Finnish researchers overcome cyanobacteria-based ethylene hurdle


In Finland, researchers at the University of Turku have created a cyanobacteria biofilm that produced ethylene—a major building block of the chemical industry—for more than a month.

The team genetically engineered cyanobacteria Synechocystis sp. PCC 6803 to produce ethylene by inserting a gene for ethylene-forming enzyme acquired from Pseudomonas syringae.

The only inputs were sunlight and carbon dioxide, but initial yields were low because the cyanobacteria prioritized biomass production. “[Cyanobacteria] possess a giant photosynthetic light-harvesting antenna that leads to self-shading and limited light distribution in suspension cultures, which decreases productivity. The greatest limitation is that the production period of the cells is short, only a few days,” UTurka Associate Professor Allahverdiyeva-Rinne, says in a statement.

To address this, researchers created a thin matrix of the algae, which limited cell growth and improved light utilization. The result was 3.5-times higher production for up to 40 days.

“Although very promising results have been reported on ethylene-producing recombinant cyanobacteria, the overall efficiency of the available photoproduction systems is still very low for industrial applications. The ethylene productivity of engineered cyanobacteria is the most critical variable for reducing the costs and improving efficiency,” adds Postdoctoral Researcher Sindhujaa Vajravel.

Renewable pathways to commonly used chemicals are seen as a key mitigator for global climate change.