Cyanobacterial biofilm can sustain green ethylene production for over a month.

 Cyanobacterial biofilm can sustain green ethylene production for over a month.

photo credit: cyanobacterial biofilm.

Photosynthetic microorganisms, like Cyanobacteria and algae, show potential for satisfying our demand for renewable chemicals and lessening the global dependence on fossil fuels. These microorganisms have the ability to utilize solar energy in converting CO2 into biomass and a different energy-rich organic compounds.

Ethylene is one of the most important organic commodity chemicals. It has a global demand of more than 150 million tons and is also the main building block in the production of plastics, fibres and other organic material. 

Associate Professor Allahverdiyeva-Rinne said "In our research, we employed the genetically engineered cyanobacterium synechocystis sp. PCC 6803 that expresses the ethylene-forming enzyme (EFE) acquired from the plant pathogen, Pseudomonas syringae. The presence of EFE in Cyanobacterial cells enables them to produce ethylene using solar energy and CO2 from air".

Ethylene is an attractive fuel source because it has a high energy density. Cyanobacteria have several limitations for efficient production.

"The possess a giant photosynthetic light-harvesting antenna that leads to self-shading and limited light distribution in suspension cultures, which decreases productivity. The greatest limitations is that the production period of the cells is short, only a few days," explains Associate Professor Allahverdiyeva-Rinne. 

Reasearches have found a solution by entrapping ethylene-producing cyanobacterial cells within thin-layer alignate polymer matrix. This improves light utilisation and limits cell growth strongly. As a result, the artificial biofilms achieved sustainable photoproduction of ethylene for up to 40 Days with a light-to-ethylene conversion efficiency that is 3.5 fold higher than in conventional suspension cultures.

Culled from STAFF WRITERS.