Crystalline L-alanine Supersaturation Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The production of crystalline L-alanine from aqueous solutions, particularly those obtained through fermentation, faces challenges such as the formation of impure needle or rod-shaped crystals due to the presence of organic impurities like D-alanine and other α-amino acids, leading to poor filtration and high impurity levels, and resulting in unsatisfactory flow characteristics and storage properties.
Innovation Solution
A method involving controlled supersaturation of the L-alanine solution to achieve a concentration ratio of dissolved L-alanine to equilibrium solubility between 1:1 to 1.5:1, allowing for the crystallization of compact crystals with a low aspect ratio and reduced impurity levels, using a continuously operated crystallization apparatus to separate pure crystalline L-alanine from the mother liquor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If L-alanine is crystallized from aqueous solution containing α-amino acid impurities, then crystalline L-alanine is obtained, but needle or rod-shaped crystals with high aspect ratio are formed which are difficult to filter and contain large amounts of mother liquor
Solution Approach 1:
The patent applies parameter changes by precisely controlling the supersaturation ratio (c/c*) to specific ranges (>1:1 to 1.5:1, preferably >1:1 to 1.3:1, particularly >1:1 to 1.15:1) and maintaining controlled cooling rates (0.1-10°C/h). These parameter adjustments transform the crystal growth conditions to produce compact crystals with low aspect ratio instead of needle-shaped crystals, directly resolving the filtration difficulty while maintaining manufacturing precision.
Solution Approach 2:
The patent employs preliminary action by removing α-amino acid impurities before the crystallization process through preliminary purification steps. This pre-treatment prevents the formation of needle-shaped crystals caused by impurity interference, ensuring that the subsequent crystallization produces filterable compact crystals. The preliminary removal of D-alanine, L-valine, L-leucine, L-lysine, L-asparagine, L-glutamine, and L-arginine impurities eliminates the root cause of poor crystal morphology.
2Productivity
If L-alanine is isolated by spray drying from aqueous solution, then L-alanine powder is obtained, but amorphous solid powder with poor flow characteristics and storage properties is formed which undergoes caking
Solution Approach 1:
The patent applies parameter changes by controlling the crystallization supersaturation ratio and cooling rate to produce crystalline L-alanine with specific morphology (compact crystals, low aspect ratio). This phase transition from amorphous to crystalline form, achieved through controlled crystallization parameters, fundamentally improves storage stability and prevents caking while maintaining isolation efficiency.
Solution Approach 2:
The patent employs phase transitions by inducing controlled crystallization from the aqueous solution phase to the solid crystal phase. By carefully controlling the supersaturation ratio (c/c*) and cooling rate, the process transforms L-alanine from an amorphous solid (prone to caking) to a crystalline solid with stable flow and storage properties. The controlled phase transition ensures formation of compact crystals rather than amorphous powder.
3Quantity of substance
If conventional crystallization is used to obtain L-alanine, then solid L-alanine is obtained, but high impurity content remains due to spontaneous crystallization of supersaturated solutions
Solution Approach 1:
The patent applies parameter changes by precisely controlling the supersaturation ratio (c/c*) to specific ranges and implementing controlled cooling rates (0.1-10°C/h). These parameter adjustments prevent spontaneous crystallization and promote controlled crystal growth, which inherently excludes impurities from the crystal lattice. The result is high-purity crystalline L-alanine with maintained yield.
Solution Approach 2:
The patent employs preliminary action by removing α-amino acid impurities before crystallization through preliminary purification steps. This pre-treatment eliminates substances that would otherwise be incorporated into the crystal structure during spontaneous crystallization. By removing D-alanine, L-valine, L-leucine, L-lysine, L-asparagine, L-glutamine, and L-arginine impurities beforehand, the final product achieves high purity while maintaining quantitative yield.
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 method effectively produces compact crystalline L-alanine with a low aspect ratio and reduced impurity content, improving handling and storage properties by achieving a high purity level and specific particle size range, while minimizing the presence of impurities below 10% by weight.
Implementation Method 1
subjecting the aqueous solution of L-alanine to a crystallization by inducing conditions of a controlled supersaturation
Implementation Method 2
inducing in the solution of L-alanine conditions of a controlled supersaturation in a manner that the ratio c : c* of the concentration c of dissolved L-alanine to equilibrium solubility c* of L-alanine
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The present invention relates to a method for obtaining crystalline L-alanine from an aqueous solution of L-alanine, in particular from an aqueous solution of L-alanine, which is obtained from a fermentation process.