The bioreactor microbiome of mass cultivated marine diatoms for industrial carbon capture and utilization
Marine microalgae with effective photosynthetic carbon fixation can be harnessed for innovative carbon capture and utilization (CCU) biotechnologies that contributes to atmospheric CO2 reduction along emission mitigation. A non-axenic mass cultivation of microalgae in large CCU photobioreactors is also mass cultivation of cooccupant multikingdom microbial communities. Very little is known how the microbiome interacts with microalgae and affects the stability of CCU-specific operations. Semi continuous mass cultivation of the marine cold-water centric diatom Porosira glacialis UiT201 in an industrial scale CCU operation was combined with an investigation of the prokaryotic and microeukaryotic community compositions and temporal succession patterns. The data was collected across two consecutive time series experiments of which the first ended to a culture “crash” of the focal strain after 39 days and the second culture stayed “healthy” for 60 days as the P. glacialis kept its abundance and growth until the end. The large, vertical airlift CCU bioreactor comprised a complex and diverse microbial community, especially prokaryotes, along robust production of P. glacialis biomass. The co-occurring community dynamics and maintained growth conditions were distinct between the time series experiments. The culture collapse of P. glacialis occurred along changes in microbiome community structure and was caused by competition or antagonist interaction. The prokaryotic community succession was driven by strong contribution of species replacement i.e., turnover as a result of selective bioreactor environment and/or biological interactions. Nevertheless, the bioreactor harbors a reoccurring and abundant core microbiome suggesting that closely associated bacterial community is structured by microalgae-specific manner and can persist in a variable environment. The findings suggest that coinhabiting microbial taxa within industrial microalgae cultivation likely plays a critical role in stabilizing the conversion of industrial CO2 into marine biomass and the changes in community structure translates to signature of success or crash.