PHA Isolation via Sodium Hypochlorite Lysis and Dimethyl Carbonate Extraction
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Solution Overview
Problem
Current methods for isolating polyhydroxyalkanoate (PHA) from bacterial biomass face challenges such as the use of undesirable halogenated solvents, high energy consumption, and complex solvent combinations, which hinder efficient and environmentally friendly recovery processes.
Innovation Solution
A method involving the treatment of PHA-rich bacterial biomass with sodium hypochlorite for lysis, followed by water and methanol washing, and extraction with dimethyl carbonate (DMC), culminating in PHA precipitation using a cold non-solvent, which minimizes solvent usage and environmental impact while maintaining PHA quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If halogenated solvents are used for PHA extraction, then extraction efficiency is improved, but environmental harm increases
Solution Approach 1:
The patent changes the chemical parameters of the extraction system by replacing halogenated solvents with non-halogenated alternatives (such as esters, ethers, or supercritical fluids). This parameter change maintains extraction efficiency while eliminating the harmful environmental effects associated with halogenated compounds, directly resolving the contradiction between productivity and environmental harm.
Solution Approach 2:
The patent employs solvents that are environmentally benign and can be easily degraded or disposed of without causing long-term environmental damage. These short-living, non-persistent solvents replace traditional halogenated solvents, allowing efficient extraction while avoiding the accumulation of harmful substances in the environment.
2Productivity
If traditional solvent extraction methods are used, then PHA recovery is achieved, but energy consumption increases
Solution Approach 1:
The patent utilizes phase transition phenomena, particularly in supercritical fluid extraction where the solvent transitions between supercritical and gaseous phases. This phase change allows for efficient PHA recovery without the need for high-energy evaporation steps required by traditional liquid solvents, thereby maintaining productivity while reducing energy consumption.
Solution Approach 2:
The patent replaces mechanical energy-intensive processes (such as high-temperature evaporation and extensive washing) with alternative mechanisms such as supercritical fluid expansion and compression. This substitution reduces reliance on thermal energy while maintaining effective PHA recovery through controlled phase transitions and solvent property changes.
3Manufacturing precision
If multiple solvents are used for PHA extraction, then extraction completeness is improved, but process complexity increases
Solution Approach 1:
The patent employs a universal solvent or solvent system that can extract multiple PHA types and compositions effectively with a single agent. This multi-functional solvent replaces the need for multiple specialized solvents, achieving complete extraction while simplifying the process by eliminating the need for sequential extraction steps and multiple solvent handling procedures.
Solution Approach 2:
The patent combines the extraction and washing functions into a single solvent system, where one solvent performs both extraction of PHA and removal of contaminants. This merging of functions achieves complete extraction while reducing process complexity by eliminating separate washing steps and reducing the number of unit operations required.
4Loss of time
If biomass is not washed before extraction, then process time is reduced, but PHA purity decreases
Solution Approach 1:
The patent introduces a pre-treatment intermediary step that prepares the biomass for extraction by removing surface contaminants and opening cell structures. This intermediary treatment ensures that the subsequent extraction achieves high purity in a single step, eliminating the need for multiple washing operations and thereby reducing overall process time while maintaining or improving PHA purity.
Data Source
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Figure 3A~3C
AI summary
The present invention relates to a method for isolating polyhydroxyalkanoate (PHA) from a PHA-rich bacterial biomass, to the PHA isolated by said method and to a PHA having specific properties. The method comprises treating an aqueous suspension of the PHA-rich bacterial biomass with a minimal amount of sodium hypochlorite, a methanol wash and extraction of PHA from the biomass with dimethyl carbonate (DMC).