyzing profenofos by HMUiO-66 (Ce) nano enzyme under an alkaline condition to produce 4-bromo-2-chlorophenol; the method comprises the following steps: dissolving 4-bromine-2-chlorophenol and 4-aminoantipyrine in water to obtain a solution, regulating the solution to be acidic, performing laccase-like activity by HMUiO-66 (Ce) nano-enzyme under an acidic condition, complexing 4-bromine-2-chlorophenol and 4-aminoantipyrine into quinoneimine, detecting the ultraviolet absorbance of the quinoneimine at 508nm, and calculating the concentration of profenofos. The invention finds that the nano enzyme has good selectivity on profenofos, is extremely simple and convenient in detection operation and low in cost, and makes on-site rapid detection of profenofos possible.

The invention belongs to the field of microorganisms, and particularly relates to bacillus Z161 capable of efficiently degrading straw as well as a screening method and application of the bacillus Z161. The bacillus subtilis Z161 is bacillus mexicanus, the preservation number of the bacillus mexicanus Z161 is CGMCC (China General Microbiological Culture Collection Center) NO.36393, and the bacillus mexicanus Z161 is preserved in the China General Microbiological Culture Collection Center on October 29, 2025. The bacillus Z161 screened by the invention has strong laccase activity and high temperature resistance, and can efficiently degrade lignin under the condition of 50 DEG C; the problem that in the prior art, normal-temperature zymophyte is mostly adopted, and the requirement for fermentation conditions in the fermentation process is harsh is solved, and therefore the rapid compost fermentation technology is easier to achieve. The bacillus Z161 provided by the invention has the advantages of genetic and functional character stability, has good tolerance at high temperature, enables lignin to be quickly depolymerized, and improves the decomposition efficiency.

The invention discloses a method for detecting pesticide based on a colorimetric sensing array of a copper-based MOF composite material, and relates to the technical field of pesticide detection.The method comprises the steps that a Co, Zn and Cu-MOF (VB2) composite nano-enzyme material with peroxidase-like activity and laccase-like activity is prepared; before and after a pesticide analyte to be detected is added, the peroxidase-like activity and laccase-like activity of the Co, Zn and Cu-MOF (VB2) composite nano-enzyme material catalyze different substrates in a neutral environment, so that catalytic products have different colorimetric responses to detect the pesticide analyte to be detected. The method can be used for simultaneously distinguishing and detecting five pesticides including carbendazim, pendimethalin, thiophanate-methyl, triadimefon and acetamiprid, and has the advantages of simplicity and convenience in operation and high detection speed.

The invention discloses a method for detecting ethyl carbamate in liquor based on laccase-like active nano-enzyme bimodal. The method comprises the following steps: step 1, determining absorbance values A of to-be-detected solutions of ethyl carbamate standard substances with different concentration gradients at 420nm; 2, measuring the fluorescence intensity signal ratio F420nm / F550nm of the to-be-measured solutions of the ethyl carbamate standard substances with different concentration gradients at 420nm and 550nm under the excitation of the wavelength of 330nm; 3, constructing a linear regression equation of the standard substance; and 4, taking a sample to be detected, repeating the steps 1 and 2 to obtain the absorbance value of the sample to be detected and the fluorescence intensity signal ratio F420nm / F550nm of the sample to be detected, and respectively substituting the absorbance value and the fluorescence intensity signal ratio F420nm / F550nm into the corresponding linear equations to obtain the concentration of ethyl carbamate in the sample to be detected. According to the bimodal detection, the advantages of a colorimetric method and a fluorescence method are combined, and the comprehensiveness and accuracy of detection are improved. The colorimetric method provides visual information, but the sensitivity is limited; and the fluorescence method has higher sensitivity and selectivity. By combining the two methods, the bimodal detection can more reliably identify and quantify the target substance in the actual sample, and has higher accuracy compared with the single detection.

