According to estimates by Fraunhofer UMSICHT, approximately 0.1% of the polymers produced annually in Germany are used as active substances or auxiliary agents in detergents, personal care and cleaning products. Of these, 55 tonnes per year are released into the environment as microplastics, and 23,200 tonnes per year as dissolved, gel-like, or liquid polymers.

This group includes polyacrylates, which significantly enhance the performance of detergents and cleaning agents. Moreover, polyacrylates are a key component of care coatings that positively influence soil resistance, cleanability, and the durability of resilient floor coverings.

The objective of the research project was to isolate microorganisms or microbial consortia from environmental samples and to identify enzymes capable of degrading polyacrylates. Enzymes were classified based on the reactions they catalyze (substrate specificity), providing insights into the types of chemical bonds they cleave.

Based on the findings (e.g. substrate specificity of identified enzymes), polyacrylates with chemically and enzymatically cleavable bonds in the polymer backbone were synthesized to enhance microbial or enzymatic degradation.

Microbial consortia were isolated from environmental samples and cultivated in media containing either a polyacrylate (e.g. polyacrylic acid, polymethyl methacrylate) or a monomer (MMA: methyl methacrylate; HEMA: 2-hydroxyethyl methacrylate) as the sole carbon source.

The bacterial composition of these cultures was analyzed using diversity profiling and 16S rRNA gene sequencing. Additionally, a bacterial strain capable of utilizing HEMA and MMA for growth was identified. To determine the key enzymes involved in polyester acrylate degradation, whole-genome sequencing was conducted.

Polyester acrylates were synthesized via radical ring-opening polymerization of cyclic ketene acetals – primarily MDO (2-methylene-1,3-dioxepane) – in combination with various monomers such as MMA, styrene, HEMA, and MAA (methacrylic acid), using a bulk polymerization approach.

The resulting copolymers were dispersed using a solvent exchange method (from THF to water) to formulate care dispersions aligned with industry-standard formulations. When applied to resilient floor coverings, the resulting films demonstrated comparable performance to conventional care coatings in terms of adhesion, abrasion resistance, slip resistance (coefficient of friction), soil repellency and barrier properties.

However, they exhibited reduced removability during deep cleaning procedures. No perceptible impact on the color of the floor coverings was observed. The polyester acrylates were susceptible to alkaline hydrolysis, and esterases capable of cleaving ester bonds within the polymer backbone were identified.

The research report is available on request from FRT.