Engineered Bacteria for Nitrogen Fixation in Non-Legumes
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Solution Overview
Problem
Current methods fail to efficiently provide nitrogen to non-leguminous plants, such as corn, wheat, and rice, under nitrogen-limiting conditions and in the presence of oxygen, which is essential for sustainable agriculture to meet the growing global food demand.
Innovation Solution
Genetically engineered Klebsiella variicola and Kosakonia sacchari bacteria are used to increase atmospheric nitrogen fixation in plants by modifying genes regulating nitrogen fixation and assimilation, allowing them to colonize plant roots and fix nitrogen even in fertilized fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If genetically engineered bacteria are used to fix nitrogen under nitrogen limiting conditions, then nitrogen fixation efficiency is improved, but bacterial ability to function in presence of oxygen deteriorates
Solution Approach 1:
The patent modifies bacterial genes to change the oxygen sensitivity parameters of nitrogen fixation enzymes, allowing them to function at higher oxygen concentrations than naturally occurring systems. This involves altering the oxygen tolerance threshold of the nitrogenase enzyme system through genetic engineering.
Solution Approach 2:
The patent introduces intermediary protective mechanisms, such as oxygen-scavenging enzymes or protective proteins, that act as mediators between the oxygen environment and the oxygen-sensitive nitrogen fixation enzymes, allowing both conditions to coexist.
2Adaptability or versatility
If genetically engineered bacteria colonize multiple rhizosphere niches, then colonization capability is improved, but competition with native bacteria worsens
Solution Approach 1:
The patent engineers bacteria with different local adaptations for different rhizosphere niches, such as varying adhesion properties, metabolic capabilities, or environmental tolerances that allow colonization of specific microenvironments (aerobic vs. anaerobic zones, root surface vs. root interior) without uniform competition across all niches.
Solution Approach 2:
The patent divides the rhizosphere into multiple niches and assigns different bacterial strains or functional capabilities to each niche, reducing direct competition by spatial and functional segmentation of the bacterial population.
3Use of energy by moving object
If conventional nitrogen fixation methods are used, then energy consumption is reduced, but nitrogen availability to non-leguminous plants deteriorates
Solution Approach 1:
The patent employs self-service mechanisms where the bacteria autonomously sense nitrogen availability and environmental conditions, then automatically regulate their nitrogen fixation activity without external energy input or human intervention, optimizing the balance between energy consumption and nitrogen production.
Solution Approach 2:
The patent creates universal bacterial systems that can fix nitrogen for multiple types of plants including non-leguminous crops, making the nitrogen fixation capability broadly applicable across different plant species and agricultural systems without requiring plant-specific engineering.
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 genetically engineered bacteria effectively increase atmospheric nitrogen availability in plants, reducing the need for chemical fertilizers and enhancing plant growth under various nitrogen conditions.
Implementation Method 1
N2 must be combined with hydrogen to be utilized. This process of combining of hydrogen with N2 is referred to as nitrogen fixation. Nitrogen fixation, whether accomplished chemically or biologically, requires an investment of large amounts of energy. In biological systems, the enzyme known as nitrogenase catalyzes the reaction which results in nitrogen fixation.
Data Source
AI summary
Methods and systems are provided for generating and utilizing a genetically engineered bacterium comprising a modification in a gene regulating nitrogen fixation or assimilation, wherein the modification in the gene regulating nitrogen fixation or assimilation results in one or more of: constitutive expression of a nifA gene in nitrogen limiting and non-nitrogen limiting conditions, activity of nifA in non-nitrogen limiting conditions, decreased uridylyl-transferase activity of GlnD, decreased adenylyl-removing activity of GlnE, and increased ammonium excretion.