Aerobic Fermentation Dissolved Oxygen Control via Segmented Feeding

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Solution Overview

Problem

Existing technologies face challenges in effectively controlling dissolved oxygen concentration in aerobic biosynthesis processes, particularly in maintaining it within a safe range that balances microbial productivity and safety, especially at elevated pressures and in non-stirred bioreactors.

Innovation Solution

A method for controlling dissolved oxygen concentration in continuous aerobic gas fermentation processes involves providing a microorganism to a fermenter, introducing at least two feed streams with one containing gaseous oxygen and another with a flammable gas, measuring oxygen concentrations, and regulating the oxygen mass transfer rate to maintain dissolved oxygen within optimal limits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If oxygen concentration is increased to maximise oxygen mass transfer and optimise productivity, then productivity is improved, but the gaseous oxygen concentration in the headspace exceeds the limiting oxygen concentration (LOC) for flammability

Engineering Contradiction:

ImproveproductivityVSAvoidflammability

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The oxygen feed stream is divided into multiple separate streams introduced at different locations within the fermenter. This segmentation allows oxygen to be distributed more evenly throughout the liquid phase, maximizing mass transfer to microorganisms while preventing excessive accumulation in the headspace gas phase, thus maintaining safety below the LOC

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention transitions from controlling only the bulk liquid oxygen concentration to also controlling the spatial distribution of oxygen throughout the fermenter volume. By introducing oxygen at multiple vertical positions, the system manages oxygen gradients in the vertical dimension, ensuring adequate supply to microbes while preventing headspace saturation that would create flammable conditions

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Productivity

If pressure is increased above atmospheric pressure, then oxygen solubility increases and productivity is improved, but control of dissolved oxygen and gaseous oxygen concentration becomes more difficult

Engineering Contradiction:

ImproveproductivityVSAvoidcontrol complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The system employs feedback control by continuously measuring dissolved oxygen concentration in the liquid phase and gaseous oxygen concentration in the headspace, then using these measurements to dynamically adjust oxygen feed rates and distribution. This dual-feedback approach enables precise control of both productivity-enhancing dissolved oxygen levels and safety-critical headspace oxygen levels under elevated pressure conditions

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The oxygen feed system is made dynamic by allowing continuous adjustment of oxygen flow rates and distribution patterns based on real-time measurements. Under elevated pressure, the system can dynamically respond to changing solubility conditions and microbial oxygen uptake rates, maintaining optimal dissolved oxygen levels while preventing dangerous headspace accumulation

Inventive Principle:

Principle #15Dynamics

3Productivity

If oxygen mass transfer rate is increased to meet microbial oxygen demand, then microbial growth and productivity are improved, but the gaseous oxygen concentration in the headspace approaches or exceeds the LOC

Engineering Contradiction:

Improvemicrobial growthVSAvoidgaseous oxygen concentration

Core Design Contradiction:

ProductivityVSQuantity of substance

Solution Approach 1:

By segmenting the oxygen feed into multiple streams at different locations, the system increases the total oxygen mass transfer rate to meet microbial demand while distributing the oxygen input throughout the liquid phase. This prevents excessive oxygen from reaching the headspace, thereby maintaining gaseous oxygen concentration below the LOC even at high productivity rates

Inventive Principle:

Principle #1Segmentation

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 approach allows for precise control of dissolved oxygen concentrations, ensuring optimal microbial growth and productivity while safely operating below the limiting oxygen concentration for flammability, thus enhancing process safety and efficiency.

Implementation Method 1

the rate of oxygen mass transfer from the gas phase to the liquid phase is a known rate-limiting step for most aerobic microbial biosynthetic reactions

Methodology Applied

Scientific EffectOxygen mass transfer: Absorption (physical)

Data Source

PatentUS12338428B2Materials and methods for managing aerobic gas fermentation

Publication Date: 2025.06.24 INV NYLON CHEMICALS AMERICAS LLC

AI summary

Disclosed are materials and methods for managing aerobic biosynthesis. The materials include a fermenter system comprising a fermenter, a microorganism provided to the fermenter, and at least two control loops. The methods are directed to measuring and controlling different oxygen concentrations within the fermenter.