The influence of laundry washing parameters on the release of microfibers (MF) from polyester textiles was studied. These fibers are an important type of microplastic pollution. However, the factors which affect MF release during laundry are poorly understood and more rigorous methods for quantifying this release are needed. A novel method was therefore developed using a tergotometer with eight 1000 mL washing vessels and the CIELab color space measure of lightness (L*). L* was related to the mass of released MFs by creating a calibration curve to quantify the amounts of MFs released from textiles during washing. This method was used to investigate the effect of water-volume, agitation, temperature, and duration of the wash on MF release. Counterintuitively, increased water-volume, characteristic of European "delicate" cycles, resulted in the greatest release of MFs. Full-scale testing was then carried out using domestic washing machines with real consumer cycles to determine the effect of cycle type on MF release. In the first wash, delicate wash cycles released 800 000 more MFs (94 mg/kg) per wash than a lower water-volume standard wash and also increased MF release in subsequent washing cycles (P < 0.05). These results indicate that a high water-volume-to-fabric ratio is the most influential factor for MF release, rather than agitation as previously thought. Therefore, consumers can reduce MF release by avoiding high water-volume washes (delicate cycles), transitioning to appliances that use a lower water-volume (North American high-efficiency washing machines), and ensuring that full wash loads are used.

Fiber release during domestic textile washing is a cause of marine microplastic pollution, but better understanding of the magnitude of the issue and role of fabric care products, appliances and washing cycles is needed. Soiled consumer wash loads from U.K. households were found to release a mean of 114 ± 66.8 ppm (mg microfiber per kg fabric) (n = 79) fibers during typical washing conditions and these were mainly composed of natural fibers. Microfiber release decreased with increasing wash load size and hence decreasing water to fabric ratio, with mean microfiber release from wash loads in the mass range 1.0-3.5 kg (n = 57) found to be 132.4 ± 68.6 ppm, significantly (p = 3.3 x 10 −8) higher than the 66.3 ± 27.0 ppm of those in the 3.5-6.0 kg range (n = 22). In further tests with similar soiled consumer wash loads, moving to colder and quicker washing cycles (i.e. 15˚C for 30 mins, as opposed to 40˚C for 85 mins) significantly reduced microfiber generation by 30% (p = 0.036) and reduced whiteness loss by 42% (p = 0.000) through reduced dye transfer and soil re-deposition, compared to conventional 40˚C cycles. In multicycle technical testing, detergent pods were selected for investigation and found to have no impact on microfiber release compared to washing in water alone. Fabric softeners were also found to have no direct impact on microfiber release in testing under both European and North American washing conditions. Extended testing of polyester fleece garments up to a 48-wash cycle history under European conditions found that microfiber release significantly reduced to a consistent low level of 28.7 ± 10.9 ppm from eight through 64 washes. Emerging North American High-Efficiency top-loading washing machines generated significantly lower microfiber release than traditional top-loading machines, likely due to their lower water fill volumes and hence lower water to fabric ratio, with a 69.7% reduction observed for polyester fleece (n = 32, p = 7.9 x 10 −6) and 37.4% reduction for polyester T-shirt (n = 32, p = 0.0032). These results conclude that consumers can directly reduce the levels of microfibers generated per wash during domestic textile washing by using colder and quicker wash cycles, washing complete (but not overfilled) loads, and (in North America) converting to High-Efficiency washing machines. Moving to colder and quicker cycles will also indirectly reduce microfiber release by extending the lifetime of clothing, leading to fewer new garments being purchased and

Cellobiose dehydrogenase from the ascomycete fungus Myriococcum thermophilum (MtCDH) was tested for the ability to generate bleaching species at a pH suitable for liquid detergents. The catalytic properties of MtCDH were investigated for a large variety of carbohydrate substrates using oxygen as an electron receptor. MtCDH produces H2O2 with all substrates tested (except fructose) but only in the presence of a chelant. Insoluble substrates like cellulose and cotton could as well be oxidized by MtCDH. To enhance the amount of cello-oligosaccharides in solution, different cellulases on cotton were used and in combination with MtCDH an increased H2O2 concentration could be measured. Additionally, the degradation of pure anthocyanins in solution (as model substrates for bleaching) was investigated in the absence and presence of a horseradish peroxidase. MtCDH was able to produce a sufficient amount of H2O2 to decolorize the anthocyanins within 2 h.

This is a repository copy of Improved garment longevity and reduced microfibre release are important sustainability benefits of laundering in colder and quicker washing machine cycles.

The carbohydrate oxidase from Microdochium nivale (CAOX), heterologously expressed in Aspergillus oryzae, and cellobiose dehydrogenase from Myriococcum thermophilum (MtCDH), were assessed for their ability to generate bleaching species at a pH suitable for liquid detergents. The substrate specificities of CAOX and MtCDH were analyzed on a large variety of soluble and insoluble substrates, using oxygen as an electron receptor. Even insoluble substrates like cellulose were oxidized from both CAOX and MtCDH, but only MtCDH produced H₂O₂ on cotton as the sole substrate. To enhance the amount of cello-oligosaccharides formed from cotton as substrates for CAOX and MtCDH, various cellulases were used in combination with MtCDH or CAOX, leading to a 10-fold increase in H₂O₂. As model substrates for colored stains, the degradation of pure anthocyanins and stain removal of blueberry stains by CAOX and MtCDH was examined in the absence and presence of a horseradish peroxidase. Both enzymes were able to produce an amount of H₂O₂ sufficient to decolorize the pure anthocyanins within 2 h and showed significant cleaning benefits on the stains.