38 results on '"Raghavendran V"'
Search Results
2. An Analysis of Advanced FaceNet Deep Learning Algorithm in Facial Authentication
- Author
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Gayathri, D., Raghavendran, V., Appolloni, Andrea, Series Editor, Caracciolo, Francesco, Series Editor, Ding, Zhuoqi, Series Editor, Gogas, Periklis, Series Editor, Huang, Gordon, Series Editor, Nartea, Gilbert, Series Editor, Ngo, Thanh, Series Editor, Striełkowski, Wadim, Series Editor, Suresh, N. V., editor, and Buvaneswari, P. S., editor
- Published
- 2024
- Full Text
- View/download PDF
3. Functionality of Digital Twin in Shopfloor Employees Training with AI and ML Technologies
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Mohini, C.P. Chandra, Raghavendran, V., Appolloni, Andrea, Series Editor, Caracciolo, Francesco, Series Editor, Ding, Zhuoqi, Series Editor, Gogas, Periklis, Series Editor, Huang, Gordon, Series Editor, Nartea, Gilbert, Series Editor, Ngo, Thanh, Series Editor, Striełkowski, Wadim, Series Editor, Suresh, N. V., editor, and Buvaneswari, P. S., editor
- Published
- 2024
- Full Text
- View/download PDF
4. Normal Peak Expiratory Flow Rate Of Children Attending A Medical College Hospital In Puducherry.
- Author
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KUMARAN, S. S., ANEBARACY, V., REKHA, C., PANDI, A. KARUPPIAH, RAGHAVENDRAN, V. D., MAHESHWARI, K., and SHRIVASTAVA, ABHIJEET
- Subjects
EXPIRATORY flow ,MEDICAL schools ,SCHOOL children ,FLOW meters ,AGE groups - Abstract
Objectives: To measure the Peak expiratory flow rate (PEFR)of healthy school children and to find out the correlation between PEFR values and anthropometric parameters, to create a nomogram of PEFR for children and formulate a regression formula for PEFR. Methods: A cross-sectional study was conducted on children between the age group of 8 years and 12years attending medical college hospital at Puducherry. After collecting baseline data, PEFR was measured using a mini Wright peak flow meter. The highest of three measurements were recorded for analysis. Results: Of the 1500 students screened, 1000 were included in the study. Out of which 655 were boys and 345 were girls. Significant linear correlation was seen in PEFR with height, weight, BMI and BSA (r = 0.991, r = 0.983, r = 0.775 & r = 0.987 respectively, p < 0.001). Nomograms were plotted based on the observed values of PEFR in the study population. Prediction equations were derived for PEFR for the following variants like age, height, weight, BMI, BSA, male and female are as follows PEFR = (AgeX25.667)-18.326, PEFR = (HtX4.104)-324.420, PEFR = (WtX6.883)+13.070, PEFR = (BMIX42.585)-496.875, PEFR = (BSAX287.029)-80.705, PEFR = (HtX4.094)-322.930 & PEFR = (HtX4.121)-326.935 respectively Conclusions: Significant correlation was noted between PEFR and anthropometric parameters like height, weight and BMI and BSA. Hence nomograms and formulas created can be used in the study area. [ABSTRACT FROM AUTHOR]
- Published
- 2023
5. Clinico - Laboratory Profile of Scrub Typhus — An Emerging Rickettsiosis in India
- Author
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Narayanasamy, Dinesh Kumar, Arunagirinathan, Arul Kumaran, Kumar, Revathi Krishna, and Raghavendran, V. D.
- Published
- 2016
- Full Text
- View/download PDF
6. A microbubble-sparged yeast propagation–fermentation process for bioethanol production
- Author
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Raghavendran, V., Webb, J.P., Cartron, M.L., Springthorpe, V., Larson, T.R., Hines, M., Mohammed, H., Zimmerman, W.B., Poole, R.K., and Green, J.
