ISU Discovery Genetically Increases Algae Biomass by More Than 50 Percent

ISU algae researcher Martin Spalding

This story contains great news about an exciting Iowa State University discovery for genetically modifying biomass production from algae. Attached to this story, however, is an emphatic word of caution bout completely understanding and controlling the potential impacts of such genetic mutations.

According to the Iowa State University news service, research headed by Martin Spalding, professor in the Department of Genetics, Development, and Cell Biology, has led to discovery of a genetic method that can increase biomass in algae by 50 to 80 percent. To accomplish this feat, ISU researchers say they’ve unlocked a genetic pathway in algae that can dramatically increase the amount of CO2 consumed by the organisms, thus helping recycle more of the greenhouse gas and increasing oil yields for non-food based biofuels.

Spalding says the key to this increase in biomass is a combination of two genes that increase the photosynthetic carbon conversion into organic matter. The breakthrough comes from expressing certain genes in algae that increase the amount of photosynthesis in the plant, thus leading to more biomass.

“There is no doubt in my mind that this brings us closer [to affordable, domestic biofuel],” said Spalding. In natural settings, algae are limited from growing faster because they don’t get enough carbon dioxide from the atmosphere, according to Spalding.

In environments that have relatively low levels of carbon dioxide (CO2), such as air in earth’s atmosphere, two genes in algae, LCIA and LCIB, are expressed — or turned on — to help capture and then channel more carbon dioxide from the air into the cells to keep the algae alive and growing.

However, when algae are in environments with high carbon dioxide levels, such as in soil near plant roots that are expiring carbon dioxide, the two relevant genes shut down because the plant is getting enough carbon dioxide.

Research by Spalding’s group shows that algae can be made to produce biomass.

“Based on some prior research we had done, we expected to see an increase, probably in the 10 to 20 percent range” he said. “But we were surprised to see this big of an increase.”

In experiments to get the algae type (Chlamydomonas reinhardtii) to produce more biomass, Spalding first expressed LCIA and LCIB separately. Each effort granted a significant 10 to 15 percent increase in biomass.

When the two genes were expressed together, Spalding was surprised to see the 50 to 80 percent biomass increase.

“Somehow these two genes are working together to increase the amount of carbon dioxide that’s converted through photosynthesis into biomass by the algae under conditions where you would expect there would already be enough carbon dioxide,” said Spalding.

Spalding’s research was funded in part by grants from the Department of Agriculture’s National Institute of Food and Agriculture and the Department of Energy, Advanced Research Projects Agency – Energy.

As for words of caution, author Stephen Lacey writes, “Franken-algae may be key to reducing carbon emissions. But do they represent a different environmental threat?”

“While this research is promising for limiting carbon emissions and expanding biofuels, it’s not really new. Genetically modified algae are a key part of the “secret sauce” of companies like Sapphire Energy, Solazyme, Synthetic Genomics and TransAlgae, which are all toying with different genetic changes in order to increase oil production.

“But what if these organisms — which can very easily leave the lab on clothing, skin or through the air — escape into the natural environment and contaminate the gene pool of wild algae and dramatically increase growth rates?”

Ever-vigilant caution must be practiced as scientific developments move forward.
ISU photo by Bob Elbert