Oxidative deterioration of polypropylene by redox mediators and yeast expressing a fungal recombinant laccase

Abstract

Biodegradation of polyolefins is a multistep process that might integrate physical, chemical, enzymatic and/or microbial actions. In this work, we report the use of the laccase redox mediators ABTS and DMP (2,2’ azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) and 2,6-dimethoxyphenol, respectively), recycled by laccase activity in aerobic conditions, to induce oxidation of polypropylene film (PP): the laccase was produced in the reaction medium by a recombinant Kluyveromyces lactis yeast strain, expressing a fungal heterologous laccase gene. As a result, we evidenced the formation of oxidize groups on PP surface which increased its water wettablity. We also showed a clear modification of the polymer surface with the appearance of humped and exfoliated regions which favored the break of PP film.