‘Vampire’ algae killer threatens to make important biofuels useless

23 Jul 2019

Image: © chokniti/Stock.adobe.com

A ‘vampire’ algae killer that sucks the life out of biofuels could scupper efforts to wean ourselves off fossil fuels.

Over the past few years, researchers have been working to develop renewable biofuels, particularly from algae, that could be used as an alternative to polluting fossil fuels. However, researchers in the US Department of Energy and Los Alamos National Laboratory have warned that a surprising genetic diversity in a bacterium poses a grave threat to algae’s future.

In a paper published to Phycological Research, scientists described how this bacterium, with the evocative name Vampirovibrio chlorellavorus, is a predatory pest that sucks out the contents of algae cells. In doing so, it turns a productive, thriving, green algae pond into a large vat of useless, rotting sludge.

“DNA sequences show what are likely different species, suggesting a much larger diversity in this family than we originally assumed,” said Blake Hovde, a Los Alamos National Laboratory biologist. “That means the treatment for one algae pest might not work for another, which can be a big problem for large-scale algae cultivation in the future.”

As part of the research, two strains of the bacterium from the same pond were sequenced, each collected one year apart from the other. The biologists then sequenced and analysed the genomes to identify the genes that play an integral part in the infection and cell death of the valuable chlorella algae that the bacterium targets.

“Our genomic analyses identified several predicted genes that encode secreted proteins that are potentially involved in pathogenicity, and at least three apparently complete sets of virulence genes,” Hovde added.

With chlorella considered a key source of harvestable biomass for biofuels and bioproducts, this research could be extremely important in bettering our understanding of how the bacterium and green algal host interact.

The researchers are now looking to characterise six more pest genomes from the same family to see if the organisms continue to expand or if they can start categorising these pests into species groups.

Colm Gorey was a senior journalist with Silicon Republic