Currently green nanotechnology presents a smart solution to produce novel nanostructured materials that are highly safe and environmentally friendly. In this work, zinc oxide nanoparticles (ZnO NPs) were prepared by employing aqueous mint (M. piperita) seeds extract at 60 ^oC, as a green synthesis method. Mint seeds extract was chosen among the 6 plant seeds that were the subject of this study as it represents the highest polyphenol and flavonoid seeds extract as well as antioxidant activity. High Performance Liquid Chromatography (HPLC) showed that syringic acid (16%), rutin (22%), and apigenin-7-O-glucoside (29%) were the main component of 70% ethanol mint seeds extract.  The obtained ZnO NPs were examined using an ultraviolet-visible spectrophotometer (UV-VIS), X-ray diffraction (XRD) and transmission electron microscope (TEM). The UV spectrum revealed maximum absorption value at 376 nm, related to bio-syntheized ZnO NPs. The XRD study demonstrated the creation of ZnO NPs. The green synthesized ZnO NPs were spherical in shape with average particles size 80±36 nm. Antibacterial activity of aqueous mint seeds extract and synthesized ZnO NPs were investigated on E. coli and S. aureus and antioxidant activity as well.

The “Sistema Arrecifal Veracruzano” (SAV) is a vital marine ecosystem; its resources are continually perturbed due to contamination by anthropogenic activities, with multiple contaminants such as plastics. In aquatic ecosystems, plastics are almost immediately coated by inorganic and organic matter, which is then colonized by microbes to form a biofilm on plastic surfaces. This work aimed to isolate and identify plastic-degrading microorganisms isolated mainly from plastic residues of the SAV biosphere reserve. Eight bacteria and three fungi were isolated from a biofilm in plastic residues from islands of SAV. All the bacteria and one fungus showed evidence of degrading PET, over 10% for two bacteria and 17% for the fungus. All fungi belong to the genus Aspergillus, and bacteria belong to the genera Aneurinibacillus, Bordetella, Bacillus, and Lysinibacillus. Aneurinibacillus migulanus and Aspergillus flavus showed the highest values for PET degradation. Carboxylic ester hydrolase (CEH) activity was detected in all crude extracts from fungi and bacteria growing with PET triturates as a carbon source; the maximum CEH in bacteria was 255 U mg^-1 and 780 U mg^-1 for fungi.