Fusion Polypeptides for Cellulose Saccharification

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Solution Overview

Problem

Current methods for converting lignocellulosic feedstocks into ethanol are inefficient due to the difficulty in effectively degrading cellulose, a key component of these materials, which limits the production of fermentable sugars.

Innovation Solution

Development of polypeptides with cellobiohydrolase activity, specifically variants of the T. byssochlamydoides GH7 polypeptide, that can efficiently hydrolyze cellulose, enabling the conversion of cellulose into fermentable sugars for ethanol production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional methods are used to convert lignocellulosic feedstocks into ethanol, then the process is simple and straightforward, but the efficiency of cellulose degradation and sugar production is low

Engineering Contradiction:
Improvecellulose degradation efficiencyVSAvoidenzyme system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent creates a fusion protein that combines cellobiohydrolase and beta-glucosidase activities into a single enzyme molecule. This multi-functional enzyme can simultaneously perform cellulose chain breakdown and cellobiose hydrolysis, eliminating the need for separate enzyme systems and improving overall cellulose degradation efficiency.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The invention merges two separate cellulolytic enzymes (cellobiohydrolase and beta-glucosidase) into a single fusion protein. This combining of enzyme functions into one molecular entity allows coordinated action on cellulose substrates, improving productivity while managing system complexity through unified enzyme architecture.

Inventive Principle:
Principle #5Merging (Combining)

2Productivity

If multiple cellulolytic enzymes are used to effectively degrade cellulose, then the saccharification efficiency improves, but the cost and complexity of the enzyme system increases

Engineering Contradiction:
Improvesaccharification efficiencyVSAvoidnumber of enzymes required
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The fusion protein encompasses multiple enzymatic functions within a single molecule, including cellobiohydrolase activity for processive cellulose degradation and beta-glucosidase activity for cellobiose hydrolysis. This multi-functionality achieves high saccharification efficiency while reducing the number of separate enzyme components needed.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

By combining cellobiohydrolase and beta-glucosidase into one fusion protein, the patent reduces the enzyme system from multiple separate components to a single integrated enzyme. This merging maintains high saccharification efficiency while simplifying the overall enzyme system architecture.

Inventive Principle:
Principle #5Merging (Combining)

3Quantity of substance

If conventional cellulose degradation methods are used, then the process is straightforward, but the production of fermentable sugars is limited

Engineering Contradiction:
Improvefermentable sugar productionVSAvoidconversion efficiency
Core Design Contradiction:
Quantity of substanceVSProductivity

Solution Approach 1:

The fusion protein's dual enzymatic activities enable complete cellulose hydrolysis to glucose in a single enzymatic system. The cellobiohydrolase portion generates cellobiose units while the beta-glucosidase portion immediately converts them to glucose, maximizing fermentable sugar production with improved conversion efficiency.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The fusion protein structure enables continuous enzymatic action where cellobiose produced by the cellobiohydrolase domain is immediately processed by the beta-glucosidase domain. This continuous action eliminates intermediate accumulation and maximizes the conversion of cellulose to fermentable sugars, improving both quantity and efficiency.

Inventive Principle:
Principle #20Continuity of useful action

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 use of these polypeptides significantly enhances the degradation of cellulose, increasing the efficiency of converting lignocellulosic materials into ethanol by improving the saccharification process and reducing the need for additional cellulolytic enzymes.

Implementation Method 1

Cellobiohydrolases sequentially release molecules of cellobiose from the ends of the cellulose polymer

Methodology Applied
Scientific EffectHydrolysis: Hydrolysis

Implementation Method 2

The present invention provides polypeptides having cellobiohydrolase activity

Methodology Applied
Scientific EffectEnzyme: Enzyme

Implementation Method 3

Beta-glucosidases hydrolyze cellobiose to glucose

Methodology Applied
Scientific EffectHydrolysis: Hydrolysis

Data Source

PatentUS11203746B2Polypeptides having cellobiohydrolase activity and polynucleotides encoding same
Publication Date: 2021.12.21 NOVOZYMES INC

AI summary

The present invention relates to isolated polypeptides having cellobiohydrolase activity and isolated polynucleotides encoding the polypeptides. The invention also relates to nucleic acid constructs, vectors, and host cells comprising the polynucleotides as well as methods of producing and using the polypeptides.