The growth of filamentous microalgae is increased on biochar solid supports

Growth of filamentous microalgae and filamentous cyanobacteria can be enhanced when porous substrates are introduced into photobioreactors as solid supports. In this study, a biochar was tested as a solid support for cultures of Klebsormidium flaccidum and Anabaena cylindrica using BG11 culture medium, and their growth was compared with cultures without solid support. After 20 days of incubation with a 16:8 (light: dark) photoperiod, dry biomass and total carbon and nitrogen contents were determined in cultures of these microalgae with and without carbonaceous solid supports. Growth of A. cylindrica was enhanced by 80% in the presence of biochar as compared to the cultures without biochar. Also, the total nitrogen content of the material harvested from the solid support cultures with A. cylindrica was enhanced by about 10%. Scanning Electron Microscopy (SEM) images showed biofilm formation on the surface of the biochar with extension of the filaments attached to the external surfaces.