Combined use of Bacillus strains and Miscanthus for accelerating biodegradation of poly(lactic acid) and poly(ethylene terephthalate)

Grażyna B Dąbrowska; Katarzyna Janczak; Agnieszka Richert

doi:10.7717/peerj.10957

Combined use of Bacillus strains and Miscanthus for accelerating biodegradation of poly(lactic acid) and poly(ethylene terephthalate)

PeerJ. 2021 Mar 30:9:e10957. doi: 10.7717/peerj.10957. eCollection 2021.

Authors

Grażyna B Dąbrowska¹, Katarzyna Janczak², Agnieszka Richert¹

Affiliations

¹ Department of Genetics, Faculty of Biological and Veterinary Science, Nicolaus Copernicus University, Toruń, Kuyavian-Pomeranian, Poland.
² Research Network Łukasiewicz, Institute for Engineering of Polymer Materials and Dyes, Research Network Łukasiewicz, Toruń, Kuyavian-Pomeranian, Poland.

Abstract

Background: The aim of this study was to verify whether the presence of Bacillus strains and of miscanthus influence biodegradation and formed of biofilm of poly(lactic acid) (PLA) and poly(ethylene terephthalate) (PET).

Methods: The experiment conducted in compost soil showed that strains Bacillus subtilis and Bacillus cereus isolated from heavy metal contaminated environment have biochemical activity and accelerate biodegradation of both plastic materials.

Results: For PLA film it was found that the carbonyl index dropped by over 15% in the presence of B. subtilis, while the film tensile strength decreased by 35% and the oxygen to carbon O/C ratio was higher by 3% in the presence of B. cereus, and the presence of miscanthus resulted in a loss of weight. For PET film, a decrease in the carbonyl index by 16% was observed following inoculation with B. cereus. The metabolic activity of this strain contributed to the reduction of the film's tensile strength by 17% and to the increase in the permeability to O₂ and CO₂. The most intense degradation of PET film was observed in the presence of bacteria and plants. B. subtilis strain combined with miscanthus plantings may be a promising method for accelerating PLA and PET degradation in compost soil.

Keywords: Biodegradation; Biofilm; Metabolic Activity; PET; PLA; Bacillus sp..

Grants and funding

This work was financed from the statutory operations of the Department of Genetics, Faculty of Biological and Veterinary Science, Nicolaus Copernicus University in Toruń, Poland. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.