37 results on '"Singhal RS"'
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2. A supercritical fluid co-extract of turmeric powder and dried coconut shreds shows neuroprotection against AlCl 3 -induced Alzheimer's disease in rats through nose to brain delivery.
- Author
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Sharma A, Ray A, Sathaye S, and Singhal RS
- Subjects
- Rats, Male, Animals, Aluminum Chloride, Aluminum Compounds adverse effects, Aluminum Compounds metabolism, Chlorides adverse effects, Chlorides metabolism, Curcuma, Powders adverse effects, Powders metabolism, Rats, Wistar, Neuroprotection, Acetylcholinesterase metabolism, Cocos metabolism, Brain metabolism, Alzheimer Disease chemically induced, Alzheimer Disease drug therapy, Alzheimer Disease metabolism
- Abstract
This study was aimed at investigating the neuroprotective potential of a co-extract obtained by supercritical fluid extraction (SFE) of turmeric powder and dried coconut shreds against aluminium chloride (AlCl
3 )-induced Alzheimer's disease (AD) in male Wistar rats. Fifty animals were allocated to five groups, which received saline (vehicle control, group 1), a combination of saline and aluminium chloride (AlCl3 ) (disease control, group 2), coconut oil (COO) (SFE extracted, treatment group 3), turmeric oleoresin (Cur) (SFE extracted, treatment group 4) and SFE co-extract of turmeric powder and coconut shreds (CurCOO) (treatment group 5). Animals were subjected to behavioural evaluation. In addition, the hippocampal section of the brain from all groups was subjected to biochemical, molecular and histopathological evaluations. The results showed CurCOO administered intranasally improved cognitive abilities, reversed histological alterations in the brain, reduced hippocampus inflammation studied through proinflammatory cytokine markers like TNF-α and IL-6 as compared to the disease control group. The impact of CurCOO on preventive neurodegeneration was also observed through a reduction in protein transcription factor NF-kB in the treated group 5 as compared to a disease control group. The effect of intranasal delivery of CurCOO on the neurons responsible for memory consolidation was evident from low acetylcholinesterase (AChE) enzyme activity in the treated groups with respect to AlCl3 induced group. Summarily, the results demonstrated intranasal delivery of CurCOO to show better efficacy than Cur and COO in preventing neurodegeneration associated with AlCl3 induced Alzheimer's disease., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Abhinav Sharma reports financial support was provided by Department of Science and Technology (DST), Government of India. Abhinav Sharma reports a relationship with Department of Science and Technology (DST), Government of India that includes: funding grants. not required., (Copyright © 2023 Elsevier Inc. All rights reserved.)- Published
- 2024
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3. The potential of paraprobiotics and postbiotics to modulate the immune system: A Review.
- Author
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Mehta JP, Ayakar S, and Singhal RS
- Abstract
Probiotics are viable microorganisms that provide beneficial health effects when consumed in adequate quantity by the host. Immunomodulation is one of the major beneficial effects of probiotics that is a result of the colonization of probiotic microorganisms in the gut, their interaction with the intestinal cells, production of various metabolites and by-products. The last few years have displayed an increasing number of studies on non-viable probiotics (paraprobiotics) and microbial by-products (postbiotics) that prove beneficial to human health by providing positive immune responses even in the inactivated form. The increasing number of research studies compare the effects of viable and non-viable probiotics, their by-products, and metabolites. This review focuses on the ability of different types of paraprobiotics and postbiotics to modulate the immune system. A majority of paraprobiotics are developed from Lactobacillus and Bifidobacterium strains. The postbiotic components that modulate the biological reactions include lipoteichoic acids, bacteriocins, short-chain fatty acids, peptidoglycan, and exopolysaccharides have been reported. We have reviewed paraprobiotics and postbiotics that are commercial as well as in research. Paraprobiotics and postbiotics can be a possible replacement for live probiotics for immunocompromised people. Paraprobiotics display an active role in maintaining T-cell mediated immunity and have been shown to treat colitis. Postbiotic components exhibit properties of pro and anti-immune, anti-tumor, anti-microbial, antioxidant, and anti-biofilm. More research is required on the efficient conversion of probiotics to paraprobiotics, the isolation and purification of different postbiotics, and stability studies during the shelf life. The majority of the articles report the effects of direct ingestion of different '-biotics' without blending in any food product., Competing Interests: Declaration of Competing Interest None., (Copyright © 2023 Elsevier GmbH. All rights reserved.)
- Published
- 2023
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4. Enzymatic response of Moina macrocopa to different sized zinc oxide particles: An aquatic metal toxicology study.
- Author
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Borase HP, Muley AB, Patil SV, and Singhal RS
- Subjects
- Animals, Ecosystem, Lethal Dose 50, Cladocera, Water Pollutants, Chemical analysis, Water Pollutants, Chemical toxicity, Zinc Oxide toxicity
- Abstract
Zinc oxide particles (ZnOPs) of both nanometer and sub-micron sizes are important components of high demand consumer products such as sunscreen, paint, textile, food packaging, and agriculture. Their ultimate discharge in the aquatic ecosystem is nearly unavoidable. For sustainable use of ZnOPs, there is an urgent need to assess its ecotoxicity using ecological indicator organisms. Moina macrocopa, an important component of the aquatic ecosystem is one such less explored indicator organism. In the present investigation, ZnOPs of two different sizes (250 ± 20 and 500 ± 50 nm) were selected for risk assessment as most of the previous reports were based on the use of 10-100 nm ZnOPs. ZnOPs of 500 nm were more lethal than that of 250 nm size, with respective LC
50 of 0.0092 ± 0.0012 and 0.0337 ± 0.0133 mg/L against M. macrocopa after 48 h of exposure. We further used a sublethal concentration of 500 nm (0.00336 mg/L) and 250 nm (0.00092 mg/L) ZnOPs followed by measurement of enzymatic biomarkers of toxicity (acetylcholinesterase, digestive enzymes, antioxidant enzymes). A size-dependent variation in enzymatic response to 250 and 500 nm ZnOPs was seen. Exposure to ZnOPs inhibited acetylcholinesterase and digestive enzymes (trypsin, amylase), and elevated antioxidant enzymes (catalase, glutathione S-transferase) levels. The exposure also decreased the superoxide dismutase activity and increased that of β-galactosidase. Microscopic investigation revealed the accumulation of ZnOPs in the digestive tract of M. macrocopa that possibly disrupts enzyme activities. The present study will contribute to establishing regulatory policy on the maximum permissible limit of ZnOPs in different water bodies., (Copyright © 2020 Elsevier Inc. All rights reserved.)- Published
- 2021
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5. Enzymatic synthesis of fatty acid esters of trehalose: Process optimization, characterization of the esters and evaluation of their bioactivities.
