Biotransformation of Indigo Pigment by Indigenously Isolated Pseudomonas sp. HAV-1 and Assessment of Its Antioxidant Property.

Chemical synthesis of indigo poses harsh environmental hazards and adverse human health effects. This necessitates an environment-friendly and producer-friendly approach for indigo production. The present study was thus significant as it reports an indigenously isolated potential indigo pigment producing culture identified as Pseudomonas sp. HAV-1 with noteworthy antioxidant property. The bioindigo pigment was characterized using various analytical techniques. The pigment production was enhanced from 412 µg mL(-1) to 700 µg mL(-1) by optimizing the growth parameters. Furthermore, the antioxidant property of indigo pigment is hitherto unexplored. This property can significantly append to its therapeutic potential. The bioindigo pigment produced by Pseudomonas sp. HAV-1 depicted 2.2 µM ascorbic acid equivalent antioxidant property. More to the point, the present work addresses a footstep towards green production of indigo.

Evaluation of in vitro efficacy for decolorization and degradation of commercial azo dye RB-B by Morganella sp. HK-1 isolated from dye contaminated industrial landfill.

Reactive Black-B (RB-B) - one of the multi-sulphonated reactive azo dye - is being used extensively in textile as well as paper industries. Reactive azo dyes comprise of a significant group of synthetic compounds categorized as xenobiotics and its abatement from the environment still remains a challenge. In the present study, a newly isolated indigenous bacterial strain Morganella sp. HK-1 was exploited for its ability to decolorize and degrade RB-B dye. The isolate completely degraded RB-B (20 g L(-1)) within 24h under static conditions. Furthermore, the visible and FTIR spectral analysis established the bio-degradation of RB-B. The degraded metabolites of RB-B by Morganella sp. HK-1 were identified by GC-MS analysis as disodium 3,4,6-triamino-5-hydroxynaphthalene-2,7-disulfonate, 4-aminophenylsulfonylethyl hydrogen sulfate, naphthalene-1-ol, aniline and benzene. Based on this information, a putative pathway of degradation of RB-B by Morganella sp. HK-1 has been proposed. This study is the first report on elucidation of mechanism of bacterial degradation of RB-B dye. Furthermore, phytotoxicity, genotoxicity and aquatic acute toxicity studies of the parent dye and the bio-degraded dye products revealed drastic reduction in the toxicity of metabolites as compared to the parent dye. This implies that the biotreatment of the dye is of non-toxic nature. This study thus indicates the effectiveness of Morganella sp. HK-1 for the treatment of textile effluents containing sulphonated azo dyes.

In vitro studies on degradation of synthetic dye mixture by Comamonas sp. VS-MH2 and evaluation of its efficacy using simulated microcosm.

Reactive azo dyes are considered as one of the most detrimental pollutants from industrial effluents and therefore their biodegradation is receiving constant scientific consideration. A bacterial isolate VS-MH2, originating from dye contaminated sites of Gujarat, India, was exploited for its ability to degrade a synthetic dye mixture (SDM) (comprising of four azo reactive dyes) under static conditions. The identification of the isolate by 16S rRNA gene sequencing revealed it to be Comamonas sp. The biodegradation of the SDM was analyzed by UV-vis spectroscopy, IR spectroscopy and GC-MS analysis. The isolate showed high metabolic activity towards SDM and degraded it completely (100 mg L(-1)) within 30 h at pH 7 and 35 °C. Simulated microcosm studies in the presence and absence of indigenous microflora confirmed the ability of Comamonas sp. VS-MH2 for dye degradation and to colonize the soil. This is the first investigation reporting the degradation of SDM by Comamonas sp. under simulated soil microcosms.

Kinetic modelling and microbial community assessment of anaerobic biphasic fixed film bioreactor treating distillery spent wash.

