New insights into developing antibiofouling surfaces for industrial photobioreactors

Abstract

The biofouling formation of the marine microalga Nannochloropsis gaditana on nontoxic surfaces was quantified on rigid materials, both coated (with fouling release coatings and nanoparticle coatings) and noncoated, to cover a wide range of surface properties from strongly hydrophobic to markedly hydrophilic under conditions similar to those prevailing in outdoor massive cultures of marine microalgae. The effect of seawater on surfaces that presented the best antibiofouling properties was also evaluated. The adhesion intensity on the different surfaces was compared with the predictions of the biocompatibility theories developed by Baier and Vogler using water adhesion tension (τ 0 ) as the quantitative parameter of surface wettability. For the most hydrophobic surfaces, τ 0 ≤ 0, the microalgae adhesion density increased linearly with τ 0 , following the Baier's theory trend. However, for the rest of the surfaces, τ 0 ≥ 0, a tendency toward minimum adhesion was observed for amphiphilic surfaces with a τ 0 = 36 mJ/m 2 , a value close to that which minimizes cell adhesion according to Vogler's theory. The understanding and combination of the two biocompatibility theories could help to design universal antibiofouling surfaces that minimize the van der Waals forces and prevent foulant adsorption by using a thin layer of hydration. K E Y W O R D Santibiofouling, biocompability theory, fouling release coatings, microalga, photobioreactor

Long-term biofouling formation mediated by extracellular proteins in Nannochloropsis gaditana microalga cultures at different medium N/P ratios

“…were calculated, as was the change in the free energy of cohesion (ΔG iwi ), the water adhesion tension with the surface (τ o ) and the critical surface tension (γ ς ,) for each surface, as described earlier (Zeriouh et al, 2019a). Table 1 shows the values of the above parameters.…”

“…Biofouling represents a major limitation for the long-term culture of microalgae in photobioreactors (Zeriouh et al, 2019a;Zeriouh et al, 2017b). The ubiquity of cells and extracellular organic substances (EOS) secreted by microalgae in industrial photobioreactors (PBRs) creates a competition in both to colonize the PBR walls in contact with the culture.…”

“…A wide variety of anti-biofouling materials and coatings considered for use in PBRs has been studied (Talluri et al, 2020;Wang et al, 2017;Wang et al, 2020;Zeriouh et al, 2019a). All of them have failed to completely prevent long-term biofouling.…”

“…This work aims to evaluate the biofouling susceptibility of different materials and coatings immersed in cultures of the marine microalgaNannochloropsis gaditana , a species used as model in studies on biofouling formation in photobioreactors (Zeriouh et al, 2019a;Zeriouh et al, 2019b;Zeriouh et al, 2017a). As a first step, the surfaces were tested in short-term batch adhesion experiments with the model protein BSA (Wang et al, 2017).…”

Bioenergy from Microalgae – Vision or Reality?

“…A common problem featured by all of the above‐mentioned systems is the so‐far unsatisfying implementation of efficient temperature control and cleaning to avoid biofouling , which has a negative impact on productivity, preventing the microalgae technology from reaching its full potential. Cooling is frequently achieved by making use of evaporation after spraying the reactors with water.…”