Recombinant Yeast Protease Expression for Nitrogen-Limited Fermentation

Solution Overview

Problem

Saccharomyces cerevisiae's limited ability to generate a nitrogen source during fermentation slows down the process, requiring exogenous nitrogen sources like urea, which increases costs and reduces fermentation efficiency in ethanol production.

Innovation Solution

Expression of heterologous proteases in recombinant yeast host cells, such as Saccharomyces cerevisiae, to enhance fermentation rates, increase ethanol yields, and decrease glycerol production, using genetic modifications to introduce and optimize nucleic acid sequences for protease expression.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If exogenous nitrogen sources such as urea are added to improve fermentation, then nitrogen availability increases, but production costs increase

Engineering Contradiction:

Improvenitrogen availabilityVSAvoidproduction cost

Core Design Contradiction:

Quantity of substanceVSEase of manufacture

Solution Approach 1:

The yeast strain is genetically modified to express heterologous proteases that enable it to autonomously hydrolyze protein in the mash and generate free amino nitrogen internally, eliminating the need for external nitrogen supplementation and associated costs

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The yeast is pre-engineered with heterologous protease expression capabilities before fermentation begins, allowing it to immediately access nitrogen from protein sources in the mash without requiring exogenous nitrogen additions during the process

Inventive Principle:

Principle #10Preliminary action

2Productivity

If commercial proteases are added to increase fermentation rate, then free amino acid availability improves, but production costs increase

Engineering Contradiction:

Improvefermentation rateVSAvoidproduction cost

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

The yeast strain is genetically modified to express heterologous proteases that enable it to autonomously hydrolyze protein in the mash and generate free amino nitrogen internally, eliminating the need for external nitrogen supplementation and associated costs

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The function of commercial protease addition is merged into the yeast genome itself, with the yeast expressing the protease activity it needs directly, eliminating the separate step of adding commercial enzymes

Inventive Principle:

Principle #5Merging (Combining)

3Productivity

If fermentation efficiency is improved by nitrogen supplementation, then ethanol production increases, but process complexity increases

Engineering Contradiction:

Improveethanol yieldVSAvoidprocess complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The yeast strain is genetically modified to express heterologous proteases that enable it to autonomously hydrolyze protein in the mash and generate free amino nitrogen internally, eliminating the need for external nitrogen supplementation and associated costs

Inventive Principle:

Principle #25Self-service

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 recombinant yeast host cells with heterologous proteases improve fermentation efficiency, reducing the need for external nitrogen sources and lowering production costs while increasing ethanol yield and minimizing glycerol formation.

Implementation Method 1

the heterologous protease is capable of hydrolyzing a protein, such as, for example, zein

Methodology Applied

Scientific EffectProteolysis: Hydrolysis

Implementation Method 2

Saccharomyces cerevisiae is used in the commercial production of distilled spirits and fuel ethanol. This organism is proficient in fermenting glucose to ethanol

Methodology Applied

Scientific EffectAlcoholic fermentation: Fermentation

Data Source

PatentUS20260002143A1Heterologous protease expression for improving alcoholic fermentation

Publication Date: 2026.01.01 DANSTAR FERMENT AG

AI summary

The present disclosure relates to proteases for improving alcoholic fermentation. The proteases are expressed from a recombinant host cell. The present disclosure also provides a population of recombinant host cells expressing an heterologous protease that can be used in combination with recombinant host cells expressing an heterologous glucoamylase and/or an heterologous glycerol reduction system.