- Author
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Marathe SJ, Shah NN, and Singhal RS
- Subjects
- Anti-Bacterial Agents chemistry, Anti-Bacterial Agents metabolism, Anti-Inflammatory Agents, Non-Steroidal chemistry, Anti-Inflammatory Agents, Non-Steroidal metabolism, Arachidonate 15-Lipoxygenase metabolism, Basidiomycota enzymology, Biocatalysis, Dose-Response Relationship, Drug, Escherichia coli drug effects, Esters chemistry, Esters metabolism, Humans, Microbial Sensitivity Tests, Molecular Structure, Palmitic Acid chemistry, Palmitic Acid metabolism, Pseudomonas aeruginosa drug effects, Staphylococcus aureus drug effects, Structure-Activity Relationship, Trehalose chemistry, Trehalose metabolism, Anti-Bacterial Agents pharmacology, Anti-Inflammatory Agents, Non-Steroidal pharmacology, Esters pharmacology, Lipase metabolism, Palmitic Acid pharmacology, Trehalose pharmacology
- Abstract
One-pot synthesis of caprylic, lauric and palmitic acid mono- and diesters of trehalose was catalyzed by the lipase Fermase CALB™ 10000. An optimized molar conversion of 35% of trehalose to its palmitate esters was obtained in acetone at 60 °C with a trehalose:palmitic acid molar ratio of 1:5 in 4 h. Trehalose fatty acid esters (THFAE) were purified by column chromatography and characterized using TLC, HPTLC, HR-MS, ATR-FTIR, and differential scanning calorimetry. THFAE were studied for their antimicrobial potential against four bacterial, and two fungal species. Trehalose monolaurate and trehalose dicaprylate demonstrated MIC of 0.45 mM and 16 mM against Pseudomonas aeruginosa and Escherichia coli, respectively. Trehalose monocaprylate showed the highest inhibition of biofilm forming property against Staphylococcus aureus (86.25%) at 99.2 mM and trehalose dipalmitate had lowest IC50 of 13.23 mM. Furthermore, their anti-inflammatory property was studied in vitro using 15-LOX inhibition assay and human red blood cell membrane stabilization assay. In the confirmatory in vivo tests using carrageenan-induced rat paw edema assay, inflammation in disease control group reached up to 63% as against 32% and 20% for trehalose dilaurate and diclofenac treated groups, respectively. THFAE can hence find potential applications in pharmaceuticals, functional foods, and nutraceuticals., (Copyright © 2019 Elsevier Inc. All rights reserved.)
- Published
- 2020
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6. Influence of food commodities on hangover based on alcohol dehydrogenase and aldehyde dehydrogenase activities.
- Author
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Srinivasan S, Dubey KK, and Singhal RS
- Abstract
Alcohol consumption often leads to hangover, a condition characterized by several symptoms, characteristically headache, nausea, fatigue and drowsiness. Hangover may be alleviated by altering the rate of alcohol metabolism and facilitating elimination of acetaldehyde by affecting the activity of alcohol dehydrogenase (ADH) and/or aldehyde dehydrogenase (ALDH) enzymes. In the present study, several food commodities like fruits, vegetables, cereals, pulses, dairy products, spices and other miscellaneous products (ascorbic acid, cocoa sample, tea, coffee, egg yolk and date samples) were investigated for their effect on the in vitro activities of the enzymes and their antioxidant properties. Of the many screened food commodities, few showed an increase in the activity of either one or both the enzymes, ADH and ALDH. Studies showed no correlation between ADH and ALDH enzyme activities and antioxidant property of the selected food commodities for anti-hangover effect. Further, an anti-hangover (AHO) product was developed using pear (65%), sweet lime (25%) and coconut water (10%) and, validated for in vitro ADH and ALDH enzyme activities. AHO product was found to enhance ADH and ALDH activities by 23.31% and 70.02%, respectively., (© 2019 The Authors.)
- Published
- 2019
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7. Stabilization of cutinase by covalent attachment on magnetic nanoparticles and improvement of its catalytic activity by ultrasonication.
- Author
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Muley AB, Chaudhari SA, Bankar SB, and Singhal RS
- Abstract
This paper reports on stabilization of serine cutinase activity by immobilizing it through cross linking with glutaraldehyde on magnetic nanoparticles (Fe-NPs) and intensification of catalytic activity by ultrasonic treatment. The optimum parameters were cross linking with 10.52 mM glutaraldehyde for 90 min using 1:2 (w/w) ratio of enzyme:Fe-NPs. The characterization of cutinase-Fe-NPs was done by different instrumental analysis. Ultrasonic power showed a beneficial effect on the activity of free and immobilized cutinase at 5.76 and 7.63 W, respectively, after 12 min. Immobilization and ultrasonic treatment led to increments in kinetic parameters (K
m and Vmax ) along with noticeable changes in the secondary structural fractions of cutinase. Cutinase-Fe-NPs showed augmented pH (4-8) and thermal stability (40-60 °C). Considerably higher thermal inactivation kinetic constants (kd , t1/2 and D-value) and thermodynamic constants (Ed , ΔH°, ΔG° and ΔS°) highlighted superior thermostability of cutinase-Fe-NPs. Cutinase-Fe-NPs and ultrasound treated cutinase-Fe-NPs retained 61.88% and 38.76% activity during 21-day storage, and 82.82 and 80.69% activity after fifth reusability cycle, respectively., (Copyright © 2019 Elsevier B.V. All rights reserved.)- Published
- 2019
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8. Nano-eco toxicity study of gold nanoparticles on aquatic organism Moina macrocopa: As new versatile ecotoxicity testing model.
- Author
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Borase HP, Muley AB, Patil SV, and Singhal RS
- Subjects
- Acetylcholinesterase metabolism, Amylases metabolism, Animals, Behavior, Animal drug effects, Catalase metabolism, Cladocera physiology, Glutathione Transferase metabolism, Heart Rate drug effects, Lethal Dose 50, Superoxide Dismutase metabolism, Toxicity Tests methods, Trypsin metabolism, Cladocera drug effects, Gold toxicity, Metal Nanoparticles toxicity, Water Pollutants, Chemical toxicity
- Abstract
In the field of nanoecotoxicology, very few reports have focused on biochemical changes in non-target organisms after nanoexposure. A less explored aquatic non-target crustacean, Moina macrocopa, was used in the present study to analyze toxicity effects of gold nanoparticles (AuNPs), an emerging nanomaterial. AuNPs was fabricated using tannic acid and were 29 ± 2 nm in size. The 48 h LC
50 value of AuNPs was 14 ± 0.14 mg/L against M. macrocopa. The sub-lethal exposure of M. macrocopa juveniles to AuNPs (1.47 and 2.95 mg/L) decreased the activities of acetyl cholinesterase and digestive enzymes (trypsin and amylase). A concentration dependant increase in the activities of antioxidant enzymes such as catalase, superoxide dismutase and glutathione S-transferase suggested the generation of oxidative stress in M. macrocopa after AuNPs exposure. Changes in enzyme activity can be utilized as biomarker(s) for early detection of nanoparticle contamination in aquatic habitat. AuNPs accumulation in gut of M. macrocopa increased the metal bio burden (11 mg/L) and exhibited inhibitory action on digestive enzymes. Complete depuration of AuNPs was not observed after transferring nano-exposed M. macrocopa to normal medium without AuNPs. AuNPs tended to adhere on external body parts such as setae, carapace of M. macrocopa which interfered with swimming activity and also changed the behavioral pattern. AuNPs underwent agglomeration in the medium used for maintenance of M. macrocopa. As nanomaterials are emerging pollutants in aquatic systems, the present work highlights the hazardous effect of AuNPs and development of enzymatic biomarkers to curtail it at community level., (Copyright © 2019 Elsevier B.V. All rights reserved.)- Published
- 2019
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9. Moina macrocopa as a non-target aquatic organism for assessment of ecotoxicity of silver nanoparticles: Effect of size.
