Chemical composition, nutritive value and health benefits of edible clam Meretrix casta (Chemnitz) from West Coast of India.

The present study was undertaken with a view to determine the nutraceutical value of the commonly consumed edible clam, Meretrix casta (Chemnitz), based on the identification of its organic chemical constituents particularly lipids and carbohydrates. Electrospray ionization tandem mass analysis of the bivalve indicated maltodextrins to be the major carbohydrate constituent. Triacylglycerols (TAGs) (0.88%, dry weight) were rich in C14:0, C16:0 to C18:0 (6-11%) saturated and monounsaturated palmitoleic (C16:1n9c; 11.76%) and oleic fatty acids (C18:1n9c; 14.53%). Though the clams contained PUFAs which are known to be beneficial in lowering the risk of cardiovascular diseases, they were devoid of docosahexaenoic acid (C22:6n3). Maltodextrins being less digestible than glucose beneficially affects the host by selectively stimulating the growth of gut microflora particularly Lactobacillus and Bifidobacteria. These microflora inhibit colonization of pathogens by producing butyrate. The profile of sterols (1.67%, dry wt.) showed it to be a complex mixture of C26, C27, C29 and C30. To our knowledge no reports are available in the literature on the identification of maltodextrins and of positional distribution of PUFA's at the sn2 position of TAGs in M. casta. The results of this study demonstrated the positive attributes of the bivalve for human consumption.

Biotransformation and Detoxification of Xylidine Orange Dye Using Immobilized Cells of Marine-Derived Lysinibacillus sphaericus D3.

Lysinibacillus sphaericus D3 cell-immobilized beads in natural gel sodium alginate decolorized the xylidine orange dye 1-(dimethylphenylazo)-2-naphthol-6-sulfonic acid sodium salt in the laboratory. Optimal conditions were selected for decolorization and the products formed were evaluated for toxicity by disc diffusion assay against common marine bacteria which revealed the non-toxic nature of the dye-degraded products. Decolorization of the brightly colored dye to colorless products was measured on an Ultra Violet-Vis spectrophotometer and its biodegradation products monitored on Thin Layer Chromatographic plate and High Performance Liquid Chromatography (HPLC). Finally, the metabolites formed in the decolorized medium were characterized by mass spectrometry. This analysis confirms the conversion of the parent molecule into lower molecular weight aromatic phenols and sulfonic acids as the final products of biotransformation. Based on the results, the probable degradation products of xylidine orange were naphthol, naphthylamine-6-sulfonic acid, 2-6-dihydroxynaphthalene, and bis-dinaphthylether. Thus, it may be concluded that the degradation pathway of the dye involved (a) reduction of its azo group by azoreductase enzyme (b) dimerization of the hydrazo compound followed by (c) degradation of monohydrazo as well as dimeric metabolites into low molecular weight aromatics. Finally, it may be worth exploring the possibility of commercially utilizing L. sphaericus D3 for industrial applications for treating large-scale dye waste water.

Fermentation products of solvent tolerant marine bacterium Moraxella spp. MB1 and its biotechnological applications in salicylic acid bioconversion.

As part of a proactive approach to environmental protection, emerging issues with potential impact on the environment is the subject of ongoing investigation. One emerging area of environmental research concerns pharmaceuticals like salicylic acid, which is the main metabolite of various analgesics including aspirin. It is a common component of sewage effluent and also an intermediate in the degradation pathway of various aromatic compounds which are introduced in the marine environment as pollutants. In this study, biotransformation products of salicylic acid by seaweed, Bryopsis plumosa, associated marine bacterium, Moraxella spp. MB1, have been investigated. Phenol, conjugates of phenol and hydroxy cinnamic acid derivatives (coumaroyl, caffeoyl, feruloyl and trihydroxy cinnamyl) with salicylic acid (3-8) were identified as the bioconversion products by electrospray ionization mass spectrometry. These results show that the microorganism do not degrade phenolic acid but catalyses oxygen dependent transformations without ring cleavage. The degradation of salicylic acid is known to proceed either via gentisic acid pathway or catechol pathway but this is the first report of biotransformation of salicylic acid into cinnamates, without ring cleavage. Besides cinnamic acid derivatives (9-12), metabolites produced by the bacterium include antimicrobial indole (13) and ß-carbolines, norharman (14), harman (15) and methyl derivative (16), which are beneficial to the host and the environment.

The fungus Gliocephalotrichum simplex as a source of abundant, extracellular melanin for biotechnological applications.

Melanins are commonly produced by bacteria, fungi, plants and animals, where they play a role in many biological functions. They protect organisms against UV and ionizing radiations. Their potential applications in biotechnological industries such as cosmetics and paints, where UV protection is required, are hampered by the lack of suitable organisms or methods to produce them abundantly. We report here the production of high amounts of extracellular melanin by the fungus Gliocephalotrichum simplex in cultures supplemented with tyrosine. Their typical UV-absorbance, as well as i.r., (13)C solid-state and (1)H NMR spectra indicated that the melanin is a eumelanin, being a copolymer of dihydroxyindole carboxylic acid and dihydroxyindole, associated with some carbohydrates and proteinaceous matter. Optimal culture conditions established by a Plackett-Burman experiment, followed by a full factorial experiment based on tyrosine and peptone yielded a maximum of up to 6.6 g melanin l(-1). The high yields of extracellular melanin from G. simplex enables its use in biotechnology.

The sponge-associated bacterium Bacillus licheniformis SAB1: a source of antimicrobial compounds.

Several bacterial cultures were isolated from sponge Halichondria sp., collected from the Gujarat coast of the Indo Pacific region. These bacterial cultures were fermented in the laboratory (100 mL) and the culture filtrate was assayed for antibiotic activity against 16 strains of clinical pathogens. Bacillus sp. (SAB1), the most potent of them and antagonistic to several clinically pathogenic Gram-positive, Gram-negative bacteria and the fungus Aspergillus fumigatus was chosen for further investigation. Analysis of the nucleotide sequence of the 16S rDNA gene of Bacillus sp. SAB1 showed a strong similarity (100%) with the 16S rDNA gene of Bacillus licheniformis HNL09. The bioactive compounds produced by Bacillus licheniformis SAB1 (GenBank accession number: DQ071568) were identified as indole (1), 3-phenylpropionic acid (2) and a dimer 4,4'-oxybis[3-phenylpropionic acid] (3) on the basis of their Fourier Transform Infrared (FTIR), Nuclear Magnetic Resonance (NMR) and Electrospray Ionization Mass Spectrometer (ESI-MS) data. There is a single reference on the natural occurrence of compound 3 from the leaves of a terrestrial herb Aptenia cordifolia in the literature, so to the best of our knowledge, this is a first report of its natural occurrence from a marine source. The recovery of bacterial strains with antimicrobial activity suggests that marine-invertebrates remain a rich source for the isolation of culturable isolates capable of producing novel bioactive secondary metabolites.