Available online at www.derpharmachemica.com Scholars Research Library Der Pharma Chemica, 2013, 5(2):224-229 (http://derpharmachemica.com/archive.html) ISSN 0975-413X CODEN (USA): PCHHAX 224 www.scholarsresearchlibrary.com Antibacterial activity of algae mediated synthesis of gold nanoparticles from Turbinaria conoides S Rajeshkumar 1,2 , C Malarkodi 1 , M Vanaja 1 , G Gnanajobitha 1,2 , K Paulkumar 1 , C Kannan 2 * and G Annadurai 1 * 1 Environmental Nanotechnology Division, Sri Paramakalyani Centre for Environmental Sciences, Manonmaniam Sundaranar University, Alwarkurichi, Tamilnadu, India 2 Department of Chemistry, Manonmaniam Sundaranar University, Tirunelveli, Tamilnadu, India _____________________________________________________________________________________________ ABSTRACT Green synthesis of metal nanoparticles is an important technique in improved methods of eco-friendly nanoparticles production. In this investigation, the biomedically valid gold nanoparticle was synthesized by using marine brown algae Turbinaria conoides. The colour changes from brown to pinkish red confirmed the gold nanoparticles synthesis. The triangle, rectangle and square shaped and 60 nm average sized gold nanoparticles were observed by Scanning Electron Microscope (SEM). The nature of elemental gold was analysed by using Energy dispersive analysis (EDS). Finally the antibacterial activity of gold nanoparticles was performed; it shows Streptococcus sp having the maximum inhibition and medium range of inhibition was examined against Bacillus subtilis and Klebsiella pneumoniae. Keywords: gold nanoparticles, green synthesis, marine algae, antibacterial activity, Turbinaria conoides. _____________________________________________________________________________________________ INTRODUCTION Bioinspired nanoparticles play an important role in the field of biomedical technology. There are various microbes, plants, algae and biochemical compounds are play an important role in the field of green nanoparticles synthesis. In orderly the bacterial isolates used for the synthesis of NPs are Desulfovibrio desulfuricans [1], Shewanella algae [2], Geobacter sulfurreducens [3], Bacillus subtilus [4], Plectonema boryanum UTEX 485 Cyanobacterium [5], Serratia nematodiphila [6]. The fungal strains are like Thermomonospora sp. [7], F. oxysporum [8], F. oxysporum F. sp. Lycopersici [9], A. flavus [10], F. semitectum [11], Cladosporium cladosporioides [12], Trichoderma asperellum [13], Neurospora crassa [14]. The plants are major sources of nature involved vigorously for the synthesis of nanoparticles now a day. In this the different parts of plants such as leaves [15], seeds [16], and bark [17] are also used for the synthesis protocol. Some plants involved for the procedure are like Pelargonium graveolens (Geranium leaf) [18], Cinnamomum camphora [19], Magnolia kobus and Diopyros kaki leaf extracts [20], Anti-maglinant guava leaf (Psidium guava) [21], Pear fruit extract [22], Rosa hybrid petal extract [23], Nyctanthes Arbortristis ethanolic flower extract [24], natural precursor Clove (Szygium aromaticum) [25], Chenopodium album leaf extract [26].