Gene Deletion Boosts Ethylene Yield in Cyanobacteria
Removing glycogen synthesis forces cells to redirect carbon flow, impacting growth and enzyme efficiency.
Updated on Oct. 27, 2026 in Life Sciences
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Researchers have genetically modified Synechocystis sp. PCC 6803 by deleting the glgC gene to redirect carbon flow toward ethylene production. This research-stage study reveals that while removing glycogen synthesis creates metabolic bottlenecks, it successfully increases the activity of the ethylene-forming enzyme (EFE).
Why it matters
By forcing cyanobacteria to divert carbon away from energy storage, scientists are exploring how to maximize the synthesis of bio-based chemicals. This study highlights the inherent trade-offs between cell growth and high-yield product output in metabolic engineering.
The study utilized a light intensity gradient ranging from 35 to 300 μmol photons m-2 s-1 to measure growth rates and ethylene yield. Researchers found that deleting the glgC gene triggers inorganic phosphate limitation, which subsequently activates photoprotection pathways.
The players
Synechocystis sp. PCC 6803
A model strain of cyanobacteria widely used in biotechnology research for studying photosynthesis and carbon metabolism.
The details
The EFE enzyme functions by converting 2-oxoglutarate, a central metabolite, into ethylene, but this process competes with the GS-GOGAT-phosphate cycle, which is essential for nitrogen assimilation. By deleting glgC, the enzyme responsible for glycogen synthesis, the researchers forced the cells to channel excess carbon and reducing power into this ethylene-forming pathway. The resulting strain experiences stunted growth due to the continuous drain on 2-oxoglutarate levels within the cellular metabolic node.
Timeline
October 2026: Study findings were published in a peer-reviewed repository.
The Tech Race
This work advances efforts to optimize cyanobacterial cell factories by targeting glycogen storage to improve yield. It follows a known pattern of balancing metabolic rerouting against the growth-inhibiting side effects of high-level chemical production.
This development currently exists only at the research stage and does not impact commercial industrial bio-manufacturing. Future viability will depend on balancing the observed trade-offs between cell health and the efficiency of the ethylene-producing enzymes.
The takeaway
The research demonstrates that redirecting metabolic pathways can increase target chemical output but often at the cost of overall organism viability. Readers should watch for future studies addressing these growth constraints, as they are critical for moving this technology from lab-scale to production-scale facilities.
Further reading
Learn more about the latest research in Life Sciences.
More information
View the complete biorxiv research publication for detailed data.
Source note: This article includes information reported by Biorxiv.
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