- Author
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Borase HP, Patil SV, and Singhal RS
- Subjects
- Animals, Antioxidants metabolism, Aquatic Organisms drug effects, Ecotoxicology methods, Oxidoreductases metabolism, Particle Size, Silver toxicity, Cladocera drug effects, Metal Nanoparticles toxicity
- Abstract
The release of nanomaterials in water reservoirs is hazardous. Very few reports are available on the interaction of different sized nanoparticles with aquatic organisms and aquatic environment. In the present study, silver nanoparticles (AgNPs) having an average particle size of 20.80 ± 2.31 and 40.04 ± 4.72 nm were synthesized using polyvinylpyrrolidone and l-tyrosine. Ecotoxicological effects of AgNPs were evaluated on less explored crustacean species, Moina macrocopa. The 48 h lethal values (48 h LC
50 ) of 20 and 40 nm AgNPs were 0.11 ± 0.02 and 0.12 ± 0.03 mg/L, respectively. Further, a size dependent inhibition of AgNPs on acetyl cholinesterase and digestive enzymes (trypsin, amylase, β-galactosidase) was observed, while that of the antioxidant enzymes (catalase, superoxide dismutase, glutathione-S-transferase) and alkaline phosphatase were enhanced as compared to control group. These results strengthen the potential of enzymes as biomarker in environmental risk assessment of AgNPs. AgNPs accumulated in the gut of M. macrocopa which could not be completely eliminated, thereby resulting in an increased metal body burden. The accumulation of AgNPs of 20 nm was lower than that of 40 nm indicating the influence of size of nanoparticles on uptake and toxicity. AgNPs agglomerated in moderately hard water medium (MHWM) and this agglomeration influenced the exposure the organism thereto. The size of AgNPs influenced the toxicity to M. macrocopa through interplay between uptake, accumulation, aggregation, and excretion in the organism and environment., (Copyright © 2018 Elsevier Ltd. All rights reserved.)- Published
- 2019
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10. Evaluation and application of prebiotic and probiotic ingredients for development of ready to drink tea beverage.
- Author
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Tewari S, Dubey KK, and Singhal RS
- Abstract
Ready-to-drink (RTD) ice tea is a ready prepared tea, produced from green and black tea originating from same plant Camellia sinensis . The objective of this study was to determine the effect of prebiotics [galacto-oligosaccharide (GOS), fructo-oligosaccharide (FOS), and inulin] or synbiotic ingredients (GOS, FOS, inulin, and Lactobacillus acidophilus ) on the sensory properties and consumer acceptability of RTD. The quality of green tea extract (GTE) and black tea extract (BTE) was improved with pretreatment of cellulase and pectinase enzymes. The combined enzymatic extraction amplified total extractives up to 76% in GTE and 72% in BTE. Total polyphenol was found to be enhanced to 24% in GTE and 19% in BTE. GTE was further selected for development of RTD in two different formats; synbiotic RTD and prebiotic RTD premix and analyzed for sensory attributes (colour, aroma, taste, and acceptability). Synbiotic RTD was also evaluated for stability over a period of 28 days at 4 °C. Synbiotic RTD developed an unpleasant flavor and aroma during the shelf life. Premix format of RTD developed using spray drying was reconstituted and found to be functionally and sensorially acceptable., Competing Interests: Compliance with ethical standardsWe declare that the work described is approved by all authors and the responsible authorities where the work was carried out.
- Published
- 2018
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11. Antioxidant Compounds in Traditional Indian Pickles May Prevent the Process-Induced Formation of Benzene.
- Author
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Kharat MM, Adiani V, Variyar P, Sharma A, and Singhal RS
- Subjects
- Food Contamination analysis, Food Handling, Gas Chromatography-Mass Spectrometry, India, Antioxidants chemistry, Ascorbic Acid chemistry, Benzene analysis, Cucumis sativus chemistry, Food Additives chemistry
- Abstract
Pickles in the Indian market contain ascorbic acid from the raw material used and benzoate as an added preservative that are involved in the formation of benzene in soft drinks. In this work, 24 market pickle samples were surveyed for benzene content, as well as its precursors and other constituents that influence its formation. The analysis showed that pickle samples were high in acid content (low pH) and showed significant amount of ascorbic acid, minerals (Cu and Fe), and benzoic acid present in them. Also, most samples exhibited high antioxidant activity that might be attributed to the ingredients used, such as fruits and spices. The solid-phase microextraction headspace gas chromatography-mass spectrometry method was developed in-house for benzene analysis. Eleven of 24 samples had benzene, with the highest concentration of 4.36 ± 0.82 μg of benzene per kg of pickle for a lime pickle that was also reported to have highest benzoic acid and considerably less hydroxyl radical ((•)OH) scavenging activity. However, benzene levels for all 11 samples were considerably below the World Health Organization regulatory limit of 10 μg/kg for benzene in mineral water. Studies on model systems revealed that the high antioxidant activity of Indian pickles may have had a strong inhibitory effect on benzene formation.
- Published
- 2016
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12. Interaction of carbohydrates with alcohol dehydrogenase: Effect on enzyme activity.
- Author
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Jadhav SB, Bankar SB, Granström T, Ojamo H, Singhal RS, and Survase SA
- Subjects
- Alcohol Dehydrogenase chemistry, Enzyme Inhibitors chemistry, Enzyme Inhibitors metabolism, Enzyme Inhibitors pharmacology, Glucose chemistry, Glucose pharmacology, Hydrogen-Ion Concentration, Kinetics, Oxidation-Reduction, Pectins chemistry, Pectins pharmacology, Protein Binding, Spectrometry, Fluorescence, Starch chemistry, Starch pharmacology, Sulfhydryl Compounds metabolism, Alcohol Dehydrogenase antagonists & inhibitors, Alcohol Dehydrogenase metabolism, Glucose metabolism, Pectins metabolism, Starch metabolism
- Abstract
Alcohol dehydrogenase was covalently conjugated with three different oxidized carbohydrates i.e., glucose, starch and pectin. All the carbohydrates inhibited the enzyme. The inhibition was studied with respect to the inhibition rate constant, involvement of thiol groups in the binding, and structural changes in the enzyme. The enzyme activity decreased to half of its original activity at the concentration of 2 mg/mL of pectin, 4 mg/mL of glucose and 10 mg/mL of starch within 10 min at pH 7. This study showed oxidized pectin to be a potent inhibitor of alcohol dehydrogenase followed by glucose and starch. Along with the aldehyde-amino group interaction, thiol groups were also involved in the binding between alcohol dehydrogenase and carbohydrates. The structural changes occurring on binding of alcohol dehydrogenase with oxidized carbohydrates was also confirmed by fluorescence spectrophotometry. Oxidized carbohydrates could thus be used as potential inhibitors of alcohol dehydrogenase., (Copyright © 2015 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.)
- Published
- 2015
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13. Chaotropicity: a key factor in product tolerance of biofuel-producing microorganisms.
