CO2 pH Adjustment in Cholinium Ionic Liquid Biomass Pretreatment
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Solution Overview
Problem
Current biomass pretreatment methods using ionic liquids face challenges such as low biocompatibility, inhibition of enzymatic activity, and microbial growth, requiring extensive water washes or specialized enzyme mixtures, and pH adjustment methods lead to salt accumulation and high costs.
Innovation Solution
A method involving the use of biocompatible ionic liquids like cholinium lysinate and carbon dioxide to adjust pH, allowing for a one-pot pretreatment and saccharification process without the need for water washes or specialized enzymes, using CO2 to lower the pH and facilitate enzymatic breakdown of biomass.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If imidazolium based ionic liquids are used for biomass pretreatment, then pretreatment effectiveness is improved, but biocompatibility deteriorates causing enzyme inhibition and microbial growth inhibition
Solution Approach 1:
The patent changes the chemical parameters of the ionic liquid by switching from imidazolium-based ILs to cholinium-based ILs (such as cholinium lysinate). This parameter change maintains pretreatment effectiveness while improving biocompatibility, allowing commercial enzymes and wild-type microbes to function without extensive washing or specialized enzyme mixtures.
2Ease of operation
If pH adjustment is performed using conventional acids (HCl, H2SO4, H3PO4, or organic acids), then pH matching between pretreatment and saccharification is improved, but salt accumulation and separation cost increase
Solution Approach 1:
The patent uses CO2 as a temporary, easily removable pH adjustment agent. CO2 dissolves in the aqueous cholinium lysinate solution to form carbonic acid, lowering the pH to match saccharification requirements. After saccharification, CO2 can be removed by sparging or heating, avoiding permanent salt accumulation from conventional acids.
3Object-affected harmful factors
If extensive water washes are performed to remove ionic liquids, then biocompatibility is improved, but process complexity and water consumption increase
Solution Approach 1:
The patent uses cholinium-based ionic liquids that are inherently biocompatible and do not require extensive water washes to remove. The cholinium ions are recognized as safe by regulatory agencies and do not inhibit commercial enzymes or wild-type microbes, allowing the IL to remain in the system throughout the entire process without separation steps.
4Reliability
If specialized enzyme mixtures are used to tolerate ionic liquids, then enzymatic activity in presence of IL is improved, but cost and enzyme complexity increase
Solution Approach 1:
The patent changes the ionic liquid type from imidazolium-based to cholinium-based, which fundamentally alters the interaction with enzymes. Cholinium-based ILs do not denature or inhibit commercial cellulase and hemicellulase mixtures, allowing the use of standard, cost-effective enzymes without requiring specialized IL-tolerant enzyme formulations.
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 approach enables efficient saccharification and fermentation of biomass with high yields of glucose and xylose, eliminating the need for extensive washing and specialized enzymes, while reducing costs and environmental impact by avoiding salt accumulation and enabling direct fermentation with wild-type hosts.
Implementation Method 1
contacting the first solution and carbon dioxide such that the first solution results in a lower pH
Implementation Method 2
introducing an enzyme capable of enzymatically to breakdown at least one bond in the polysaccharide
Implementation Method 3
a microorganism that capable of producing the enzyme and/or fermenting the polysaccharide or a breakdown product of the polysaccharide
Data Source
AI summary
The present invention provides for a method of fermenting or saccharifying a biomass comprising: (a) (i) contacting a biomass comprising a polysaccharide, and an ionic liquid (IL) to form a first solution, or (ii) providing the first solution comprising the biomass and the IL, (b) contacting the first solution and carbon dioxide such that the first solution results in a lower pH, (c) introducing (i) an enzyme capable of enzymatically to breakdown at least one bond in the polysaccharide or a breakdown product of the polysaccharide, and/or (ii) a microorganism that capable of producing the enzyme and/or fermenting the polysaccharide or a breakdown product of the polysaccharide, such that the polysaccharide is at least partially broken down and the first solution is transformed into a second solution.