Associated bacteria of <i>Botryococcus braunii</i> (Chlorophyta)

Abstract

<i>Botryococcus braunii</i> (Chlorophyta) is a green microalga known for producing hydrocarbons and exopolysaccharides (EPS). Improving the biomass productivity of <i>B. braunii</i> and hence, the productivity of the hydrocarbons and of the EPS, will make <i>B. braunii</i> more attractive for industries. Microalgae usually cohabit with bacteria which leads to the formation of species-specific communities with environmental and biological advantages. Bacteria have been found and identified with a few <i>B. braunii</i> strains, but little is known about the bacterial community across the different strains. A better knowledge of the bacterial community of <i>B. braunii</i> will help to optimize the biomass productivity, hydrocarbons, and EPS accumulation. To better understand the bacterial community diversity of <i>B. braunii</i>, we screened 12 strains from culture collections. Using 16S rRNA gene analysis by MiSeq we described the bacterial diversity across 12 <i>B. braunii</i> strains and identified possible shared communities. We found three bacterial families common to all strains: <i>Rhizobiaceae</i>, <i>Bradyrhizobiaceae</i>, and <i>Comamonadaceae</i>. Additionally, the results also suggest that each strain has its own specific bacteria that may be the result of long-term isolated culture.