The invention discloses a method for efficiently expressing laccase by regulating endoplasmic reticulum stress reaction of coprinus cinereus, and belongs to the field of gene engineering and fermentation engineering. According to the invention, by regulating endoplasmic reticulum stress reaction action genes der1, Anhac1 and Cchac1 of filamentous fungi coprinus cinereus, recombinant extracellular expression of laccase Lcc5 is finally improved and regulated. Wherein the extracellular laccase activities of the recombinant bacteria can be respectively improved by 18%, 70% and 26% through interference of der1, overexpression of Anhac1 and overexpression of Cchac1, and the obtained extracellular laccase activities are respectively 31.4 U / mL, 45.1 U / mL and 33.6 U / mL, which is the highest level of coprinus cinereus homologous recombination expression laccase Lcc5 reported at present. The invention firstly indicates that the regulation and control of the coprinus cinereus endoplasmic reticulum stress reaction can promote the efficient expression of laccase in coprinus cinereus, and the invention further promotes the development of a coprinus cinereus expression system.

The invention belongs to the field of environment and food pollution detection, and relates to a microcystic toxin-LR (MC-LR) bimodal detection method based on regulation and control of MIP-Cu at CDs laccase activity. Copper chloride dihydrate, citric acid and ethidene diamine are used as synthetic substrates, a fluorescent nano-enzyme with laccase-like activity is synthesized in one step through a hydrothermal method, and the MC-LR can be specifically recognized and the laccase-like activity of MIP-Cu at CDs can be regulated and controlled through wrapping of a molecular imprinting method, so that a colorimetric and fluorescent dual-mode rapid MC-LR determination method is established. The method is short in detection time, high in sensitivity and low in cost. Built-in cross reference correction is provided by dual modes, so that the MC-LR detection reliability and accuracy in a complex environment sample are greatly improved, and false positive output of a detection result is avoided.

The invention provides alkaline laccase WCotA and application thereof, and belongs to the technical field of biological engineering. According to the invention, assumed protein codons from bacillus amyloliquefaciens are optimized by a bioengineering technology, then are heterologously expressed on a carrier, and are transferred into escherichia coli with clear genetic background and fast growth cycle for amplification and expression to obtain a protein product; the amino acid sequence of the protein product is as shown in SEQ ID NO.1, and the nucleotide sequence for coding the protein product is as shown in SEQ ID NO.2; according to the present invention, the characterization results show that the protein product has high laccase activity, and is marked as alkaline laccase WCotA; the alkaline laccase WCotA has the outstanding advantages of alkali resistance, high temperature resistance, wide pH action range and the like, and has good application in the fields of textile industry, food processing, pulping processing, industrial wastewater treatment and the like.

The invention is suitable for the technical field of pesticide residue detection, and provides a method for distinguishing and detecting pesticide based on copper-platinum bimetallic nano-enzyme. According to the method, a colorimetric sensing array with three sensing channels is constructed by synthesizing a copper-platinum bimetallic nano-enzyme (CuPtNPs) with oxidase-like activity, laccase-like activity and superoxide dismutase-like activity. A fingerprint spectrum is obtained based on specific effects of different pesticides and enzyme-like activities, and qualitative distinguishing and quantitative detection of various pesticides are realized by combining a machine algorithm. According to the method, nine pesticide residues can be measured at a time, six of the nine pesticide residues can be quantitatively analyzed, and the problem that a traditional method only can be used for single detection is solved. A strategy of constructing three channels based on a single nano-enzyme receptor CuPtNPs has the remarkable advantages of simple synthesis process, convenient operation flow and low detection cost, is good in applicability in actual agricultural product samples such as Chinese cabbages and apples, and provides an efficient solution for high-throughput detection of pesticide residues.

The invention relates to an application of a pelagic fermentation broth, and the pelagic fermentation broth is prepared by the following steps: inoculating pelagic HE39 into a culture medium, carrying out fermentation culture, centrifuging, and taking the supernatant; the preservation number of the Phlebiopsis pilaris HE39 is CGMCC (China General Microbiological Culture Collection Center) No.41168, and the preservation number of the Phlebiopsis pilaris HE39 is CGMCC No.41168. The fermentation liquor can be used for degrading lignin and cellulose, has good degradation capacity on lignin in ground cover combustible materials, has good laccase activity, lignin peroxidase activity and manganese peroxidase activity, and can improve the weight loss rate of the combustible materials in forest land.

