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  • Author or Editor: Ajay Kumar x
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The cheese whey, a by-product of dairy industry proved to be an attractive substrate for production of β-carotene. The β-carotene production from Mucor azygosporus MTCC 414 by using deproteinized waste whey filtrate under submerged fermentation was investigated. Various fermentation variables, such as lactose content in whey, initial pH, production temperature, incubation time, and carbon and nitrogen sources played significant role on β-carotene production. Maximum β-carotene production (385 μg/g dcw) was obtained with the whey (pH 5.5) containing 3.5% (w/v) lactose supplemented with soluble starch at (1.0%, w/v) at 30°C after a 5 days incubation. Moreover, unlike other microorganisms which utilize pre-hydrolyzed lactose, this Mucor azygosporus MTCC 414 was found to be capable of utilizing unhydrolyzed lactose present in the whey.

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The efficiency of three oxygen-vectors liquid paraffin, silicone oil and n-dodecane in the production of tyrosine phenol lyase (TPL) by Citrobacter freundii MTCC 2424 was evaluated at 4% (v/v) concentration. The liquid paraffin as oxygenvectors was found to exhibit a stimulatory effect on TPL synthesis. The liquid paraffin at 6% (v/v) resulted in 34% increase in the TPL synthesis accompanied by a 13% increase in the production of cell mass at a 10 L scale. This improvement in TPL and cell mass production in the presence of liquid paraffin can be related to the fact that liquid paraffin was capable of maintaining dissolved O2 concentration above 28% throughout the course of the fermentation. Maintenance of the dissolved O2 concentration above 28% could be viewed in terms of an adequate oxygen supply to the rapidly dividing cells of the bacterium, which in turn resulted in enhanced synthesis of TPL and cell mass.

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Abstract

The kinetics of the periodate oxidation of p-toluidine (TOL) in acetone–water medium has been followed by monitoring the increase in the absorbance of the reaction intermediate, C4, and the main reaction product is 4-methyl-1,2-benzoquinone. Results under pseudo first order conditions, [IO4 ] > [TOL], are in agreement with the rate law d[C]/dt = kK 3 K 4 K w[MnII] [S] [IO4 ]0 [H+]/{K 2 K w + (K w + K b K 2)[H+] + K b [H+]2} where kK 3 K 4 is the empirical composite rate constant, K w is ionic product of water, K 2 is acid dissociation constant of H4IO6 , K b is base dissociation constant of TOL i.e. substrate [S] and [IO4 ]0 represents the concentration of periodate that has been taken in excess in most of the kinetic runs. In agreement with the rate law, the 1/k cat versus pH profile passes through a minimum. Free radical scavengers do not affect the reaction rate. The rate is found to decrease with an increase in ionic strength and decrease in dielectric constant of the medium. Activation parameters evaluated are: ∆E = 12.2 ± 1.1 kJ mol−1, A = (1.57 ± 0.005) × 107 dm3 mol−1 s−1; ∆S # = −115.9 ± 0.2 J mol−1 K−1, ∆G # = 46.2 ± 0.9 kJ mol−1 and ∆H # = 9.60 ± 0.06 kJ mol−1.

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Authors: S. Srivastava, Ajay Jain, Satish Kumar, Raj Singh and Sushma Agrawal

Abstract  

Ion-exchange papers were prepared by impregnating chromatographic Whatman No. 3 paper with pyridinium tungstoarsenate exchanger. The composition of the material loaded on the paper shows that the compound has the formula (C5H5NH)3 W1 2AsO4 0·Rf values of 30 metal ions were determined on these ion-exchange papers by developing with ascending technique in solvents containing mixtures of n-propanol and hydrochloric or nitric acid. Several binary, ternary and some quaternary separations were also achieved on these papers. Studies were also made on plain papers for comparison.

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Authors: Pushpendra Kumar Shukla, Ankita Misra, Manish Kumar, Soundararajan Rajan, Pawan Kumar Agrawal, Ajay Kumar Singh Rawat and Sharad Srivastava

Plant metabolite varies with season and geographic conditions. The present study is aimed at the identification of the potential chemotypes of Coleus forskohlii, available in the natural habitat of Nilgiri hills and adjoining area, in order to provide a basic lead for the industry concerning commercial exploitability, including the location-specific commercial cultivation of the plant. The effect of intra-specific variability in the forskolin content among the populations was estimated using high-performance thin-layer chromatography (HPTLC)—densitometric method. The roots of fourteen naturally occurring populations from the entire hill range were collected, covering the wide topography from foot hills up to the highest peak. The method developed for the quantification of forskolin was validated and found to be linear, specific, and accurate with precision and accuracy. The limit of detection (LOD) and limit of quantification (LOQ) were 1.04 and 3.16 ng spot−1. Precision studies (both inter-day and intra-day) were within the standard limit of relative standard deviation (RSD) (%) less than 3%. The quantification of forskolin within the population revealed that it varied from 0.0046 ± 0.0005 (NBC-36) to 1.156 ± 0.003% (NBC-46). The analysis of variance (ANOVA) suggested that there are significant differences in forskolin content among the populations. A positive correlation (Karl Pearson) was found between the altitude and the forskolin content. The cluster analysis of the population on forskolin content suspected the presence of two chemotypes. The study suggests the presence of chemotaxonomic variation among the populations which can be due to the change in phytogeographical factors.

