In vitro evaluation of antimicrobial activities from aqueous and methanolic extracts of cyanobacteria

In this present study, antimicrobial activities of aqueous and methanolic extracts of cyanobacteria against some of fungi and pathogenic bacteria were investigated. Cyanobacteria strains Fischerella ambigua ISC67 and Schizothrix vaginata ISC108 were cultured in BG-11 medium. Extraction was performed by adding the solvent to cyanobacterial biomass and then filtering and drying of the mixture. The antimicrobial activity was evaluated by disc diffusion method and broth microdilution method was applied to determine the minimum inhibitory concentration. The results show that the aqueous and methanolic extracts of F. ambigua has a significant antimicrobial effect while, the tested extracts of S. vaginata was no significant antibacterial and antifungal activity. Highest antibacterial activity from aqueous extract of F. ambigua was against S. aureus (PTCC 1112) which the average zone diameter around it was 33.33 mm. The antibacterial effect of aqueous extracts against Gram-positive bacteria was more than Gram-negative bacteria significantly. Antifungal activity showed that methanolic extract of F. ambigua have significant antifungal activity. Minimum inhibitory concentration of active extract against most tested bacterial and fungal was 125 mg/ml. The present study has proved that the aqueous and methanolic extracts of F. ambigua possessed strong antibacterial and antifungal properties against the pathogenic microorganism. Therefore, cyanobacteria can be a rich source for natural products with antimicrobial activity. DOI: http://dx.doi.org/10.5281/zenodo.346363

Production and optimization of polyhydroxybutyrate (PHB) from Bacillus megaterium as biodegradable plastic

Among biodegradable plastics polyhydroxy alkanate and its polymers have received more attention than other biodegradable polymers because of their complete degradability, flexibility, water resistance and also the ease of production process. Polyhydroxybutyrate is one of the types of polyhydroxy alkanates that is seen as a storage granule in many microorganisms. In this study, Bacillus megaterium was prepared from Iranian microbial collection. Glucose and yeast extract were used as the main components of the medium in seed media 9 and 2.5 g/l and in fermentation medium 30 and 7.5 g/l respectively. GC-MASS and FTIR were used to identify the PHB produced. The results showed that the highest amount of biomass (0.221 g/l) and PHB (0.080 g/l) were obtained with glucose at 37°C and shaker speed of 150 rpm for 72 h incubation. The results of GC MASS and FTIR showed the production of PHB by Bacillus under investigation. Based on the mean of data on total cell growth conditions, the rate of cell biomass and PHB production in B. megaterium were 0.0869 and 0.0171 respectively. According to the results of the experiments, temperature had the greatest effect on biomass production and PHB production. The bioplastics produced by microbes are also highly degradable in the environment, and due to their specific chemical structure, they have been widely used in various fields of the food, pharmaceutical and chemical industries and are likely to replace today's plastics in the near future. DOI: http://dx.doi.org/10.5281/zenodo.371140

In vitro evaluation of antimicrobial activities from aqueous and methanolic extracts of cyanobacteria

In this present study, antimicrobial activities of aqueous and methanolic extracts of cyanobacteria against some of fungi and pathogenic bacteria were investigated. Cyanobacteria strains Fischerella ambigua ISC67 and Schizothrix vaginata ISC108 were cultured in BG-11 medium. Extraction was performed by adding the solvent to cyanobacterial biomass and then filtering and drying of the mixture. The antimicrobial activity was evaluated by disc diffusion method and broth microdilution method was applied to determine the minimum inhibitory concentration. The results show that the aqueous and methanolic extracts of F. ambigua has a significant antimicrobial effect while, the tested extracts of S. vaginata was no significant antibacterial and antifungal activity. Highest antibacterial activity from aqueous extract of F. ambigua was against S. aureus (PTCC 1112) which the average zone diameter around it was 33.33 mm. The antibacterial effect of aqueous extracts against Gram-positive bacteria was more than Gram-negative bacteria significantly. Antifungal activity showed that methanolic extract of F. ambigua have significant antifungal activity. Minimum inhibitory concentration of active extract against most tested bacterial and fungal was 125 mg/ml. The present study has proved that the aqueous and methanolic extracts of F. ambigua possessed strong antibacterial and antifungal properties against the pathogenic microorganism. Therefore, cyanobacteria can be a rich source for natural products with antimicrobial activity. DOI: http://dx.doi.org/10.5281/zenodo.346363