The invention discloses an Hg < 2 + > detection method for enhancing Hg < 2 + > intrinsic laccase-like activity based on ZIF-8-Au. The invention finds that the mercury ions have laccase-like activity, the enzyme activity of the mercury ions is obviously enhanced under the action of ZIF-8-Au, and the color of the reaction catalyzed by the mercury ions is obviously changed along with the increase of the concentration of Hg < 2 + >, so that a colorimetric analysis method for detecting the mercury ions is developed on the basis, the Turn-On type visual analysis is realized, and the application prospect is wide. The method realizes simple, rapid, sensitive and high-selectivity detection of Hg < 2 + > residues in water and food. The invention provides a new method and principle for the fields of Hg < 2 + > environment monitoring and food safety, and provides a new direction for the development of a heavy metal ion detection technology.

The invention provides a laccase gene LAC18 screened from apples and aphid resistance application of the laccase gene LAC18 in catalytic synthesis of plant lignin, the nucleotide sequence of the gene is SEQ ID NO: 1, and the amino acid sequence of encoded protein of the gene is SEQ ID NO: 2. According to the method, the aphid resistance of the transgenic tobacco is comprehensively evaluated by inoculating aphids on leaves of the transgenic laccase gene tobacco and observing indexes such as the survival rate and the aphid yield. The result shows that the laccase activity and the lignin content of the transgenic laccase tobacco are remarkably improved, the lignin of cell walls is thickened, and the lignification degree is remarkably improved. The translaccase gene tobacco not only can effectively reduce the survival rate of myzus persicae, but also has a remarkable inhibition effect on the average reproductive capacity of the myzus persicae, and the aphid resistance of plants is greatly improved.

The invention is applicable to the technical field of colorimetric detection, and provides a bisphenol A colorimetric detection method based on copper-based nano enzyme. The copper-based nano-enzyme with laccase-like activity is prepared in an alkaline water phase system through a one-step method by taking low-price natural plant protein-zein as a ligand, divalent soluble copper salt as a metal precursor and hydroxylamine and the like as a reducing agent. The copper-based nano enzyme is superior to natural laccase in the aspects of catalytic activity, substrate affinity and stability, and bisphenol A can be catalyzed to be oxidized to generate quinone compounds; the quinone compound is further subjected to a coupling reaction with 4-aminoantipyrine, and a red product with a remarkable characteristic absorption peak at the wavelength of 510 nm is generated. The quantitative analysis of bisphenol A can be realized by measuring the absorbance of the system at 510nm. The method has the advantages of high sensitivity, low detection cost, simplicity and convenience in operation and the like, and is suitable for rapid detection of bisphenol A in drinking water and environmental water.

The application discloses a silver-based metal organic framework nano-enzyme loaded with silver nanoparticles and having multi-enzyme-like activity, and a preparation and application thereof. The application uses 2-methyl imidazole as an organic ligand, triethylamine as a deprotonation reagent and a basic environment provider, methanol as a solvent and a silver ion reducing agent, and obtains a silver-based metal organic framework by using the coordination of the deprotonated 2-methyl imidazole and the silver ion. Meanwhile, the silver ion adsorbed on the surface of the silver-based metal organic framework is reduced into silver nanoparticles by using methanol under the alkaline condition, and a silver-based metal organic framework nano-enzyme loaded with silver nanoparticles is prepared. The nano-enzyme can exhibit multi-enzyme-like activities such as oxide enzyme-like activity, peroxide enzyme-like activity and laccase enzyme-like activity under different conditions, and can realize the colorimetric detection of a plurality of trace analysis objects in different types of complex samples by using different enzyme-like activities under different detection conditions.

