Heterologous Bacterial Hemoglobin for Oxygen-Limited Fermentation

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Solution Overview

Problem

Industrial fermentations face challenges with oxygen limitation due to low solubility and high demand, leading to suboptimal growth and productivity in microorganisms, particularly in large-scale processes where improving bioreactor components and media can be costly and inefficient.

Innovation Solution

A genetic engineering approach is employed by introducing a library of heterologous bacterial hemoglobin genes into microbial hosts, linked to specific promoters, to enhance oxygen availability and productivity, allowing microorganisms to thrive in oxygen-poor conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If bioreactor components and media are optimized to improve oxygen delivery, then oxygen availability increases, but capital and operating costs increase

Engineering Contradiction:

Improveoxygen availabilityVSAvoidcapital and operating cost

Core Design Contradiction:

Quantity of substanceVSEase of manufacture

Solution Approach 1:

The patent changes the biological parameter of the microorganism by introducing heterologous bacterial hemoglobin genes, which alter the oxygen binding and transport properties at the molecular level. This genetic modification enables the microbe to utilize available oxygen more effectively without changing physical bioreactor parameters or media composition.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces mechanical oxygen delivery systems (bioreactor mixing, aeration equipment) with a biological solution (hemoglobin-based oxygen transport). Instead of mechanically forcing more oxygen into the system, the microorganism's intrinsic oxygen transport capacity is enhanced through genetic engineering.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Quantity of substance

If mixing rates and dispersion systems are improved to increase oxygen partial pressure, then oxygen delivery improves, but turbulence and shear rates increase producing undesirable rheological properties

Engineering Contradiction:

Improveoxygen partial pressureVSAvoidturbulence and shear rates

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent substitutes mechanical agitation and dispersion methods with a biological mechanism. Hemoglobin molecules within the microorganism bind and transport oxygen at the cellular level, eliminating the need for high-speed mixing and intense aeration that create turbulence and shear stress in the culture medium.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

Hemoglobin acts as an intermediary molecule that facilitates oxygen transport from the external environment to the microorganism's metabolic pathways. This molecular mediator enables efficient oxygen utilization without requiring harsh physical conditions or high shear rates in the bioreactor.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Quantity of substance

If culture media are modified to improve oxygen delivery, then oxygen availability increases, but growth rates become suboptimal

Engineering Contradiction:

Improveoxygen availabilityVSAvoidgrowth rate

Core Design Contradiction:

Quantity of substanceVSProductivity

Solution Approach 1:

The patent changes the physiological parameters of the microorganism through genetic modification, specifically enhancing its oxygen transport and utilization capabilities. This allows the organism to maintain optimal growth rates in oxygen-limited environments by improving its internal oxygen management rather than altering external media conditions.

Inventive Principle:

Principle #35Parameter changes

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 increases the partial pressure of oxygen within microbial hosts, leading to improved growth and productivity of biomolecules such as amino acids and organic acids, without the need for costly bioreactor modifications or media optimization.

Implementation Method 1

bacterial hemoglobin and/or flavohemoglobin genes... increasing the partial pressure of oxygen

Methodology Applied

Scientific EffectOxygen binding and transport:

Data Source

PatentUS10544390B2Methods for generating a bacterial hemoglobin library and uses thereof

Publication Date: 2020.01.28 ZYMERGEN INC

AI summary

The present disclosure describes methods for generating microbial strains expressing a heterologous bacterial hemoglobin gene that produce biomolecules of interest. In aspects, the disclosure provides novel bacterial strains, which express a heterologous bacterial hemoglobin gene whose expression is controlled by a native Corynebacterium glutamicum promoter or a mutant promoter derived therefrom. Also provided herein are methods for producing a library of bacterial hemoglobin genes using a promoter ladder comprising a plurality of promoters derived from Corynebacterium glutamicum.