- Author
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Cray JA, Stevenson A, Ball P, Bankar SB, Eleutherio EC, Ezeji TC, Singhal RS, Thevelein JM, Timson DJ, and Hallsworth JE
- Subjects
- Animals, Anti-Bacterial Agents biosynthesis, Butanols metabolism, Ethanol metabolism, Fermentation, Humans, Saccharomyces cerevisiae metabolism, Biofuels
- Abstract
Fermentation products can chaotropically disorder macromolecular systems and induce oxidative stress, thus inhibiting biofuel production. Recently, the chaotropic activities of ethanol, butanol and vanillin have been quantified (5.93, 37.4, 174kJ kg(-1)m(-1) respectively). Use of low temperatures and/or stabilizing (kosmotropic) substances, and other approaches, can reduce, neutralize or circumvent product-chaotropicity. However, there may be limits to the alcohol concentrations that cells can tolerate; e.g. for ethanol tolerance in the most robust Saccharomyces cerevisiae strains, these are close to both the solubility limit (<25%, w/v ethanol) and the water-activity limit of the most xerotolerant strains (0.880). Nevertheless, knowledge-based strategies to mitigate or neutralize chaotropicity could lead to major improvements in rates of product formation and yields, and also therefore in the economics of biofuel production., (Copyright © 2015 Elsevier Ltd. All rights reserved.)
- Published
- 2015
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14. Is there a common water-activity limit for the three domains of life?
- Author
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Stevenson A, Cray JA, Williams JP, Santos R, Sahay R, Neuenkirchen N, McClure CD, Grant IR, Houghton JD, Quinn JP, Timson DJ, Patil SV, Singhal RS, Antón J, Dijksterhuis J, Hocking AD, Lievens B, Rangel DE, Voytek MA, Gunde-Cimerman N, Oren A, Timmis KN, McGenity TJ, and Hallsworth JE
- Subjects
- Archaea metabolism, Artifacts, Ascomycota metabolism, Carbohydrates chemistry, Fungi metabolism, Hydrogen-Ion Concentration, Sodium Chloride chemistry, Staphylococcus aureus metabolism, Temperature, Water physiology, Water Microbiology, Aspergillus metabolism, Bacteria metabolism, Halobacterium metabolism
- Abstract
Archaea and Bacteria constitute a majority of life systems on Earth but have long been considered inferior to Eukarya in terms of solute tolerance. Whereas the most halophilic prokaryotes are known for an ability to multiply at saturated NaCl (water activity (a(w)) 0.755) some xerophilic fungi can germinate, usually at high-sugar concentrations, at values as low as 0.650-0.605 a(w). Here, we present evidence that halophilic prokayotes can grow down to water activities of <0.755 for Halanaerobium lacusrosei (0.748), Halobacterium strain 004.1 (0.728), Halobacterium sp. NRC-1 and Halococcus morrhuae (0.717), Haloquadratum walsbyi (0.709), Halococcus salifodinae (0.693), Halobacterium noricense (0.687), Natrinema pallidum (0.681) and haloarchaeal strains GN-2 and GN-5 (0.635 a(w)). Furthermore, extrapolation of growth curves (prone to giving conservative estimates) indicated theoretical minima down to 0.611 aw for extreme, obligately halophilic Archaea and Bacteria. These were compared with minima for the most solute-tolerant Bacteria in high-sugar (or other non-saline) media (Mycobacterium spp., Tetragenococcus halophilus, Saccharibacter floricola, Staphylococcus aureus and so on) and eukaryotic microbes in saline (Wallemia spp., Basipetospora halophila, Dunaliella spp. and so on) and high-sugar substrates (for example, Xeromyces bisporus, Zygosaccharomyces rouxii, Aspergillus and Eurotium spp.). We also manipulated the balance of chaotropic and kosmotropic stressors for the extreme, xerophilic fungi Aspergillus penicilloides and X. bisporus and, via this approach, their established water-activity limits for mycelial growth (∼0.65) were reduced to 0.640. Furthermore, extrapolations indicated theoretical limits of 0.632 and 0.636 a(w) for A. penicilloides and X. bisporus, respectively. Collectively, these findings suggest that there is a common water-activity limit that is determined by physicochemical constraints for the three domains of life.
- Published
- 2015
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15. Investigations on ideal mode of cell disruption in extremely halophilic Actinopolyspora halophila (MTCC 263) for efficient release of glycine betaine and trehalose.
- Author
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Kar JR and Singhal RS
- Abstract
Actinopolyspora halophila produces glycine betaine and trehalose intracellularly in considerable quantities. These biomolecules are commercially important as they have applications in food, pharmaceuticals, and agricultural sector. Development of an efficient cell disruption technique is an important step for the release of these biomolecules. In this study, various cell disruption methods such as chemical, enzymatic, physico-mechanical and physical methods were evaluated. Cell disruption by osmotic shock was found to be the best suited method for A. halophila which also has a potential to be industrially scaled up. Cell bursting pressure that is generated during osmotic shock in A. halophila was computed using Morse equation and was found to be π = 238.37 ± 29.54 atm or 2.35 ± 0.29 kPa. In addition, it was found that osmotic shock followed a first order release rate kinetics in A. halophila . The findings can be used for commercially important biomolecules from other halophilic and/or halotolerant microbes.
- Published
- 2014
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16. Degradation of colour in beetroot (Beta vulgaris L.): a kinetics study.
- Author
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Chandran J, Nisha P, Singhal RS, and Pandit AB
- Abstract
The kinetics of colour (measured as Hunter 'a/b' value) degradation in beetroot puree (Beta vulgaris L.) was studied over a temperature range of 50-120 °C (isothermal process), and also during normal open pan cooking, pressure-cooking and a newly developed and patented fuel-efficient 'EcoCooker' (non-isothermal heating process). The degradation of visual colour as measured as Hunter 'a/b' value was found to follow a first order kinetics, where the rate constant increased with an increase in the temperature. The temperature dependence of degradation was adequately modeled by Arrhenius equation. A mathematical model has been developed using the kinetic parameters obtained from the isothermal experiments to predict the losses of color in the non-isothermal heating/processing method based on the time-temperature data for each of the methods. The results obtained indicate a colour degradation of similar magnitude in all the three modes of cooking used in the study.
- Published
- 2014
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17. Enhanced stability of alcohol dehydrogenase by non-covalent interaction with polysaccharides.
- Author
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Jadhav SB, Bankar SB, Granström T, Ojamo H, Singhal RS, and Survase SA
- Subjects
- Enzyme Stability, Hydrogen-Ion Concentration, Kinetics, Protein Binding, Temperature, Alcohol Dehydrogenase chemistry, Alcohol Dehydrogenase metabolism, Gum Arabic metabolism
- Abstract
Non-covalent interaction of alcohol dehydrogenase with polysaccharides was studied using three neutral and three anionic polysaccharides. The process of interaction of alcohol dehydrogenase with gum Arabic was optimized with respect to the ratio of enzyme to gum Arabic, pH, and molarity of buffer. Alcohol dehydrogenase-gum Arabic complex formed under optimized conditions showed 93% retention of original activity with enhanced thermal and pH stability. Lower inactivation rate constant of alcohol dehydrogenase-gum Arabic complex within the temperature range of 45 to 60 °C implied its better stability. Half-life of alcohol dehydrogenase-gum Arabic complex was higher than that of free alcohol dehydrogenase. A slight increment was observed in kinetic constants (K(m) and V(max)) of gum Arabic-complexed alcohol dehydrogenase which may be due to interference by gum Arabic for the binding of substrate to the enzyme. Helix to turn conversion was observed in complexed alcohol dehydrogenase as compared to free alcohol dehydrogenase which may be responsible for observed stability enhancement.