The invention provides an efficient microbial fermentation inoculant for straws and a preparation method thereof, and relates to the technical field of biodegradation. The efficient microbial fermentation inoculant for the straw is formed by compounding four strains including trichoderma reesei, streptomycete, lactobacillus plantarum and bacillus amyloliquefaciens according to the mass ratio, the ratio of the viable count of the four strains is that the ratio of the viable count of the trichoderma reesei to the viable count of the streptomycete to the viable count of the lactobacillus plantarum to the viable count of the bacillus amyloliquefaciens is 3: 2: 2: 1.5, the total viable count of the inoculant is larger than or equal to 1.3 * 10 CFU / g, and the cellulase activity is larger than or equal to 85 U / g. The laccase activity is greater than or equal to 42U / g. The invention can effectively solve the industrial pain points of difficult degradation of straws, poor quality and weak stability, and in agricultural production, the microbial inoculum can increase the content of organic matters in soil, can reduce the feed cost in the feed field, and can be used for production of straw-based organic fertilizers in the environmental protection field, and can reduce the use amount of chemical fertilizers.

The present invention discloses a laccase, its gene and application, belonging to the technical field of genetic engineering. The laccase gene of the present invention is obtained by codon optimization of the laccase gene of Cerrena unicolor, and the nucleotide sequence is as shown in SEQ ID NO.2. The laccase gene provided by the present invention is recombinantly expressed by transforming Aspergillus niger, and high-activity laccase can be mass-produced industrially. The highest enzyme activity in shake flask culture reaches 39 U / ml, and after culturing in a 7L fermenter for 125 h, the total laccase activity reaches 9234 U / ml. At the same time, the laccase provided by the present invention and the mediator methyl syringate have a significant destructive effect on zearalenone, which is beneficial to grain transportation and storage.

The invention discloses a colorimetric detection method for daucoside based on enhanced octahedral silver oxide laccase activity and application, and belongs to the technical field of agricultural product safety detection. According to the present invention, the nucleic acid aptamer capable of being specifically combined with the danioside is adopted as the original recognition element, and the colorimetric detection method for enhancing the activity of the octahedral silver oxide laccase by using the nucleic acid aptamer is constructed, and is used for rapid danioside detection; the method is high in sensitivity and strong in specificity, the lowest detection limit of the droomcorn glycoside is 0.0743 mu g / mL, the color change can be distinguished by naked eyes, the method has the advantages that the operation is simple and convenient, the reaction is rapid, large-scale instruments are not needed and the like, the recovery rate in a sorghum sample reaches 89.66%-100.87%, and the method is suitable for on-site screening of the droomcorn glycoside in practical samples such as sorghum.

The present invention relates to a strain of Phlebiopsis pilatii and its applications. The strain name is Phlebiopsis pilatii HE39, with the preservation number of CGMCC No. 41168. It was deposited on February 5, 2024 at the China General Microbiological Culture Collection Center (CGMCC), and the deposit address is Institute of Microbiology, Chinese Academy of Sciences, No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing, China. This strain can be used to degrade lignin and cellulose, has good degradation ability for lignin in ground cover combustibles, has good laccase activity, lignin peroxidase and manganese peroxidase activities, and can increase the weight loss rate of forest combustibles.

The present application relates to a kind of preparation methods of phaeolus schweinitzii fungicide, phaeolus schweinitzii (P. Phlebiopsis pilatii ) HE39 is inoculated medium fermentation culture, centrifugation, and the supernatant is taken;The preservation number of phaeolus schweinitzii (P. Phlebiopsis pilatii ) HE39 is CGMCC No.41168.The phaeolus schweinitzii fungicide prepared in the present application can be used for degrading lignin and cellulose, has good degradation ability to lignin in ground combustible, has good laccase activity, lignin peroxidase and manganese peroxidase activity, and can improve the weight loss rate of forest combustible.

