Structural and electronic determinants of lytic polysaccharide monooxygenase reactivity on polysaccharide substrates

Lytic polysaccharide monooxygenases (LPMOs) are industrially important copper-dependent enzymes that oxidatively cleave polysaccharides. Here we present a functional and structural characterization of two closely related AA9-family LPMOs from Lentinus similis (LsAA9A) and Collariella virescens (CvAA9A). LsAA9A and CvAA9A cleave a range of polysaccharides, including cellulose, xyloglucan, mixed-linkage glucan and glucomannan. LsAA9A additionally cleaves isolated xylan substrates. The structures of CvAA9A and of LsAA9A bound to cellulosic and non-cellulosic oligosaccharides provide insight into the molecular determinants of their specificity. Spectroscopic measurements reveal differences in copper co-ordination upon the binding of xylan and glucans. LsAA9A activity is less sensitive to the reducing agent potential when cleaving xylan, suggesting that distinct catalytic mechanisms exist for xylan and glucan cleavage. Overall, these data show that AA9 LPMOs can display different apparent substrate specificities dependent upon both productive protein–carbohydrate interactions across a binding surface and also electronic considerations at the copper active site

Lytic xylan oxidases from wood-decay fungi unlock biomass degradation

Wood biomass is the most abundant feedstock envisioned for the development of modern biorefineries. However, the cost-ef-fective conversion of this form of biomass into commodity products is limited by its resistance to enzymatic degradation. Here we describe a new family of fungal lytic polysaccharide monooxygenases (LPMOs) prevalent among white-rot and brown-rot basidiomycetes that is active on xylans—a recalcitrant polysaccharide abundant in wood biomass. Two AA14 LPMO members from the white-rot fungus Pycnoporus coccineus substantially increase the efficiency of wood saccharification through oxida-tive cleavage of highly refractory xylan-coated cellulose fibers. The discovery of this unique enzyme activity advances our knowledge on the degradation of woody biomass in nature and offers an innovative solution for improving enzyme cocktails for biorefinery applications

1394AP: A protocol for deterministic industrial communication via IEEE 1394

In this contribution we present an application layer called 1394AP (1394 Automation Protocol) for the industrial use of the IEEE 1394 "FireWire" standard which is favorable for factory automation because of its inherently deterministic network behavior. Starting from an analysis of industrial communication requirements and an overview of the principles of IEEE 1394, it will be shown that also other advantages make IEEE 1394 a promising network for industrial use. The following sections describe the 1394AP protocol in detail and explain how to implement the necessary hardware and software based on general purpose architecture of an IEEE 1394 embedded node. The paper will conclude with an outlook on the next steps in the ongoing specification process of 1394AP

Maillard induced saccharide degradation and its effects on protein glycation and aggregation

Saccharides are known to influence the maximum Maillard degree of glycation (DGmax) and protein aggregation reached. This research focused on the link between the fate of saccharide content, saccharide degradation and Maillard glycation and aggregation. Heat-treatment of α-lactalbumin with surplus glucose, maltotriose and galacturonic acid resulted in a DGmax lower than 100% (88, 21 and 57% for AG, AMtt and AGalA). Saccharide content still decreased after DG had plateaued and after 48 h enough saccharide was still present to further increase the DG of all samples, to 100% in AG/AMtt or to 85% in AGalA. Up to 17, 12 and 24% of the saccharide carbon in AG, AMtt and AGalA degraded to organic acids (e.g. acetic, formic, lactic, glycolic and succinic acid). Acetic and formic acid were the most abundant organic acids in all samples. Lactic acid was only identified in samples containing Maillard aggregation (AG and AGalA), and likely derives from the degradation of excess methylglyoxal, a protein cross-linking agent formed during the Maillard reaction

Enzymatic activity of lytic polysaccharide monooxygenase

The present invention is in the area of enzymes for (hemi-)cellulose degradation and/or modification, more in particular the degradation and/or modification of xylan. The invention is based on a newly discovered enzymatic activity of a class of lytic polysaccharide monooxygenases (LPMOs), i.e. oxidative cleavage of xylan in addition to oxidative cleavage of cellulose. The present invention therefore relates to a method for degrading and/or modifying xylan in a xylan-comprising substrate, a method for preparing a product from a xylan-comprising substrate, a kit of parts, a liquid, paste or solid formulation, and a xylan-comprising composition, comprising said LPMO. The invention further relates to a use of said LPMO, said kit of parts, said formulation and/or said composition, in a method of the invention

Enzymatic activity of lytic polysaccharide monooxygenase

The present invention is in the area of enzymes for (hemi-)cellulose degradation and/or modification, more in particular the degradation and/or modification of xylan. The invention is based on a newly discovered enzymatic activity of a class of lytic polysaccharide monooxygenases (LPMOs), i.e. oxidative cleavage of xylan in addition to oxidative cleavage of cellulose. The present invention therefore relates to a method for degrading and/or modifying xylan in a xylan-comprising substrate, a method for preparing a product from a xylan-comprising substrate, a kit of parts, a liquid, paste or solid formulation, and a xylan-comprising composition, comprising said LPMO. The invention further relates to a use of said LPMO, said kit of parts, said formulation and/or said composition, in a method of the invention