- Published
- 2014
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18. Characterization and in vitro probiotic evaluation of lactic acid bacteria isolated from idli batter.
- Author
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Iyer BK, Singhal RS, and Ananthanarayan L
- Abstract
An Indian traditional fermented food, idli batter, was used as a source for isolation of lactic acid bacteria (LAB). A total of 15 LAB strains were isolated on the basis of their Gram nature and catalase activity. Of these, one lactobacilli strain and one lactococci strain which showed antimicrobial activity were identified using biochemical characterization, sugar utilization and molecular sequencing. The microbes, labeled as IB-1 (Lactobacillus plantarum) and IB-2 (Lactococcus lactis) were tested for their in vitro tolerance to bile salts, resistance to low pH values and acidifying activity. Both the strains showed good viability (IB1- 58.11%; IB2- 60.84%) when exposed to high bile salt concentration (2%) and acidic pH of ≤pH 3.0 (IB1- 88.13%; IB2- 89.85%). Lactic acid (IB1- 181.93 mM; IB2- 154.44 mM), biomass production (IB1- 0.65; IB2- 0.58 g/l) after 54 h as well as qualitative estimation of β-galactosidase and vitamin B12 production were also studied to check their suitability as an industrially important strain for production of important biomolecules.
- Published
- 2013
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19. Determination of common genetic variants in cytidine deaminase (CDA) gene in Indian ethnic population.
- Author
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Iyer SN, Ankala A, Singhal RS, and Hegde MR
- Subjects
- Adult, Cohort Studies, DNA Mutational Analysis, Enzyme Activation, Gene Frequency, Genetic Markers, Genetics, Population, Humans, India, Introns, Neoplasms enzymology, Neoplasms genetics, Pilot Projects, Polymerase Chain Reaction, Asian People genetics, Cytidine Deaminase genetics, Ethnicity genetics, Polymorphism, Single Nucleotide
- Abstract
Cytidine deaminase (CDA) is the major enzyme involved in metabolism of gemcitabine, a pyrimidine analog widely used for chemotherapy of solid tumors. While only low amounts of administered gemcitabine undergo intracellular phosphorylation into active forms and involve in antineoplastic activities, majority of it is rapidly inactivated by CDA and excreted to avoid drug toxicity. Knowledge of the genetic polymorphisms mildly effecting cellular activity of the enzyme CDA is therefore crucial to understanding drug-induced toxicities associated with gemcitabine. Functional significance and allele frequencies for common SNPs including 79A>C (*2) and 208G>A (*3) have been reported in various ethnic populations including Caucasian, African, Korean and Japanese. However, such studies have not been reported in any Indian sub-population. In the present study, conventional polymerase chain reaction (PCR) based amplification using gene specific primers and Sanger sequencing were performed to identify CDA variants in 50 healthy individuals from Indian sub-population. Established common variant 79A>C known to reduce CDA activity was observed at a frequency of 0.14 in the study cohort. In addition to other known variants, one novel variant, c.325-209T>C was detected at a frequency of 0.06. Genetic variants in CDA gene and their frequencies established in our study hold value in pharmacogenetics., (Copyright © 2013 Elsevier B.V. All rights reserved.)
- Published
- 2013
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20. Genotype frequencies of drug-metabolizing enzymes responsible for purine and pyrimidine antagonists in a healthy Asian-Indian population.
- Author
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Iyer SN, Tilak AV, Mukherjee MS, and Singhal RS
- Subjects
- Adolescent, Adult, Alleles, Asian People genetics, Enzyme Activation, Female, Genetics, Population methods, Genotype, Genotyping Techniques, Humans, India, Male, Middle Aged, Polymerase Chain Reaction, Polymorphism, Genetic, Polymorphism, Restriction Fragment Length, Prevalence, Young Adult, Cytidine Deaminase genetics, Dihydrouracil Dehydrogenase (NADP) genetics, Gene Frequency, Methyltransferases genetics, Purines antagonists & inhibitors, Pyrimidines antagonists & inhibitors
- Abstract
Purine and pyrimidine antimetabolites are used to treat leukemias, autoimmune diseases, and solid tumors. Detection of slow metabolizers before administration of the drugs is necessary to prevent any subsequent drug toxicity. With this aim, we determined the frequencies of normal and slow alleles in our population. Polymorphisms in genes encoding cytidine deaminase (CDA), dihydropyrimidine dehydrogenase (DPYD), and thiopurine-S-methyltransferase (TPMT) were documented in 225 healthy volunteers. The polymorphisms typed included CDA*3, DPYD*2A, TPMT*2A, TPMT*3B, and TPMT*3C. Methods used for genotyping included standard PCR-RFLP and allele-specific PCR reactions. The frequencies were 0.44 % for DPYD*2A, 0.67 % for TPMT*3B, and 0.89 % for TPMT*3C. The CDA*3 and TPMT*2A alleles were not detected. Although these polymorphisms have been demonstrated to be associated with drug toxicity in other populations, they appear to be very rare in the adult Indian population.
- Published
- 2012
- Full Text
- View/download PDF
21. Improved activity and stability of Rhizopus oryzae lipase via immobilization for citronellol ester synthesis in supercritical carbon dioxide.
- Author
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Dhake KP, Deshmukh KM, Patil YP, Singhal RS, and Bhanage BM
- Subjects
- Acyclic Monoterpenes, Enzyme Stability, Enzymes, Immobilized metabolism, Equipment Reuse, Esterification, Esters chemistry, Esters metabolism, Laurates, Lipase metabolism, Monoterpenes chemistry, Spectroscopy, Fourier Transform Infrared, Temperature, Time Factors, Carbon Dioxide chemistry, Enzymes, Immobilized chemistry, Lipase chemistry, Monoterpenes metabolism, Rhizopus enzymology
- Abstract
In present work, Rhizopus oryzae lipase immobilized on a film prepared using blend of hydroxylpropyl methyl cellulose (HPMC) and polyvinyl alcohol (PVA) was investigated for synthesis of citronellol esters with supercritical carbon dioxide (Sc-CO(2)) as a reaction medium. The transesterification reaction was optimized for various reaction parameters like effect of molar ratio, acyl donor, time, temperature, enzyme concentration, effect of pressure and co-solvent to achieve the maximum yield of desired product. The results obtained signify remarkable increment (about eightfold) in the yield of citronellol acetate (91%) as compared to that of free lipase (11%) in Sc-CO(2). The developed biocatalytic methodology provides a substantial advantage of low biocatalyst loading (1.5%, w/v), lower reaction temperature (45°C) and lower pressure (8 MPa) as compared to previous reports. The immobilization method has significantly enhanced the operational stability of lipase for ester synthesis under Sc-CO(2) conditions. The developed methodology was successfully applied for synthesis of three different industrially important citronellol esters namely citronellol acetate (91%), citronellol butyrate (98%), citronellol laurate (99%) with excellent yields using vinyl esters as acyl donor under Sc-CO(2) conditions. In addition, the immobilized biocatalyst was effectively recycled for three consecutive recycles., (Copyright © 2011 Elsevier B.V. All rights reserved.)
