Aspergillus chevalieri and its fermented melanin and application in textile printing and dyeing

Abstract

The application provides a kind of Aspergillus chevalieri and its fermented melanin and application in textile printing and dyeing, belong to the field of microbial fermentation.The application provides a kind of Aspergillus chevalieri (Aspergillus chevalieri) BG-T1, the preservation number is GDMCC No: 65023, has been preserved in Guangdong Microbial Culture Collection Center on August 20, 2024.The application uses potato glucose medium as fermentation substrate, uses Aspergillus chevalieri BG-T1 as fermentation strain, and obtains melanin fermentation broth in fermentation tank, which can be used for silk, cashmere, cotton and other textile fabric dyeing.The dyed textile has high color fastness, is resistant to sunlight, overcomes the problem that most microbial pigments are sensitive to light;And the dyeing process does not need chemical auxiliaries, and the dyed textile is environmentally friendly, healthy, safe and non-toxic.

Description

Technical Field

[0001] This invention belongs to the field of microbial fermentation, and relates to the fermentation of Aspergillus chevallis, specifically to Aspergillus chevallis and the melanin fermented from it and its application in textile printing and dyeing. Background Technology

[0002] Textile dyeing and printing is a water-intensive and heavily polluting industry. Chemical dyes derived from petrochemical raw materials, as well as chemical auxiliaries and mordants used in the dyeing process, cause serious environmental pollution. Using natural dyes can not only greatly reduce environmental pollution, but also produce healthier fabrics. Natural dyes mainly include plant dyes, animal dyes, and mineral dyes. In recent years, dyes derived from microorganisms have also begun to be used in textile dyeing and printing.

[0003] Fu brick tea is a distinctive product among traditional Chinese dark teas, belonging to the post-fermented tea category. The tea brick contains a special "golden flower fungus," which gives Fu brick tea its unique color, aroma, and health benefits. Current research has identified this "golden flower fungus" as a probiotic with physiological activities such as producing active enzymes, lowering lipids, antioxidation, and anti-tumor activity. This fungus is unique to Fu brick tea and, under certain conditions, can produce spores, forming yellow cleistothecia that fill the interior of the brick tea with "golden flowers." Its taxonomic position is not yet fully clear, but molecular identification based on the internal transcribed spacer (ITS) sequence indicates it is *Aspergillus chevaleri* (…). Aspergillus chevalieri However, traditionally, domestic mycologists have considered it to be named *Eurotium cristatum*. Eurotium cristatum When this "golden flower fungus" grows in a specific culture medium, it metabolizes and produces a large amount of pigments. Initially, it mainly produces yellow pigments, but in the later stages of cultivation, it produces a large amount of extracellular melanin, turning the entire fermentation broth black.

[0004] Coronavirus ( Euotium cristatum This fungus belongs to the Ascomycetes class, Aspergillus order, Aspergillus family. As a holotype producing both sexual and asexual forms, its typical characteristics include ascospores with a crown-like projection and a distinctly rough surface with small warts, and conidia with small spines. Based on the characteristics of its spores, the sexual form of this fungus is identified as *Aspergillus cristatus*. Eurotium cristatum The asexual form was identified as Aspergillus spicata ( ), Aspergillus spiculosus ), also known as Aspergillus cristatus ( Aspergillus cristatum*Aspergillus cristatus* is aerobic and drought-tolerant, with an optimal pH of 5 and an optimal growth temperature of 28-30℃. This fungus is highly adaptable, reproducing sexually on tea bricks and hypotonic medium (0.5M NaCl). Its reproduction gradually shifts to asexual reproduction as osmotic pressure increases, and it only reproduces asexually under high osmotic pressure (≥3M NaCl). Its spores can still survive after being steeped at 85℃ for 5 minutes. Carbon and nitrogen sources significantly affect mycelial growth and sporulation, with carbon sources being essential for sporulation. Different strains utilize different types of carbon sources to varying degrees. Solid-state fermentation prefers D-fructose, glucose, sucrose, D-xylose, and maltose, while utilizing sorbitol, agar, tannins, and starch poorly. Liquid fermentation shows lower dependence on carbon source type. Carbon source concentration and nitrogen source type also affect the type and quantity of sporulation. Inorganic nitrogen sources promote spore germination better, while organic nitrogen sources have a greater promoting effect on colony growth. Therefore, in actual training, a combination of the two methods is often adopted.

