Microorganisms produce a wide range of natural products (NPs) with clinically and agriculturally relevant biological activities. In bacteria and fungi, genes encoding successive steps in a biosynthetic pathway tend to be clustered on the chromosome as biosynthetic gene clusters (BGCs). Historically, “activity-guided” approaches to NP discovery have focused on bioactivity screening of NPs produced by culturable microbes. In contrast, recent “genome mining” approaches first identify candidate BGCs, express these biosynthetic genes using synthetic biology methods, and finally test for the production of NPs. Fungal genome mining efforts and the exploration of novel sequence and NP space are limited, however, by the lack of a comprehensive catalog of BGCs encoding experimentally-validated products. In this study, we generated a comprehensive reference set of fungal NPs whose biosynthetic gene clusters are described in the published literature. To generate this dataset, we first identified NCBI records that included both a peer-reviewed article and an associated nucleotide record. We filtered these records by text and homology criteria to identify putative NP-related articles and BGCs. Next, we manually curated the resulting articles, chemical structures, and protein sequences. The resulting catalog contains 197 unique NP compounds covering several major classes of fungal NPs, including polyketides, non-ribosomal peptides, terpenoids, and alkaloids. The distribution of articles published per compound shows a bias towards the study of certain popular compounds, such as the aflatoxins. Phylogenetic analysis of biosynthetic genes suggests that much chemical and enzymatic diversity remains to be discovered in fungi. Our catalog was incorporated into the recently launched Minimum Information about Biosynthetic Gene cluster (MIBiG) repository to create the largest known set of fungal BGCs and associated NPs, a resource that we anticipate will guide future genome mining and synthetic biology efforts toward discovering novel fungal enzymes and metabolites.

The effect of incorporation of silicone oils into a siloxane-polyurethane fouling-release coatings system was explored. Incorporation of phenylmethyl silicone oil has been shown to improve the fouling-release performance of silicone-based fouling-release coatings through increased interfacial slippage. The extent of improvement is highly dependent upon the type and composition of silicone oil used. The siloxane-polyurethane (SiPU) coating system is a tough fouling-release solution, which combines the mechanical durability of polyurethane while maintaining comparable fouling-release performance with regard to commercial standards. To further improve the fouling-release performance of the siloxane-PU coating system, the use of phenylmethyl silicones oils was studied. Coatings formulations were prepared incorporating phenylmethyl silicone oils having a range of compositions and viscosities. Contact angle and surface energy measurements were conducted to evaluate the surface wettability of the coatings. X-ray photoelectron spectroscopy (XPS) depth profiling experiments demonstrated self-stratification of silicone oil along with siloxane to the coating-air interface. Several coating formulations displayed improved or comparable fouling-release performance to commercial standards during laboratory biological assay tests for microalgae (Navicula incerta), macroalgae (Ulva linza), adult barnacles (Balanus amphitrite syn. Amphibalanus amphitrite), and mussels (Geukensia demissa). Selected silicone-oil-modified siloxane-PU coatings also demonstrated comparable fouling-release performance in field immersion trials. In general, modifying the siloxane-PU fouling-release coatings with a small amount (1-5 wt % basis) of phenylmethyl silicone oil resulted in improved performance in several laboratory biological assays and in long-term field immersion assessments.

Bioderived polycarbamates were cross-linked with petrochemically derived and biomass-derived dialdehydes to form nonisocyanate polyurethanes (NIPUs). The bioderived polycarbamates were synthesized from a soybean oilderived alkyd polyol and epoxidized sucrose soyate polyol via transcarbamoylation. The polycarbamates were cross-linked with 1,4-cyclohexanedicarboxaldehyde and 2,5diformylfuran (DFF) to form coatings under either laboratory ambient conditions or through an elevated temperature cure. The coatings were characterized spectroscopically, thermally, and via standard ASTM-coating characterizations. The coatings cured under ambient conditions had similar properties to those subjected to the elevated temperature cure. Ambient-cured coatings exhibited fast tack-free times, T g values from 67 to 96 °C, high hardness, and good solvent resistance; however, they were brittle and had poor adhesion on aluminum substrates. Coatings cured at elevated temperatures showed increases in T g values to 75−150 °C. Coatings on pretreated steel substrates had good adhesion. This study demonstrates the potential for bioderived DFF to function as a dialdehyde cross-linker to form NIPUs with bioderived carbamate functional resins resulting in a bioderived NIPU capable of ambient curing. Given the potential to form a multitude of aldehyde-functionalized furanic structures from 5-(hydroxymethyl)furfural, this increases the dialdehyde cross-linker options under consideration for formulation in bioderived NIPUs utilizing aldehyde-carbamate cross-linking.

Highly functional bio-based methacrylate and acrylate resins were synthesized from epoxidized sucrose soyate (ESS) and incorporated into formulations for stereolithographic (SLA) printing. These formulations were compared to a commercial SLA resin and with formulations where the bioderived resins were replaced with commercial urethane acrylates. The tensile, flexural, rheological, and thermomechanical performances of the respective formulations and their prints were compared. All of the formulations were able to be printed satisfactorily with a Peopoly Moai SLA 3D printer. The acrylated ESS resin showed the highest viscosity while the methacrylated ESS resins had lower viscosities than the control urethane acrylates. The prints made from the formulations containing the methacrylated ESS resins had similar T g s to that of the urethane acrylate control formulations while the prints from the acrylated ESS resin had a lower T g . The tensile and flexural properties were consistent with the T g values in terms of modulus, but some of the prints showed surface cracking that compromised the strength properties. This study demonstrated the ability of a bio-derived material to be functionally modified and incorporated into an SLA formulation and printed in different orientations.