Highly Selective Enzymatic Recovery of Building Blocks from Wool-Cotton-Polyester Textile Waste Blends

Abstract

In Europe, most of the discarded and un-wearable textiles are incinerated or landfilled. In this study, we present an enzyme-based strategy for the recovery of valuable building blocks from mixed textile waste and blends as a circular economy concept. Therefore, model and real textile waste were sequentially incubated with (1) protease for the extraction of amino acids from wool components (95% efficiency) and (2) cellulases for the recovery of glucose from cotton and rayon constituents (85% efficiency). The purity of the remaining poly(ethylene terephthalate) (PET) unaltered by the enzymatic treatments was assessed via Fourier-transformed infrared spectroscopy. Amino acids recovered from wool were characterized via elementary and molecular size analysis, while the glucose resulting from the cotton hydrolysis was successfully converted into ethanol by fermentation with Saccharomyces cerevisiae. This work demonstrated that the step-wise application of enzymes can be used for the recovery of pure building blocks (glucose) and their further reuse in fermentative processes.

Characterization and engineering of a two-enzyme system for plastics depolymerization

“…Given that natural microbial systems evolved over millions of years to optimally degrade recalcitrant polymers, perhaps it is thus not surprising, in hindsight, that a soil bacterium such as I. sakaiensis evolved the ability to utilize a crystalline polyester substrate with, to our collective knowledge, a two-enzyme system ( 10 , 16 ). Extending the analogy of cellulase enzymes and plant cell wall deconstruction for breaking down diverse polysaccharides simultaneously, the concept of deconstructing synthetic polymers in the form of mixed plastics waste with advanced enzyme mixtures is an exciting research direction beyond PET to other polyesters, natural fibers (e.g., cellulose from cotton, proteins from wool) ( 70 ), polyamides, polyurethanes ( 71 ), and other polymers susceptible to enzymatic depolymerization. Going forward, the design of multienzyme systems for depolymerization of mixed polymer wastes is a promising and fruitful area for continued investigation.…”

Effect of Different Compatibilizers on Injection-Molded Green Fiber-Reinforced Polymers Based on Poly(lactic acid)-Maleinized Linseed Oil System and Sheep Wool

“…However, there is a breed of sheep that are specifically raised for their milk and to produce cheese—wool derived from this industry is not suitable for the textile sector. In consequence, the wool coming from this activity is considered a by-product [26,27,28,29,30]. Additionally, low material cost, biodegradability and the low energy required for processing make natural fibers a good replacement for conventional synthetic fibers such as carbon or glass fibers, from both an economic and environmental point of view.…”

“…Additionally, low material cost, biodegradability and the low energy required for processing make natural fibers a good replacement for conventional synthetic fibers such as carbon or glass fibers, from both an economic and environmental point of view. However, bio-origin fibers often present significantly lower mechanical properties or higher water uptake compared to synthetic fibers, which can be enhanced by fiber surface modification [5,17,29,31,32]. The hydrophilic surface of wool fibers needs to be chemically modified in order to improve compatibility with a hydrophobic polymer matrix.…”

Increased Flame Retardancy of Enzymatic Functionalized PET and Nylon Fabrics via DNA Immobilization

“…As demonstrated by Watanabe (Watanabe and Sakai, 2003), the major emission of brominated and chlorinated compounds occurs directly during production. Moreover, the amount of landfilled and incinerated textiles per years also constitutes a problem for the environment (Quartinello et al, 2018). Most of the FRC are absorbed on surface material, therefore their leaching and consequently accumulation, cause major health risks also for marine environment and in the end also for human health due to their dietary.…”