Protection of algae grown for biofuel using a consortium of environmentally harvested bacteria

Crop loss due to infection by pests and pathogens is a major barrier to the large-scale production of algal biofuels. Test systems have seen loss of green algae crops due to infection by the fungus-like Amoeboaphelidium occidentale FD01. While current antifungal compounds are effective in inhibiting the infection, their application raises the overall cost of the crop and lowers its economic viability as a biofuel source. Here we show that co-culturing environmentally harvested bacteria alongside algae crops can drastically lower the rate of infection in two different green algae species of interest for biofuel production. These bacteria-algae consortia increase the mean time to crop failure (MTTF) by up to 350% when tested under environmentally relevant conditions. While there was an increase in diversity over time, there was no statistically significant correlation between an increase in diversity and a longer MTTF. Community composition analysis reveals similarities between the bacterial genera growing alongside both green algae species even as bacterial harvest locations differed, although there was not a single dominant genus responsible for the increase in crop protection. These results show a promising new method of anti-fungal crop protection that can be applied to algal biofuels with no increase in fuel cost. HighlightsO_LIBacteria-algal cocultures protect against fungal pests without impact to productivity C_LIO_LIBacterial community composition is variable over time even as protection persists C_LIO_LIBacterial consortia can increase mean time to failure by 350% C_LI