The present application provides a kind of marine bacteria capable of degrading lignin and removing nitrite, which is a deep-sea seabed sulfide source, and has the function of degrading lignin and removing nitrite.The strain of Halomonas sp.has a preservation number of CGMCC No.34690.The strain screened in the present application can grow and reproduce in seawater, can utilize guaiacol as a carbon source, and can remove nitrite.The strain of the present application has laccase activity, has laccase gene and nitrite reductase gene.The experimental results show that the cumulative removal rate of guaiacol after 2 days of culture is 56%, and the removal rate of nitrite after 4 days of culture is close to 70%, which has great application potential in the marine aquaculture industry.

The invention discloses a FeCu-based Prussian blue nano-enzyme colorimetric sensor array and an application thereof in identification of tetracycline antibiotics and urinary tract infection bacteria. The difference affinity of different tetracycline antibiotics or gram negative / positive bacteria on the FeCu-based prussian blue nano-enzymes with three laccase activities and the difference inhibition effect on the laccase-like catalytic activity of the FeCu-based prussian blue nano-enzymes are utilized; a three-channel colorimetric sensor array, a gel colorimetric sensor array kit and a paper chip colorimetric sensor array kit are respectively constructed, a new method is provided for rapid and portable determination and identification of tetracycline antibiotics in environment, food and biological fluid, and especially a new means is provided for early rapid identification of live bacteria infected by urinary tract. The method can be used for high-sensitivity and high-selectivity determination and identification of tetracycline antibiotics in river water, honey, chicken, urine and the like, and rapid colorimetric identification of escherichia coli, staphylococcus aureus and methicillin-resistant staphylococcus aureus in urinary tract infection.

This invention discloses a laccase derived from *Coprinus gracilis*, its recombinant expression strain, and a highly efficient expression method, belonging to the fields of microbiology and bioengineering technology. Using *Aspergillus niger* MA70.15 as the experimental strain, this invention employs a random integration strategy to achieve pC3-P... citA -SP GlaA - lcc9‑ T trpC ‑pyrG The expression vector was integrated into the upstream region of the promoter of the host bacterium citrate synthase in the form of nine consecutive copies. To investigate the effects of microparticles and osmotic regulators in the fermentation medium on laccase production by recombinant Aspergillus niger, this invention added different types and concentrations of microparticles and osmotic regulators, resulting in a laccase activity of 1566.7 U / L in shake-flask fermentation of recombinant strain AnRcgL1 and 1961 U / L in a 1 L fermenter, successfully achieving efficient recombinant expression of laccase Lcc9 in Aspergillus niger.

The present invention discloses a preparation method based on a DNA tweezers-driven nanozyme / bioenzyme cascade composite material and its application in the on-site rapid detection of methicillin. The present invention uses a nanoflower-structured copper-based nanozyme synthesized at room temperature using copper sulfate and DNA to exhibit excellent laccase-like activity and stability; utilizing the principle of base complementary pairing and the high affinity of the aptamer to the molecular target, the DNA tweezers fix AChE on the surface of the nanozyme to form a CuNFs-Apt-AChE cascade enzyme composite material. The output signal of the sensing system is further enhanced by the synergistic effect of the enzyme cascade system, thereby improving the detection sensitivity. The CuNFs-Apt-AChE cascade enzyme composite material is fixed by sodium alginate hydrogel to prepare a high-stability instant response platform for the detection of methicillin residues. This sensor has demonstrated good sensitivity, portability and stability in practical applications, providing an innovative platform for on-site rapid detection.

The invention belongs to the technical field of microorganisms, and particularly relates to bacillus velezensis, a straw degradation agent, a preparation method, a straw degradation method and application. The invention provides a bacillus velezensis LLS, and the preservation number of the bacillus velezensis LLS is CGMCC (China General Microbiological Culture Collection Center) No.35634. The bacillus velezensis LLS provided by the invention is high in cellulase total activity, endo beta-1, 4-glucosidase activity, exo beta-1, 4-glucosidase activity, beta-1. 4-glucosidase activity, lignin peroxidase activity, laccase activity and manganese peroxidase activity, can tolerate low temperature, and can be used for preparing the bacillus velezensis LLS. The straw degradation effect is good under the low-temperature condition.

