The present study was conducted to investigate efficacy of unicellular microalga Scenedesmus obliquus either as solo culture or in combination with the bacterium Shewanella sp in removal of arsenic from aqueous media. For this purpose, pure culture of the microalga was fed with arsenic solution and removal rate was monitored. Moreover, impact of pH, temperature and initial biomass was studied. In the second phase, a consortium of S. obliquus- Shewanella was prepared and used to investigate the effect of bacterium presence in terms of removal enhancement. The results showed that pH 7.0, temperature of 29 oC and initial biomass of 0.8 g/L caused the highest rate of arsenic removal. Comparison of pure culture of S. obliquus and S. obliquus- Shewanella consortium revealed that the latter significantly enhanced removal efficacy.
phycoremediation, Scenedesmus obliquus, Shewanella sp, arsenic
Regarding the growing trend of multi-drug resistant strains of Staphylococcus aureus, the search for alternative and novel antimicrobial agent has been intensified. For this purpose, the present study was carried out to investigate the antagonistic effect of the brown seaweed Sargassum angustifolium on growth and virulence factors of S. aureus. A typical microdilution assay was performed to monitor inhibitory effect of S. angustifolium extraction on growth of the bacteria within a 6 hours period. Furthermore, Real-Time PCR assay with specific primers was conducted to evaluate the impact of extraction on expression of genes encoding staphylococcal enterotoxins (sea) and capsule formation (cap8). The results revealed that S. angustifolium extract inhibited bacterial growth in a dose-dependent way; so that bacterial growth was fully stopped at the end of the assay. Antibacterial effect was enhanced by increasing in S. angustifolium extraction concentration. The results of Real-Time PCR assay indicated seaweed extraction was able to decrease virulence genes expression significantly. Again, by increasing extraction concentration, stronger inhibitory effect was observed. As a whole, the findings of this study suggest that S. angustifolium extract has potent antimicrobial effect that can be used for development of new generation of anti-staphylococcal medicines.
Antimicrobial, Seaweed, Sargassum angustifolium, extraction, Staphylococcus aureus, Virulence factor.