Main content area

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.