Robust Oxidase-Mimetic Supramolecular Nanocatalyst for Lignin Biodegradation.

Enzymatic catalysis presents an eco-friendly, energy-efficient method for lignin degradation. However, challenges arise due to the inherent incompatibility between enzymes and native lignin. In this work, we introduce a supramolecular catalyst composed of fluorenyl-modified amino acids and Cu2+, designed based on the aromatic stacking of the fluorenyl group, which can operate in ionic liquid environments suitable for the dissolution of native lignin. Amino acids and halide anions of ionic liquids shape the copper site's coordination sphere, showcasing remarkable catechol oxidase-mimetic activity. The catalyst exhibits thermophilic property, and maintains oxidative activity up to 75 °C, which allows the catalyzed degradation of the as-dissolved native lignin with high efficiency even without assistance of the electron mediator. In contrast, at this condition, the native copper-dependent oxidase completely lost its activity. This catalyst with superior stability and activity offer promise for sustainable lignin valorization through biocatalytic routes compatible with ionic liquid pretreatment, addressing limitations in native enzymes for industrially relevant conditions.

Biodegradation of poly (epsilon-caprolactone) film in the presence of Lysinibacillus sp. 70038 and characterization of the degraded film.

Poly (epsilon-caprolactone) (PCL) is one of the commercial biodegradable plastics and biocompatible polyesters that can be assimilated by microorganisms. Lysinibacillus sp. 70038 which degrades PCL film was screened from stock cultures by cultivation using an enrichment culture medium containing PCL film with the weight-averaged molecular weight (Mw) of 160,000 as a sole carbon source. Lysinibacillus sp. 70038 degraded 9.0% of PCL at 30 degrees C, 100 rpm, after 30 d. Scanning electron microphotograph (SEM) analysis of the degraded PCL film showed nearly 4 /i m of surface erosion, and the molecular weight distribution of the surface area of PCL film became broad and a low molecular weight polymer (Mn=6,900) was confirmed by gel permeation chromatography (GPC) after cultivation.

An efficient synthesis method targeted to a novel aziridine derivative of p-menthane from turpentine and its herbicidal activity.

A novel aziridine compound N-acetyl-1,2-azacyclo-p-menthane d was synthesised using turpentine as raw material and characterised by FT-IR, 1H NMR, 13C NMR, ESI+-MS and HRMS. The pre-emergence herbicidal activities of d and its synthetic intermediates cis- and trans-N,N'-diacetyl-p-menthane-1,8-diamine (b2 and b1) were determined. The result showed that d exhibited much higher herbicidal activities against annual ryegrass, Digitaria sanguinalis and Ixeris denticulate than b2 and b1. The IC50 of d against the root and shoot growth of these three plants were lower than 1 mmol L-1. In contrast, the IC50 of b1 and b2 against the root and shoot growth of these plants were more than 10 mmol L-1.

Metallo-deuteroporphyrin as a biomimetic catalyst for the catalytic oxidation of lignin to aromatics.

A series of metallo-deuteroporphyrins derived from hemin were prepared as models of the cytochrome P450 enzyme. With the aid of the highly active Co(II) deuteroporphyrin complex, the catalytic oxidation system was applied for the oxidation of several lignin model compounds, and high yields of monomeric products were obtained under mild reaction conditions. It was found that the modified cobalt deuteroporphyrin that has no substituents at the meso sites but does have the disulfide linkage in the propionate side chains at the ß sites exhibited much higher activity and stability than the synthetic tetraphenylporphyrin. The changes in the propionate side chains can divert the reactivity of cobalt deuteroporphyrins from the typical CC bond cleavage to CO bond cleavage. Furthermore, this novel oxidative system can convert enzymolysis lignin into depolymerized products including a significant portion of well-defined aromatic monomers.