PET-degrading microorganisms isolated from residues of the SAV biosphere reserve and identification of carboxylic ester hydrolase activity during their growth in the presence of polymer

Abstract

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.