Disk Diffusion Assay to Assess the Antimicrobial Activity of Marine Algal Extracts

  • Andrew P. Desbois
  • Valerie J. Smith
Part of the Methods in Molecular Biology book series (MIMB, volume 1308)


Marine algae are a relatively untapped source of bioactive natural products, including those with antimicrobial activities. The ability to assess the antimicrobial activity of cell extracts derived from algal cultures is vital to identifying species that may produce useful novel antibiotics. One assay that is used widely for this purpose is the disk diffusion assay due to its simplicity, rapidity, and low cost. Moreover, this assay gives output data that are easy to interpret and can be used to screen many samples at once irrespective of the solvent used during preparation. In this chapter, a step-by-step protocol for performing a disk diffusion assay is described. The assay is particularly well suited to testing algal cell extracts and fractions resulting from separation through bioassay-guided approaches.

Key words

Antibacterial Antibiotic Bactericidal Bioassay-guided fractionation Natural products 


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Copyright information

© Springer Science+Business Media, New York 2015

Authors and Affiliations

  1. 1.Marine Biotechnology Research Group, Institute of Aquaculture, School of Natural SciencesUniversity of StirlingStirlingshireUnited Kingdom
  2. 2.Scottish Oceans Institute, School of BiologyUniversity of St AndrewsSt AndrewsUnited Kingdom

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