Exploitation of microbes for degradation of plastic
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Date
2018
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UMT, Lhr
Abstract
The present study aimed at isolation of a novel microorganism capable of degrading polyethylene. Soil and plastic samples were isolated from different dumpsites and landfill sites of Bhera and Lahore. This study comprises of identification of potential strains by biochemical characterization as well as by ribotyping for their potential to degrade polymer. Exploitation of microbes for the degradation of plastic and to increase the biodegradation process by adding effective microbes which increase degradation process as compared to natural degradation that takes long time are main objectives of following study.
Total forty samples were collected from different dumpsites and landfill sites consisting plastics with some soil present over it. Soil was inoculated in media for overnight to get maximum growth of microbes. Next day one ml from overnight media is taken and put in enriched media having pre weight small plastic strips to analyze degradation of polyethylene for one week. Only nine samples showed positive results out of forty i.e. loss of weight of polyethylene strips. The study was proceeded with only two samples (ID: 2A and 6) which have high degradation capacity. Based on 16S rRNA sequencing sample 2A was identified as Bacillus wudalianchiensis_UMT and sample 6 was identified as Pseudomonas aeruginosa_UMT. Bacillus wudalianchiensis_UMT degraded 6.6% polymer and Pseudomonas aeruginosa_UMT degraded 4.8% polyethylene. This study reveals that Bacillus wudalianchiensis_UMT has high potential to degrade polyethylene.
Growth temperature of the microorganisms ranged from 37°C to 60°C. Cells of Pseudomonas aeruginosa_UMT were highly motile rods but Bacillus wudalianchiensis_UMT was non motile. The full-length 16S rRNA sequence was 99% homologous to that of Bacillus wudalianchiensis_UMT and there was also 99% homology with Pseudomonas aeruginosa_UMT. These two strains were identified and characterized in this study. The microbes characterized in this study are potential candidates for degrading plastic.