In this study, yerba mate waste (YMW) was used to produce a kombucha beverage, and the obtained microbial cellulose produced as a byproduct (KMW) was used to reinforce a mechanically recycled poly(lactic acid) (r-PLA) matrix. Microbial cellulosic particles were also produced in pristine yerba mate for comparison (KMN). To simulate the revalorization of the industrial PLA products rejected during the production line, PLA was subjected to three extrusion cycles, and the resultant pellets (r3-PLA) were then plasticized with 15 wt.% of acetyl tributyl citrate ester (ATBC) to obtain optically transparent and flexible films by the solvent casting method. The plasticized r3-PLA-ATBC matrix was then loaded with KMW and KMN in 1 and 3 wt.%. The use of plasticizer allowed a good dispersion of microbial cellulose particles into the r3-PLA matrix, allowing us to obtain flexible and transparent films which showed good structural and mechanical performance. Additionally, the obtained films showed antioxidant properties, as was proven by release analyses conducted in direct contact with a fatty food simulant. The results suggest the potential interest of these recycled and biobased materials, which are obtained from the revalorization of food waste, for their industrial application in food packaging and agricultural films.

The growth of the aquaculture sector poses challenges in maintaining product quality, particularly regarding contamination, which risks aquatic organisms and human health. Advanced oxidation processes using UV-C radiation can remove persistent compounds and pathogens from aqueous matrices through the generation of reactive species. However, their chemical non-selectivity may produce toxic disinfection by-products (DBPs), which require cautious ecotoxicological assessment. This study aimed to evaluate the ecotoxicological effects of UV-C/oxidant processes on aquaculture effluents by employing survival assays with Daphnia magna (D. magna) and growth inhibition assays with Pseudokirchneriella subcapitata (P. subcapitata). UV-C treatment of synthetic and real aquaculture effluents was intensified by hydrogen peroxide (H₂O₂), peracetic acid (PAA), sodium hypochlorite (NaClO), potassium peroxymonosulfate (PMS), and sodium persulfate (PS). UV-C treatment combined with PAA, PMS, or PS showed promising reductions in toxicity and high D. magna survival rates, whereas treatments with H₂O₂ and NaClO resulted in significant adverse effects on its survival. This is likely due to residual oxidants and DBPs, as dark controls showed lower toxicity, and UV-C alone had a negligible effect. For P. subcapitata bioassays, UV-C/PMS and UV-C/PS were identified as the most suitable treatments. Our findings support the use of UV-C-based AOPs for aquaculture effluent treatment, with prudent selection and addition levels, while highlighting dilution via recirculation in recirculating aquaculture systems (RAS) as an intrinsic advantage for mitigating relevant ecotoxicological risks.

Yerba mate waste (YMW) were used to produce kombucha beverage, and the obtained microbial cellulose produced as by product (KMW) was used to reinforce mechanically recycled poly(lactic acid) (r-PLA) matrix. Microbial cellulosic particles were also produced in pristine yerba mate for comparison (KMN). To simulate the revalorization of industrial PLA products rejected during the production line, PLA was subjected to three extrusion cycles and the resultant pellets (r3-PLA) were then plasticized with 15 wt.% of acetyl tributyl citrate ester (ATBC) to obtain optically transparent and flexible films by solvent casting method. The plasticized r3-PLA-ATBC matrix was then loaded with KMW and KMN in 1 and 3 wt.%. The use of plasticizer allowed a good dispersion of microbial cellulose particles into the r3-PLA matrix, allowing to obtain flexible and transparent films which showed good structural and mechanical performance. Additionally, the obtained films showed antioxidant properties, as it was proven by release analyses conducted in direct contact with a fatty food simulant. The results suggest the potential interest of these recycled and biobased materials that are obtained from the revalorization of food waste for their industrial application in food packaging or agricultural films.