[0005] *Aspergillus cristatus* typically produces abundant pigments, primarily yellow and black pigments, during its growth and metabolism on potato and other culture media. The yellow pigment content is positively correlated with the number of sexual spores and is related to the color of the "golden flower" (a type of flower). Extraction of the yellow pigment from the liquid fermentation of *Aspergillus cristatus* in Shaanxi Fuzhuan tea using petroleum ether revealed it to be a fat-soluble pigment with a maximum absorption wavelength of 398 nm. It is intolerant of high temperatures, acid-resistant but not alkali-resistant, and contains metal ions (Fe). 3+ Fe 2+ Cu 2+ Sunlight and other conditions can degrade it. Spectroscopic analysis suggests that yellow pigments contain functional groups such as -CH, CO, and C=C. Melanin is a general term for a class of complex and diverse phenolic or indole-based biomacromolecules, possessing functions such as preventing photodamage, strong antioxidant properties, anti-radiation, and immunomodulation. The extracellular melanin produced by *Aspergillus cristatus* has a maximum absorption wavelength of 298 nm, exhibits strong heat resistance below 70℃, and is relatively stable to natural light.

[0006] Existing technology CN111635915A uses *Aspergillus cristatus* as the fermentation strain to prepare a fermentation product with high melanin content through a specific liquid fermentation medium formula. This fermentation product includes *Aspergillus cristatus* melanin fermentation broth and its concentrate. The technology first inoculates activated *Aspergillus cristatus* strain into potato dextrose liquid medium for expansion culture to obtain expanded *Aspergillus cristatus* strain. Then, the obtained expanded *Aspergillus cristatus* strain is inoculated into a liquid fermentation medium and cultured at 26-32℃ for more than 5 days to obtain an intermediate melanin fermentation product. Then, the melanin fermentation stock broth is obtained through fermentation, and the melanin fermentation stock broth is concentrated to obtain *Aspergillus cristatus* melanin fermentation products of different concentrations. This melanin fermentation product can be used for coloring Changsha stinky tofu and biscuits. The disadvantage of this technology is that the fermentation medium has many components, requiring the addition of peptone and tyrosine, resulting in high cost.

[0007] Yang Ni et al. optimized the fermentation conditions for extracellular melanin produced by *Aureobasidium cristatum* and studied the stability of the melanin using response surface methodology. Using different culture temperatures, culture medium pH, and shaking speed as evaluation factors, and the absorbance of the resulting melanin solution as the response value, a three-factor, three-level Box-Behnken response surface experiment was established. The results showed that the optimal fermentation conditions for *Aureobasidium cristatum* extracellular melanin were a shaking speed of 184 r / min, a culture temperature of 29℃, and a culture medium pH of 6.8. Under these conditions, 4.27 g / L of *Aureobasidium cristatum* extracellular melanin was extracted (Yang Ni, Liu Suchun, Wang Jigang, et al. Optimization and stability study of fermentation conditions for extracellular melanin production by *Aureobasidium cristatum* [J]. Food and Fermentation Industries, 2020). Although this technology provides fermentation conditions for *Aureobasidium cristatum* extracellular melanin, its application in melanin production has not been studied in depth. Summary of the Invention

[0008] This invention addresses the problem of the lack of effective application of extracellular melanin from *Aspergillus chevaleri*, providing a method using *Aspergillus chevaleri*, its fermented melanin, and its application in textile printing and dyeing. This invention isolates *Aspergillus chevaleri* (…) from Anhua dark tea… Aspergillus chevalieri BG-T1, with accession number GDMCC No: 65023, was deposited at the Guangdong Provincial Center for Microbial Culture Collection on August 20, 2024. By fermenting this Aspergillus chevallis, a dye containing melanin can be prepared for dyeing textiles such as silk, cashmere, wool, and cotton, with good dyeing results.

