Extracellular degradation of a polyurethane oligomer involving outer membrane vesicles and further insights on the degradation of 2,4-diaminotoluene in Pseudomonas capeferrum TDA1

Abstract

The continuing reports of plastic pollution in various ecosystems highlight the threat posed by the ever-increasing consumption of synthetic polymers. Therefore, Pseudomonas capeferrum TDA1, a strain recently isolated from a plastic dump site, was examined further regarding its ability to degrade polyurethane (PU) compounds. The previously reported degradation pathway for 2,4-toluene diamine, a precursor and degradation intermediate of PU, could be confirmed by RNA-seq in this organism. In addition, different cell fractions of cells grown on a PU oligomer were tested for extracellular hydrolytic activity using a standard assay. Strikingly, purified outer membrane vesicles (OMV) of P. capeferrum TDA1 grown on a PU oligomer showed higher esterase activity than cell pellets. Hydrolases in the OMV fraction possibly involved in extracellular PU degradation were identified by mass spectrometry. On this basis, we propose a model for extracellular degradation of polyester-based PUs by P. capeferrum TDA1 involving the role of OMVs in synthetic polymer degradation.

Assessment of New and Genome-Reduced Pseudomonas Strains Regarding Their Robustness as Chassis in Biotechnological Applications

“…The strain TDA1 contains the ttgABC genes; however, none of the gene sets for TtgGHI nor for TtgDEF are complete. Several genes related to biofilm formation and induction, multidrug resistance proteins and RND transporters were identified as differentially expressed (upregulated) in P. capeferrum TDA1 grown on the aromatic compound 2,4-diaminotoluene [22], however, ttgABC were not among them. Thus, TtgABC was most probably not involved in the adaptation to 2,4-diaminotoluene.…”

“…Additionally, the bacterial strain Pseudomonas capeferrum TDA1 was included in the assessment, based on reports about its metabolic ability to degrade a polyurethane monomer and a polyurethane oligomer [22] and first applications in biotechnological approaches [24]. The genome of Pseudomonas capeferrum TDA1 was first published under the species name Pseudomonas sp.…”

“…Furthermore, the recently isolated strain P. capeferrum TDA1 has been reported as a plastic monomer and oligomer degrader [22,23], which shows its metabolic capacity and broad potential to degrade recalcitrant compounds. Together with three P. putida KT2440 derivatives in a defined microbial mixed culture, TDA1 was deployed in the metabolization of polyurethane hydrolysates.…”

Bacterial Membrane Vesicles for In Vitro Catalysis

“…The authors note that P. putida was previously known to be well-suited for bioremediation with the documented ability to degrade toluene and other toxic pollutants, potentially using the same versatile phenolic compound-degrading enzymes with activity in lignin catabolism, suggesting P. putida OMVs have potential as tools in synthetic biology and biotechnological applications beyond improving microbial lignin conversion in biotechnology venues [ 24 ]. Another species, P. capeferrum, has recently been shown to biodegrade extracellular polyurethane via OMVs where the degradation potentially involves both periplasmic as well as membrane-bound hydrolases [ 25 ].…”

Characterization and engineering of branched short-chain dicarboxylate metabolism in Pseudomonas reveals resistance to fungal 2-hydroxyparaconate

“…Microbial upcycling requires efficient funneling of plastic monomers into the central metabolism of suitable microorganisms. Pseudomonas putida KT2440 and related species are well known in this respect, and strains have been isolated or engineered to funnel prevalent plastic monomers such as ethylene glycol ( Franden et al, 2018 ; Li et al, 2019 ), 1,4-butanediol ( Li et al, 2020 ), adipate ( Ackermann et al, 2021 ), terephthalate ( Narancic et al, 2021 ), and 2,4-toluenediamide ( Puiggené et al, 2022 ) into their central metabolism. Furthermore, non-pathogenic Pseudomonads enable safe and practical research and were also engineered to produce a variety of value-added compounds, including polyhydroxyalkanoates (PHAs) ( Dalton et al, 2022 ; Mezzina et al, 2021 ), aromatic compounds ( Schwanemann et al, 2020 ) as well as rhamnolipids ( Tiso et al, 2020 ).…”