- Abstract
Background\ud \ud Industrial biotechnology will play an increasing role in creating a more sustainable global economy. For conventional aerobic bioprocesses supplying O2 can account for 15% of total production costs. Microbubbles (MBs) are micron-sized bubbles that are widely used in industry and medical imaging. Using a fluidic oscillator to generate energy-efficient MBs has the potential to decrease the costs associated with aeration. However, little is understood about the effect of MBs on microbial physiology. To address this gap, a laboratory-scale MB-based Saccharomyces cerevisiae Ethanol Red propagation–fermentation bioethanol process was developed and analysed.\ud \ud \ud Results\ud \ud Aeration with MBs increased O2 transfer to the propagation cultures. Titres and yields of bioethanol in subsequent anaerobic fermentations were comparable for MB-propagated and conventional, regular bubble (RB)-propagated yeast. However, transcript profiling showed significant changes in gene expression in the MB-propagated yeast compared to those propagated using RB. These changes included up-regulation of genes required for ergosterol biosynthesis. Ergosterol contributes to ethanol tolerance, and so the performance of MB-propagated yeast in fed-batch fermentations sparged with 1% O2 as either RBs or MBs were tested. The MB-sparged yeast retained higher levels of ergosteryl esters during the fermentation phase, but this did not result in enhanced viability or ethanol production compared to ungassed or RB-sparged fermentations.\ud \ud \ud Conclusions\ud \ud The performance of yeast propagated using energy-efficient MB technology in bioethanol fermentations is comparable to that of those propagated conventionally. This should underpin the future development of MB-based commercial yeast propagation.
- Published
- 2020
7. Neither 1 G nor 2 G fuel ethanol: setting the ground for a sugarcane-based biorefinery using an iSUCCELL yeast platform
- Author
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Bermejo, P.M., Raghavendran, V., and Gombert, A.K.
- Abstract
First-generation (1 G) fuel ethanol production in sugarcane-based biorefineries is an established economic enterprise in Brazil. Second-generation (2 G) fuel ethanol from lignocellulosic materials, though extensively investigated, is currently facing severe difficulties to become economically viable. Some of the challenges inherent to these processes could be resolved by efficiently separating, and partially hydrolysing the cellulosic fraction of the lignocellulosic materials into the disaccharide cellobiose. Here we propose an alternative biorefinery, where the sucrose-rich stream from the 1 G process is mixed with a cellobiose-rich stream in the fermentation step. The advantages of mixing are threefold: 1) decreased concentrations of metabolic inhibitors that are typically produced during pretreatment and hydrolysis of lignocellulosic materials; 2) decreased cooling times after enzymatic hydrolysis prior to fermentation; 3) decreased availability of free glucose for contaminating microorganisms and undesired glucose repression effects. The iSUCCELL platform will be built upon the robust Saccharomyces cerevisiae strains currently present in 1 G biorefineries, which offer competitive advantage in non-aseptic environments, and into which intracellular hydrolyses of sucrose and cellobiose will be engineered. It is expected that high yields of ethanol can be achieved in a process with cell recycling, lower contamination levels and decreased antibiotic use, when compared to current 2 G technologies.
- Published
- 2020
8. Ternary CAM Memory Design using MOS Transistors
- Author
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Raghavendran, V., primary
- Published
- 2020
- Full Text
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9. The Techniques of Hydroponic System
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Mariyappillai, Anbarasu, primary, Arumugam, Gurusamy, additional, and Raghavendran, V B, additional
- Published
- 2020
- Full Text
- View/download PDF
10. A novel hybrid organosolv: steam explosion method for the efficient fractionation and pretreatment of birch biomass
- Author
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Matsakas, L., Nitsos, C., Raghavendran, V., Yakimenko, O., Persson, G., Olsson, E., Rova, U., Olsson, L., and Christakopoulos, P.
