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Biodegradation of Poly(lactic acid) in Soil Microcosms at Ambient Temperature: Evaluation of Natural Attenuation, Bio-augmentation and Bio-stimulation
- Satti, Sadia Mehmood, Shah, Aamer Ali, Marsh, Terence L., Auras, Rafael
- Journal of polymers and the environment 2018 v.26 no.9 pp. 3848-3857
- Pseudomonas aeruginosa, Sphingobacterium, ambient temperature, bacteria, bioaugmentation, biodegradation, microbial communities, mineralization, nitrification, polylactic acid, soil, soil ecology, soil quality
- Biodegradation of poly(lactic acid)—PLA—films in soil matrix under mesophilic conditions was evaluated using natural attenuation, bio-augmentation and bio-stimulation. Rate of mineralization was found to be very slow as 10% in soil at 150 days and there was no evidence of abiotic degradation of the polymer at 30 °C. Bioaugmentation with previously isolated PLA-degrading bacteria, Sphingobacterium sp. strain S2 and Pseudomonas aeruginosa strain S3 and stimulating the native microbial community with 0.2% sodium lactate significantly enhanced the mineralization rate of PLA to 22 and 24%, respectively at 150 days. No adverse effect on soil health as well as its nitrification potential was observed in response to biodegradation and bioremediation strategies. Bio-stimulation and bio-augmentation enhanced more the rate of mineralization of PLA in soil than the natural rate of degradation, and both strategies have no ecotoxic effect on soil microbial population; hence, they can be considered as potential routes to enhance the degradation of PLA at ambient temperature.