One-Step Spraying Strategy for Fabricating Bioinspired, Graphene-Based, and Multifunctional-Integrated Coatings on Structural Steel with Good Water Repellency, Fireproofing, Anticorrosion, and Durability.

Traditionally, many coatings were merely concentrated on settling the inherent fire protection problem of steel structures, while surface contamination and corrosion susceptibility should also be considered. Concurrently addressing these problems in fireproof efficiency and surface multifunctionality has become an issue of great significance in further expanding the application value in industrial and daily scenarios. Based on this condition, ecofriendly, graphene-based, and superhydrophobic coatings with multifunctional integration were constructed on steel via a one-step spraying method. The as-prepared coatings mainly consist of epoxy resin (EP), silicone resin (SR), a cyclodextrin-based flame retardant (MCDPM), expandable graphite (EG), and multilayered graphene (MG). The results demonstrate that the water contact angle (WCA) and water sliding angle (WSA) of as-prepared coatings can reach 156.8 ± 1.6 and 5.8 ± 0.7°, respectively, revealing good water repellency and self-cleaning properties. The coatings can also exhibit adequate adaptability for various substrates including wood, polyurethane foam, and cotton fabrics. Besides, good durability and robustness of coatings have been also verified via acid/alkali immersion, outdoor exposure, O2/plasma etching, and linear abrasion tests. Simultaneously, the coatings can exhibit excellent anticorrosion capacity for steel materials via a double barrier effect. Most importantly, the coatings have exhibited the lowest backside temperature (234.5 °C) during fire impact tests, suggesting excellent fireproof and heat insulation performance. This fact can be ascribed to the conjunct action between the physical/chemical charring process of flame retardants and the remarkable thermal stability of graphene. Consequently, this article can be expected to further promote the development and application of multifunctional-integrated coatings for steel structures in more fields.

UV-ARTP compound mutagenesis breeding improves macrolactins production of Bacillus siamensis and reveals metabolism changes by proteomic.

Macrolactins are a type of compound with complex macrolide structure which mainly be obtained through microbiological fermentation now. They have excellent antifungal, antibacterial and antitumor activity. In order to improve macrolactins production, Bacillus siamensis YB304 was used as the research object, and a mutant Mut-K53 with stable genetic characters was selected by UV-ARTP compound mutagenesis. The yield of macrolactins was 156.46 mg/L, 3.95 times higher than original strain. The metabolic pathway changes and regulatory mechanism of macrolactins were analyzed by quantitative proteomics combined with parallel reaction monitoring. This study revealed that 1794 proteins were extracted from strain YB304 and strain Mut-K53, most of them were related to metabolism. After UV-ARTP compound mutagenesis treatment, the expression of 628 proteins were significantly changed, of which 299 proteins were significantly up-regulated. KEGG pathway analysis showed that differentially expression proteins mainly distributed in biological process, cellular component, and molecular function processing pathways. Such as utilization of carbon sources, glycolysis pathway, and amino acid metabolism pathway. Furthermore, key precursor substances such as acyl-CoA and amino acids of macrolactin biosynthesis are mostly up-regulated, which are one of the main reasons for increased production of macrolactin.This study will provide a new way to increase the yield of macrolactins through mutagenesis breeding and proteomics.