Chlorococcum sp. biofilm growth on biochar from olive kernels solid support

BACKGROUND: Biofilm is a complex community of microorganisms including microalgae, bacteria and protozoa, which are adhered to a surface. The purpose of an integrated microalgal processing system is the production of biofuels, biomass and other valuable bioproducts as well as wastewater remediation. Biochar is a carbon-rich and porous substrate, capable of adsorbing nutrients. RESULTS: In this study, biochar produced from olive kernels pyrolyzed at 400 degrees C was tested as a solid support candidate for adhering Chlorococcum sp. cultures. The substrate used was BG-11 with 1/3 nitrates and BG-11 without nitrates and phosphates. After 15 days of cultivation, the biomass attached to biofilm was measured, while different parameters were determined in the liquid. Among the different concentrations of biochar used, the culture containing 1 g L-1 biochar gave the best performance, resulting in 1.28 and 1.24 g microalgae g(-1) biochar in the presence and absence of nitrates, respectively. CONCLUSION: The cultures containing BG-11 without nitrogen and phosphorus showed leaching of nutrients in the liquid of the reactor. The present findings provide an alternative use of biochar, enhancing the growth of microalgae, and thus encouraging its use as supporting material in bioreactors. (c) 2023 Society of Chemical Industry (SCI).