- Subjects
High-gravity ,Ethanol ,lcsh:TP315-360 ,Hybrid organosolv-steam explosion ,lcsh:Biotechnology ,lcsh:TP248.13-248.65 ,Birch ,Cellulose-enriched biomass ,Fractionation ,lcsh:Fuel - Abstract
Background:\ud The main role of pretreatment is to reduce the natural biomass recalcitrance and thus enhance sac-\ud charification yield. A further prerequisite for efficient utilization of all biomass components is their efficient fractiona-\ud tion into well-defined process streams. Currently available pretreatment methods only partially fulfill these criteria. \ud Steam explosion, for example, excels as a pretreatment method but has limited potential for fractionation, whereas \ud organosolv is excellent for delignification but offers poor biomass deconstruction.\ud Results:\ud In this article, a hybrid method combining the cooking and fractionation of conventional organosolv pre\ud -\ud treatment with the implementation of an explosive discharge of the cooking mixture at the end of pretreatment was \ud developed. The effects of various pretreatment parameters (ethanol content, duration, and addition of sulfuric acid) \ud were evaluated. Pretreatment of birch at 200\ud °C with 60%\ud v/v ethanol and 1%\ud w/w\ud biomass\ud H\ud 2\ud SO\ud 4\ud was proven to be the \ud most efficient pretreatment condition yielding pretreated solids with 77.9%\ud w/w cellulose, 8.9%\ud w/w hemicellulose, \ud and 7.0\ud w/w lignin content. Under these conditions, high delignification of 86.2% was demonstrated. The recovered \ud lignin was of high purity, with cellulose and hemicellulose contents not exceeding 0.31 and 3.25%\ud w/w, respectively, \ud and ash to be
- Published
- 2018
11. Anaerobiosis revisited: growth of Saccharomyces cerevisiae under extremely low oxygen availability
- Author
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Vale da Costa, B.L., Basso, T.O., Raghavendran, V., and Gombert, A.K.
- Abstract
The budding yeast Saccharomyces cerevisiae plays an important role in biotechnological applications, ranging from fuel ethanol to recombinant protein production. It is also a model organism for studies on cell physiology and genetic regulation. Its ability to grow under anaerobic conditions is of interest in many industrial applications. Unlike industrial bioreactors with their low surface area relative to volume, ensuring a complete anaerobic atmosphere during microbial cultivations in the laboratory is rather difficult. Tiny amounts of O2 that enter the system can vastly influence product yields and microbial physiology. A common procedure in the laboratory is to sparge the culture vessel with ultrapure N2 gas; together with the use of butyl rubber stoppers and norprene tubing, O2 diffusion into the system can be strongly minimized. With insights from some studies conducted in our laboratory, we explore the question ‘how anaerobic is anaerobiosis?’. We briefly discuss the role of O2 in non-respiratory pathways in S. cerevisiae and provide a systematic survey of the attempts made thus far to cultivate yeast under anaerobic conditions. We conclude that very few data exist on the physiology of S. cerevisiae under anaerobiosis in the absence of the anaerobic growth factors ergosterol and unsaturated fatty acids. Anaerobicity should be treated as a relative condition since complete anaerobiosis is hardly achievable in the laboratory. Ideally, researchers should provide all the details of their anaerobic set-up, to ensure reproducibility of results among different laboratories.\ud \ud A correction to this article is available online at http://eprints.whiterose.ac.uk/131930/\ud \ud https://doi.org/10.1007/s00253-018-9036-z
- Published
- 2018
12. Spondylocostal Dysostosis with Sprengel Deformity: A Rare Association
- Author
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Raghavendran V D, Indu S, Balaji Sukumaran, and Dinesh Kumar N
- Subjects
musculoskeletal diseases ,Rib cage ,medicine.medical_specialty ,business.industry ,Anatomy ,musculoskeletal system ,medicine.disease ,Rib anomalies ,Spondylocostal dysostosis ,Surgery ,Scapula ,Vertebral segmentation defect ,medicine ,Deformity ,medicine.symptom ,business ,Jarcho-Levin syndrome - Abstract
Spondylocostal dysostosis (SCDO) refers to multiple segmentation defects of the vertebrae in combination with abnormalities of the ribs. Sprengel deformity is a congenital elevation of the scapula. Here, we would like to present a case of SCDO with associated Sprengel deformity, which has been reported only twice previously (to the best of our knowledge).
