Sterile Heterotrophic Bioreactor with Microporous Bubble Diffuser
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current bioreactors for heterotrophic algae growth lack sufficient sterility and are costly, with existing systems being expensive and energy-intensive, and they fail to maintain optimal oxygen levels due to inefficient gas exchange, leading to limited biomass and DHA production.
Innovation Solution
A sterile, cost-effective bioreactor system using a plastic reactor bag with integrated coupling devices and a bubble diffuser that generates micron-sized oxygen bubbles for uniform distribution, preventing bacterial contamination and ensuring continuous oxygen supply through microbubble formation and coalescence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional bioreactor systems are used for heterotrophic algae growth, then algae biomass production can be achieved, but sterility is insufficient leading to bacterial contamination
Solution Approach 1:
The bioreactor system performs preliminary sterilization by gamma irradiation before operation, and maintains sterility through a closed bag system with sterile filtration. This preliminary action ensures sterility is established before contamination can occur, resolving the contradiction between achieving high sterility and avoiding complex continuous sterilization systems.
2Productivity
If conventional gas exchange methods are used, then oxygen can be supplied to algae, but oxygen distribution is inefficient leading to limited biomass production
Solution Approach 1:
The system employs porous spargers that generate fine microbubbles for oxygen transfer. The porous structure creates numerous small bubbles with large total surface area, dramatically improving gas-liquid mass transfer efficiency and oxygen distribution throughout the culture medium, thereby enhancing biomass production without requiring excessive energy input.
3Ease of manufacture
If simple bag systems are used, then cost is reduced, but sterility and gas exchange efficiency are insufficient for heterotrophic growth
Solution Approach 1:
The system utilizes disposable sterile bags that are pre-sterilized and sealed. These single-use bags eliminate the need for complex sterilization infrastructure and can be replaced between runs, maintaining high sterility standards while keeping the overall system cost-effective and simple to manufacture.
Solution Approach 2:
Porous spargers are integrated into the simple bag system to provide efficient gas exchange. These porous components enable fine bubble generation and effective oxygen transfer, upgrading the performance of an otherwise simple and low-cost bag system to meet the requirements for heterotrophic algae growth.
4Productivity
If sunlight exposure is used for autotrophic growth, then algae can grow, but growth is limited by sunlight penetration at high culture densities
Solution Approach 1:
The system transitions from autotrophic (light-dependent) to heterotrophic (oxygen-dependent) growth mode by changing the fundamental growth parameter from light intensity to dissolved oxygen concentration. This parameter change allows growth to continue at high densities where light penetration becomes limiting, as oxygen can be efficiently supplied through the porous sparger system regardless of culture density.
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 bioreactor achieves high yield and quality algae biomass production with improved sterility and reduced operational costs, enabling efficient heterotrophic and mixotrophic growth while maintaining optimal oxygen levels.
Implementation Method 1
a bubble diffuser that generates micron-sized oxygen bubbles for uniform distribution
Implementation Method 2
The microporous bubble diffuser allows oxygen gas to pass through the porous material
Data Source
AI summary
A sterile bioreactor is formed of a combination of a bag and a bubble diffuser retained in the bag. The bubble diffuser is formed of a microporous sheet material that produces substantially uniform micro gas bubbles for enhancing plant organism growth within the bag. The bag is made in a cost-effective manner and with desired sterility by sealing coupling devices and/or ports, the tube ends sealed and gamma irradiated. The coupling devices/ports are established in one side wall of the bag. Contents may be inserted into and removed from the bag through the coupling devices/ports, which may be surface mounted portals.