Egert, Markus

Jacksch, Susanne

Weide, Mirko

English

Hochschulschriftenserver der Hochschule Furtwangen

Dispersin-based modification of bacterial community composition in domestic washing machinesSusanne Jacksch a, Mirko Weide b, Markus Egert a,*a Microbiology and Hygiene Group, Institute of Precision Medicine, Faculty of Health, Medical & Life Sciences, Furtwangen University, Villingen-Schwenningen, Germanyb Microbiology, International R&D, Henkel Consumer Brands, Henkel AG & Co. KGaA, Düsseldorf, GermanyA R T I C L E  I N F OKeywords:HygieneMalodorLaundryBacteriotaA B S T R A C TEPS-attached soil targeting dispersin represent a new, sustainable approach to improve laundry and washing machine hygiene at low temperatures. We present initial data that dispersin, formulated into a liquid laundry detergent, can influence the bacterial community composition in sump samples of domestic washing machines, thereby supporting washing machine hygiene.Modern, sustainability-driven washing trends include washing at lower temperatures, higher shares of textile-friendly, bleach-free liquid detergents, and the increasing use of water-saving programs. However, from a hygienic point of view, these trends are critical, as they can hamper sufficient inactivation of microbes in washing machines and on washed laundry, leading to unwanted effects, such as laundry and ma-chine malodor formation (Bockmühl et al., 2019).Enzymes represent an attractive means to improve detergent per-formance and laundry hygiene at low washing temperatures and without the use of harsh or antimicrobial chemicals. The use of enzymes, such as proteases, amylases, lipases and cellulases has a long tradition in laundry hygiene and the formulation of laundry detergents by improving stain and malodor removal (Osta-Ustarroz et al., 2024). Dispersin, however, is new to the field of laundry hygiene. Dispersins (EC 3.2.1.52, β-N-acetylhexosaminidase), together with proteases and deoxyribonucleases, represent enzymes that are currently under exten-sive investigation for hygienic purposes due to their ability to disperse (microbial) biosoil by cleaving extracelullar polymeric substances (EPS) (Wang et al., 2023) and thereby also attached soil and other organic and inorganic compounds such as soap or skin residues (Munk-Veijborg et al., 2023). Recently it was shown that a dispersin-containing laundry detergent can indeed significantly improve stain removal, visual pref-erence and malodor sensory score for laundry washed in comparison to a dispersin-free detergent, probably by facilitating soil dispersal from the textiles (Munk-Veijborg et al., 2023).The aim of the pilot study presented here, was to investigate whether a dispersin-containing laundry detergent also has the potential to shape the washing machine microbiota and thereby ameliorate washing ma-chine hygiene in addition to laundry hygiene. Notably, different parts of domestic washing machines can be colonized by a dense and diverse microbiota, including potentially pathogenic and malodor-causing bacteria (Jacksch et al., 2019, 2021). In addition, it has been shown that the washing machine microbiota can re-contaminate laundry, e. g. during the rinse cycle after washing (Callewaert et al., 2015).Washing experiments were performed in the Henkel laboratories, Düsseldorf, using 6 domestic washing machines (Miele Softtronic W1935, Miele, Gütersloh, Germany) and a washing program for colored laundry at 30 ◦C and ~ 120 min. Prior to the experiments, the washing machines were disinfected by repeated empty runs at 90 ◦C with a bleach-containing solid heavy-duty detergent. Dispersin (Novozymes A/ S, Bagsvaerd, Denmark) was formulated into a commercially available liquid universal detergent (Persil Universal Gel with and w/o added dispersin at concentrations of 0.2 and 0.5 % (w/v), respectively. Sub-sequently, 60 washing cycles were conducted with ballast load of 2 kg soiled polyester-textiles in each machine, whereas two machines (con-trols, C) received 50 ml detergent per cycle without dispersin, while the other four received detergent with the lower (LD) or higher (HD) dis-persin concentration, respectively. The soiling consisted of a mixture of