In vitro activity of nine cyanobacterial and ten microalgal newly isolated or culture collection strains against eight significant food-borne pathogens has been evaluated and compared. Water extracts and culture liquids of Gloeocapsa sp. and Synechocystis sp. demonstrated the widest spectrum of activity with minimal inhibitory concentration (MIC) ranging from 1.56 to 12.5 mg mL À1 . Culture liquid of Anabaena sp. had the highest activity (MIC = 0.39 mg mL À1 ) but only to Gram-positive bacteria. Ethanol extracts and fatty acids from all cyanobacteria and microalgae were active against Streptococcus pyogenes and/or Staphylococcus aureus. The fatty acids of Synechocystis sp. inhibited the growth of Bacillus cereus, Escherichia coli and Candida albicans (MIC values of 2.5-1.25 mg mL À1 , respectively). Exopolysaccharides (EPS) of Gloeocapsa sp. were the sample that exhibited activity against all test pathogens with lowest MIC values (0.125-1 mg mL À1 ). High activity with a narrower range of susceptible targets demonstrated the exopolysaccharides of Synechocystis sp. and Rhodella reticulata. Antimicrobial activity was proven for phycobiliproteins isolated from Synechocystis sp., Arthrospira fusiformis, Porphyridium aerugineum and Porphyridium cruentum, respectively. In conclusion Gloeocapsa sp. and Synechocystis sp. and especially their exopolysaccharides showed the most promising potential against the examined food pathogens.In vitro antimicrobial activity of microalgae H. Najdenski et al. ResultsSamples of all investigated cyanobacterial and microalgal strains were initially evaluated for antimicrobial activity by agar diffusion test. No biological activity of In vitro antimicrobial activity of microalgae H. Najdenski et al. 1539 In vitro antimicrobial activity of microalgae H. Najdenski et al.

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A rapid, inexpensive and reliable procedure for separation and purification of C-phycocyanin (C-PC) and allophycocyanin (APC) from Arthronema africanum based on a previously described rivanol-sulfate method for C-PC purification was developed. Exclusion of NaCl from the extraction buffer resulted in complete separation of APC and C-PC, two-fold reduction of rivanol treatments, and a higher yield and purity of C-PC. Pure C-PC (A(620)/A(280) of 4.52) and APC (A(652)/A(280) of 2.41) were obtained. The estimated molecular masses of the alpha and beta subunits were 17 and 19 kDsmall a, Cyrillic for capital ES, Cyrillic-phycocyanin and 16 and 18 kDsmall a, Cyrillic for APC, respectively. The overall C-PC recovery of 55% (w/w) from its content (100 mg) in the crude extract was 10-20% higher than so far reported. The procedure appears promising for scaling up and broader applications.