Association between algal productivity and phycosphere composition in an outdoor Chlorella sorokiniana reactor based on multiple longitudinal analyses

Summary Microalgae as a biofuel source are of great interest. Bacterial phycosphere inhabitants of algal cultures are hypothesized to contribute to productivity. In this study, the bacterial composition of the Chlorella sorokiniana phycosphere was determined over several production cycles in different growing seasons by 16S rRNA gene sequencing and identification. The diversity of the phycosphere increased with time during each individual reactor run, based on Faith’s phylogenetic diversity metric versus days post‐inoculation (R = 0.66, P
Microalgae can be efficiently cultivated to produce biomass suitable for conversion to liquid biofuels. Long term experiments conducted over multiple growing seasons in the arid Southwest region of the United States revealed significant associations between algal productivity and the bacterial members of the culture phycospheres. These species offer targets for improving algal biomass yields in mass cultivation.