Lipid Production via Multi-Nutrient Limitation
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Solution Overview
Problem
Current methods for producing polyunsaturated fatty acids (PUFAs) in fermenters do not achieve optimal yields, as they typically rely on reducing only one limiting nutrient source, such as nitrogen or oxygen, without considering the simultaneous reduction of multiple essential nutrients.
Innovation Solution
A method involving a biomass density increasing phase followed by a lipid production phase where both nitrogen and phosphate sources are reduced, while maintaining a carbon source supply, to induce microorganisms to accumulate PUFAs, with the limiting nutrient concentrations falling below detectable levels for significant portions of the lipid production phase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If only one limiting nutrient source (e.g., nitrogen) is reduced to induce lipid production, then lipid accumulation is enhanced, but further yield improvement is limited
Solution Approach 1:
The nutrient limitation strategy is segmented into multiple distinct limiting nutrient sources (nitrogen, phosphate, and potentially other nutrients) rather than relying on a single limitation. This segmentation allows for staged or combined nutrient depletion, creating a more comprehensive stress response that drives enhanced lipid accumulation beyond what single nutrient limitation can achieve.
Solution Approach 2:
The invention changes the parameter of nutrient concentration by simultaneously reducing multiple limiting nutrient sources below detectable levels. This multi-parameter change (nitrogen < detectable, phosphate < detectable) creates a synergistic effect that pushes the metabolic state of microorganisms toward maximum lipid production, overcoming the plateau effect of single nutrient limitation.
2Quantity of substance
If multiple limiting nutrient sources are reduced simultaneously, then PUFA yields are significantly increased, but the process complexity increases
Solution Approach 1:
The fermentation medium formulation is designed with multi-functionality, where a single medium composition serves multiple purposes: it supports initial biomass growth and then enables sequential or simultaneous limitation of multiple nutrients (nitrogen, phosphate, and others) without requiring separate medium adjustments. This universal medium design simplifies the overall process despite the multi-nutrient limitation strategy.
Solution Approach 2:
The invention applies preliminary action by pre-formulating the fermentation medium with specific concentrations of multiple nutrient sources that are designed to be depleted in a controlled manner. The medium is prepared in advance with nitrogen, phosphate, and other nutrients at levels that will naturally create the desired multi-nutrient limitation scenario during fermentation, eliminating the need for complex real-time control mechanisms.
3Quantity of substance
If carbon source supply is maintained during nutrient limitation, then lipid accumulation is enhanced, but nutrient depletion time is extended
Solution Approach 1:
The carbon source supply is maintained continuously during the nutrient limitation phase to ensure uninterrupted lipid synthesis. While nitrogen and phosphate are depleted to undetectable levels, the continuous carbon supply keeps the metabolic machinery active, allowing microorganisms to convert available carbon directly into lipids without interruption, thereby maximizing lipid concentration despite the extended fermentation period.
Solution Approach 2:
The invention applies partial action by maintaining carbon source supply at levels sufficient for lipid production but not necessarily for complete biomass growth. This partial carbon feeding strategy provides just enough energy and carbon skeletons for lipid synthesis while the multi-nutrient limitation prevents excessive cell division, extending the fermentation time but ensuring high lipid concentration in the final product.
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 significantly increases PUA yields, with microorganisms producing at least 10 wt.% of their biomass as lipids, particularly enhancing the production of highly unsaturated fatty acids like EPA and DHA, by maintaining carbon source availability and controlling nutrient deprivation.
Implementation Method 1
which comprises a biomass density increasing phase and a lipid production phase, comprising adding during the biomass density increasing phase to a fermentation medium containing said microorganisms
Data Source
AI summary
The present invention is directed to a method of enhanced production of lipids by limitation of at least two limiting nutrient sources during the fermentation of the lipids producing cells.