Hematoporphyrin-based amphiphiles boost the washing performance of protease-containing formulations in a biomimetic approach

Proteases are key ingredients in bio-based washing formulations. However, stabilization approaches – especially in aqueous formulations where autoproteolysis is an issue – usually entail a decrease in their proteolytic activity. Various additives are used in order to overcome this drawback and to ensure anti-redeposition properties of the formulations, otherwise not provided by the enzymes. The present work proposes a biomimetic alternative based on the use of a hematoporphyrin containing amphiphilic copolymer, here called photozyme, able to: (i) stabilize the enzyme against higher temperatures and pHs, (ii) enhance its activity by 10% and (iii) generate singlet oxygen upon light irradiation, thereby degrading efficiently colored stains. Enhanced by 20% stain removal was achieved with the photozyme containing protease formulations as a result of improved enzyme performance along with anti-redeposition effect. Light irradiation of stained fabrics in presence of the photozyme brought about 37% higher cleaning degree compared to the samples irradiated without photozyme. Fluorescence spectroscopy techniques were used to confirm the self-assembling behavior of the photozymes in aqueous solutions, their interaction with the protease and the generation of singlet oxygen, thus elucidating the rationale behind the boosted cleaning performance of photozyme containing bio-based formulations.