Towards Sustainable Textile Cleaning: A Fractal Approach for Assessing Fabric Surface Changes Post- Enzymatic Bio Laundering

Bio laundering is an approach like bio polishing and bio scouring together without using chemicals. This used natural cocktail of enzymes, thereby reducing the use of harsh chemicals and offering sustainable environment. This also benefits in a way where the furnished cloth is made to remove dullness and dirt with the help to enzymes. Enzyme based drycleaning can be gentler on fabrics, potentially extending life of clothing. It will also create a healthier environment for dry cleaners. Eventually, leading to a more sustainable textile care industry. The current chemical dry-cleaning industry is worth 3988.658 million dollars by 2030 which is forecasted to be growing at 21% every year. (www.databridgemarketresearch.com/ reports/global-dry-cleaning-and-laundry-services-market) [1].

The conventional chemical dry-cleaning industry, projection, faces significant environmental challenges due to the use of harsh chemicals and high chemical oxygen demand (COD) in textile effluents. Here comes the need for bio laundering as busy lifestyles, increasing fashion needs and people becoming more environment friendly. In a world, where everyone is talking about reuse, reduce and recycles, bio laundering is a need of the hour to meet the increasing demand and to provide a sustainable solution. Between 50 and 80% of chemical oxygen demand (COD) in effluents of textile world is caused by polluting agents, which contribute to water pollution at a major level (Opwis et al., 1999). Bio laundering offers a sustainable way to clean clothes along with making them feel softer.

Formulation of enzyme cocktail

Cellulase is being used in the textile world due to its nature of hydrolyzing cellulosic micro-fibrils which are bulging out of the yarn surface as they are more prone to enzymatic attack (Araujo et al., 2008). Pectinase which is being used specifically to remove pectin act as the biological gum on the surface of fabric, which again is used specifically in bioscouring (Buchert et al., 2000; Jayani et al., 2005; Solbak et al., 2005). Cellulases may assist pectinases by increasing their accessibility to the pectin material. Amylases are enzymes that hydrolyze starch molecules to give various products which are used in different industries, including dextrins and smaller polymers composed of glucose units [2]. Amylases are used to target complete removal of the size without any harmful effects on the fabric. All these 3 enzymes are being used in textile industry for different purposes.

An enzyme cocktail is made using these 3 enzymes. Enzyme based bio laundering will be carried out by use of enzymes maintaining temperature, pH, time and concentration of enzymes. All three enzymes as listed in table1 have their action specifically targeted at particular temperature and pH. After using this cocktail on fabric, changes were notices and SEM analysis was done to review the changes caused by enzyme cocktail. Biodry cleaning can be further used for delicate and sensitive clothes. Characterization of the fabric surface is done by box counting method for greige method as well as enzymatic treated cloth. We used SEM as a primary analytical tool, which is a powerful method for surface morphology using fractal dimension analysis. Surface changes are crucial for both cleaning efficacy and fabric damage. To compare the performance of enzyme-cocktail-based bio laundering with greige fabric methods in terms of fabric integrity and cleaning efficacy. Table 1 showing the current chemical dry-cleaning process and the bio cleaning process which we are using along with the already used conventional methods with the novel approach. The table also shows the temperature and Ph used and where all 3 process can be combined and a optimum pH and temperature is maintained for the cocktail solution.

Table 1:

Enzymes like cellulase, amylase, and pectinase are revolutionizing dry cleaning by offering targeted solutions for fabric care. Cellulase enhances fabric lustre through cellulose hydrolysis, replacing traditional polishing with polyethylene glycol. Meanwhile, amylase ensures dimensional stability by depolymerizing starch, an enzymatic alternative to hydrochloric acid in desizing. Lastly, Aspergillus niger’s pectinase significantly improves stain removal by degrading pectin, substituting harsh sodium hydroxide in scouring processes (Sheikh et al., 2019). Pectinase enzymes play a crucial role in bio-scouring, a textile pretreatment process that uses enzymes to remove impurities from cotton fibers, making them more absorbent and suitable for dyeing (Burman et al., 2014). A solution will be formed of these enzymes maintaining a Ph and temperature where all 3 will function together. In layman terms we can say that cellulase is known to remove dullness. Amylase is used to keep the shape and size of the dry-cleaned cloth. Pectinase is used for removing dirt.