[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0010] This invention provides a *Aspergillus schwanniferus* (Schwarzkopf) Aspergillus chevalieri BG-T1, with accession number GDMCC No: 65023, was deposited at the Guangdong Provincial Center for Microbial Culture Collection on August 20, 2024. The ITS sequence of this strain is shown in SEQ ID NO.3.

[0011] On the other hand, this invention provides the application of Aspergillus chevaleri BG-T1 in the fermentation production of melanin. When Aspergillus chevaleri grows in a specific culture medium, it metabolizes and produces a large amount of pigment substances. Initially, it mainly produces yellow pigment, and in the later stages of cultivation, it produces a large amount of extracellular melanin, turning the entire fermentation broth black.

[0012] On the other hand, the present invention provides a method for preparing melanin fermentation broth, wherein the preparation method involves inoculating Aspergillus chevaleri BG-T1 into a culture medium for fermentation.

[0013] Preferably, the preparation method includes the following steps:

[0014] S1. Inoculate Aspergillus chevaleri BG-T1 into the culture medium to obtain an activated strain;

[0015] S2. Inoculate the activated bacterial strain into the seed culture medium and culture to obtain the primary liquid bacterial strain;

[0016] S3. Inoculate the primary liquid culture medium into the liquid culture medium and culture to obtain the secondary liquid culture.

[0017] S4. Inoculate the secondary liquid bacterial culture into the fermentation medium for fermentation to obtain melanin fermentation broth.

[0018] Preferably, the preparation method includes the following steps:

[0019] S1. Transfer Aspergillus chevaleri BG-T1 onto a plate culture medium and activate it in an incubator to obtain an activated strain;

[0020] S2. Inoculate the activated bacterial strain into a shake flask containing seed culture medium and culture it to obtain a primary liquid bacterial strain;

[0021] S3. Inoculate the primary liquid culture into a shake flask containing liquid culture medium and culture to obtain the secondary liquid culture.

[0022] S4. Inoculate the secondary liquid bacterial culture into a fermenter containing fermentation medium to obtain melanin fermentation broth.

[0023] Preferably, the preparation method includes the following steps:

[0024] S1. Transfer Aspergillus chevaleri BG-T1 onto potato dextrose agar plates and activate them in an incubator to obtain activated strains;

[0025] S2. The activated bacterial strain is inoculated into a shake flask containing potato glucose seed culture medium and cultured to obtain a primary liquid bacterial strain.

[0026] S3. Inoculate the primary liquid culture into a shake flask containing liquid culture medium and culture to obtain the secondary liquid culture.

[0027] S4. Inoculate the secondary liquid bacterial culture into a fermenter containing fermentation medium to obtain melanin fermentation broth.

[0028] Preferably, step S1 involves transferring the preserved Aspergillus slant culture BG-T1 onto a plate containing potato dextrose agar (PDA) medium and activating it in an incubator at 26-30°C for 7 days.

[0029] Preferably, step S2 involves using an inoculation hook to pick up two 0.5cm pieces of material. 2The activated BG-T1 strain was inoculated into a 250 mL shake flask containing 100 mL of potato glucose (PD) seed culture medium and cultured with shaking at 26-30℃ and 160 rpm for 6 days to obtain the primary liquid strain.

[0030] Preferably, step S3 involves inoculating the primary liquid culture of BG-T1 into a shake flask containing liquid culture medium at an inoculation amount of 5% (v / v), and then culturing it at 26-30°C and 160 rpm for 7 days to obtain the secondary liquid culture.

[0031] Preferably, step S4 involves inoculating the secondary liquid strain of BG-T1 into a 30L fermenter containing fermentation medium, controlling the temperature at 26-30℃ and the stirrer speed at 120-200 rpm, and continuously culturing for 10-12 days. After fermentation, the fermentation broth is centrifuged at 5000 rpm for 15 min to remove the bacterial cells, and then filtered through a 0.45 μM filter membrane to obtain the melanin fermentation broth.

