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Comparative Genomic Studies of hypothetical proteins in Cyanophages
No full textThe Cyanophages are the phages infecting cyanobacteria. They are potential agents for the horizontal gene transfer. The complete genome of 10 known Cyanophages deciphered the presence of various gene sequences for hypothetical proteins whose functions are not yet understood. Our attempt is to predict the structure and function of these hypothetical proteins by the application of computational methods and Bioinformatics. The probable function prediction for the hypothetical proteins was done by using Bioinformatics web tools like CDD-BLAST, INTERPROSCAN, PFAM and COGs by searching protein databases for the presence of conserved domains. While tertiary structures were constructed using PS2 Server- Protein Structure Prediction server. This study revealed presences of functional domain in 258 uncharacterized proteins. These deciphered enzymatic data for hypothetical proteins can be used for the understanding of functional, structural and evolutionary development of cyanophages and its life cycle along with their role in host evolution
Characterization of Chromophoric Dissolved Organic Matter (CDOM) in Rainwater Using Fluorescence Spectrophotometry
No full textThe fluorescence excitation–emission matrix of
Chromophoric dissolved organic matter (CDOM) samples
from rainwater collected at Rameswaram, Tamilnadu,
India are analysed. Total five peaks were observed for
humic/marine and protein likes substances respectively.
The peak A and C intensities varies form 1.98 ± 0.28 and
0.97 ± 0.11 QSU respectively represents humic like substances.
The peak B and T intensities varies from
3.94 ± 0.75 and 7.42 ± 1.43 QSU showed association of
protein like substances whereas peak M intensities varies
from 1.92 ± 0.37 QSU indicates marine contributio
Visible light induced photoreduction of water by N-doped mesoporous titania
No full textN-doped mesoporous titania was synthesized by templating method. Three different types
of photocatalysts were synthesized by varying chitosan to titania compositions and
designated as N-doped mesoporous titania (1:1), (1:2) and (1:3). These synthesized photocatalysts
were characterized by XRD, BET-SA, UV-DRS, SEM-EDX and XPS. This photocatalyst
is active in visible range with band gap energy of 2.65 eV. Formation of TieN bond
reveals the decrease in the band gap of TiO2. The synthesized photocatalysts were
screened initially for their photocatalytic activity using water splitting reaction. The
maximum hydrogen yield of 2654.57 mmol/h/g of photocatalyst was obtained for N-doped
mesoporous titania (1:2). This yield is 16 times higher as compared to the bench mark
material Degussa P-25 (161 mmol/h/g of photocatalyst). The best performing photocatalyst
N-doped mesoporous titania (1:2) was investigated in detail to study the influence of
various operating parameters. Reuse and recycle study results in steady hydrogen yield of
9605.56 mmoles for 30 h
Effect of zeolites on thermal decomposition of ammonia borane
No full textChemical hydrides due to their light weight and high storage capacity are considered to be
promising hydrogen storage materials for both mobile and stationary applications.
Ammonia Borane (AB) is a novel material with very high hydrogen content (19.6 wt %) per
mass. The decomposition of AB takes place in three steps at desorption temperatures of
about 100 �C, 140 �C and above 1000 �C respectively releasing 1 mol of hydrogen in each
step. The major obstacle towards the use of AB as a hydrogen store is its irreversibility and
slow kinetics. With the additives the decomposition temperature could be reduced and the
kinetics can be improved. Effect of addition of Zeolites on decomposition of Ammonia
Borane at different temperatures is reported in this paper. It was observed that the kinetics
behaviour is greatly affected by addition of Zeolites with considerable reduction in the
induction or warm-up period
Catalytic dehydrogenation of cyclohexane over Ag-M/ACC catalysts for hydrogen supply
No full textDehydrogenation of cyclohexane to benzene has been carried out over Ag supported on
activated carbon cloth (Ag/ACC) catalysts using a spray- pulse reactor. Hydrogen evolution
was studied for hydrogen storage and supply system applications. The maximum rate of
hydrogen evolution rate using monometallic Ag/ACC catalysts was 6.9 mmol/gmet/min for
Ag loading of 10 wt%. An enhanced hydrogen evolution was observed by adding a small
amount of noble metal (1 wt% Pt, Pd, Rh) to the Ag based catalysts. A synergistic effect was
observed in the case of the Pt promoted catalysts on the hydrogen production were twice as
compared to 10 wt% Ag catalyst only
Dehydrogenation of methylcyclohexane over Pt/V2O5 and Pt/Y2O3 for hydrogen delivery applications
No full textDehydrogenation of methylcyclohexane (MCH) for hydrogen transportation and delivery
application was carried out over 3 wt% Pt/V2O5 and 3 wt% Pt/Y2O3 catalyst. The catalytic
activity was tested using a spray-pulse mode of reactor. Effective dehydrogenation of MCH
under spray-pulse mode of reactant injection was observed. In terms of hydrogen evolution
rate at 60 min from start of reaction the activity of 958 mmol/g/min was obtained at
temperature of 350 �C. Nearly 100% selectivity toward hydrogen was obtained. A relatively
high conversion of 98% was observed with 3 wt% Pt/Y2O3 at 60 min using an advanced
spray-pulse reactor system. The catalysts were characterized using x-ray diffraction
pattern (XRD), CO-chemisorption metal analysis, scanning electron microscopy (SEM) and
X-ray photoelectron spectroscopy (XPS) analysis
Combustion of volatile organic compounds over Cu–Mn based mixed oxide type catalysts supported on mesoporous Al2O3, TiO2 and ZrO2
No full textA series of supported Cu–Mn based catalysts have been synthesized using three different supports
mesoporous Al2O3, mesoporous TiO2 and mesoporous ZrO2. Cu–Mn precursors were incorporated on
mesoporous supports using wet impregnation method. These catalyst supports were prepared by templating
method using a natural biopolymer namely, chitosan. The catalytic activity for benzene and
acetaldehyde combustion was studied for these catalysts. The synthesized catalysts have been characterized
by XRD, BET-SA, O2-TPD and H2-TPR in a view of material characterization, as well as to investigate
the mechanistic aspects of catalytic reactions. The bimetallic supported catalysts follow the activity
sequence—Cu–Mn/TiO2 > Cu–Mn/ZrO2 > Cu–Mn/Al2O3 for both the reactions studied. These results interestingly
show, that the catalytic activity is dependent on the support used, however, quite independent
of the surface area of these supports. The better activity of TiO2 and ZrO2 based catalysts is likely due to
their redox properties. The existence of low temperature peaks in both O2-TPD and H2-TPR explain better
redox properties as well as catalytic performance of TiO2 and ZrO2 supported catalysts as compared to
those Al2O3 supported mixed oxides
Variability of BTEX in Residential Indoor Air of Kolkata Metropolitan City
No full textMono-aromatic hydrocarbons, namely benzene,
toluene, ethylbenzene and isomers of xylene (BTEX)
were studied within a group of typical urban residences.