- Published
- 2011
- Full Text
- View/download PDF
22. Cyclosporin A--a review on fermentative production, downstream processing and pharmacological applications.
- Author
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Survase SA, Kagliwal LD, Annapure US, and Singhal RS
- Subjects
- Amino Acid Sequence, Animals, Cyclosporine chemistry, Cyclosporine pharmacokinetics, Drug Interactions, Humans, Molecular Sequence Data, Structure-Activity Relationship, Biotechnology methods, Cyclosporine metabolism, Cyclosporine pharmacology, Fermentation drug effects
- Abstract
In present times, the immunosuppressants have gained considerable importance in the world market. Cyclosporin A (CyA) is a cyclic undecapeptide with a variety of biological activities including immunosuppressive, anti-inflammatory, antifungal and antiparasitic properties. CyA is produced by various types of fermentation techniques using Tolypocladium inflatum. In the present review, we discuss the biosynthetic pathway, fermentative production, downstream processing and pharmacological activities of CyA., (Copyright © 2011 Elsevier Inc. All rights reserved.)
- Published
- 2011
- Full Text
- View/download PDF
23. Improved poly-ε-lysine biosynthesis using Streptomyces noursei NRRL 5126 by controlling dissolved oxygen during fermentation.
- Author
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Bankar SB and Singhal RS
- Subjects
- Bioreactors microbiology, Culture Media, Fermentation, Glycerol metabolism, Kinetics, Streptomyces classification, Streptomyces metabolism, Biotechnology methods, Oxygen metabolism, Polylysine biosynthesis, Streptomyces growth & development
- Abstract
The growth kinetics of Streptomyces noursei NRRL 5126 was investigated under different aeration and agitation combinations in a 5.0 l stirred tank fermenter. Poly-epsilon-lysine biosynthesis, cell mass formation, and glycerol utilization rates were affected markedly by both aeration and agitation. An agitation speed of 300 rpm and aeration rate at 2.0 vvm supported better yields of 1,622.81 mg/l with highest specific productivity of 15 mg/l.h. Fermentation kinetics performed under different aeration and agitation conditions showed poly- epsilon-lysine fermentation to be a growth-associated production. A constant DO at 40% in the growth phase and 20% in the production phase increased the poly-epsilon-lysine yield as well as cell mass to their maximum values of 1,992.35 mg/l and 20.73 g/l, respectively. The oxygen transfer rate (OTR), oxygen utilization rate (OUR), and specific oxygen uptake rates (qO2) in the fermentation broth increased in the growth phase and remained unchanged in the stationary phase.
- Published
- 2011
24. Gellan gum as an immobilization matrix for the production of cyclosporin A.
- Author
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Suvase SA, Annapure US, and Singhal RS
- Subjects
- Biomass, Leucine metabolism, Mycelium metabolism, Valine metabolism, Cyclosporine metabolism, Hypocreales metabolism, Industrial Microbiology methods, Polysaccharides, Bacterial chemistry
- Abstract
This study explored the use of gellan gum as an immobilization matrix for production of cyclosporin A (CyA) by immobilized spores and mycelia of Tolypocladium inflatum MTCC 557. Different carriers, such as gellan gum, sodium alginate, celite beads and silica, were tested as immobilization carriers, along with the role of the carrier concentration, biomass weight, number of spore-inoculated beads, and repeated utilization of the immobilized fungus. The maximum CyA production was 274 mg/l when using gellan gum (1 % w/v) and a mycelial weight of 7.5 % w/v supported the maximum production of CyA. Additionally, a combination of L-valine (6 g/l) and L-leucine (5 g/l) after 48 h of fermentation produced 1,338 mg/l when using gellan gum. The immobilized mycelia beads were found to remain stable for four repetitive cycles, indicating their use for semi-continuous CyA production.
- Published
- 2010
- Full Text
- View/download PDF
25. Evolutionary operation (EVOP) to optimize whey independent serratiopeptidase production from Serratia marcescens NRRL B-23112.
- Author
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Pansuriya RC and Singhal RS
- Subjects
- Bacterial Proteins chemistry, Culture Media metabolism, Fermentation, Hydrogen-Ion Concentration, Milk Proteins metabolism, Peptide Hydrolases chemistry, Serratia marcescens chemistry, Temperature, Whey Proteins, Bacterial Proteins metabolism, Culture Media chemistry, Peptide Hydrolases metabolism, Serratia marcescens enzymology
- Abstract
Serratiopeptidase (SRP), a 50 kDa metalloprotease produced from Serratia marcescens species is a drug with potent anti-inflammatory property. In this study, a powerful statistical design, Evolutionary operation (EVOP) was applied to optimize the media composition for SRP production in shake-flask culture of Serratia. marcescens NRRL B-23112. Initially, factors such as inoculum size, initial pH, carbon source and organic nitrogen source were optimized using one factor at a time. Most significant medium components affecting the production of SRP were identified as maltose, soybean meal and KHPO. The SRP so produced was not found to be dependent on whey protein, rather notably induced by most of the organic nitrogen sources used in the study and free from other concomitant protease contaminant revealed by protease inhibition study. Further, experiments were performed using different sets of EVOP design with each factor varied at three levels. The experimental data were analyzed with standard set of statistical formula. The EVOP optimized medium, maltose 4.5%, soybean meal 6.5%, KHPO 0.8% and NaCl 0.5% w/v gave SRP production of 7,333 EU/ml, which was 17-fold higher than the unoptimized media. The application of EVOP resulted in significant enhancement of SRP production.
- Published
- 2010
- Full Text
- View/download PDF
26. Production of glutaminase(E.C. 3.2.1.5) from Zygosaccharomyces rouxii in solid-state fermentation and modeling the growth of Z. rouxii therein.
- Author
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Iyer P and Singhal RS
- Subjects
- Fermentation, Glutaminase metabolism, Models, Biological, Models, Statistical, Zygosaccharomyces metabolism, Glutaminase biosynthesis, Industrial Microbiology methods, Zygosaccharomyces enzymology, Zygosaccharomyces growth & development
- Abstract
Glutaminase production in Zygosacchromyces rouxii by solid-state fermentation (SSF) is detailed. Substrates screening showed best results with oatmeal (OM) and wheatbran (WB). Further, a 1:1 combination of OM: WB gave 0.614units/gds with artificial sea water (ASW) as moistening agent. Evaluation of additional carbon, nitrogen, aminoacids and minerals supplementation was done. A central composite design was employed to investigate effects of four variables, viz. moisture content, glucose, corn steep liquor and glutamine on production. A 4-fold increase in enzyme production was obtained. Studies were undertaken to analyze the time course model the microbial growth and nutrient utilization during SSF. Logistic equation (R2=0.8973), describing the growth model of Z.rouxii was obtained, with maximum values of micronm and Xm at 0.326h-1 and 7.35% of dry matter weight loss, respectively. A good-fit model to describe utilization of total carbohydrate (R2=0.9906) nitrogen concentration (R2=0.9869) with time was obtained. The model was used successfully to predict enzyme production (R2=0.7950).