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Authors: Mulayam Singh Gaur, Reeta Singh, Pramod Kumar Singh, Ajay Pal Indolia and Ranjit Singh

Abstract

Short circuit thermally stimulated discharge current (TSDC) has been recorded in corona-charged ethyl cellulose foil samples at different annealing time. An analysis of the data reveals significant changes in the TSDC curves of the samples as a function of annealing time. The possible relaxation processes accounting for the changes are discussed, not only a shift of peak temperature of the observed peak to higher temperatures, but also a lowering in its height has been observed with increase in annealing time. Peak temperature higher than 343 K did not arise even for the annealing time of 240 h. The activation energy (A) has been found to increase, while the trapped charge carrier n t decrease with increase in annealing time. Linear relationship between ln A and n t indicated an exponential distribution of traps.

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Abstract  

During this work the determination of uranium in the range of μg·L−1 to tens of μg·L−1 was done by alpha-spectrometry after electroplating the aliquots of water sample using (NH4)2SO4 as an electrolyte. In general, the determination of uranium by alpha-spectrometry needs its separation from other transuranics specially thorium. The process described here does not involve any sample digestion and radiochemical separation of uranium from other transuranics. In this method an aliquot (1 to 3 mL) of the sample was dried and dissolve in (NH4)2SO4 and thereafter the sample was electroplated on a stainless steel (SS) planchet by using an electrochemical cell of special design. The proposed techniques have a distinct advantage over the determination of uranium by adsorptive stripping voltammetry (AdSV) in which uranium-chloranilic (2,5-dichloro-3,6-dihydroxy-1,4-benzoquinone) acid complex was used for concentrating the uranium from the solution. Since in the case of AdSv, the determination of uranium was not possible for samples having dissolved organic carbon (DOC) more than 15 mg·L−1 and Cl concentration is in the range of 40,000 μ·g−1. In the case of spike experiments with 232U the recovery was observed in the range of 90–95% in aqueous medium having higher concentration of Cl and DOC as indicated above.

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The extraction of crude drugs by using different solvents provides polarity-based fractions containing specific types of secondary metabolites. Averrhoa carambola L. fruits were extracted and fractionated, and petroleum ether extract was processed by fatty acid methyl ester (FAME) technique for characterization by gas chromatography‒mass spectrometry (GC‒MS) analysis. The remaining part was extracted with methanol for high-performance thin-layer chromatography (HPTLC) analysis, for simultaneous quantitative determination of gallic acid, protocatechuic acid, and quercetin in methanolic fractions. Petroleum ether and methanol fractions were found to be the best for the highest possible recovery of target analytes. The chromatographic elutions of FAME compounds generated from ether extract were evaluated by GC‒MS profiling. Ten fatty acid compounds were separated with the highest quantity of oleic acid methyl ester (42.88%). On other hand, polar fraction was processed by HPTLC profiling. For achieving good separation, a mobile phase of toluene‒ethyl acetate‒formic acid (5:4:1, v/v) was used. The densitometric determination was carried out at 310 nm in reflection–absorption mode. The calibration curves were linear in the range of 100–600 ng per spot for gallic acid, protocatechuic acid, and quercetin. During the analysis, the dried raw material from A. carambola L. fruits showed the presence of gallic acid (0.96%), protocatechuic acid (0.05%), and quercetin (0.40%). The proposed method is simple, precise, specific, and accurate. The statistical analysis of the data obtained proves that the method is reproducible and selective and can be used for the routine analysis of the reported phenolic compounds in crude drug and extracts. The results indicated that the methanolic extracts of the plant contained a considerable amount of bioactive compounds. The presence of phytochemicals especially phenolics and flavonoids explains its use in various diseases. It may be concluded that the results obtained from the quantitative evaluation of quercetin by HPTLC fingerprinting could be useful in its authentication, the quality control of the drug, and in ensuring therapeutic efficacy.

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A high-performance thin-layer chromatography (HPTLC) method for the simultaneous quantitative determination of ursolic acid and β-sitosterol in the methanolic fraction of Paederia foetida L. leaves was developed for the first time. For achieving good separation, a mobile phase of toluene‒ethyl acetate‒formic acid (8:2:0.1, v/v) was used. The densitometric determination was carried out at 550 and 522 nm in reflection/absorption mode for ursolic acid and β-sitosterol. The calibration curves were linear in the range of 100-600 ng per spot for ursolic acid and β-sitosterol. During the analysis, the methanolic fraction of P. foetida L. leaves showed the presence of ursolic acid (0.12 ± 0.05%) and β-sitosterol (0.08 ± 0.12%). The proposed method is simple, precise, specific, accurate, less time-consuming, and cost-effective. The statistical analysis of the data obtained proves that the method is reproducible and selective and can be used for the routine analysis of the reported phenolic compounds in crude drug and extracts. The simultaneous quantification of these compounds has not yet been reported in P. foetida L. leaves which may be utilized for the proper standardization of the plant.

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