[0032] Preferably, the preparation methods of the liquid culture medium in step S3 and the fermentation culture medium in step S4 include the following steps:

[0033] Weigh out the washed and peeled potatoes, cut them into small pieces and put them in a pot. Add distilled water and heat to a boil. Filter the solution through two layers of gauze, then add glucose to the filtrate. After fully dissolving the glucose, add distilled water and sterilize at 121°C.

[0034] Preferably, the preparation methods of the liquid culture medium in step S3 and the fermentation culture medium in step S4 include the following steps:

[0035] Weigh 200g of washed and peeled potatoes, cut them into small pieces and put them in a pot. Add 1000mL of distilled water, heat to boiling and maintain for 20 minutes. Filter through two layers of gauze, add 20g of glucose to the filtrate, dissolve it completely, add distilled water to 1000mL, and sterilize at 121℃ for 30 minutes.

[0036] On the other hand, the present invention provides a melanin fermentation broth prepared by the above preparation method.

[0037] On the other hand, the present invention provides the application of the above-mentioned melanin fermentation liquid in textile printing and dyeing.

[0038] On the other hand, the present invention provides a method for printing and dyeing textiles with the above-mentioned melanin fermentation liquid, comprising the following steps:

[0039] Add the melanin fermentation liquid mentioned above to the dyeing vat, adjust the pH value to acidic, and then dye the textiles.

[0040] Preferably, the method for printing and dyeing textiles with the above-mentioned melanin fermentation liquid includes the following steps:

[0041] Determine the melanin concentration in the melanin fermentation broth; add 0.5-5.0% (owf, calculated based on the amount of melanin) of the above melanin fermentation broth to the dyeing vat at a liquor ratio of 1:20-1:60, adjust the pH value to 3.0-6.0 with acetic acid, dye the textile at room temperature, and simultaneously raise the temperature at a rate of 1°C / min until the temperature reaches 60-90°C, and dye for 20-60 min.

[0042] Preferably, the method for printing and dyeing textiles with the above-mentioned melanin fermentation liquid includes the following steps:

[0043] Set up standard samples of melanin fermentation broth with different concentrations, and construct a standard curve after measuring the absorbance value A298; measure the absorbance value A298 of the melanin fermentation broth to be tested, and calculate the concentration of melanin in the fermentation broth to be tested based on the standard curve of absorbance value and melanin content.

[0044] Add 1.0% (owf, calculated based on the amount of melanin) of the above melanin fermentation broth to the dyeing vat at a liquor ratio of 1:30, adjust the pH value to 3.5 with acetic acid, dye the textile at room temperature, and simultaneously raise the temperature at a rate of 1°C / min. When the temperature reaches 80°C, dye for 30 minutes.

[0045] Preferably, the textiles include, but are not limited to, silk, cotton, wool, cashmere, or leather.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] 1. The melanin content in the fermentation broth of Aspergillus schwanniferus BG-T1 for melanin production can reach up to 4.62 g / L;

[0048] 2. The melanin produced by Aspergillus chevaleri BG-T1 has excellent coloring effects on silk, wool, and cotton fabrics, with the amount of melanin used ranging from 0.5% to 5.0% (owf). The dyed silk, cashmere, and cotton fabrics exhibit excellent colorfastness to perspiration, soaping, wet and dry rubbing, non-chlorine bleaching, dry cleaning, and sunlight, meeting the colorfastness requirements for textile fabrics.

[0049] Preservation Instructions

[0050] Strain name: Aspergillus chevaleri BG-T1;

[0051] Taxonomic name: Aspergillus chevalieri ;

[0052] Preservation institution: Guangdong Provincial Center for Microbial Culture Collection;

[0053] The depository is abbreviated as GDMCC.

[0054] Address: 5th Floor, Experimental Building, No. 100 Xianlie Middle Road, Yuexiu District, Guangzhou, Guangdong Province;

[0055] Deposit date: August 20, 2024;

[0056] Registration number at the Preservation Center: GDMCC No: 65023. Attached Figure Description

[0057] Figure 1 Growth of Aspergillus schwanniferus BG-T1 on culture medium.

