Explore the vast range of titles available.

Poly(ethylene terephthalate) (PET) is a major source of plastic pollution. Biodegradation technologies are of paramount interest in reducing or recycling PET waste. In particular, a synergistic microbe-enzyme treatment may prove to be a promising approach. In this study, a synergistic system composed of Microbacterium oleivorans JWG-G2 and Thermobifida fusca cutinase (referred to as TfC) was employed to degrade bis(hydroxyethyl) terephthalate (BHET) oligomers and a high crystalline PET film. A novel degradation product that was obtained by M. oleivorans JWG-G2 treatment alone was identified as ethylene glycol terephthalate (EGT). With the addition of TfC as a second biocatalyst, the highest synergy degrees for BHET oligomers and PET film degradation were 2.79 and 2.26, respectively. The largest amounts of terephthalic acid (TPA) and mono(2-hydroxyethyl) terephthalate (MHET) (47 nM and 330 nM, respectively) were detected after combined treatment of PET film with M. oleivorans JWG-G2 at 5 × 103 μL/cm2 and TfC at 120 μg/cm2, and the degree of PET film surface destruction was more significant than those produced by each treatment alone. The presence of extracellular PET hydrolases in M. oleivorans JWG-G2, including three carboxylesterases, an esterase and a lipase, was predicted by whole genome sequencing analysis, and a predicted PET degradation pathway was proposed for the synergistic microbe-enzyme treatment. The results indicated that synergistic microbe-enzyme treatment may serve as a potentially promising tool for the future development of effective PET degradation.Key points• An ecofriendly synergistic microbe-enzyme PET degradation system operating at room temperature was first introduced for degrading PET.• A novel product (EGT) was first identified during PET degradation.• Potential PET hydrolases in M. oleivorans JWG-G2 were predicted by whole genome sequencing analysis.

Three Gram-reaction-positive bacterial strains, designated KSW-18T, KSW2-22, and KSW4-11T, were isolated from seawater, and two dried seaweed samples collected at Gwakji Beach in Jeju, Republic of Korea, respectively, and their taxonomic positions were examined by a polyphasic approach. The 16S rRNA gene phylogeny showed that strain KSW4-11T was tightly associated with Microbacterium oleivorans NBRC 103075T, while strains KSW-18T and KSW2-22 formed a distinctive subline at the base of a clade including the above two strains. The three isolates showed high sequence similarity with one another (99.7–99.9%; 1–4 nt differences) and Microbacterium oleivorans (99.8–99.9%; 1–3 nt differences). The chemotaxonomic features were typical for the genus Microbacterium; Lysine as the diagnostic diamino acid and N-glycolylated muramic acid of the peptidoglycans, the predominant menaquinones of MK-11, MK-10 and MK-12, the major fatty acids of anteiso-C15:0 and anteiso-C17:0, and the major polar lipids including diphosphatidylglycerol, phosphatidylglycerol, and two or three unidentified glycolipids. In core genome-based phylogenetic tree, strains KSW-18T and KSW2-22 were closely associated with Microbacterium oleivorans NBRC 103075T, while strain KSW4-11T formed a distinctive subline at the base of a clade including the above three strains, in contrast to the 16S rRNA gene tree. Strains KSW-18T and KSW2-22 shared an OrthoANIu of 98.6% and a digital DNA–DNA hybridization of 87.6% with each other, representing that they were strains of a species, while the OrthoANIu and digital DNA–DNA hybridization values between strains KSW-18T and KSW4-11T, and between both of these isolates and all members of the genus Microbacterium were ≤86.5% and ≤30.7%, respectively. The analyses of overall genomic relatedness indices and phenotypic distinctness support that the three isolates represent two new species of the genus Microbacterium. Based on the results obtained here, Microbacterium aquilitoris sp. nov. (type strain KSW-18T = KCTC 49623T = NBRC 115222T) and Microbacterium gwkjiense sp. nov. (type strain KSW4-11T = KACC 23321T = DSM 116380T) are proposed.