Discover how the single-cell green alga Chromochloris zofingiensis, an emerging model organism, is shedding light on the complex interplay between photosynthesis, metabolism, and biofuel production. Researchers have uncovered a fascinating strategy that utilizes iron supplements and glucose to maintain photosynthesis while still accumulating valuable lipids.
Fine-Tuning Photosynthesis to Maximize Lipid Accumulation
A newly discovered single-cell green alga called Chromochloris zofingiensis has proved its importance in the overall research on photosynthesis and metabolism. In earlier studies, researchers discovered that in the presence of glucose, this alga ceases to photosynthesize and instead re-directs its metabolism to make copious amounts of lipid (the raw material for biofuels) and astaxanthin (a valuable anti-oxidant).
But now a group of scientists from the University of California, Berkeley, and the Environmental Molecular Sciences Laboratory (EMSL) has uncovered something unexpected. By giving the cells more iron and glucose, they could even partially rescue the alga’s photosynthetic capacity and preserve its thylakoid membranes – the important structures in which photosynthetic energy transfer takes place. Surprisingly, these cells still accumulated BNLs despite being grown in synthetic media with a drastically limited supply of lipids, suggesting new avenues for biofuel development.
Folding Back the Metabolic Spade
The researchers further examined the metabolic events that enable this spectacular achievement. With the power of proteomics from EMSL to assist, they were able to pierce into the intricate wiring responsible for how cells metabolize. This showed that the glucose-mediated repression of photosynthesis was due to a redirection of iron resources. The cells used the iron for respiration rather than channeling it to the photosynthetic complexes.
In addition, the researchers found that a ferredoxin-reliant desaturase pastime becomes important for selling lipid storage as opposed to thylakoid lipid synthesis Transmission electron microscopy images of the cells at different stages of photosynthesis and lipid accumulation provided a kinetic view of the thylakoid structure dynamics across the cells: e.g., starch and triglyceride production in the chloroplast as some cell cultures lost their capacity for lipid synthesis.
Conclusion
A new study taking a closer look at the well-known single-cell green alga, Chromochloris zofingiensis, reveals an unusual system that allows plants to maintain photosynthesis in tandem with concentrating valuable lipids — for biofuel programs. The study has revealed a novel way to fine-tune the tradeoff between these important cellular processes that now includes targeting iron and glucose synergistically. The unique findings have a basic research aspect to increase our grasp on the mechanisms behind photosynthesis and metabolism, as well as applicative potential in the field of bioenergy crop/bioproduct enhancement that can contribute to sustainable solutions.
