Poly-3-hydroxyalkanoate Aggregation via Nitrogen Control
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Solution Overview
Problem
Industrial separation and purification of poly-3-hydroxyalkanoic acid (PHA) from microorganisms face challenges in achieving PHA particles with arbitrary volume mean particle diameter and low contaminants while minimizing organic solvent use and avoiding high temperature treatments or additive use.
Innovation Solution
Adjusting the organic nitrogen content in the aqueous suspension to not greater than 1,500 ppm through ninhydrin reaction, allowing PHA to aggregate at temperatures below its melting point without heating or using coagulants, using a solvent mixture of water and an organic solvent miscible with water.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If PHA particles are directly recovered as primary particles from aqueous suspension, then separation efficiency is improved, but fine powders increase making handling difficult
Solution Approach 1:
The patent applies preliminary action by controlling the organic nitrogen content to ≤1,500 ppm before the aggregation step. This preliminary purification of the aqueous suspension ensures that when PHA particles are subsequently aggregated and recovered, they form larger granules rather than fine powders, thereby solving the handling difficulty while maintaining separation efficiency.
2Productivity
If heating is applied to aggregate PHA particles, then aggregation is achieved, but molecular weight of PHA decreases due to heating to melting point
Solution Approach 1:
The patent applies parameter changes by controlling the organic nitrogen content parameter (≤1,500 ppm) in the aqueous suspension. This parameter control enables aggregation to occur at temperatures below the melting point of PHA, thus achieving both aggregation efficiency and molecular weight stability simultaneously.
3Productivity
If coagulants or polymeric additives are used to aggregate PHA, then aggregation is improved, but contamination of PHA with additives increases
Solution Approach 1:
The patent applies the taking out principle by removing contaminants (controlling organic nitrogen content to ≤1,500 ppm) from the aqueous suspension before aggregation. This extraction of impurities eliminates the need for coagulants or polymeric additives, thereby achieving aggregation while maintaining high PHA purity without additive contamination.
4Manufacturing precision
If high temperature treatment is applied to purify PHA, then purity is improved, but molecular weight reduction occurs
Solution Approach 1:
The patent applies preliminary action by controlling organic nitrogen content to ≤1,500 ppm as a preliminary purification step before aggregation. This preliminary purification achieves the required PHA purity without requiring subsequent high-temperature treatment, thereby maintaining molecular weight stability while ensuring product purity.
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 method enables the production of PHA agglomerates with superior productivity and reduced fine powders, preventing molecular weight reduction and contamination, and allowing for controlled particle size without the need for high-temperature treatments or additives.
Implementation Method 1
a method in which a PHA suspension is heated
Implementation Method 2
at a temperature not higher than the melting point of PHA
Implementation Method 3
allowing poly-3-hydroxyalkanoic acid to be aggregated in the aqueous suspension, thereby obtaining agglomerates of poly-3-hydroxyalkanoic acid
Data Source
AI summary
When industrially s e p arating and purifying poly-3-hydroxyalkanoic acid produced by a microorganism, to obtain poly-3-hydroxyalkanoic acid particles having an arbitrary volume mean particle diameter with favorable productivity and with decreased amount of an organic solvent used is enabled while decreasing contaminants derived from constitutive components of cellular bodies. According to the present invention, aggregated matter of poly-3-hydroxyalkanoic acid is obtained by adjusting the amount of organic nitrogen in an aqueous s suspension containing poly-3-hydroxyalkanoic acid to not greater than 1,500 ppm per weight of poly-3-hydroxyalkanoic acid; and thereafter allowing poly-3-hydroxyalkanoic acid to be aggregated in the aqueous suspension.