Adhesion of Microalgae

Attachment of three organisms on perspex, glass, titanium, stainless steel, copper, aluminum brass and admiralty brass were studied.

Influence of surface roughness, pH of the medium, culture density, age, cell viability and the presence of organic and bacterial films on the attachment of Nitzschia amphibia was studied to find out factors which influence the attachment of this diatom on the surfaces.

Topic

Laboratory studies on adhesion of microalgae to hard substrates

Abstract

Adhesion of Chlorella vulgaris(chlorophyceae), Nitzschia amphibia(bacillariophceae) and Chroococcus minutus(cyanobacteria) to hydrophobic (perspex, titanium and stainless steel 316-L), hydrophilic (glass) and toxic (copper, aluminium brass and admiralty brass) substrata were studied in the laboratory.

The influence of surface wettability, surface roughness, pH of the medium, culture age, culture density, cell viability and presence of organic and bacterial films on the adhesion of Nitzschia amphibia was also studied using titanium, stainless steel and glass surfaces.

All three organisms attached more on titanium and stainless steel and less on copper and its alloys. The attachment varied significantly with respect to exposure time and different materials. The attachment was higher on rough surfaces when compared to smooth surfaces. Attachment was higher on pH 7 and above.

The presence of organic film increased the attachment significantly when compared to control. The number of attached cells was found to be directly proportional to the culture density. Attachment by log phase cells was significantly higher when compared to stationary phase cells. Live cells attached more when compared to heat killed and formalin killed cells. Bacterial films of Pseudomonas putida increased the algal attachment significantly.

Conclusion

Surface property (wettability and roughness) and composition of the material play an important role in microalgal attachment to its surface. The attachment was also found to be influenced by pH, organic film, culture age, culture density, cell viability and bacterial films. Though all the above mentioned factors were found to influence the algal attachment, further experiments are required to find out the mechanisms involved in the attachment process.

R. Sekar, V. P. Venugopalan, K. K. Satpathy, K. V. K. Nair & V. N. R. Rao

  • Water and Steam Chemistry Laboratory, Bhabha Atomic Research Centre Facilities, IGCAR Campus,
    Kalpakkam 603 102, India
  • Centre of Advanced Study in Botany, University of Madras, Guindy Campus, Chennai 600 025, India
  • Dept of Molecular Ecology, Max-Planck Institute for Marine Microbiology,  Germany

Keywords: adhesion, microalgae, biofilms, chlorophyceae, bacillariophyceae, cyanobacteria

Extracts

Microorganisms attach on all submerged surfaces in the aquatic environment which leads to formation of ‘biofilm’.

Characklis & Cooksey (1983)

Microalgae are one of the major components in the biofilm.

Cell surface hydrophobicity was a property aiding adhesion of cyanobacteria, similar to bacterial hydrophobicity.

Fattom & Shilo (1984)

Attachment was more on hydrophobic surfaces when compared to hydrophilic surfaces (glass).

Becker & Wahl (1991) and Becker (1996)

Though copper, aluminum brass and admiralty brass are relatively hydrophobic, the attachment on those substrata was poor, possibly due to their toxic nature.

The rough surfaces provide more surface area for attachment when compared to smooth surfaces.

Microalgae grow well in the pH range between 6 and 9. Attachment was favoured at pH 7 and above.

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