household-related soils and stains, mainly based on fat and sebum.Subsequently, microbiota samples were taken from the sump filter with sterile swabs. The sump was chosen as sampling site as it integrates all microbial life running off from a washing machine after washing. The * Corresponding author at: Microbiology and Hygiene Group, Institute of Precision Medicine, Faculty of Health, Medical & Life Sciences, Furtwangen University, Jakob-Kienzle-Str. 17, 78054 Villingen-Schwenningen, Germany.E-mail address: Markus.Egert@hs-furtwangen.de (M. Egert). Contents lists available at ScienceDirectJournal of Microbiological Methodsjournal homepage: www.elsevier.com/locate/jmicmethhttps://doi.org/10.1016/j.mimet.2025.107154Received 21 March 2025; Received in revised form 22 May 2025; Accepted 28 May 2025  Journal of Microbiological Methods 235 (2025) 107154 Available online 31 May 2025 0167-7012/© 2025 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license ( http://creativecommons.org/licenses/by/4.0/ ). bacterial community composition was analyzed as described elsewhere (Jacksch et al., 2024). In brief, DNA was extracted from the swabs and used as template for amplification of bacterial 16S rRNA genes by PCR. Amplicons were purified and sequenced on an in-house Illumina MiSeq platform. Amplicon sequences were quality-controlled and annotated using QIIME2 (version 2019.7; Bolyen et al., 2019). Statistical analyses were performed using R (R Core Team, 2023).In general, the obtained bacterial community profiles (Fig. 1A) were strongly dominated by genera affiliated with Pseudomonadota, which are known to represent an abundant phylum in washing machine samples (Jacksch et al., 2019, 2021). However, washing machines in which washing was carried out with dispersin, showed a distinctly different bacterial community profile. Interestingly, the four dispersin-profiles were rather similar (Fig. 1A and B), suggesting no strong influence of the used dispersin concentrations. At least two out of three measures for alpha diversity (Table 1) suggested a decreasing diversity with increasing dispersin concentration. The most obvious difference be-tween the control and the dispersin-profiles was a strong increase in the relative abundance of rhizobia-related bacteria. Interestingly, rhiziobia were recently reported to be associated with non-smelling washing machines (Zinn et al., 2022). So, this trend might be interpreted positive in terms of washing machine hygiene. The genus Moraxella, often associated with laundry and machine malodor (Kubota et al., 2012), was not detected in the whole dataset.In summary, our data suggest that dispersin-containing detergent formulations might influence the bacterial community composition in domestic washing machines. It is tempting to speculate that this influ-ence might be caused by taxon-specific differences in the EPS-matrix leading to a different susceptibility to EPS degradation by dispersin. Future research, based on a higher number of replicates and including additional quantitative assessments of the microbial load in different parts of washing machines, will be needed to confirm the trends Fig. 1. A: Relative abundance of major bacterial genera detected in the sump samples of domestic washing machines, which received a liquid laundry detergent containing different concentrations of dispersin over 60 wash cycles. Genera with a relative abundance less than 1 % were summarized as “others”. B: Principial component analysis (PCoA) plots displaying the similarity of the bacterial community profiles of the six sump samples based on weighted and unweighted uni-frac analyses.Table 1 Average (n = 2) diversity means calculated for the bacterial community composition in the sump samples of domestic washing machines which received a liquid laundry detergent containing different concentrations of dispersin over 60 wash cycles.Dispersin Observed Shannon SimpsonControl 79.5 3.01 0.930.2 % 120.0 2.89 0.910.5 % 120.5 2.76 0.89S. Jacksch et al.                                                                                                                                                                                                                                 