Cellulase Enzyme Based Wet‐Pretreatment of Lotus Fabric to Improve Antimicrobial Finishing withA. indicaExtract and Enhance Natural Dyeing: Sustainable Approach for Textile Finishing
Authors: Vajpayee Mona , Dave Hemen , Singh Mumal , Ledwani Lalita 
Published: July 2022

Lotus fibers/textile products have gained interest in recent years as a sustainable alternative of man‐made textiles as well as natural cellulose fibers. Lotus is an important cash crop; lotus fibers are derived from stem residues left in pond after harvesting which otherwise considered as a waste. Though the lotus fibers are chiefly composed to cellulose, non‐cellulosic impurities intrinsically present which causing problems during processing and finishing. In this study, application of cellulase enzyme explored for eco‐friendly wet processing of commercially available lotus fabric as pre‐treatment to improve the surface properties of the fabric. The enzymatic treatment for wet processing of lotus fabric optimized with respect to different process variables such as concentration of enzyme, pH, MLR, time, temperature. The optimum condition for the enzymatic treatment is 2 % enzyme concentration, 5.5 pH, 1 : 20 MLR, at 55 °C for 60 minutes. Effect of the enzymatic treatment on surface properties of the lotus fabric characterized by Attenuated total reflectance Fourier transform infrared spectroscopy (ATR‐FTIR), Scanning Electron Microscopy (SEM), and Atomic Force Microscopy (AFM), water contact angle, whereas on bulk properties studied by % weight loss, X‐Ray Diffraction (XRD), Thermal gravimetric analysis (TGA), tensile strength measurement, wet out time, water absorption percentage. The treatment resulted in removal of non‐cellulosic impurities, improvement in surface properties of the fabric such as increase in wettability, changes in surface morphology and roughness. Improvement in surface properties of lotus fabric due to the cellulase enzyme treatment results in favorably better absorption of natural product to impart antimicrobial property and also enhancement in natural dyeing. In this study, leaf extract ofAzadirachta indica(Neem Tree) in water, methanol, and water‐methanol utilized to impart antimicrobial activity to the lotus fabric. The extracts analyzed by phytochemical screening and HPLC for qualitative and quantitative assessment of antimicrobial constituents. Quercetin and Azadirachtin is main antimicrobial constituents present in the leaf extract ofAzadirachta indica, which found maximum in the water‐methanol extract of leaves ofAzadirachta indica. The antimicrobial activity of the enzyme treated lotus fabric finished with water‐methanol extract of leavesAzadirachta indicahas been determined qualitatively as well as quantitatively using zone of Inhibition and modified Hohenstein test. In the case of fabric treated with the enzyme and finished with water‐methanol extract of leavesAzadirachta indica, 97 % of reduction forS. aureusand 94 % of reduction forE.coliachieved with good durability of the antimicrobial finish up to three washing cycle whereas for the untreated fabric, antimicrobial finish lost after first washing. The enzyme treatment also resulted in improvement in dye uptake for the lotus fabric with commercial natural dyes Jaipuri Pink and Apsara yellow. For both the dyes, more than 300 % improvement in color depth observed with improvement in wash fastness in case of the enzyme treated lotus fabric.