PHA Recovery Process Using High-Pressure Homogenization
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Solution Overview
Problem
Current methods for recovering and purifying polyhydroxyalkanoates (PHA) from cell cultures are inefficient, costly, and environmentally problematic due to the use of organic solvents and batch processes, which can reduce the molecular weight of PHA and complicate large-scale processing.
Innovation Solution
A continuous process involving acidification of the cell culture to pH ≤ 6, followed by high-pressure homogenization, basification, tangential filtration, bleaching, and drying, which eliminates the need for organic solvents and reduces molecular weight degradation, allowing for high-purity PHA production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If organic solvents are used to solubilize PHA for removal from cells, then PHA can be extracted from cell walls, but the process becomes extremely costly and environmentally problematic due to high solvent viscosity requiring huge dilution amounts and complex recovery steps
Solution Approach 1:
The patent extracts and removes the harmful organic solvents from the process entirely, replacing them with water-based solutions. The cell wall destruction is achieved through alkaline treatment and mechanical action without requiring organic solvents, thus eliminating the extraction complexity and environmental problems associated with solvent recovery.
Solution Approach 2:
The patent changes the chemical parameters of the extraction medium from organic solvents to aqueous alkaline solutions. By adjusting pH and using water-based systems, the process achieves PHA extraction without the viscosity and recovery problems of organic solvents, fundamentally changing the extraction approach.
2Stability of the object's composition
If mechanical action is applied after alkalization to break cell membranes, then cell breaking is achieved, but PHA molecular weight is substantially reduced
Solution Approach 1:
The patent performs cell membrane disruption through mechanical action (homogenization) before applying alkaline treatment. This preliminary mechanical breaking opens cell walls to allow alkaline penetration and PHA solubilization without subjecting the already-weakened polymer to further mechanical stress that would reduce molecular weight.
Solution Approach 2:
The patent replaces subsequent mechanical action with chemical action (alkaline treatment) for completing cell wall destruction. After initial mechanical homogenization, the alkaline solution chemically dissolves cell wall components, achieving complete cell breaking without additional mechanical stress that would damage PHA molecular structure.
3Quantity of substance
If batch centrifugation is used to separate PHA from cell mass, then PHA can be separated, but the process becomes complex for large-scale operations and reduces productivity
Solution Approach 1:
The patent implements continuous tangential filtration instead of batch centrifugation. The filtration system operates continuously to separate PHA-containing solution from cell debris, eliminating the stop-start nature of batch processes and enabling sustained high-speed separation that improves overall productivity and simplifies large-scale operations.
4Stability of the object's composition
If high temperature and prolonged time are used for solubilization, then cell mass solubilization is achieved, but the process requires excessive energy and time
Solution Approach 1:
The patent changes the solubilization approach from high-temperature thermal treatment to low-temperature alkaline chemical treatment. By using strong alkaline solutions at moderate temperatures, the process achieves complete cell mass solubilization and PHA release without the excessive energy input required by high-temperature methods.
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 process achieves high-purity PHA with maintained molecular weight and increased yield, reducing environmental impact and operational costs by avoiding solvent use and batch centrifugation, enabling scalable and efficient production.
Implementation Method 1
adding an alkaline product under stirring and mechanical action for breaking the cell membranes
Implementation Method 2
mechanical action on the suspension carried out for example through an emulsifying device or a high pressure homogenizer
Implementation Method 3
adding an alkaline substance, for example a strong base, so as to obtain a pH value from 9 to 13.5
Implementation Method 4
adjusting the pH of the suspension to a value from 7 to 11
Implementation Method 5
separation of the solid PHA from the dissolved cell mass is obtained by prolonged high speed centrifugation (4000 g for 20 minutes)
Implementation Method 6
diluting the PHA suspension and submitting it to tangential filtration so as to obtain a concentrated PHA suspension as retentate and an aqueous phase as permeate
Implementation Method 7
treating the PHA thus obtained with an enzyme and/or a surfactant for solubilizing impurities contained in the PHA
Implementation Method 8
drying the solid PHA thus obtained
Data Source
AI summary
Process for recovering and purifying PHA from a cell culture, which comprises acidifying the cell culture so as to obtain a pH value equal to or lower than 6, and submitting said cell culture to a cell fractionation treatment by means of high pressure homogenization at a temperature from 10°C to 80°C, so as to obtain a PHA suspension. After the homogenization, the PHA suspension is basified up to obtain a pH value equal to or higher than 8, diluted and then subjected to tangential filtration. The PHA suspension is then bleached, diluted and again subjected to a tangential filtration. The product thus obtained is then dried. Such a process can be carried out continuously, without the use of organic solvents, and ensures that PHA is obtained in a pure form without causing a reduction in the molecular weight.