Adding glucose to a green microalga culture induces accumulation of fatty acids and other valuable bioproducts.
Algae can make dramatic shifts in their metabolism in response to changes in their environment. Some microscopic green algae stop photosynthesizing and start accumulating fats and other valuable molecules when certain changes happen. However, scientists don’t know the details of those swift metabolic changes. A team examined a green microalga to better understand this process. After a few days of feeding this microbe sugar, it completely dismantled its photosynthetic apparatus while accumulating fat. In contrast, after the team stopped feeding it sugar, the microbe returned to its normal metabolism.
Algae could be a sustainable source of biofuels and other valuable chemicals. As they trap carbon dioxide from the air by photosynthesis, they convert greenhouse gases into oils and other useful industrial products. Scientists need to know how algae control their metabolism to engineer strains that can make desirable products. This study showed that feeding glucose (sugar) to this alga affects one-third of its genes. This extensive catalog of affected genes opens the door to identify and manipulate critical genes that will dramatically increase oil production along with other tailored bioproducts.
Microalgae can produce large quantities of valuable oils and other chemicals, but their tight metabolic regulation poses a challenge for engineering these organisms for industrial-level production of biofuels and bioproducts. Using a variety of imaging and genomics technologies, a team from the University of California and national laboratories determined that only a few days after adding glucose to a culture of the green alga Chromochloris zofingiensis growing in the light, algal cells accumulate large amounts of the biofuel precursors triacylglycerols, as well as economically important products such as carotenoids. Further, they observed that photosynthesis shut off and the photosynthetic apparatus disappeared, while the overall culture biomass increased. At the same time, nearly one-third of the genes in the genome changed their expression during these growth and metabolic alterations. The researchers also discovered that these changes were readily reversed when they removed the glucose from the culture. Elucidation of the pathways that lead to high accumulation of those biofuels and bioproducts will allow scientists to engineer algae as sustainable biofactories.
U.S. Department of Energy Office of Science, Office of Biological and Environmental Research
Biological Systems Science Division (SC-23.2)
Foundational Genomics Research and Biosystems Design
University of California, Berkeley
Krishna K. Niyogi
University of California, Berkeley
This research was supported by the Office of Biological and Environmental Research within the U.S. Department of Energy (DOE) Office of Science. The authors acknowledge work performed by the DOE Joint Genome Institute (a DOE Office of Science user facility), the DOE Joint BioEnergy Institute, and the National Center for X-ray Tomography. The cryo-soft X-ray tomography was supported by the Photosynthetic Systems program in the Office of Basic Energy Sciences within the DOE Office of Science. The authors also acknowledge funding and support from the U.S. Department of Agriculture National Institute of Food and Agriculture, the National Institutes of Health, the National Science Foundation, and the Howard Hughes Medical Institute.
Roth, M. S., S. D. Gallaher, D. J. Westcott, et al. “Regulation of oxygenic photosynthesis during trophic transitions in the green alga Chromochloris zofingiensis.” The Plant Cell 31, 579–601 (2019). [DOI:10.1105/tpc.18.00742].
University of California, Los Angeles news release: Discovery of an alga’s ‘dictionary of genes’ could lead to advances in biofuels, medicine
SC-33.2 Biological Systems Science Division, BER
BER supports basic research and scientific user facilities to advance DOE missions in energy and environment. More about BER
Jan 11, 2022
No Honor Among Copper Thieves
Findings provide a novel means to manipulate methanotrophs for a variety of environmental and in [more...]
Dec 06, 2021
New Genome Editing Tools Can Edit Within Microbial Communities
Two new technologies allow scientists to edit specific species and genes within complex laborato [more...]
Oct 27, 2021
Fungal Recyclers: Fungi Reuse Fire-Altered Organic Matter
Degrading pyrogenic (fire-affected) organic matter is an important ecosystem function of fungi i [more...]
Oct 19, 2021
Microbes Offer a Glimpse into the Future of Climate Change
Scientists identify key features in microbes that predict how warming affects carbon dioxide emi [more...]
Aug 25, 2021
Assessing the Production Cost and Carbon Footprint of a Promising Aviation Biofuel
Biomass-derived DMCO has the potential to serve as a low-carbon, high-performance jet fuel blend [more...]
List all highlights (possible long download time)