Anaerobic digestion, microbial community structure and kinetics were studied in a biphasic continuously fed, upflow anaerobic fixed film reactor treating high strength distillery wastewater. Treatment efficiency of the bioreactor was investigated at different hydraulic retention times (HRT) and organic loading rates (OLR 5-20 kg COD m⁻³ d⁻¹). Applying the modified Stover-Kincannon model to the reactor, the maximum removal rate constant (U(max)) and saturation value constant (K(B)) were found to be 2 kg m⁻³ d⁻¹ and 1.69 kg m⁻³ d⁻¹ respectively. Bacterial community structures of acidogenic and methanogenic reactors were assessed using culture-independent analyses. Sequencing of 16S rRNA genes exhibited a total of 123 distinct operational taxonomic units (OTUs) comprising 49 from acidogenic reactor and 74 (28 of eubacteria and 46 of archaea) from methanogenic reactor. The findings reveal the role of Lactobacillus sp. (Firmicutes) as dominant acid producing organisms in acidogenic reactor and Methanoculleus sp. (Euryarchaeotes) as foremost methanogens in methanogenic reactor.

Advances in molecular and "-omics" technologies to gauge microbial communities and bioremediation at xenobiotic/anthropogen contaminated sites.

Microbial bioremediation has been well-demonstrated as an ecofriendly and cost-competitive strategy for elimination of xenobiotic and or anthropogenic compounds from the polluted environments. However, successful execution of these versatile bioremediation strategies requires a thorough understanding of factors governing the growth, metabolism, dynamics and functions of indigenous microbial communities at contaminated sites. Recent innovative breakthroughs in genotypic profiling, ultrafast genome pyrosequencing, metagenomics, metatranscriptomics, metaproteomics and metabolomics along with bioinformatics tools have provided crucial in-sights of microbial communities and their mechanisms in bioremediation of environmental pollutants. Moreover, advances in these technologies have significantly improved the process of efficacy determination and implementation of microbial bioremediation strategies. The current review is focused on application of these molecular and "-omics" technologies in gauging the innate microbial community structures, dynamics and functions at contaminated sites or pollution containment facilities.

Biosynthesis of indigo dye by newly isolated naphthalene-degrading strain Pseudomonas sp. HOB1 and its application in dyeing cotton fabric.

Indigo is one of the oldest dyes manufactured chemically and is mostly used in textile, food, and pharmaceutical industries. However, owing to the environmental hazards posed by the chemical production, the present scenario in the field stipulates a biosynthesis alternative for indigo production. The present study describes an indigenously isolated naphthalene-degrading strain Pseudomonas sp. HOB1 producing a blue pigment when indole was added in the growth medium. This blue pigment was analyzed by high-pressure thin-layer chromatography and other spectroscopic techniques which revealed it to be the indigo dye. Pseudomonas sp. HOB1 showed ability to produce 246 mg indigo liter(-1) of the medium. The K (m) for the enzyme naphthalene dioxygenase which is involved in indigo formation is 0.3 mM, and V (max) was as high as 50 nmol min(-1) mg dry biomass(-1). The bacterial indigo dye was further successfully applied for dyeing cotton fabrics. The high indigo productivity of Pseudomonas sp. HOB1 using naphthalene as growth substrate and its applicability on cotton fabrics, therefore, stems the probability of using this culture for commercial indigo production.

Naphthalene degradation by Pseudomonas sp. HOB1: in vitro studies and assessment of naphthalene degradation efficiency in simulated microcosms.

Naphthalene, being a ubiquitous pollutant of the environment and a perilous material, its biodegradation has been receiving constant scientific consideration. Highly potential, naphthalene degrading bacteria were isolated from sediments of polluted Amlakadi canal, Gujarat, India. Among the isolates, Pseudomonas sp. HOB1, showed ability to degrade 2000 ppm naphthalene within 24h. The culture exhibited potential to tolerate as high as 60,000 ppm of naphthalene. Statistical approach was used to analyze the effect of physiological parameters and initial biomass concentration on naphthalene degradation. Naphthalene degradation was found to be augmented in the pH range of 7.5-8.5. Naphthalene degradation was maximum in the temperature range of 35-37 degrees C and initial inoculum size of more than 1.8 ml of 1.0 A(660). Simulated microcosm studies in the presence and absence of indigenous microflora confirmed its ability for naphthalene degradation and to colonize the soil. Pseudomonas sp. HOB1 was found to be highly potent in degrading higher concentrations of naphthalene under laboratory conditions as well as in simulated microcosms.