Fermentation Process Using Cellulolytic Enzymes for Starch Conversion
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Solution Overview
Problem
Current processes for producing fermentation products from starch-containing materials, such as ethanol, result in significant residual starch material not being converted, leading to suboptimal yields due to the formation of non-fermentable Maillard products.
Innovation Solution
A process involving liquefaction of starch-containing materials at temperatures above the initial gelatinization temperature using alpha-amylase, optionally thermostable protease, and carbohydrate-source generating enzymes, followed by saccharification and fermentation with a cellulolytic composition present, to enhance conversion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional liquefaction and saccharification processes are used, then the process is simple and well-established, but significant residual starch remains unconverted forming non-fermentable Maillard products
Solution Approach 1:
The patent applies parameter changes by adjusting pH to alkaline conditions (pH 8-10) during the fermentation process, which enables the conversion of residual starch and dextrins that remain unconverted in conventional acidic processes. This pH modification allows cellulolytic enzymes to effectively hydrolyze remaining starch materials into fermentable sugars, thereby improving overall fermentation product yield while reducing residual starch loss.
Solution Approach 2:
The patent employs a composite enzymatic system combining amylases for starch hydrolysis with cellulolytic enzymes (cellulases, hemicellulases) that work synergistically under alkaline conditions. This composite approach allows simultaneous degradation of both starch and cellulose-containing materials, converting residual carbohydrates into fermentable sugars that would otherwise form non-fermentable Maillard products.
2Productivity
If higher conversion of residual starch is achieved, then fermentation product yield increases, but process complexity increases due to additional enzymes and pH control
Solution Approach 1:
The patent merges the saccharification and fermentation steps into a simultaneous process conducted under alkaline pH conditions. By combining these operations and using a multi-functional enzyme system that works under the same conditions, the process reduces the need for separate processing stages and pH adjustments, thereby managing complexity while achieving higher conversion of residual starch to fermentation products.
Solution Approach 2:
The alkaline pH environment serves multiple functions simultaneously: it activates cellulolytic enzymes, stabilizes the enzyme system, and prevents Maillard reaction formation. This self-service approach where the pH condition performs multiple roles reduces the need for additional process controls and interventions, managing complexity while improving productivity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This process increases fermentation product yield by effectively converting residual starch into ethanol, improving the overall efficiency of the fermentation process.
Implementation Method 1
liquefying the starch-containing material at a temperature above the initial gelatinization temperature using an alpha-amylase
Implementation Method 2
saccharifying using a carbohydrate-source generating enzyme
Implementation Method 3
fermenting using a fermenting organism
Implementation Method 4
a cellulolytic composition is present or added during fermentation or simultaneous saccharification and fermentation
Data Source
AI summary
The present invention relates to processes for producing fermentation products from starch-containing material, wherein an alpha-amylase and optionally a thermostable protease, pullulanase and/or glucoamylase are present and/or added during liquefaction, wherein a cellulolytic composition is present and/or added during fermentation or simultaneous saccharification and fermentation. The invention also relates to a composition suitable for use in a process of the invention.