This talk describes the surface and colloid properties that affect the interactions between the attached filamentous green alga Stigeoclonium and polymeric substrates. Algae are increasingly seen as a promising sustainable raw material for numerous applications including environmental remediation, biofuels, pharmaceuticals, cosmetics, animal feed, human food, fertilizer, industrial enzymes, and bioplastics. However, dewatering costs and lack of understanding of how to increase the yield of specific alga with the optimum chemical composition for a given application remains to be a challenge in the field. To date, much of the focus has been on cultivating suspended colloidal microalgae. Alternatively, dewatering costs can be dramatically reduced by cultivating attached filamentous alga which can grow meters in length. However, the complexities of shape and size dispersity and specialized attachment mechanisms make understanding the interaction of this type of algae with surfaces more complex than typical microbial-surface interactions. As a result, the scientific understanding to effectively design substrates for the growth of specific filamentous alga is lacking. In this work, a Data Physics OCA 50 was used to measure contact angles and surface energies on polylactic acid (PLA), nylon, and polyethylene terephthalate glycol (PETG) substrates used for Stigeoclonium cultivation. An Anton Paar SurPass electrokinetic analyzer was used to measure the zeta potential of these surfaces. Methods for measuring these parameters on solid surfaces are well established, but understanding the thermodynamic interactions requires developing methods for obtaining algae properties. This talk highlights the practical considerations that are important in developing methods for meaningful measurement of filamentous algae’s physicochemical properties. The results of can be used to obtain further insights into the results of algal growth studies. They can also be used in modeling the thermodynamic interactions between these complex biological materials and surfaces with xDLVO theory and other approaches. This will enable achieving the ultimate goal of including physicochemical characteristics as design parameters and enhancing the efficiency of attached algal cultivation.

Investigating the effect of thermodynamic surface characteristics on attached growth of filamentous algae Stigeoclonium

ACS Fall 2021

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