- Published
- 2010
27. Response surface methodology for optimization of production of lovastatin by solid state fermentation.
- Author
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Pansuriya RC and Singhal RS
- Abstract
Lovastatin, an inhibitor of HMG-CoA reductase, was produced by solid state fermentation (SSF) using a strain of Aspergillus terreus UV 1718. Different solid substrates and various combinations thereof were evaluated for lovastatin production. Wheat bran supported the maximum production (1458 ± 46 µg g(-1) DFM) of lovastatin. Response surface methodology (RSM) was applied to optimize the medium constituents. A 2(4) full-factorial central composite design (CCD) was chosen to explain the combined effects of the four medium constituents, viz. moisture content, particle size of the substrate, di -potassium hydrogen phosphate and trace ion solution concentration. Maximum lovastatin production of 2969 µg g(-1) DFM was predicted by the quadratic model which was verified experimentally to be 3004 ± 25 μg g(-1) DFM. Further RSM optimized medium supplemented with mycological, peptone supported highest yield of 3723.4±49 µg g(-1) DFM. Yield of lovastatin increased to 2.5 fold as with compared to un-optimized media.
- Published
- 2010
- Full Text
- View/download PDF
28. Statistical optimization for improved production of cyclosporin a in solid-state fermentation.
- Author
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Survase SA, Annapure US, and Singhal RS
- Subjects
- Ammonium Sulfate chemistry, Ammonium Sulfate metabolism, Coconut Oil, Culture Media chemistry, Culture Media metabolism, Dietary Fiber metabolism, Glycerol chemistry, Glycerol metabolism, Hypocreales growth & development, Hypocreales metabolism, Industrial Microbiology methods, Iron Compounds chemistry, Iron Compounds metabolism, Leucine chemistry, Leucine metabolism, Plant Oils chemistry, Plant Oils metabolism, Time Factors, Valine chemistry, Valine metabolism, Cyclosporine metabolism, Fermentation, Models, Biological, Models, Statistical
- Abstract
This work evaluates the effect of different amino acids on production of CyA production in solid-state fermentation that was previously optimized for different fermentation parameters by one-factor-at-a-time for the maximum production of CyA by Tolypocladium inflatum MTCC 557. Based on the Plackett-Burman design, glycerol, ammonium sulfate, FeCl3, and inoculum size were selected for further optimization by response surface methodology (RSM). After identifying effective nutrients, RSM was used to develop mathematical model equations, study responses, and establish the optimum concentrations of the key nutrients for higher CyA production. It was observed that supplementation of medium containing (% w/w) glycerol, 1.53; ammonium sulfate, 0.95; FeCl3, 0.18; and inoculum size 6.4 ml/5g yielded a maximum of 7,106 mg/kg as compared with 6,480 mg CyA/kg substrate using one factor at a time. In the second step, the effect of amino acids on the production of CyA was studied. Addition of L-valine and L-leucine in combination after 20 h of fermentation resulted in maximum production of 8,166 mg/kg.
- Published
- 2009
- Full Text
- View/download PDF
29. Effect of precultural and nutritional parameters on compactin production by solid-state fermentation.
- Author
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Shaligram NS, Singh SK, Singhal RS, Szakacs G, and Pandey A
- Subjects
- Bioreactors, Culture Media chemistry, Glucose chemistry, Glucose metabolism, Industrial Microbiology methods, Lovastatin biosynthesis, Maltose chemistry, Maltose metabolism, Penicillium growth & development, Penicillium metabolism, Polysaccharides chemistry, Polysaccharides metabolism, Fermentation, Lovastatin analogs & derivatives
- Abstract
In the present study, production of compactin by Penicillium brevicompactum WA 2315 was studied. In the first step, various precultural parameters were studied by substituting one factor at a time. Subsequently, the effect of maltodextrin DE 18 on compactin production was studied. The optimized parameters gave maximum compactin production of 850 mug/gds as compared with 678 mug/gds before optimization. Statistical study was performed to further improve the production and develop a robust model. An improved yield of 950 mug/gds was obtained using the conditions proposed by the experimental model. The present study emphasizes the importance of precultural and nutritional parameters on the production of compactin, and further confirms the usefulness of solid-state fermentation for the production of industrially important secondary metabolites. It also confirms that complex nitrogen sources such as oil cakes can be used for the production of compactin.
- Published
- 2009
- Full Text
- View/download PDF
30. Glucose oxidase--an overview.
- Author
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Bankar SB, Bule MV, Singhal RS, and Ananthanarayan L
- Subjects
- Bioreactors, Enzymes, Immobilized chemistry, Enzymes, Immobilized genetics, Enzymes, Immobilized metabolism, Kinetics, Recombinant Proteins chemistry, Recombinant Proteins genetics, Recombinant Proteins metabolism, Glucose Oxidase chemistry, Glucose Oxidase genetics, Glucose Oxidase metabolism
- Abstract
Glucose oxidase (beta-D-glucose:oxygen 1-oxidoreductase; EC 1.1.2.3.4) catalyzes the oxidation of beta-D-glucose to gluconic acid, by utilizing molecular oxygen as an electron acceptor with simultaneous production of hydrogen peroxide. Microbial glucose oxidase is currently receiving much attention due to its wide applications in chemical, pharmaceutical, food, beverage, clinical chemistry, biotechnology and other industries. Novel applications of glucose oxidase in biosensors have increased the demand in recent years. Present review discusses the production, recovery, characterization, immobilization and applications of glucose oxidase. Production of glucose oxidase by fermentation is detailed, along with recombinant methods. Various purification techniques for higher recovery of glucose oxidase are described here. Issues of enzyme kinetics, stability studies and characterization are addressed. Immobilized preparations of glucose oxidase are also discussed. Applications of glucose oxidase in various industries and as analytical enzymes are having an increasing impact on bioprocessing.
- Published
- 2009
- Full Text
- View/download PDF
31. A novel medium for the enhanced production of cyclosporin A by Tolypocladium inflatum MTCC 557 using solid state fermentation.
- Author
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Survase SA, Shaligram NS, Pansuriya RC, Annapure US, and Singhal RS
- Subjects
- Carbon chemistry, Carbon metabolism, Claviceps growth & development, Coconut Oil, Culture Media metabolism, Dietary Fiber metabolism, Hydrogen-Ion Concentration, Hydrolysis, Industrial Microbiology methods, Nitrogen chemistry, Nitrogen metabolism, Plant Oils chemistry, Plant Oils metabolism, Salts chemistry, Salts metabolism, Temperature, Claviceps metabolism, Culture Media chemistry, Cyclosporine metabolism, Fermentation
- Abstract
Cyclosporin A (CyA) produced by Tolypocladium inflatum is a promising drug owing to its immunosuppressive and antifungal activities. From an industrial point of view, the necessity to obtain a suitable and economic medium for higher production of CyA was the aim of this work. The present study evaluated the effect of different fermentation parameters in solid state fermentation, such as selection of solid substrate, hydrolysis of substrates, initial moisture content, supplementation of salts, additional carbon, and nitrogen sources, as well as the inoculum age and size, on production of CyA by Tolypocladium inflatum MTCC 557. The fermentation was carried out at 25+/-2 degrees for 9 days. A combination of hydrolyzed wheat bran flour and coconut oil cake (1:1) at 70% initial moisture content supported a maximum production of 3,872+/-156 mg CyA/kg substrate as compared with 792+/-33 mg/kg substrate before optimization. Furthermore, supplementation of salts, glycerol (1%w/w), and ammonium sulfate (1%w/w) increased the production of CyA to 5,454+75 mg/kg substrate. Inoculation of 5 g of solid substrate with 6 ml of 72-h-old seed culture resulted in a maximum production of 6,480+95 mg CyA/kg substrate.