Cellulase production done by Raikamal Bhattacharya [3] using a sustainable method called solid-state fermentation (SSF). The production process was optimized by controlling parameters such as airflow, leading to high enzyme yields. This approach is a more economical and environmentally friendly alternative to traditional methods. The optimal temperature for the cellulase enzyme was determined to be 50 °C, where it retained its stability. Other optimal conditions for maximum cellulase production included a six-day fermentation period and a temperature of 30 °C in the bioreactor. The ideal moisture ratio of the substrate was 1:2 (67%). The optimal pH for maximum production was found to be 5. A twostep membrane filtration process used to filter the crude cellulase extract. First, micro filtration with a 0.45μm pore size membrane recovers 94% of the enzyme. This is followed by ultrafiltration using a 10kDa membrane, which recovers 71% of the enzyme. The final product is a concentrated cellulolytic enzyme with an activity of 13.54FPU/mL. Coming to our next issue of shrinkages, which happens when clothes are dry cleaned due to which sizes and shapes change, thereby making the fit go away. For this problem enzymatic biodesizing where we will use amylase, exhibiting the best amylase activity among the isolate, produced 341.7U/mL of amylases under optimized conditions of incubation period (6 days), incubation temperature (35 °C), and incubation pH (6.0), using nutrient salt solution (NSS). The crude enzyme preparation, so obtained from the test strain under optimized conditions of SSF, was found to be thermos alkali stable, as it retained about 90% of its maximum activity at pH 8.0 and more than 50% of its maximum activity at a temperature of 75 °C. Banana peel powder through enzymatic hydrolysis using crude pectinases derived from A. niger at different substrate concentrations, pH, temperature, and duration. Pectinase was produced at optimum condition in sufficient amount to carry out further experiments. Some part of the pectinase thus produced was partially purified using ethanol. This is mixed with 1 part of amylase and 1 part of cellulase. The biobased methods operate under specific pH and temperature ranges, signifying a shift towards more sustainable and effective textile treatments.

Optimization of different parameters

Concentration: Enzymes (cellulose and amylase) each 1part fraction respectively, were mixed with pectinase which was made by banana leaf. The cultivation of A. niger for pectinase production was carried out in 250ml Erlenmeyer flasks. Each flask contained 100ml of distilled water supplemented with the following basal medium components (all %w/v): Monopotassium Phosphate (KH2PO4): 0.02%, Magnesium Sulfate (MgSO4): 0.01%, Ammonium Sulfate ((NH4)2SO4): 0.04%, Ferrous Sulfate (FeSO4): 0.01%, Manganese Sulfate (MnSO4): 0.001%. Dried banana peel powder was used as the pectic substrate, with its concentration varied according to the experimental design for optimization. The prepared medium was then sterilized by autoclaving and subsequently cooled to room temperature. The pH of the medium was adjusted to 5.8 using a citrate buffer. Each sterilized flask was inoculated with approximately 2×108 spores of A. niger. The flasks were then incubated in an incubator shaker at a shaking speed of 150rpm. Incubation time and temperature were determined by the experimental design. Following incubation, the culture filtrate was cooled to 4 °C and centrifuged at 10,000rpm for 10 minutes in a refrigerated centrifuge. The resulting supernatants, containing the crude enzyme, were collected for subsequent investigations. Bulk production of pectinase was subsequently conducted under the optimized conditions. This pectinase was then used for partial purification and clarification of banana juice. For a feasibility analysis, this produced pectinase was combined with commercial cellulase and amylase. An enzyme cocktail was formulated by mixing the three enzymes (pectinase, cellulase, and amylase) in a 1:1:1 ratio. Hence, the optimum enzyme cocktail concentration was taken and filtered. Now the filtered enzyme cocktail is sprayed on the greige fabric.

Treatment time: The percentage weight loss observed in enzyme-treated cotton fabrics increased proportionally with the application of the enzyme cocktail to the greige fabric. Following treatment, the fabrics were immersed in the cocktail solution for 2 hours prior to examination. According to Klug (2004), the isoelectric point of pectate lyase is pH 8.5, which aligns with its observed maximal activity. Notably, the pectin removal efficiency of pectinase significantly decreased at pH values above 9.0.

Selection of optimal range of temperature and pH for solution of enzyme cocktail: Optimal Temperature Range: The process 1 has temperature of 50 °C while process 2 has temperature of 25-55 °C and process 3 has temperature of 40-50 °C. The intersection of Process 2 (25-55 °C) and Process 3 (40-50 °C) is 40-50 °C. Process 1 operates optimally at 50 °C. Since 50 °C falls within the 40-50 °C range, the common optimal temperature for all three processes is 50 °C.

Optimal Ph Range: For the Ph range, as there is no similar Ph range, so we opted to mix the 3 enzymes keeping ph between 5-7 so that all two process (cellulase and pectinase process) are adjusted a little bit and amylase is done at its required range.

Table 1 shows the enzymes used, their origin and the reaction they will be going through. An enzyme cocktail using ratio 1:1:1. the material to liquor ratio is 1:4. Cellulase is known to remove dullness. Amylase is used to keep the shape and size of the drycleaned cloth. Pectinase is used for removing dirt. The cocktail combining three process -bio polishing (using cellulase enzyme) and bio desizing (using amylase), bio scouring (using pectinases) together for commercial purpose of dry cleaning. There is a major problem of shrinkage which happens when clothes are dry cleaned due to which sizes and shapes changes, thereby making the fit go away. For this problem enzymatic bio desizing where we will use amylase. The process is followed by bio desizing using amylase as an enzyme for restraining any shrinkage in the apparel so that the final apparel is dry cleaned keeping the same shape and size.