Improved molecular disassembly and depolymerization of grain starch to glucose are key to reducing energy use in the bioconversion of glucose to chemicals, ingredients, and fuels. In fuel ethanol production, these biorefining steps use 10-20% of the energy content of the fuel ethanol. The need to minimize energy use and to raise the net yield of energy can be met by replacing high-temperature, liquid-phase, enzymatic digestion with low temperature, solid-phase, enzymatic digestion. Also called cold hydrolysis, the approach is a step toward a "green" method for the production of fuel ethanol. There has been substantial prior and increased recent interest in this approach that is presented in this first review of the subject. We include incentives, developmental research, fundamental factors of raw starch digestion, and novel approaches in enzymology and processing. The discussion draws on resources found in enzymology, engineering, plant physiology, cereal chemistry, and kinetics.

Transparent, flexible films could be made by casting aqueous solutions of alginic acid, but they dissolved in water. When films were made from a solution of alginic acid and multivalent ions, they were still water soluble. However, when alginic acid films were immersed in a solution of salts with multivalent ions, they dissolved in water much more slowly, if at all. Treatment with calcium and zinc resulted in films insoluble in water and their tensile strength increased by an order of magnitude. Iron and magnesium ions had little effect on properties of the films. Copper and aluminum showed intermediate effect, but treatment with cupric ion resulted in a fast crosslinking of the surface without affecting the inside of the film. This resulted in the formation of a tube when opposing surfaces were pulled apart.

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There is a great interest in xylanases due to the wide variety of industrial applications for these enzymes. We cloned a xylanase gene (xyn8) from an environmental genomic DNA library. The encoded enzyme was predicted to be 399 amino acids with a molecular weight of 45.9 kD. The enzyme was categorized as a glycosyl hydrolase family 8 member based on sequence analysis of the putative catalytic domain. The purified enzyme was thermolabile, had an activity temperature optimum of 20 degrees C on native xylan substrate, and retained significant activity at lower temperatures. At 4 degrees C, the apparent K (m) was 3.7 mg/ml, and the apparent k (cat) was 123/s.