- Published
- 2009
- Full Text
- View/download PDF
32. Enhanced production of poly (gamma-glutamic acid) from Bacillus licheniformis NCIM 2324 in solid state fermentation.
- Author
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Bajaj IB, Lele SS, and Singhal RS
- Subjects
- Bioreactors, Culture Media, Polyglutamic Acid biosynthesis, Polyglutamic Acid isolation & purification, Bacillus metabolism, Fermentation, Industrial Microbiology, Polyglutamic Acid analogs & derivatives
- Abstract
This work reports on the optimization of PGA production by Bacillus licheniformis NCIM 2324 in solid state fermentation (SSF). In the first step, the one factor-at-a-time method was used to investigate the effect of solid substrates, initial moisture content, pH, and additional carbon and nitrogen source on PGA production; subsequently, response surface methodology (RSM) was used to establish the optimum concentrations of the key nutrients for higher PGA production. In the second step, the effects of amino acids and TCA cycle intermediates on the production of PGA were studied. The final optimized medium gave a maximum yield of 98.64 +/- 1.61 mg gds(-1) of PGA, which is significantly higher than that reported in the literature.
- Published
- 2008
- Full Text
- View/download PDF
33. Clavulanic acid: a review.
- Author
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Saudagar PS, Survase SA, and Singhal RS
- Subjects
- Animals, Communicable Diseases drug therapy, Fermentation, Humans, Clavulanic Acid adverse effects, Clavulanic Acid biosynthesis, Clavulanic Acid chemistry, Clavulanic Acid therapeutic use
- Abstract
Natural antibiotics are almost universal secondary metabolites, not essential for the growth of the producing organisms generally produced at low growth rates or after growth has ceased. Clavulanic acid (CA), a naturally occurring powerful inhibitor of bacterial beta-lactamases is a major beta-lactam antibiotic produced by organism Streptomyces clavuligerus and is active against a wide spectrum of Gram-positive and Gram-negative bacteria. The review discusses the biosynthetic pathway, fermentative production, downstream processing and applications of CA.
- Published
- 2008
- Full Text
- View/download PDF
34. Use of insoluble yeast beta-glucan as a support for immobilization of Candida rugosa lipase.
- Author
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Vaidya BK and Singhal RS
- Subjects
- Candida enzymology, Enzyme Stability, Hydrogen-Ion Concentration, Saccharomyces cerevisiae chemistry, Temperature, Enzymes, Immobilized, Lipase metabolism, beta-Glucans chemistry
- Abstract
In the present study, insoluble yeast beta-glucan (IYG) has been explored as a support matrix for enzyme immobilization. IYG contains mainly beta-(1-3) linkages along with some intra- or inter-molecular branches of beta-(1-6) linkages with large number of free hydroxyl groups. Epichlorohydrin was used to convert these free hydroxyl groups into activated epoxy groups that are capable of forming covalent linkages with various groups of enzyme molecule. The epoxy-activated IYG was evaluated for immobilization of Candida rugosa lipase (CRL). Post-immobilization treatment of 5% glutaraldehyde was given in order to achieve stable and irreversible binding of enzyme on the support. The resultant biocatalytic IYG support expressed lipase activity of 8136.7 U/g and 59.6% activity yield. There was 51.05% retention of synthetic activity after six repeated esterification cycles, indicating its stability and reusability in non-aqueous medium. Moreover, the immobilized lipase gave the storage half-life of about 285 days (at 4 degrees C).
- Published
- 2008
- Full Text
- View/download PDF
35. Production of cephamycin C by Streptomyces clavuligerus NT4 using solid-state fermentation.
- Author
-
Bussari B, Saudagar PS, Shaligram NS, Survase SA, and Singhal RS
- Subjects
- Amino Acids metabolism, Biotechnology methods, Cottonseed Oil metabolism, Culture Media chemistry, Fermentation, Streptomyces genetics, Streptomyces growth & development, Substrate Specificity, Anti-Bacterial Agents biosynthesis, Cephamycins biosynthesis, Streptomyces metabolism
- Abstract
Cephamycin C is an extracellular broad spectrum beta-lactam antibiotic produced by Streptomyces clavuligerus, S. cattleya and Nocardia lactamdurans. In the present study, different substrates for solid-state fermentation were screened for maximum cephamycin C production by S. clavuligerus NT4. The fermentation parameters such as substrate concentration, moisture content, potassium dihydrogen phosphate, inoculum size and ammonium oxalate were optimized by response surface methodology (RSM). The optimized conditions yielded 21.68 +/- 0.76 mg gds(-1) of cephamycin C as compared to 10.50 +/- 1.04 mg gds(-1) before optimization. Effect of various amino acids on cephamycin C production was further studied by using RSM, which resulted in increased yield of 27.41 +/- 0.65 mg gds(-1).
- Published
- 2008
- Full Text
- View/download PDF
36. Statistical approach to optimization of fermentative production of gellan gum from Sphingomonas paucimobilis ATCC 31461.
- Author
-
Bajaj IB, Saudagar PS, Singhal RS, and Pandey A
- Subjects
- Culture Media, Bioreactors microbiology, Industrial Microbiology methods, Polysaccharides, Bacterial biosynthesis, Sphingomonas growth & development
- Abstract
Gellan gum, a high-molecular-weight anionic linear polysaccharide produced by pure-culture fermentation from Sphingomonas paucimobilis ATCC 31461, has elicited industrial interest in recent years as a high-viscosity biogum, a suspending agent, a gelling agent, and an agar substitute in microbial media. In this paper we report on the optimization of gellan gum production using a statistical approach. In the first step, the one factor-at-a-time method was used to investigate the effect of medium constituents such as carbon and nitrogen sources; subsequently, the intuitive analysis based on statistical calculations carried out using the L16 -orthogonal array method. The design for the L16 -orthogonal array was developed and analyzed using MINITAB 13.30 software. All the fermentation runs were carried out at 30+/-2 degrees C on a rotary orbital shaker at 180 rpm for 48 h. In the second step, the effects of amino acids and gellan precursors such as uridine-5'-diphospate (UDP) and adenosine-5'-diphospate (ADP) on the fermentative production of gellan gum were studied. Media containing 4% soluble starch, 0.025% yeast extract, 1.0 mM ADP and 0.05% tryptophan gave a maximum yield of 43.6 g l(-1) starch-free gellan gum, which was significantly higher than reported values in the literature.
- Published
- 2006
- Full Text
- View/download PDF
37. Weaning foods: a review of the Indian experience.
- Author
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Sajilata G, Singhal RS, and Kulkarni PR
- Subjects
- Humans, India, Infant, Infant Food, Infant Nutritional Physiological Phenomena physiology, Weaning
- Abstract
Although breastmilk is adequate to meet the energy and nutrient requirements of an infant up to four to six months of age, thereafter it is insufficient to sustain normal growth and needs to be supplemented with other foods, such as weaning foods. However, the capacity of a weaning diet to meet the protein and energy requirements of infants depends on its nutritional quality as well as its dietary bulk. This review highlights varieties of weaning foods, blend formulations, nutrient requirements, process characteristics, physicochemical parameters, quality evaluation, and other important aspects of developing a weaning food that satisfies all the requirements of the infant during the vulnerable transitional stage. Traditional weaning foods of India are briefly summarized.
- Published
- 2002
- Full Text
- View/download PDF
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