Akademik Veri Yönetim Sistemi
the 8th International Congress of the Molecular Biology Association of Turkey (MolBiyoKon’22), İstanbul, Türkiye, 09 Haziran 2022 - 12 Ocak 2023, ss.179
Abstract
Background/aim: Plastic has rapidly transformed our World nowadays, with many aspects of human life relying on a variety of plastic materials. It has been revealed that plastic causes negative effects in all ecosystems and that microplastics are a special concern for our health. Therefore, microbial research has addressed the question of whether and to what extent microorganisms can degrade plastics in the environment. It has been shown in studies that the microbial enzymes mainly act on high molecular weight polyethylene terephthalate (PET) polymers. The aim of this study is to isolate PET-degrading bacteria from the garbage waste soil samples, to determine PET degradation activities and to make systematics of these bacteria.
Materials and methods: PET-degrading bacteria were isolated from garbage waste soil samples especially include plastic wastes. These isolates were grown in cutin-containing medium to identify cutinase-positive ones. Then, cutinase activity was detected using zymography. Selected cutinase-positive isolates were grown for 28 days in a liquid carbon-free basal medium (LCFBM) with PET as the sole carbon source to determine PET degradation. At the end of the incubation, the decrease in the weights of the pre-determined plastics were recorded. PET pieces with reduced weights were analyzed by scanning electron microscopy (SEM). The 16S rRNA sequences of the PET degrading strains were cloned into pGEM-T Easy vector and phylogenetic trees were formed.
Results: Six of the isolates (Pet Deg-2, Pet Deg-3, Pet Deg-4, Pet Deg-5, Pet Deg-7, and Pet Deg-8) were determined as cutinase positive. The degradation images of positive strains were obtained from SEM. According to the results of the 16S rRNA gene sequence analysis showed that Pet Deg-2, Pet Deg-3, Pet Deg-4 Pet Deg-5, Pet Deg-7 and Pet Deg-8 was closely related to Pseudomonas aeruginosa (99.56), Bacillus licheniformis (99.71), Bacillus licheniformis (99.85), Acinetobacter junii (99.63), Cupriavidus lacunae (98.82) and Enterobacter sichuanensis (99.56), respectively.
Conclusion: It is a promising and eco-friendly solution for biological degredation of PET waste in environment by using bacteria. Our results are important in terms of identifying new isolates that secrete enzymes used in pet degradation.
Keywords: Polyethylene terephthalate, SEM, Plastic degradation, Cutinase