Protease Mixture for Starch Ethanol Yield and Nitrogen Reduction
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Solution Overview
Problem
Current methods for biological ethanol production from starch-containing materials face challenges in increasing ethanol yield, reducing glycerol production, and improving fermentation rates, while also requiring high nitrogen supplementation.
Innovation Solution
The use of a combination of aspartic and serine proteases during saccharification and fermentation processes enhances ethanol yield, reduces glycerol production, and improves fermentation rates by providing peptides and free amino acids as nutrients for ethanol-producing host cells, potentially reducing the need for supplemental nitrogen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional processes (liquefaction and saccharification) are used to produce fermentable feedstocks from starch, then high glucose content (>90%) is achieved, but ethanol yield and production rate are limited
Solution Approach 1:
The patent applies parameter changes by modifying the enzymatic hydrolysis conditions - using a combination of alpha-amylase and glucoamylase at optimized temperatures and pH levels to enhance starch conversion efficiency. This results in improved ethanol production rates and yields while maintaining high glucose content in the fermentable feedstock.
2Productivity
If nitrogen supplementation is increased to support microbial fermentation, then fermentation capability is improved, but process cost and complexity increase
Solution Approach 1:
The patent implements self-service by utilizing the starch-containing material itself as a nitrogen source through controlled enzymatic hydrolysis. The partial hydrolysis of starch releases nitrogen-containing compounds that can be directly utilized by the fermenting microorganisms, eliminating or reducing the need for external nitrogen supplementation and simplifying the overall process.
3Manufacturing precision
If glycerol production is reduced to improve ethanol purity, then ethanol quality is enhanced, but microbial metabolic efficiency may be affected
Solution Approach 1:
The patent applies parameter changes by optimizing fermentation conditions including temperature, pH, and oxygen levels to steer microbial metabolism toward ethanol production while minimizing glycerol formation. By carefully controlling these parameters, the process achieves high ethanol purity without significantly compromising fermentation efficiency.
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
The combined protease approach increases ethanol production rates and yields, decreases glycerol production, and lowers nitrogen requirements, thereby optimizing the ethanol production process from starch-containing materials.
Implementation Method 1
The combined use of an aspartic protease and a serine protease during a starch to ethanol fermentation process increases the ethanol yield
Implementation Method 2
heating whole ground grain (or a starch slurry) to temperatures in excess of 95° C. in the presence of alpha-amylase (a process known as 'liquefaction')
Implementation Method 3
followed by cooling, pH adjustment, and subsequent glucoamylase hydrolysis (a process known as 'saccharification'), wherein such conventional process can produce fermentable feed stocks containing, e.g., greater than 90% glucose
Implementation Method 4
fermenting the material obtained in step (b) with an ethanol production host under suitable conditions for the production of ethanol
Data Source
AI summary
The instant disclosure is generally related to microbial fermentation, grain processing and ethanol production. Certain embodiments of the disclosure are therefore related to starch-containing materials and the microbial fermentation of such starch-containing materials for the production ethanol. More particularly, certain embodiments are related to novel protease mixtures for use in processing such starch-containing materials in starch to ethanol fermentation processes described herein.