Genencor International, Inc.

Leif P Solheim

Colin Mitchinson

Carol A Requadt

Richard L Antrim

Traci H Ropp

Scott Douglas Power

Anthony G Day

Christopher Charles Barnett

Christopher Ringer

According to the invention a method is provided for liquefying starch comprising the steps of adding a sodium composition to the starch prior to or simultaneously with liquefying the starch; adding &agr;-amylase to the treated starch; and reacting the treated starch for a time and at a temperature effective to liquefy the treated starch. Preferred sodium compositions comprise sodium chloride, sodium bicarbonate, sodium benzoate, sodium sulfate, sodium bisulfite, sodium ascorbate, sodium acetate, sodium nitrate, sodium tartrate, sodium tetraborate, sodium propionate, sodium citrate, sodium succinate, monosodium glutamate, trisodium citrate, sodium phosphate or a mixture thereof.

Method for liquefying starch

Mutant .alpha.-amylase

Novel alpha-amylase mutants derived from the DNA sequences of naturally occurring or recombinant alpha-amylases are disclosed. The mutant alpha-amylases, in general, are obtained by in vitro modifications of a precursor DNA sequence encoding the naturally occurring or recombinant alpha-amylase to generate the substitution (replacement) or deletion of one or more oxidizable amino acid residues in the amino acid sequence of a precursor alpha-amylase. Such mutant alpha-amylases have altered oxidative stability and/or altered pH performance profiles and/or altered thermal stability as compared to the precursor. Also disclosed are detergent and starch liquefaction compositions comprising the mutant amylases, as well as methods of using the mutant amylases.

Oxidatively stable alpha-amylase

According to the invention a method is provided for liquefying starch comprising the steps of treating the starch prior to or simultaneously with liquefying the starch to inactivate and/or remove the enzyme inhibiting composition present in the starch and form treated starch; adding .alpha.-amylase to the treated starch; and reacting the treated starch for a time and at a temperature effective to liquefy the treated starch. Effective means to treat the starch include the addition of a phytate degrading enzyme and heat treatment, optionally followed by filtration or centrifugation, of granular starch or a starch solution.

Novel .alpha.-amylase enzymes are disclosed in which one or more asparagine residues are substituted with a different amino acid or deleted. The disclosed .alpha.-amylase enzymes show altered or improved low pH starch hydrolysis performance, stability and activity profiles.

Mutant A-amylase

According to the invention a method is provided for liquefying starch comprising the steps of adding a sodium composition to the starch prior to or simultaneously with liquefying the starch; adding .alpha.-amylase to the treated starch; and reacting the treated starch for a time and at a temperature effective to liquefy the treated starch. Preferred sodium compositions comprise sodium chloride, sodium bicarbonate, sodium benzoate, sodium sulfate, sodium bisulfite, sodium ascorbate, sodium acetate, sodium nitrate, sodium tartrate, sodium tetraborate, sodium propionate, sodium citrate, sodium succinate, monosodium glutamate, trisodium citrate, sodium phosphate or a mixture thereof.

The present invention relates to a process of liquefying starch wherein the liquefaction step is carried out at pH less than 6. It also relates to the use of antioxidants.

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Clinton, IA, United States of America

Leif P Solheim