The invention is in the field of enzymology. More in particular, it provides a method for the isomerization of glucose into fructose wherein the glucose is derived from lignocellulosic material. More in particular, the invention provides polypeptides encoding mutant glucose isomerase enzymes with improved glucose isomerase activity as compared to the corresponding wild type enzyme. The disclosed polypeptides are particularly suited for converting glucose to fructose in the presence of xylose.

A membranous immobilized cell, polypeptide, oligopeptide or protein and a preparation method thereof are provided. The method includes the following steps: 1) providing un-film-form chitosan, where the chitosan is un-pre-crosslinked or pre-crosslinked; 2) providing a mixture of the un-film-form chitosan and cell, polypeptide, oligopeptide or protein, and in the mixture, the un-film-form chitosan is in a dissolved state; 3) mixing the mixture with a crosslinking reagent to obtain a co-crosslinked product of the chitosan and the cell, polypeptide, oligopeptide or protein; and 4) drying the co-crosslinked product to obtain membranous immobilized cell, polypeptide, oligopeptide or protein. When un-pre-crosslinked chitosan is used in the step 1), the method further includes comprises the step 5) mixing the membranous immobilized cell, polypeptide, oligopeptide or protein with phosphate salt, so that chitosan molecules therein are crosslinked with each other.

The invention is in the field of enzymology. More in particular, it provides a method for the isomerization of glucose into fructose wherein the glucose is derived from lignocellulosic material. More in particular, the invention provides polypeptides encoding mutant glucose isomerase enzymes with improved glucose isomerase activity as compared to the corresponding wild type enzyme. The disclosed polypeptides are particularly suited for converting glucose to fructose in the presence of xylose.

There are disclosed compositions and methods for treating obesity using 5-D-fructose dehydrogenase. Other embodiments are also described.

Provided herein are compositions and methods for stabilizing enzymes. Also provided are systems, compositions and methods for using the stabilized enzymes to produce a desired compound.

The present disclosure provides a process for production of glucose having purity greater than 98% from pretreated cellulosic biomass comprising 50-95% cellulose, using thermo-chemical and enzymatic treatments. The process of the disclosure involves mild acid and/or alkali treatment of the pretreated cellulosic biomass for production of treated cellulosic biomass residue comprising polysaccharides containing greater than 98% glucose. The treatment results in high purity cellulose that is highly amenable to enzymatic hydrolysis and yields glucose having purity greater than 98%. The process of the disclosure also involves membrane separation of enzymes and oligosaccharides for recycling and separation of glucose to avoid product feedback inhibition.

This invention is aimed at improving an ethanol fermentation ability of a recombinant yeast strain having an ability of assimilating pentose, such as xylose or arabinose. The recombinant yeast strain haying an ability of assimilating pentose is obtained by lowering activity of a gene involved in upstream of glyceraldehyde-3-phosphate in the Embden-Meyerhof pathway.

The present disclosure provides a process for production of glucose having purity greater than 98% from pretreated cellulosic biomass comprising 50-95% cellulose, using thermo-chemical and enzymatic treatments. The process of the disclosure involves mild acid and/or alkali treatment of the pretreated cellulosic biomass for production of treated cellulosic biomass residue comprising polysaccharides containing greater than 98% glucose. The treatment results in high purity cellulose that is highly amenable to enzymatic hydrolysis and yields glucose having purity greater than 98%. The process of the disclosure also involves membrane separation of enzymes and oligosaccharides for recycling and separation of glucose to avoid product feedback inhibition.

An inventive method and a device for the biotechnological reduction of sugar substances in fruit educts for the purpose of obtaining low-sugar fruit products characterized by enzymatic and/or fermentative reaction processes. Said method is characterized by a closed-loop control process, by means of which the pH value in the low-sugar fruit product is adjusted to a predetermined higher value, as compared to the pH value in the fruit educt, in such a way that during the reduction of the sugar substances by at least 30% by weight to less than 40% by weight, the pH value is increased between 0.6 and 1.0 pH units; or that during the reduction of the sugar substances by at least 40% by weight to less than 50% by weight, the pH value is increased between 0.7 and 1.1 pH units; or that during the reduction of the sugar substances by at least 50% by weight to less than 65% by weight, the pH value is increased between 0.8 and 1.2 pH units; or that during the reduction of the sugar substances by at least 65% by weight to less than 80% by weight, the pH value is increased between 0.9 and 1.3 pH units; or that during the reduction of the sugar substances by at least 80% by weight, the pH value is increased between 1.0 and 1.4 pH units;
wherein the aforementioned pH values may also turn out to be higher or lower by up to 0.1 or up to 0.2 pH units; and/or
wherein, in the case of fermentatively formed sugar alcohols having a % by weight fraction of up to 3.0% by weight, the increase in the pH value with the simultaneous reduction of the sugar substances may turn out to be less by up to 0.3 pH units, as compared to a purely enzymatic process, wherein preferably both values correlate to each other, in particular, linearly.

The present invention can be used to obtain, in particular, low-sugar fruit products, such as fruit pures or fruit preparations or fruit powder or whole fruit beverages (smoothies) or fruit juices and/or vegetable juices (regardless of whether bottled undiluted as NFC juice or rediluted as fruit juice from fruit juice concentrate) or comparable fruit beverages that can be characterized as alcohol-free.