Project 12: Marinobacter as an algal panacea

Frederick de Boever has been appointed researcher for this project based at SAMS. In conjunction with the expertise of staff at CNRS in Roscoff, Frederick’s work is focussed on the specific contribution Marinobacter make to their algal host growth and survival, the proteins Marinobacter secrete and other functions that are believed to play a role in these interactions. As part of this project, a specific aim of Frederick’s work will be to isolate and characterise the extracellular bacterial proteome of Marinobacter (and/or Alteromonas) grown in co-culture with Nannochloropsis in both proteome analysis and bioinformatics. His research is also examining the effects of different Marinobacter grown in co-culture with Nannochloropsis on the growth rates and productivity of Nannochloropsis and whether Marinobacter block algicidal activity on other bacteria.

Frederick’s work is also aimed at generating Marinobacter gene knockouts to identify key functions important to the algae symbiosis (e.g. motility, secretion systems, PQQ production and inhibition of algicidal activity (e.g. QS and QQ). Frederick will have the opportunity to go on secondment to CNRS to undertake aspects of his research.

Nannochloropsis is a commercially important micro-algal species, and recent work at SAMS has shown that bacteria (Marinobacter) can be beneficial to Nannochloropsis and can block the adverse activity of contaminating bacteria (Alteromonas). This suggests that Nannochloropsis cultivation may benefit from having the ‘right’ type of bacteria present. This work showed that Marinobacter were a promising candidate bacterial taxa for this role, as this genus is very frequently found to be associated with algae, including Nannochloropsis, where it has shown to be beneficial to the algal host.

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Growth curves of N. oceanica, N. oculata, FDB33 and FDB36 co-cultures. a, Growth of (gray) axenic N. (oceanica left; N. oculata right) with Alteromonas sp. FDB36 (red), Marinobacter sp. FDB33 (blue) and FDB33+FDB36 (purple). b, Bacterial abundance in the respective cultures quantified by counting colony forming units

Growth curves of N. oceanica, N. oculata, FDB33 and FDB36 co-cultures. a, Growth of (gray) axenic N. (oceanica left; N. oculata right) with Alteromonas sp. FDB36 (red), Marinobacter sp. FDB33 (blue) and FDB33+FDB36 (purple). b, Bacterial abundance in the respective cultures quantified by counting colony forming units