Plants, algae and certain bacteria utilize photosynthesis to convert sunlight, water, and CO2 into oxygen and energy, which is the material basis for most biological activities on earth. However, their photosynthetic efficiency is low compared to theoretical values. Therefore, boosting this photosynthetic efficiency even a little above normal can translate to greatly increased growth and yield.
Cyanobacteria are a model organism for studying photosynthesis as they are easy to engineer, and share the energy bottlenecks ubiquitous to photosynthesis and respiration in many photosynthetic organisms. Further, cyanobacteria are frequently used industrially for their ability to produce value-added chemicals, nutraceuticals, biofuels, and more.
Researchers at Arizona State University have designed two distinct strategies to engineer the photosynthetic electron transport chain in cyanobacterium Synechocystis sp. PC 6803 to increase photosynthetic efficiency. The first approach is directed toward bringing certain components in closer proximity via linkers to reduce electron loss. The second approach is also aimed at reducing the proximity between certain components, but does so via increasing the membrane density of a specific protein complex.
These strains can serve as an excellent platform cell factory for metabolic engineering and production of various natural and/or heterologous products. Further, as these photosynthetic proteins and their arrangement is shared amongst the oxygenic photoautotrophs, the successful engineering strategy in Synechocystis may be effectively extended and implemented for crop plants, thereby increasing crop yield and productivity.
Potential Applications
- Engineered cyanobacteria
- For many industries including biofuels, biofertilizers, food, nutraceuticals, pharmaceuticals, pigments, cosmetics, etc.
- The strategy may be applied to other oxygenic photoautotrophs, such as plants or food crops
Benefits and Advantages
- Enhanced photosynthetic efficiency and improved growth
- Under different CO2 levels (1% being the highest level tested) and light conditions (low to high)
- Could exhibit improved photosynthetic efficiency and biomass accumulation even under outdoor cultivation at commercially feasible scales
- As photosynthetic light harvesting and carbon fixation is shared among all oxygenic photoautotrophs, these engineering strategies may be extended to plants or food crops
- The linker was designed such that the structure of adjoining functional proteins remains unaffected
- Facilitates leak-proof electron flow to improve biomass production over the non-engineered or wild-type strains
For more information about the inventor(s) and their research, please see