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Abstract
Aim:
The
study investigates the microplastic degradation potential of mangrove
rhizobacteria and their efficiency as a consortium.
Methodology:
Rhizosphere
sediments were collected from three common mangrove species, Avicennia
sp., Acanthus sp. and Bruguiera sp. in Kerala, India.
Rhizobacteria were isolated, characterized and a consortium was formulated,
which were analyzed for the production of plastic-degrading enzymes.
Structural changes in PVC microplastic films treated with individual cultures
and consortium were determined by FTIR spectroscopy and Scanning Electron
Microscopy.
Results:
The
most abundant bacteria from each of the three mangrove species were
identified as Priestia megaterium (SXC01) from Avicennia sp., Bacillus
cereus (1MM03) from Acanthus sp. and Priestia megaterium (1MB38)
from Bruguiera sp. Semi-quantitative and quantitative analysis showed
that Priestia megaterium (SXC01) was efficient in the production of PEG
dehydrogenase, Bacillus cereus (1MM03) in lipase production and Priestia
megaterium (1MB38) in esterase and cutinase synthesis. Interestingly, the
bacterial consortium showed higher production of enzymes and also exhibited
greater stability in their attachment to the PVC surface compared to individual
bacterial isolates. Further, FTIR spectral studies revealed pronounced
vibrations in the hydroxyl (OH) regions, C-H regions and C-Cl stretching
regions, providing evidence of bacterial PVC degradation.
Interpretation:
This
study highlights the potential of consortium in the effective degradation of
microplastics, surpassing individual isolates in enzymatic activity. To
mitigate microplastic contamination, mangrove rhizobacteria are important
players with potential uses in the restoration and maintenance of mangrove
ecosystems.
Key
words: Bacterial
consortium, Mangrove ecosystems, Microplastic degradation, Rhizobacterial
strains
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