The role of substrates towards marine diatom Cylindrotheca fusiformis adhesion and biofilm development

Microalgal biofilms can be a nuisance as surface foulants, especially in the marine environment; however, these biocoatings have practical application especially in biofilm cultivation systems to mitigate the limitations of microalgal suspension culture systems. Numerous works with regard to the modulation of extrinsic factors to study biofilm adhesion were found; however, they lack insight in the ubiquitous cell-substrate interactions which primarily govern cell adhesion in response to the surrounding environments. Thus, this work intended to shed light on the development of microalgal biofilm on four different pristine surfaces (plain drawing paper, polypropylene fabric, polyethylene plastic, and polyvinylidene fluoride flat sheet membrane) and to investigate the extent of microalgal substances resistance against disruption under liquid flow. The findings showed that algal biomass adhesion varied significantly with substratum type. The abundant hydrophilic polysaccharides extracted from Cylindrotheca fusiformis contributed the most to biofilm development for all substrata tested, while hydrophobic proteins analyzed from polypropylene fabric managed to retain biofilm structure though they are present in a much smaller amount. Extended Derjaguin, Landau, Verwey, and Overbeek (XDLVO) model revealed that the biofilm adhesion was mostly controlled by Lewis acid-base interactions (hydrophobic) in high ionic strength solution, while with the hydrokinetics present in the cultivation system showed the importance of pore size and surface roughness of substrata. It was demonstrated that materials with higher surface roughness and hydrophobicity, like plain drawing paper and polypropylene fabric, managed to provide a stronger biofilm attachment profile.

Automated summary

The study found significant differences in algal biomass adhesion on different substrata, with hydrophilic polysaccharides playing a crucial role in biofilm development. The XDLVO model revealed that biofilm adhesion in high ionic strength solution was mainly controlled by Lewis acid-base interactions, while in the cultivation system, the importance of substrata pore size and surface roughness was highlighted. Materials with higher surface roughness and hydrophobicity, such as plain drawing paper and polypropylene fabric, were shown to provide a stronger biofilm attachment profile.