[0058] A: On PDA solid medium (top); B: On PDA solid medium (bottom); C: Fermented in PD liquid medium for 12 days.

[0059] Figure 2 UV-Vis spectrum of extracellular melanin produced by strain BG-T1.

[0060] Figure 3 Linear relationship between melanin concentrations and absorbance values ​​of BG-T1 (wavelength 298nm).

[0061] Figure 4 BG-T1 melanin dyeing solution for dyeing different fabrics. Detailed Implementation

[0062] It is worth noting that the raw materials used in this invention are all commercially available products, and their sources are not specifically limited.

[0063] Example 1: Isolation and Identification of Strains

[0064] 1) Sample: Anhua dark tea with golden flowers purchased online.

[0065] 2) Isolation medium: Potato glucose agar (PDA) medium was used for strain isolation. Its composition (per liter) is: 6.0 g potato extract powder, 20.0 g glucose, 20 g agar, pH 6.2. The sterilization conditions are 121℃ autoclave for 20 min.

[0066] 3) Fermentation medium: The fermentation medium used for the strain is potato glucose medium (PD), with the following composition (per liter): 6.0 g potato extract powder, 20.0 g glucose, pH 6.2. The sterilization conditions are 121℃ autoclave for 20 min.

[0067] 4) Strain Isolation: Take 1 gram of tea leaves with obvious golden flowers, add 100 mL of sterile water, shake for 5 min, and then perform serial dilutions with sterile water. The required concentration for the experiment is 10. 2 103 10 4 Three dilutions were prepared. 100 µL of each dilution was evenly spread onto PDA solid medium using a spreader and incubated at 28°C for 7-10 days. The pigment production of the colonies was then examined. Single colonies producing pigment were selected for further isolation and purification and then stored at low temperature in 20% glycerol.

[0068] 5) Morphological observation: Among the isolated strains, BG-T1, with relatively robust hyphae and rapid growth rate, was selected and cultured on PDA medium. For example... Figure 1 As shown in A (front of the culture medium) and B (back of the culture medium), the colonies are typical of Aspergillus, nearly round, with a relatively dense texture, a yellow halo, a pale yellow edge, and a darker color in the center. Initially, they are golden yellow, and later they are dark brown. Under the microscope, typical ascocarps can be seen, which is consistent with the morphological characteristics of Aspergillus chevaleri.

[0069] 6) Strain Identification: The isolated strains were sent to Sangon Biotech (Shanghai) Co., Ltd. for identification. The internal transcribed spacer (ITS) sequence in eukaryotes is located between the 18S, 5.8S, and 28S ribosomal rDNA. It can withstand more variation during evolution, with an evolutionary rate 10 times that of 18S rDNA. It is a moderately conserved region and can be used to study taxonomic ranks at and below species. The primer sequences used were ITS1 (SEQ ID NO.1): TCCGTAGGTGAACCTGCGG and ITS4-R (SEQ ID NO.2): TCCTCCCGCTTATTG.

[0070] ATATGC. The PCR amplified fragment length was 600 bp. ITS gene sequence analysis and comparison in the NCBI database, and confirmation by the Guangdong Institute of Microbiology's strain preservation center using ITS gene sequence combined with colony morphology analysis, confirmed that strain BG-T1 belongs to *Aspergillus chevaleri*. Aspergillus chevalieri It was deposited at the Guangdong Provincial Center for Microbial Culture Collection on August 20, 2024, with accession number GDMCC No: 65023. Its ITS sequence is shown in SEQ ID NO.3.

[0071] SEQ ID NO.3:

[0072] .

[0073] Example 2: Preparation of BG-T1 melanin fermentation broth

[0074] The specific steps for preparing the BG-T1 melanin fermentation broth in this embodiment are as follows:

[0075] 1) Activation of strain BG-T1: The preserved Aspergillus slant culture of BG-T1 was transferred to a plate containing PDA medium and activated in an incubator at 28°C for 7 days.

