Substrate properties as controlling parameters in attached algal cultivation

There is growing interest in attached algae cultivation systems because they could provide a more cost- and energy-efficient alternative to planktonic (suspended algae) cultivation systems for many applications. However, attached growth systems have been far less studied than planktonic systems and have largely emphasized algae strains of most interest for biofuels. New algal biorefinery pathways have assessed the commercial potentials of algal biomass beyond biofuel production and placed more emphasis on value-added products from that biomass. Therefore, algal strain selection criteria and biomass cultivation methods need to be updated to include additional strains for improved efficiency. One possible way of improving attached cultivation systems is through engineering substrate surface characteristics to boost algal adhesion and enable strain selective algal colonization and growth. This review explores the effect of substrate chemical and topographical characteristics on the cultivation of attached algae. It also highlights the importance of considering algal community structure and attachment mechanisms in investigating attached algae systems using the example of filamentous algae found in algal turf scrubber (ATS™) systems. Key points • Attached algal cultivation is a promising alternative to planktonic cultivation. • Performance increase results from tuning surface qualities of attachment substrates. • Attachment adaptation of periphytic algae has innate potential for cultivation.