The invention discloses a strain of high-quality and high-yield sulfur gorgeous fungus and application thereof, and belongs to the technical field of microorganisms. According to the present invention, the Erioporus sulphureus 2023V48 is preserved in the China General Microbiological Culture Collection Center (CGMCC), the preservation number is CGMCC No.41575, and the preservation date is October 18, 2024, and the Erioporus sulphureus 2023V48 can be used for preparing the Erioporus sulphureus strain. The mycelial growth speed of the sulfur gorgeous fungus 2023V48 is high, culture materials can be rapidly infected, the spawn running speed is high, the fruiting body yield after fruiting is high, the content of active ingredients in mycelium fermentation liquor is high, the laccase activity is high, the sulfur gorgeous fungus 2023V48 is suitable for industrial production, the commodity performance is higher, and the application value is higher.

The invention relates to a strain of pelatinomyces piraticola and an application thereof. The name of the strain is Phlebiopsis pilari HE39, the preservation number is CGMCC No.41168, and the strain is preserved in the China General Microbiological Culture Collection Center (CGMCC) on February 5, 2024, and the preservation address is Institute of Microbiology, Chinese Academy of Sciences, No.3, No.1 Yard, West Beichen Road, Chaoyang District, Beijing, China. The strain can be used for degrading lignin and cellulose, has very good degradation capability on lignin in ground cover combustible materials, has very good laccase activity, lignin peroxidase activity and manganese peroxidase activity, and can improve the weight loss ratio of the combustible materials in forest land.

The invention discloses a laccase mutant S186D and application of the laccase mutant S186D in catalyzing oxidative polymerization of cardanol. The invention provides a laccase mutant, the laccase mutant is characterized in that the 186th amino acid serine of laccase cotABs is mutated into other amino acids, and the amino acid sequence of the laccase cotABs is as shown in SEQ ID NO: 1. According to the laccase mutant CotAS186D disclosed by the invention, amino acid at the 186th site of the laccase from bacillus subtilis B.subtilis 168 is mutated from serine S to aspartic acid D (laccase mutant CotAS186D) in a site-specific mutagenesis manner, the catalytic activity of the laccase is remarkably improved, and compared with wild type laccase, the CotAS186D shows remarkably improved laccase activity and is more suitable for industrial production. Experiments show that a recombinant strain based on the expression laccase mutant has excellent CotAS186D production capacity, and has a better industrial application prospect.

This invention discloses a method for detecting octopamine and tyramine using a laccase-like Schiff base Cu-MOF nanozyme. The method uses a Schiff base formed from glutaraldehyde and 2-aminoterephthalic acid as starting reagents as ligands to synthesize a flower-like Cu-MOF nanozyme. This Cu-MOF exhibits near-infrared light-triggered laccase-like activity. Using octopamine and tyramine as substrates, Cu-MOF catalyzes the oxidation of octopamine and tyramine, conjugating 4-aminoantipyrine to form a red coupling product. This product exhibits a high absorption spectrum at 505 nm, demonstrating high detection efficiency with detection limits of 0.18 μg / mL and 0.60 μg / mL, respectively. X-ray photoelectron spectroscopy analysis shows that the Cu(I) / Cu(II) redox reaction participates in the catalytic process. This method is characterized by high sensitivity, strong specificity, simple operation, and rapid response.

Provided is a new CueO mutant with improved activity compared with wild-type CueO. The protein according to one or more embodiments of the present invention contains an amino acid sequence [1] or [2] and has laccase activity: [1] an amino acid sequence containing at least a region of positions 29-516 in SEQ ID NO: 14 with mutations (a) and (b): (a) a substitution of D360 with an amino acid other than D; and (b) one or more selected from a substitution of G304 with an amino acid other than G, a substitution of D373 with an amino acid other than D, and a substitution of Q374 with an amino acid other than Q; or [2] an amino acid sequence 90% or more identical to the sequence [1], and having residues corresponding to positions 360, 304, 373, and 374 of SEQ ID NO: 14 identical to those of the sequence [1].