[0076] 2) Preparation of seed suspension in shake flasks: Use an inoculation hook to pick up two 0.5cm pieces of seed suspension. 2 The activated BG-T1 strain was inoculated into a sterilized 250 mL Erlenmeyer flask containing 100 mL of seed culture medium and cultured with shaking at 28 °C and 160 rpm for 6 days to obtain the seed suspension (primary liquid strain).

[0077] The seed culture medium is potato glucose (PD) medium, with the following composition (per liter): 6.0 g potato extract powder, 20.0 g glucose, pH 6.2. The sterilization conditions are: autoclaving at 121°C for 20 min.

[0078] 3) Preparation of secondary liquid culture: The primary liquid culture of BG-T1 was inoculated into a 500mL Erlenmeyer flask containing 200mL of liquid culture medium, with an inoculation amount of 5%. After inoculation, it was cultured at 28℃ and 160rpm for 7 days to obtain the secondary liquid culture.

[0079] The preparation method of the secondary liquid culture medium is as follows: weigh 200g of washed and peeled potatoes, cut them into small pieces and put them in a pot, add 1000mL of distilled water, heat to boiling, maintain for 20min, filter with two layers of gauze, add 20g of glucose to the filtrate, dissolve it completely, and then add distilled water to 1000mL. The sterilization temperature of the culture medium is 121℃ for 30min.

[0080] 4) Preparation of melanin fermentation broth: The secondary liquid inoculum of BG-T1 was inoculated into a 30L fermenter containing fermentation medium at an inoculation rate of 5%. The temperature was controlled at 26-28℃ and the rotation speed at 120-200 rpm at different fermentation stages, and the mixture was continuously cultured for 12 days. After fermentation, the fermentation broth was centrifuged at 5000 rpm for 15 min to remove the bacterial cells, and then filtered through a 0.45 μM filter membrane to obtain the melanin fermentation broth.

[0081] The fermentation medium is prepared by weighing 200g of washed and peeled potatoes, cutting them into small pieces, placing them in a pot, adding 1000mL of distilled water, heating to boiling, maintaining for 20 minutes, filtering through two layers of gauze, adding 20g of glucose to the filtrate, dissolving it completely, adding distilled water to 1000mL, preparing 21L of culture medium according to the above ratio, adding it to a 30L fermenter, and sterilizing it by high pressure with steam at a temperature of 121℃ for 30 minutes.

[0082] 5) Extraction and content determination of melanin from fermentation broth: Melanin was extracted using acid precipitation. 100 mL of 0.2 mol / L NaOH solution was added to 100 mL of fermentation broth. The mixture was placed in a 60°C water bath and shaken for 4 hours. The pH was adjusted to 2.5 with 6M hydrochloric acid solution, stirred thoroughly, and allowed to stand for 12 hours. After centrifugation at 10,000 rpm for 10 minutes, the supernatant was discarded to obtain melanin precipitate. The precipitate was then washed with distilled water until neutral, and freeze-dried to obtain crude melanin. The melanin content of the fermentation broth was determined by weighing.

[0083] 6) Determination of pigment absorption spectrum: Dissolve 1 gram of crude melanin in 100 mL of NaOH solution (0.1 mol / L), using 0.1 mol / L NaOH solution as a reference solution. Perform spectral scanning at 200-1000 nm using a UV-Vis spectrophotometer. The scanning results are as follows: Figure 2As shown, the maximum absorption peak of melanin was measured at 298 nm. The 10 mg / mL melanin solution was then diluted 2, 4, 8, and 16 times with 0.1 mol / L NaOH solution, and the absorbance of each dilution was measured at 298 nm using a spectrophotometer. Figure 3 The linear relationship between melanin concentration and absorbance value is shown by the regression equation: y = 0.0361x + 0.2044, R0. 2 =0.9966. Based on the above regression equation, the melanin content of the fermentation broth supernatant was calculated to be 4.62 g / L.