The average residential indoor levels of BTEX
were 42.0, 69.3, 22.8, 52.1 and 21.6 mg�m�3, respectively.
The indoor level was found to be significantly dependent
on the type of fuel used and extent of ventilation
but not on location of the residence or kitchen
placement inside the residence. The average indoor/
outdoor concentration ratio observed for BTEX 4 1;
and this indicates the presence of indoor sources for
these compounds along with infiltration of outdoor air.
The relative variability of the target compounds reveals
that indoor sources, other than domestic fuel, like
consumer products, cooking, etc., contribute significantly
for xylenes and least for benzene. Also with
increasing ventilation, the intrusion of outdoor air has
definite contribution in increasing the indoor level in descending order for benzene, toluene, m-, p-xylene
and ethylbenzene. For o-xylene, a removal effect was
observed with increasing rate of ventilation.
The human health risk estimation reveals that the
average integrated lifetime cancer risk considering the
exposure to benzene and ethylbenzene due to residing
for only 15 years in such indoor conditions is 2.9 E-�05,
which is sufficiently higher than the acceptable risk of
1.0 E�-06
Degradation of 2,4,6-Trinitrophenol (TNP) by Arthrobacter sp.HPC1223 Isolated from Effluent Treatment Plant
No full textArthrobacter sp. HPC1223 (Genebank Accession
No. AY948280) isolated from activated biomass of
effluent treatment plant was capable of utilizing 2,4,6 trinitrophenol (TNP) under aerobic condition at 30 �C and pH 7 as nitrogen source. It was observed that the isolated bacteria utilized TNP up to 70 % (1 mM) in R2A media with nitrite release. The culture growth media changed into orange-red color hydride-meisenheimer complex at 24 h as detected by HPLC. Oxygen uptake of Arthrobacter HPC1223 towards various nitro/amino substituted phenols such as dinitrophenol(1.2 nmol/min/mg cells), paranitrophenol (0.9 nmol/min/mg cells), 2-aminophenol (0.75 nmol/min/mg cells),
p-aminophenol (0.4 nmol/min/mg cells), phenol (0.56
nmol/min/mg cells) and TNP (2.42 nmol/min/mg cell) was
analysed, which showed its additional characteristic of broad substrate catabolic capacity. The present study thus report a novel indigenous bacteria isolated from activated sludge utilized TNP and has broad catabolic potential towards substituted phenols
Volatile Organic Compound Emissions from Municipal Solid Waste Disposal Sites: A Case Study of Mumbai, India
No full textImproper solid waste management leads to aesthetic and environmental problems. Emission of volatile organic compounds (VOCs) is one of the problems from uncontrolled dumpsite. VOCs are well known to be hazardous to human health and many of them are known or potential carcinogens. They also contribute to ozone formation at ground level and climate change as well. The qualitative and quantitative analysis of VOCs emitting from two municipal waste (MSW) disposal sites in Mumbai, India, namely Deonar and Malad, are presented in this paper. Air at dumpsites was sampled and analyzed on gas chromatography–mass spectrometry (GC-MS) in accordance with U.S. Environmental Protection Agency (EPA) TO-17 compendium method for analysis of toxic compounds. As many as 64 VOCs were qualitatively identified, among which 13 are listed under Hazardous Air Pollutants (HAPs). Study of environmental distribution of a few major VOCs indicates that although air is the principal compartment of residence, they also get considerably partitioned in soil and vegetation. The CO2 equivalent of target VOCs from the landfills in Malad and Deonar shows that the total yearly emissions are 7.89E+03 and 8.08E+02 kg, respectively. The total per hour ozone production from major VOCs was found to be 5.34E-01 ppb in Deonar and 9.55E-02 ppb in Malad. The total carcinogenic risk for the workers in the dumpsite considering all target HAPs are calculated to be 275 persons in 1 million in Deonar and 139 persons in 1 million in Malad.
Implications:
This paper describes the hazards of VOC emission from open dumpsites, a common practice, in an Indian metro city. The subsequent partitioning of the emitted VOCs in other environmental compartment from air is presented. The global warming potential and the health hazards to the dumpsite workers from the emitted VOCs have also been estimated