Via an all‐catalytic route, long‐chain diamines were prepared by the catalytic direct amination of long‐chain diols, derived from plant oils. High conversion was achieved with good selectivity, with the amount of nitrile impurities formed suppressed to a low level. From the lignocellulose‐based 5‐hydroxymethylfurfural (5‐HMF), or from bis(hydroxymethyl)furan, 2,5‐bis(aminomethyl)furan (BAMF) was generated. 5‐HMF was converted in a one‐pot, one‐step direct amination and reductive amination using ammonia. In both cases, the reaction proceeded very efficiently. In the combined amination and reductive amination, the H2 concentration is a rate‐limiting factor. Reducing the partial pressure of H2 also shortened the reaction time required significantly. Polycondensation of the long‐chain diamines with long‐chain diacids led to higher molecular weight polyamides, illustrating the quality of the diamines obtained by this synthetic approach as monomers.

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Here, we report highly efficient degradation of xylan into xylose by a single multifunctional xylanolytic enzyme from the filamentous fungus Thermothelomyces thermophila (termed Ttxy43). Ttxy43 shows three different enzyme activities toward carbohydrates, β-xylosidase (80.8 U/mg), endoxylanase (105.42 U/mg), and α-l-arabinofuranosidase enzyme activities (15.81 U/mg). Analysis of the catalytic mode of action of Ttxy43 for birchwood-xylan (BWX) reveals that endoxylanase initially degrades xylan to unbranched xylooligosaccharides (XOSs) (xylobiose, xylotriose, xylotetraose) as intermediates, which are then quickly hydrolyzed into single xylose by β-xylosidase. Site-directed mutagenesis studies indicate that Ttxy43 residues Asp134 and Glu228 are essential catalytic sites, while Glu176, Asp38, and Asp85 play an accessory role. More importantly, Ttxy43 displays higher degradation efficiency in comparison with a commercial β-xylosidase and endoxylanase “cocktail”. These findings elucidate an efficient integrated degradation mechanism of xylan under industrial reaction conditions, which provides a novel strategy to design techniques for biomass energy production.

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