[0084] Example 3: Dyeing of Silk Fabrics

[0085] 1) Preparation of melanin fermentation broth: Melanin fermentation broth was prepared by fermenting strain BG-T1 according to the method in Example 2;

[0086] 2) Add 1% (owf, calculated based on melanin content) of melanin fermentation liquid to the dyeing vat at a liquor ratio of 1:30, and adjust the pH value to 3.5 with acetic acid; start dyeing the silk fabric at room temperature, while raising the temperature at a rate of 1°C / min, and dye for 30 minutes when the temperature reaches 80°C.

[0087] 3) After dyeing, the dyed silk fabric is washed with water, soaped, washed with water again, and dried.

[0088] Example 4: Dyeing of Silk Fabric

[0089] The silk was dyed using the fermentation broth of BG-T1 as a dye according to the method in Example 3, except that the amount of melanin added was 0.5% owf.

[0090] Example 5: Dyeing of Silk Fabric

[0091] The silk was dyed using the fermentation broth of BG-T1 as a dye according to the method in Example 3, except that the amount of melanin added was 5% owf.

[0092] Example 6: Dyeing of cashmere fabric

[0093] 1) Pretreatment: Wash the pure cashmere fabric with water for 5 minutes, soap it for 10 minutes, and then wring it dry for later use;

[0094] 2) Dyeing: The cashmere was dyed using the fermentation broth of BG-T1 as dye according to the method in Example 3, with the amount of melanin added being 1.0% owf.

[0095] Example 7: Dyeing of cotton fabric

[0096] The cotton fabric was dyed using the fermentation broth of BG-T1 as a dye according to the method in Example 3, with the amount of melanin fermentation broth added being 1.0% owf.

[0097] Comparative Example 1: Dyeing of Silk Fabric

[0098] The silk was dyed using the fermentation broth of BG-T1 as a dye, following the method in Example 3, except that the pH of the dyeing solution was not adjusted (the actual pH was 6.7).

[0099] Comparative Example 2: Dyeing of Cashmere Fabric

[0100] The cashmere fabric was dyed using the fermentation broth of BG-T1 as a dye, following the method in Example 6, except that the pH of the dyeing solution was not adjusted (the actual pH was 6.7).

[0101] Comparative Example 3: Dyeing of Cotton Fabric

[0102] The cotton fabric was dyed using the fermentation broth of BG-T1 as a dye, following the method in Example 7, except that the pH of the dyeing solution was not adjusted (the actual pH was 6.7).

[0103] Comparative Example 4: Preparation of BG-T1 melanin fermentation broth

[0104] BG-T1 was fermented according to the method in Example 1 of CN111635915A. The liquid fermentation medium formula was: 10.0g of fresh peeled potato (cooked and juiced), 2.0g of glucose, 1.5g of peptone, 0.3g of tyrosine, and 100mL of water. The mixture was statically cultured at 30℃ for 8 days to obtain the melanin fermentation broth. After centrifugation and filtration, the OD300 of the original fermentation broth was diluted 20 times its original volume to a value of 0.724.

[0105] Comparative Example 5: Preparation of BG-T1 melanin fermentation broth

[0106] BG-T1 was fermented according to the method in Example 2 of CN111635915A. The liquid fermentation medium formula was: 20.0g of fresh peeled potato (juice obtained after boiling), 1.0g of maltose, 0.5g of peptone, 0.5g of tyrosine, and 100mL of water. The mixture was cultured at 28℃ and 180r / min for 6 days to obtain the melanin fermentation broth. After centrifugation and filtration, the OD300 of the original fermentation broth was diluted 20 times by volume to a value of 0.705.

[0107] Although the methods in Comparative Examples 4 and 5 can produce melanin in a shorter time and have a similar melanin yield to Example 2 of the present invention, the raw material cost increases by about 80% due to the need to add expensive peptone and tyrosine to the fermentation broth culture medium, which greatly increases the production cost.

[0108] Comparative Example 6: Dyeing of Silk Fabrics

[0109] The silk was dyed using the fermentation broth of Comparative Example 4 as a dye, following the method of Example 3.

[0110] Comparative Example 7: Dyeing of Silk Fabrics

[0111] The silk was dyed using the fermentation broth of Comparative Example 5 as a dye, following the method of Example 3.

