Hyperthermophilic xylanase and thermophilicity analysis by molecular dynamic simulation with quantum mechanics.

Thermophilic xylanases catalyzing the cleavage of β-1,4-glycosidic bonds in xylan have applications in food, feed, biorefinery, and pulp industries. In this study, a hyperthermophilic endo-xylanase was obtained by further enhancement of thermal tolerance of a thermophilic GH11 xylanase originated from metagenome of bagasse pile based on rational design. Introducing N13F and Q34L to the previously reported X11P enzyme shifted the optimal working temperature to 85 °C and led to 20.

Identification of a plastic-degrading enzyme from Cryptococcus nemorosus and its use in self-degradable plastics.

For decades, plastic waste management has been one of the major ecological challenges of our society. Despite the introduction of biodegradable alternatives such as polylactic acid (PLA), their beneficial environmental impact is limited by the requirement of specific compost facility as biodegradation of PLA in natural environment occurs at a very slow rate. In this work, a plastic-degrading enzyme was utilized to facilitate degradation process.

Enhancement of catalytic activity and alkaline stability of cellobiohydrolase by structure-based protein engineering.

Unlabelled: Alkaline cellobiohydrolases have the potential for application in various industries, including pulp processing and laundry where operation under high pH conditions is preferred. In this study, variants of Cel6A cellobiohydrolase from were generated by structural-based protein engineering with the rationale of increasing catalytic activity and alkaline stability. The variants included removal of the carbohydrate-binding module (CBM) and substitution of residues 173 and 200.

Co-production of schizophyllan and cellulolytic enzymes from bagasse by Schizophyllum commune.

Schizophyllum commune is a mushroom-forming fungus well-known for its ability to degrade lignocellulosic materials and production of schizophyllan, a high added-value product for cosmeceutical, pharmaceutical, and biomaterial industries. Conventionally, schizophyllan is produced by submerged fermentation using glucose as a carbon source. In this work, we demonstrate that alkaline pretreated bagasse can be used by Schizophyllum commune as an alternative carbon source for the production of schizophyllan.

Engineering of β-mannanase from Aspergillus niger to increase product selectivity towards medium chain length mannooligosaccharides.

Mannooligosaccharides (MOSs) are one of the most commonly used biomass-derived feed additives. The effectiveness of MOS varies with the length of oligosaccharides, medium length MOSs such as mannotetraose and mannopentaose being the most efficient. This study aims at improving specificity of β-mannanase from Aspergillus niger toward the desirable product size through rational-based enzyme engineering.

Kinetic Characterization of Prenyl-Flavin Synthase from Saccharomyces cerevisiae.

We have characterized the kinetics and substrate requirements of prenyl-flavin synthase from yeast. This enzyme catalyzes the addition of an isopentenyl unit to reduced flavin mononucleotide (FMN) to form an additional six-membered ring that bridges N5 and C6 of the flavin nucleus, thereby converting the flavin from a redox cofactor to one that supports the decarboxylation of aryl carboxylic acids. In contrast to bacterial enzymes, the yeast enzyme was found to use dimethylallyl pyrophosphate, rather than dimethylallyl phosphate, as the prenyl donor in the reaction.

Mechanism of the Novel Prenylated Flavin-Containing Enzyme Ferulic Acid Decarboxylase Probed by Isotope Effects and Linear Free-Energy Relationships.

Ferulic acid decarboxylase from Saccharomyces cerevisiae catalyzes the decarboxylation of phenylacrylic acid to form styrene using a newly described prenylated flavin mononucleotide cofactor. A mechanism has been proposed, involving an unprecedented 1,3-dipolar cyclo-addition of the prenylated flavin with the α═β bond of the substrate that serves to activate the substrate toward decarboxylation. We measured a combination of secondary deuterium kinetic isotope effects (KIEs) at the α- and β-positions of phenylacrylic acid together with solvent deuterium KIEs.