Depolymerizing lignin, the complex phenolic polymer fortifying plant cell walls, is an essential but challenging starting point for the lignocellulosics industries. The variety of ether-and carbon-carbon interunit linkages produced via radical coupling during lignification limit chemical and biological depolymerization efficiency. In an ancient fungus-cultivating termite system, we reveal unprecedentedly rapid lignin depolymerization and degradation by combining laboratory feeding experiments, lignocellulosic compositional measurements, electron microscopy, 2D-NMR, and thermochemolysis. In a gut transit time of under 3.5 h, in young worker termites, poplar lignin sidechains are extensively cleaved and the polymer is significantly depleted, leaving a residue almost completely devoid of various condensed units that are traditionally recognized to be the most recalcitrant. Subsequently, the fungus-comb microbiome preferentially uses xylose and cleaves polysaccharides, thus facilitating final utilization of easily digestible oligosaccharides by old worker termites. This complementary symbiotic pretreatment process in the fungus-growing termite symbiosis reveals a previously unappreciated natural system for efficient lignocellulose degradation.ignin is a heterogeneous plant cell wall polymer derived primarily from hydroxycinnamyl alcohols via combinatorial radical coupling reactions (1). Its depolymerization is challenging, making lignin a major barrier to gaining access to stored energy within lignocellulosic materials (2). Woody biomass, such as that contained in pine and poplar trees, represents the most abundant renewable energy resource in our terrestrial ecosystems. Because of a high content of lignin, a complex polymer that contains ether-and carbon-carbon linkages between monomerderived units (1, 3), biotechnological efforts to use this material for bioenergy require expensive chemical, physical, or biological pretreatment processes to partially delignify lignocellulose to allow access to plant polysaccharides (2).Termites are remarkably efficient at degrading woody biomass (4). Within hours, they digest 74-99% of cellulose and 65-87% of hemicellulose, leaving the lignin-rich residues as feces; that is, they process far more efficiently than other herbivores that can digest the less-lignified forages, such as grasses, leaves, and forest litter (5). Among termites, the subfamily Macrotermitinae form a monophyletic group of diverse species that originated in Africa and have cultivated specialized fungi (Termitomyces spp.) in their nests using woody or litter-based biomass for about 31 million years, and are able to almost completely decompose lignocellulose (6, 7). These termites enable the consumption of more than 90% of dead plant tissues in some arid tropical areas (7,8), and thus play central ecological roles in Old World (sub)tropical carbon cycling ( Fig. 1 A and B) (8). Throughout their evolutionary history, fungus-cultivating termites have evolved in mutualistic association with multiple microbial symbi...

In this paper we present a mathematical programming model for the Kanban system in a deterministic multi-stage capacitated assembly-tree-structure production setting. We discuss solution procedures to the problem and address three special cases of practical interest.just-in-time manufacturing: Kanban, inventory/production: deterministic models, programming

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Chunganenol (1), an unusual resveratrol hexamer, has been isolated from Vitis chunganensis. Its unprecedented structure has been assigned through detailed analyses of 2D NMR data and consideration of oligostilbene biosynthetic pathway, representing the first highly condensed stilbene oligomer from Vitaceous plants. It also featured a novel interunit lingkage where two stilbene units are connected by a methylene bridge. Moreover, 1 exhibited potent and selective quenching effects on singlet oxygen, and might play a role in the antioxidative defense system of the plant.

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A concise strategy to improve the p-NPP IJp-nitrophenyl palmitate) catalytic activity and enantioselectivity towards secondary alcohols of Pseudomonas cepacia lipase (PcL) has been described. The PcL was modified by I 3 − , N-acetyl imidazole (NAI), 1-IJ3-dimethylaminopropyl)-3-ethylcarbodiimide (EDC) and ethylenediamine (EDA) in the absence or presence of n-hexane, respectively. After being modified by the four modification reagents, the enantioselectivity (E value) of the PcL towards secondary alcohols was enhanced by 2-to 4-fold. The catalytic activity of EDA-PcL was increased by about 6-fold. The matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) analysis of modified PcL showed that Tyr 4 , Tyr 29 , Tyr 45 , Tyr 95 , Asp 36 and Asp 55 were the modified sites. When Tyr 29 was modified, the E value of PcL towards secondary alcohols was largely improved. MALDI-TOF-MS characterization and molecular dynamics simulation of the lipase indicated that Tyr 29 located inside the catalytic cavity had a significant impact on the E value. The strong steric hindrance of acetyl and iodine ion to the groups on the chiral center of the substrates is responsible for the improvement. In addition, the enhancement of hydrophobicity on the surface of the lipase due to the sidechain replacement of Asp with uncharged hydrophobic groups also improved the E value.

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Horseradish Peroxidase (HRP) is a commercially available and prevalently used peroxidase with no specific substrate binding domain.However, after being incorporated with different metal cations, new catalytic functions were found in biomimetic oxidation of resveratrol.Based on the results of screening, Ca, Cu, Fe and Mn incorporated enzymes showed distinctive effects, either decomposition or dimerization products were observed.