Microalgae Culture pH Control for Contaminant Inhibition
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Solution Overview
Problem
Conventional microalgae culture methods using neutral or alkaline culture liquids face challenges with pH variation due to CO2 introduction, leading to unwanted proliferation of other microalgae and protists, increasing culture costs and complexity.
Innovation Solution
A culture method using culture liquid with a pH of 4 or less, specifically for Coccomyxa and related genera, which inhibits the proliferation of other microalgae and protists by maintaining a stable pH and incorporating ammonia nitrogen like urea, preventing bicarbonate ion generation even with CO2 introduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If neutral or alkaline culture liquid is used for microalgae culture, then general microalgae can grow, but pH varies when CO2 is introduced causing proliferation of unwanted microalgae and protists
Solution Approach 1:
The patent changes the pH parameter of the culture liquid from neutral/alkaline to strongly acidic (pH 2-4), which fundamentally alters the chemical environment. This parameter change prevents bicarbonate ion formation when CO2 is introduced, thereby stabilizing the culture system and preventing proliferation of unwanted microalgae and protists that thrive in neutral or alkaline conditions
2Productivity
If CO2 is introduced to enhance microalgae growth, then productivity improves, but bicarbonate ion generation causes pH variation and culture instability
Solution Approach 1:
By changing the pH parameter to strongly acidic conditions (pH 2-4), the patent eliminates the chemical equilibrium that produces bicarbonate ions from CO2. In this acidic environment, CO2 remains dissolved without forming bicarbonate, thus maintaining pH stability while allowing continuous CO2 introduction to support high productivity
3Reliability
If pH adjustment is performed to maintain culture stability, then unwanted microalgae proliferation is inhibited, but culture costs and system complexity increase
Solution Approach 1:
The patent applies preliminary action by establishing strongly acidic conditions (pH 2-4) at the beginning of culture and maintaining this pH level throughout the culture process. This preliminary pH setting creates a stable environment that naturally prevents unwanted microalgae and protist proliferation, eliminating the need for continuous pH monitoring and adjustment operations
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 maintains high microalgae growth rates while preventing pH variation and unwanted microalgae proliferation, reducing culture costs through efficient nutrient reuse and simplified pH management.
Implementation Method 1
since the pH of the culture liquid is equal to or less than 4, it may be possible to inhibit proliferation of different microalgae and protist
Implementation Method 2
Since bicarbonate ion is not generated even when CO2 is introduced in the culture liquid, it may be possible to prevent variation of the pH of the culture liquid
Implementation Method 3
since the culture liquid includes ammonia nitrogen (for example, urea), it may be possible to inhibit proliferation of different microalgae and protist
Data Source
AI summary
A culture method for microalgae that cultures unicellular green microalgae belonging to the genus Coccomyxa and groups of organisms closely related thereto, or the Watanabea clade, in an open outdoor culture system using broth having a pH of 4 or lower. A culture method for microalgae that cultures microalgae of the genus Coccomyxa and groups of organisms closely related thereto, or Pseudococcomyxa, in an open outdoor culture system using broth having a pH of 4 or lower containing ammonia nitrogen.