Journal of Microbiological Methods 235 (2025) 107154 2 described here. In addition, time course analyses should show, how fast the washing machine microbiota can be shaped by dispersin-containing detergents. Finally, it remains to be confirmed that an increased (rela-tive) abundance of rhizobia indeed is beneficial in terms of malodor production.CRediT authorship contribution statementSusanne Jacksch: Writing – original draft, Visualization, Software, Investigation, Formal analysis, Data curation. Mirko Weide: Writing – review & editing, Funding acquisition, Conceptualization. Markus Egert: Writing – review & editing, Validation, Supervision, Resources, Project administration, Methodology, Funding acquisition, Conceptualization.Declaration of competing interestMW is employed by Henkel AG & Co. KGaA, a commercial producer of laundry detergents. Funding was provided by Henkel.Data availabilityThe sequencing data referred to in here were deposited at the ENA database under the accession number PRJEB75155.ReferencesBockmühl, D.P., Schages, J., Rehberg, L., 2019. Laundry and textile hygiene in healthcare and beyond. Microb. Cell. 6 (7), 299–306.Bolyen, E., Ram Rideout, J., Dillon, M.R., Bokulich, N.A., Abnet, C.A., et al., 2019. Reproducible, interactive, scalable and extensible microbiome data science using QIIME 2. Nat. Biotechnol. 37 (8), 852–857.Callewaert, C., Van Nevel, S., Kerckhof, F.M., Granitsiotis, M.S., Boon, N., 2015. Bacterial exchange in household washing machines. Front. Microbiol. 6, 1381.Jacksch, S., Kaiser, D., Weis, S., Weide, M., Ratering, S., Schnell, S., Egert, M., 2019. Influence of sampling site and other environmental factors on the bacterial community composition of domestic washing machines. Microorganisms 8 (1), 30.Jacksch, S., Zohra, H., Weide, M., Schnell, S., Egert, M., 2021. Cultivation-based quantification and identification of bacteria at two hygienic key sides of domestic washing machines. Microorganisms 9 (5), 905.Jacksch, S., Weis, S., März, M., Gruedl, S., Simmering, R., Welss, T., Egert, M., 2024. Effect of two shampoo formulations on the prokaryotic and eukaryotic microbiota composition of the human scalp. Int. J. Cosmet. Sci. 46 (1), 62–70.Kubota, H., Mitani, A., Niwano, Y., Takeuchi, K., Tanaka, A., Yamaguchi, N., Kawamura, Y., Hitomi, J., 2012. Moraxella species are primarily responsible for generating malodor in laundry. Appl. Environ. Microbiol. 78 (9), 3317–3324.Munk-Veijborg, R., Kandzia, M., Nielsen, L.J., Wilke, T., Rechenbach, T., Thuesen, K.E., Weide, M., 2023. Deep-cleaning and freshness for sustainable laundry with dispersin. SOFW J. 149 (10), 4–10.Osta-Ustarroz, P., Theobald, A.J., Whitehead, K.A., 2024. Microbial colonization, biofilm formation, and malodour of washing machine surfaces and fabrics and the evolution of detergents in response to consumer demands and environmental concerns. Antibiotics (Basel) 13 (12), 1227. https://doi.org/10.3390/antibiotics13121227.R Core Team, 2023. R: A Language and Environment for Statistical Computing. R Foundation for Statistical Computing, Vienna, Austria. https://www.R-project.org. Wang, S., Zhao, Y., Breslawec, A.P., Liang, T., Deng, Z., Kuperman, L.L., Yu, Q., 2023. Strategy to combat biofilms: a focus on biofilm dispersal enzymes. NPJ Biofilms Microbiom. 9 (1), 63.Zinn, M.K., Flemming, H.C., Bockmühl, D., 2022. A comprehensive view of microbial communities in the laundering cycle suggests a preventive effect of soil Bacteria on malodour formation. Microorganisms 10 (7), 1465.S. Jacksch et al.                                                                                                                                                                                                                                 Journal of Microbiological Methods 235 (2025) 107154 3 

Dispersin-based modification of bacterial community composition in domestic washing machines

https://opus.hs-furtwangen.de/files/11770/1-s2.0-S0167701225000703-main.pdf

Dispersin-based modification of bacterial community composition in domestic washing machines

Abstract

Similar works

Full text

Available Versions

Hochschulschriftenserver der Hochschule Furtwangen