1st First Authored Paper: Alex Paquette on Microalgal Biofilms

A.J. Paquette, C.E. Sharp, P.J. Schnurr, D.G. Allen, S.M. Short & G.S. Espie (2020) Dynamic Changes in Community Composition of Scenedesmus-Seeded Artificial, Engineered Microalgal Biofilms. Algal Research 46: 101805.   https://doi.org/10.1016/j.algal.2020.101805

Alex did his M.Sc.  (2018) co-supervised by Prof. Steve Short and Prof.George Espie.

Artificial, non-sterile, microalgal biofilms present a promising biotechnological avenue for the production of valuable biomass, biofuels and biochemicals while simultaneously engaging in photosynthetic carbon capture. Here we used a psbA amplicon library and a high-throughput 16S and 18S rRNA gene sequencing approach to investigate the effects of time and CO2 concentration on the composition and community dynamics of photoautotrophically-grown microalgal biofilms pre-conditioned with wastewater and heavily seeded with the green alga Scenedesmus obliquus. While biomass increased in a stable, linear manner, our analysis revealed that the photoautotrophic community dramatically changed over time. Photoautotrophs such as Chorella and the cyanobacterium Leptolyngbya, presumably seeded from the wastewater, rapidly established as constituents of the biofilm while the seed species was far less dominant than anticipated. Low CO2 (0.04% v/v) favoured the early proliferation of cyanobacteria while high CO2 (12%) delayed, but did not prevent their proliferation. Principal coordinate analysis reveals unique clustering patterns indicating that the composition of the initial and the final microbial communities were distinctly different from one another. Most importantly, in spite of the planned experimental bias toward S. obliquus biofilm growth, the collective data suggest that selection against undesirable microorganism also needs to be incorporated as an essential feature of biofilm photobioreactor design and operation.

February 7, 2020