NOVELTY - An in vitro, cell-free process for producing hydrogen from polysaccharide involves: reducing the number of glucan units of the polysaccharide by converting at least one glucan unit to ribulose-5-phosphate; and generating hydrogen from converting the glucan unit to ribulose-5-phosphate.    USE - As in vitro, cell-free process for producing hydrogen from polysaccharide, useful for generating electricity (claimed); in the fields of agriculture and energy production, and as alternative for storing energy, in fuel cell; as a fuel for production of energy; in the production of ammonia; in petroleum refining; in the chemical-synthesis industries; in the food industry for hydrogenation of vegetable oils; in electronic-circuitry manufacture; in the preparation of methanol, fertilizers, glass, refined metals, vitamins, cosmetics, soaps, lubricants, and cleaners; as an excellent fuel, both in traditional combustion engines as well as in fuel cells; and as a fuel in space vehicles.    ADVANTAGE - The yield of hydrogen obtained by the method is at least 10 moles of hydrogen per mole of anhydroglucose units contained in the starting polysaccharide. The method provides in vitro enzymatic process that effectively converts renewable polysaccharides into high yields of hydrogen at mild conditions, using only enzymes and water. The process produces only hydrogen and carbon dioxide as net products, translating into an inexpensive method of generating hydrogen in very large quantities from low-cost feed stocks. The process provides an inexpensive method of generating hydrogen in very large quantities. The method is capable of forming high yields of H2; provides hydrogen gas of good mass and energy efficiency; and allows production of hydrogen at low cost.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) a composition effective for generating hydrogen in vitro from a polysaccharide, comprising: a polysaccharide; water; an enzyme or enzymes capable of catalyzing the conversion of the polysaccharide to glucose-6-phosphate; an enzyme or enzymes capable of catalyzing the conversion of NADPH and protons to hydrogen; and several enzymes capable of catalyzing the steps of the pentose phosphate pathway; and    (2) a kit for producing hydrogen from a polysaccharide comprising: at least one enzyme with phosphorylase activity; at least one enzyme with phosphoglucomutase activity; at least one enzyme with hydrogenase activity; a container for combining a polysaccharide, water and the enzymes; device for heating the container to 10-100degrees C; and device for collecting or using some or all of the hydrogen gas that evolves from the container.