title: Polymer Film-Based Screening and Isolation of Polylactic Acid (PLA)-Degrading Microorganisms.
abstract: Polylactic acid (PLA) has been highlighted as an alternative renewable polymer for the replacement of petroleum-based plastic materials, and is considered to be biodegradable. On the other hand, the biodegradation of PLA by terminal degraders, such as microorganisms, requires a lengthy period in the natural environment, and its mechanism is not completely understood. PLA biodegradation studies have been conducted using mainly undefined mixed cultures, but only a few bacterial strains have been isolated and examined. For further characterization of PLA biodegradation, in this study, the PLA-degrading bacteria from digester sludge were isolated and identified using a polymer film-based screening method. The enrichment of sludge on PLA granules was conducted with the serial transference of a subculture into fresh media for 40 days, and the attached biofilm was inoculated on a PLA film on an agar plate. 3D optical microscopy showed that the isolates physically degraded the PLA film due to bacterial degradation. 16S rRNA gene sequencing identified the microbial colonies to bePseudomonassp. MYK1 andBacillussp. MYK2. The two isolates exhibited significantly higher specific gas production rates from PLA biodegradation compared with that of the initial sludge inoculum.
authors.affiliation: School of Chemical and Biomolecular Engineering, Pusan National University, Busan, 46241, Republic of Korea.
authors.forename: Mi Yeon
authors.initials: MY
authors.lastname: Kim
authors.affiliation: School of Chemical and Biomolecular Engineering, Pusan National University, Busan, 46241, Republic of Korea.
authors.forename: Changman
authors.initials: C
authors.lastname: Kim
authors.affiliation: School of Chemical and Biomolecular Engineering, Pusan National University, Busan, 46241, Republic of Korea.
authors.forename: Jungheun
authors.initials: J
authors.lastname: Moon
authors.affiliation: Advanced Characterization & Analysis Research Group, Korea Institute of Materials Science (KIMS), Changwon 51508, Republic of Korea.
authors.forename: Jinhee
authors.initials: J
authors.lastname: Heo
authors.affiliation: Department of Environmental and Energy Engineering, Chonnam National University, Gwangju 61186, Republic of Korea.
authors.forename: Sokhee P
authors.initials: SP
authors.lastname: Jung
authors.affiliation: School of Chemical and Biomolecular Engineering, Pusan National University, Busan, 46241, Republic of Korea.
authors.forename: Jung Rae
authors.initials: JR
authors.lastname: Kim
mesh_terms: D001407:Bacillus / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D001431:Bacteriological Techniques; D001673:Biodegradation, Environmental; D018441:Biofilms; D008853:Microscopy; D010578:Petroleum / Q000378:metabolism; D011091:Polyesters / Q000378:metabolism*; D011108:Polymers / Q000378:metabolism*; D011549:Pseudomonas / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D012336:RNA, Ribosomal, 16S; D017422:Sequence Analysis, DNA; D012722:Sewage / Q000382:microbiology*
chemical_list: D010578:Petroleum; D011091:Polyesters; D011108:Polymers; D012336:RNA, Ribosomal, 16S; D012722:Sewage; C033616:poly(lactide)
keywords: Bacillus sp. MYK2; PLA; Polylactic acid; Pseudomonas sp. MYK1; biodegradation; film-based isolation; specific gas production rate