eng Oriental Scientific Publishing Company Biosciences Biotechnology Research Asia 0973-1245 2016-06-10 11 Spl.Edn.1 279 289 10.13005/bbra/1421 11853 article N. Sri Kumaran 1-2 S. Bragadeeswaran 2 V. K. Meenakshi 3 Department of Marine Biotechnology, AMET University, Kanathur, Chennai - 603112, India. Faculty of Marine Science, Centre of Advanced Study in Marine Biology, Annamalai University, Parangipettai – 608 502, India. Department of Zoology, A. P. C. Mahalakshmi College for Women, Tuticorin - 628 016, India. The present study was carried for evaluate the antimicrobial properties of different solvent extracts of ascidian Didemnum granulatum against human, fish pathogenic and biofilm microbes. In this study anti microbial activities were carried out by standard disc diffusion method. In this experiment 50 human, fish bacterial, fungal pathogens and biofilm microbes were isolated and assayed against 7 different solvents such as methanol, acetone, ethanol, n-butanol, chloroform, ethyl acetate and dichloromethane. Each solvent assayed at different concentrations 25, 50, 75 and 100 mgmL-1. The ascidian extracts exhibits profound antibacterial activity against human, fish pathogens and biofilm microbes. The higher concentration of solvents showed higher inhibition of bacterial pathogens but the fungal pathogens show resistant to tested solvents. The ascidian D. granulatum could be an ideal candidate for antimicrobial lead molecule development against microbial pathogens. https://www.biotech-asia.org/vol11_nospl_edn1/in-vitro-assessment-of-antimicrobial-properties-in-different-concentration-crude-extracts-of-ascidian-didemnum-granulatum-tokioka-1954-against-isolated-human-fish-pathogenic-and-biofilm-microorganis/ Ascidian extracts; Human pathogen; Fish pathogen; Biofilm micoorganisms