Extraction and Antimicrobial Evaluation of Buffer Extracts of Marine Invertebrate Donax cuneatus M. Arputha Bibiana, C. Sherlina Daphny, M. Umamageshwari, P. Selvamani and S. Latha Department of Pharmaceutical Technology, Anna University, BIT Campus, Tiruchirappalli-620024 e-mail: arputha_bibiana@yahoo.com Abstract: Five different phenotypes of the marine edible bivalve Donax cuneatus were collected from the coastal area of Cuddalore, 11°46’N latitude, 79°45’E longitude, Tamil Nadu, India. The fve species were named as S1, S2, S3, S4 and S5 and were homogenized for crude protein with buffers Tris Hcl, Tris base and Phosphate Buffer in three range of pH (4.5, 7.4 and 9.0). The crude protein was further partially purifed by ammonium sulfate precipitation method the precipitate was diluted and stored in -20°C until antimicrobial evaluation. All the crude buffer extracts showed promising activity against highly pathogenic organisms considerably. The acidic and alkaline extract of S4 sample showed maximum zone of inhibition against Gram positive Staphylococcus sp and Gram negative Bacillus sp. The phenotypes S3 and S5 also inhibit the growth of pathogens in considerable ranges. The protein concentration was 1.0 mg/ml in S4. The SDS PAGE analysis confrms the presence of proteins by colored bands in the gel and FTIR analysis showed the presence of the protein in the crude bivalve extract by their identifed functional groups. INTRODUCTION Ocean has plenty of organisms which are being used as medicine. Among the marine sources the marine invertebrates belonging to category bivalves and crustaceans are large sized and are commonly consumed as edible food sources by the coastal area people of India [1, 2]. The rich proteins, glycogens and minerals present in them are naturally built as defenders of microbial infections. The marine ecosystem was enriched with tremendous of invertebrate species that are still unexplored for their property as biopharmaceuticals. The amazing property of invertebrates is the innate immunity developed within them to act against many infectious agents rather than active immunity [3, 4]. This property of marine invertebrates was the main attention for most of the researchers to explore the marine invertebrates for antimicrobial peptides against the human microbial pathogens [5]. Antimicrobial peptides are defned as the compounds of molecular weight below 10 kDa with antimicrobial properties of rapid response against microbial infections. The specifc physicochemical nature of antimicrobial peptides lies within them is the hydrophilic and hydrophobic regions all over the surfaces irrespective of their structure and size [6, 7]. The switching of pathogenic strains from sensitive to resistant forms was being a major challenge for the scientists in search of new antibiotics. In this regard the research is now greatly focused upon exploring the marine sources for developing it into antimicrobial pharmaceuticals. As marine sources are highly proteinaceous in nature the proteins inbuilt within them plays a lead role in immunity. Identifying the antimicrobial effect of such proteins may helps to develop new biopharmaceuticals for the serious problem of antimicrobial resistance [11-13]. The main aim of the present study is to identify the effective antimicrobial properties of the proteins extracted from the edible marine bivalve.