Use of microalgal or cyanobacterial culture to remediate waste-streams and produce biomass or bioproducts at minimal cost requires selecting an appropriate strain/strains and optimizing growth conditions. However, there is no widely used metric that allows comparison of the responses of different organisms or the variation in response of a single organism to different growth conditions. Optimal candidate organisms and conditions can be assessed explicitly by comparisons of the quantum yields of production. In the simple case of optically-thin, photosynthetic cultures, this is derived from spectral light absorption and attenuation and the specific growth rate. In the case of metabolic products with significant commercial value (protein, omega-3 fatty acids, carotenoids, anti-microbials etc.), it also requires specification of the biomass quota of the target constituent. The approach can be expanded to mixotrophic growth by considering the effects of mixotrophy on light absorption, growth rate, and internal resource partitioning. We illustrate the combined lab and modelling approach with examples of biomass and high-value compounds from organisms in photoautotrophic vs mixotrophic culture. The mixotrophic cultures were grown on media amended with high-nutrient wastes from food industries (whey permeate from cheese production; processing waste from fisheries; and vinasse from distillation).

Primary Presenter: Hugh MacIntyre, Dalhousie University (hugh.macintyre@dal.ca)

Authors:

Cat London, Dalhousie University  (Cat.London@dal.ca)

Tatyana Bouffard-Martel, Dalhousie University  (tt718656@dal.ca)

Griffin Finkbeiner, Dalhousie University  (Griffin.Finkbeiner@dal.ca)

Suzanne Budge, Dalhousie University  (Suzanne.Budge@Dal.Ca)