Seventy-five marine bacterial strains associated with four species of sponges (Echinodictyum sp., Spongia sp., Sigmadocia fibulatus and Mycale mannarensis) were isolated from the Tuticorin coast, Gulf of Mannar region. The agar-overlay method was used to screen for antibiotic production by these strains against four bacteria, viz., Bacillus subtilis, Escherichia coli, Vibrio parahaemolyticus, and Vibrio harveyi and one fungal pathogen, viz., Candida albicans. Twenty-one per cent of the bacterial strains were found to be antibiotic producers and their activities ranged from broad spectral to species specific. A strain coded SC3 was found to be highly potent and was mass cultured. The ethyl acetate extract of the culture broth was further fractionated by reverse phase HPLC and the active fraction identified. In addition, SC3 was subjected to morphological and physiological characterization. The results of the tests showed SC3 to be a Gram-positive rod, sporulating, motile, catalase and oxidase positive. Phylogenetic analysis based on comparative analysis of sequenced 16s rRNA of the active strains indicated a preponderance of bacteria belonging to Vibrio and Bacillus genera with 95-99% sequence similarities. To our knowledge this is the first report on phylogenetic identification of antibiotic producing bacteria associated with sponges from Indian waters.

This paper aims in assessing the effect of biofuel blend such as butanol, jatropha methyl ester, soya methyl ester and rapeseed methyl ester as an additive for the aviation fuel. In addition to the blends, the nanoparticle TiO2 of 3 % is added to the biofuel. The nanoparticle mixed at the concentration of 300ppm by ultrasonication process. The fuel Jet A, B27T, J27T, S27T and R27T are investigated for combustion and emission characteristics for various throttle settings in micro gas turbine engine. Addition of additives improves the ultimate property of the fuel by reducing the kinematic viscosity. The fuel blend B27T reports 25 % increase in total static thrust and 22 % reduction in thrust specific fuel consumption. From the results it is evident that, all fuel blends showed a significant reduction in emission values owing to high oxygen content. In addition, the thermal efficiency of the B27T and J27T is improved appreciably to 30 % and 10 % higher than Jet A fuel owing to the influence of the nanoparticle TiO2. On the other hand, the emissions like CO and NOx reduced drastically up to 70 % and 45 % respectively.

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