[0112] Test example: Fabric performance testing

[0113] The K / S ratio and color fastness of different textile fabrics dyed according to the methods described in Examples 3-7 and Comparative Examples 1-3, 6, and 7 were tested, and the results are shown in Table 1. The K / S value was measured using a colorimeter at a wavelength of 400 nm. The test method for light fastness was ISO 105-B02:2014; the test method for perspiration fastness was ISO 105-E04:2013; the test method for soaping fastness was ISO 105-C06:2010; the test method for rubbing fastness was ISO 105-X12:2016; the test method for non-chlorine bleach fastness was AATCCTS-001; and the test method for dry cleaning fastness was ISO 105-D01:2010.

[0114] The above results indicate that the melanin produced by Aspergillus chevaleri BG-T1 has a good dyeing effect on silk, cashmere, and cotton fabrics. Figure 4 The amount of melanin used can range from 0.5% to 5.0% (owf). The dyed silk, cashmere, and cotton fabrics exhibit excellent colorfastness to perspiration, soaping, wet and dry rubbing, non-chlorine bleach, dry cleaning, and sunlight (higher numerical values ​​indicate better colorfastness), meeting the colorfastness requirements for textile fabrics. Adjusting the pH of the dye bath to acidic significantly improves the dye uptake rate of the melanin dye. Compared to melanin fermentation broth produced by adding peptone and tyrosine to the culture medium (corresponding to ratios 6 and 7), the melanin fermentation broth described in this invention is not only cheaper but also has a higher dye uptake rate; furthermore, the dyed fabrics exhibit better colorfastness to sunlight, soaping, and rubbing.

[0115] Table 1. Detection results of melanin produced by BG-T1 dyeing on textile fabrics.

[0116]

[0117] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, and is not intended to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions made by those skilled in the art to the technical solution of the present invention do not depart from the essence and scope of the technical solution of the present invention.

Claims

1. A type of Aspergillus chevaleri ( Aspergillus chevalieri BG-T1, characterized in that, The accession number is GDMCCNo:65023, and it was deposited at the Guangdong Provincial Center for Microbial Culture Collection on August 20, 2024.

2. The application of Aspergillus chevaleri BG-T1 as described in claim 1 in the fermentation production of melanin.

3. A method for preparing melanin fermentation broth, characterized in that, The preparation method includes inoculating the Aspergillus schwanniferus BG-T1 of claim 1 into a culture medium for fermentation.

4. The preparation method according to claim 3, characterized in that, The preparation method includes the following steps: S1. Inoculate the *Aspergillus schwanniferus* BG-T1 strain according to claim 1 into a culture medium to obtain an activated strain; S2. Inoculate the activated bacterial strain into the seed culture medium and culture to obtain the primary liquid bacterial strain; S3. Inoculate the primary liquid culture medium into the liquid culture medium and culture to obtain the secondary liquid culture. S4. Inoculate the secondary liquid bacterial culture into the fermentation medium for fermentation to obtain melanin fermentation broth.

5. The preparation method according to claim 4, characterized in that, The culture temperature for the strains in steps S1, S2, S3 and S4 is 26-30℃.

6. The preparation method according to claim 4, characterized in that, The preparation methods of the liquid culture medium in step S3 and the fermentation culture medium in step S4 include the following steps: Weigh out the washed and peeled potatoes, cut them into small pieces and put them in a pot. Add distilled water and heat to a boil. Filter the solution through two layers of gauze, then add glucose to the filtrate. After fully dissolving the glucose, add distilled water and sterilize at 121°C.

7. The application of Aspergillus chevaleri BG-T1 as described in claim 1 in textile printing and dyeing.

8. The application according to claim 7, characterized in that, Includes the following steps: The melanin fermentation broth was obtained by culturing the *Aspergillus schwanniferus* BG-T1, and then added to the dyeing vat to adjust the pH to acidic for dyeing the textiles.

9. The application according to claim 8, characterized in that, The textiles include fabrics made of silk, cotton, linen, wool, cashmere, and leather.

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