Acid-Stable Beta-Glucanases for Higher Fermentation Yields
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Solution Overview
Problem
Existing processes for producing fermentation products from starch-containing materials face challenges in degrading beta-glucans under acidic conditions, leading to reduced fermentation product yields, as not all known beta-glucanases perform well under these conditions.
Innovation Solution
Development of novel beta-glucanases with improved properties, including beta-1,6-glucanase and/or exo- and/or endo-beta-1,3-glucanase activities, which exhibit significant performance and stability under acidic conditions, allowing for efficient degradation of beta-glucans in starch-containing materials during fermentation processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional beta-glucanases are used in acidic conditions for fermentation product production, then the process can proceed under acidic pH conditions, but the degradation efficiency of beta-glucans is reduced leading to lower fermentation product yields
Solution Approach 1:
The patent modifies the biochemical parameters of beta-glucanase enzymes through protein engineering to alter their functional properties. Specifically, amino acid sequences are modified to enhance enzyme stability and catalytic activity under acidic conditions (pH 4-6), transforming conventional beta-glucanases into acid-stable variants that maintain high degradation efficiency during fermentation processes
Solution Approach 2:
The invention creates composite enzyme systems by combining multiple beta-glucanase variants with different functional characteristics. The enzyme blends include combinations of endo-beta-1,3-glucanases, exo-beta-1,3-glucanases, and beta-1,6-glucanases, each contributing specific degradation activities that synergistically improve overall beta-glucan breakdown under acidic conditions
2Stability of the object's composition
If existing beta-glucanase enzymes are used to degrade beta-glucans in starch-containing materials, then the process can be implemented, but the enzymes lack sufficient stability under acidic conditions required for fermentation
Solution Approach 1:
The patent systematically modifies enzyme parameters including amino acid sequence, secondary structure, and functional groups to enhance acid stability. Specific amino acid residues are mutated to be more tolerant of acidic environments, and the enzyme's structural conformation is optimized to maintain catalytic activity at pH 4-6 while resisting denaturation
Solution Approach 2:
The invention uses computational modeling and molecular docking to simulate and copy the successful structural features of acid-stable enzymes from extremophiles. The modeling process identifies conserved structural motifs and binding sites that confer acid stability, which are then replicated in engineered beta-glucanase variants through directed protein evolution
3Productivity
If conventional enzyme blends are used for starch hydrolysis and fermentation, then the process can proceed, but beta-glucan degradation is insufficient reducing fermentation product yield
Solution Approach 1:
The patent divides the beta-glucan degradation function into specialized enzymatic segments, with each enzyme variant responsible for specific bond types or structural regions. The enzyme blend is segmented into endo-acting enzymes for internal bond cleavage, exo-acting enzymes for terminal bond hydrolysis, and branching enzymes for 1,6-linkage degradation, allowing each component to be optimized independently
Solution Approach 2:
The engineered beta-glucanase variants are designed with multi-functional capabilities, able to hydrolyze multiple beta-glucan bond types (1,3-, 1,4-, and 1,6-linkages) and act on various substrate forms (crystalline cellulose, amorphous cellulose, beta-glucans in starch). This universal activity allows a single enzyme preparation to address multiple degradation challenges simultaneously
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 novel beta-glucanases enhance fermentation product yields by effectively degrading beta-glucans under acidic conditions, improving the efficiency of processes such as ethanol production from corn, even when used in recombinant host cells or via in situ expression.
Implementation Method 1
Enzymatic hydrolysis of cellulose to glucose requires the use of endo beta-glucanases (e.g. EC 3.2.1.4), cellobiohydrolases (e.g. EC 3.2.1.91) and beta-glucosidases (e.g. EC 3.2.1.21). Laminarinases can be used to catalyse the hydrolysis of the beta-1,3-glucosidic bonds
Data Source
AI summary
The present invention relates to isolated polypeptides having beta-glucanase activity, catalytic domains, carbohydrate binding modules and polynucleotides encoding the polypeptides, catalytic domains or carbohydrate binding modules. 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, catalytic domains or carbohydrate binding modules. The present invention further relates to processes for producing fermentation products from starch-containing or cellulosic-containing material, as well as an enzyme blend or composition, or a recombinant host cell or fermenting organism suitable for use in processes of the invention.