FDCA (2,5-furandicarboxylic acid) can be enzymatically converted from HMF (5-hydroxymethylfurfural). Pseudomonas putida S12 is promising for FDCA production, but generating stable P. putida S12 is difficult due to its polyploidy and lack of genome engineering tools. Here we showed that coupling CRISPR and λ-Red recombineering enabled one-step gene integration with high efficiency and frequency, and simultaneously replaced endogenous genes in all chromosomes. Using this approach, we generated two stable P. putida S12 strains expressing HMF/furfural oxidoreductase (HMFH) and HMF oxidase (HMFO), both being able to convert 50 mM HMF to ≈42−43 mM FDCA in 24 h. Cosupplementation of MnO 2 and CaCO 3 to the medium drastically improved the cell tolerance to HMF and enhanced FDCA production. Cointegrating HMFH and HMFT1 (HMF transporter) genes further improved FDCA production, enabling the cells to convert 250 mM HMF to 196 mM (30.6 g/L) FDCA in 24 h. This study implicates the potentials of CRISPR for generating stable P. putida S12 strains for FDCA production.

fundamental properties from the physical perspective (e.g., surface roughness, hydrophobicity, elasticity, surface structure/ geometry, and mechanical strength) and the chemical perspective (e.g., bio and/or chemical functionality) can affect cellular responses, including cell attachment, proliferation, migration, differentiation, and apoptosis. [1][2][3][4] For instance, cells respond extensively to synthetic extracellular matrix (ECM) on substrates with multiple features, such as chemical composition, geometry and topological features, ligand organization, and substrate stiffness. [5][6][7][8]

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Vapor deposition of polymers is known to result in densified thin films, and recent developments have advanced these polymers with interesting fabrication techniques to a variety of controlled structures other than thin films. With the advantages of chemical modification and functionalization of these polymers, advancements have combined both the physical and chemical properties of these vapor-deposited polymers to obtain controlled anisotropic polymers, including layer-by-layer, gradient, hierarchical, porosity, and the combination of the above, meaning that the produced polymers are functional and are addressed in devised physical configurations and chemical compositions. The main purpose of using polymer coatings as a tool for surface modification is to provide additional properties that decouple the natural properties of the underlying materials (including metals, polymers, oxides/ceramics, glass, silicon, etc.), and recent advancements have rendered novel insights into combined physical and chemical properties to fulfill the increasing needs of sophisticated requirements of materials for users. The review herein intends to deliver messages of recent progress of the advancements of vapor-deposited polymers, with discussions of the variations of the physical structures and chemical functionalities, and how these two aspects are integrated with novel fabrication techniques.