- Published
- 2014
13. Efficacy of training and development in technological colleges in DakshinaKannada district
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Raghavendran, V, primary and Kumuthadevi, K, additional
- Published
- 2018
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14. Effect of feeding hydroponic maize fodder in the milk yield of crossbred dairy cows.
- Author
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Raghavendran, V. B., Subramanian, E., and Anbarasu, M.
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MILK yield ,DAIRY cattle ,CORN breeding ,ANIMAL feeds ,CORN as feed ,FAT content of milk - Abstract
A 60 day lactation trial was conducted using 12 lactating cross bred cows by randomly allotting them into two groups of 6 animals each (control and treatment) to study the effect of replacing green fodder with hydroponic maize fodder on milk yield and composition, fat and SNF. The average heights (cm) of whole hydroponic maize plant during the 7 day growth period were 1.53, 2.78, 6.03, 10.1, 16.03, 22.13 and 30.97 on 1, 2, 3, 4, 5, 6 and 7th day, respectively The daily average milk yield (kg) increased by 2.9 per cent in cows fed rations supplemented with hydroponic maize fodder as compared to those fed control ration. However, the difference between the two groups was not significant (P>0.05). The daily average butter fat content of milk of lactating crossbred cows was 3.61±0.36 and 3.56±0.17 per cent in control and treatment groups, respectively. The average solids not fat per cent in control and treatment groups was 8.42±0.12 and 8.34±0.19 per cent, respectively. However, the difference between the groups was not significant (P>0.05). The SNF per cent of milk decreased marginally in crossbred cows fed hydroponic maize fodder as compared to those in the control group, but the differences were not significant (P>0.05). It was concluded that replacement of hydroponic maize fodder resulted in marginal increase in milk yield and decrease in fat and SNF content. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
15. NEURONAL MIGRATION DISORDER
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Raghavendran V D, Sivaraman S, and Revathi K
- Subjects
Neuronal migration disorder ,business.industry ,Medicine ,business ,medicine.disease ,Neuroscience - Published
- 2015
16. A RARE CASE OF SCHIZENCEPHALY
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Revathi K, Raghavendran V D, and Sivaraman S
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medicine.medical_specialty ,Schizencephaly ,business.industry ,Rare case ,Medicine ,business ,medicine.disease ,Dermatology - Published
- 2015
17. Genetic polymorphism of retinol binding protein 4 locus and its association with litter traits in pigs
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B, RAGHAVENDRAN V, primary, VENKATACHALAPATHY, R THIRUPATHY, additional, P, USHA A, additional, and PRAMOD, S, additional
- Published
- 2013
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18. Adhesion of Thermoplastic Matrices to Carbon Fibers: Effect of Polymer Molecular Weight and Fiber Surface Chemistry
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Drzal, L. T., primary and Raghavendran, V. K., additional
- Published
- 2003
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- View/download PDF
19. Effect of surface oxygen content and roughness on interfacial adhesion in carbon fiber–polycarbonate composites
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Raghavendran, V. K., primary, Drzal, L. T., additional, and Askeland, P., additional
- Published
- 2002
- Full Text
- View/download PDF
20. Grafting of bisphenol-A polycarbonate and polymethyl methacrylate on to the surface of carbon fibers via anionic polymerization
- Author
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Raghavendran, V. K., primary and Drzal, L. T., additional
- Published
- 2002
- Full Text
- View/download PDF
21. Carcass Characteristics of Meat Rabbits in Different Housing Systems.
- Author
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Bharathy, N., Ramesh, V., Akila, N., Chandrasekaran, D., and Raghavendran, V. B.
- Abstract
The article discusses a study which examined the carcass characteristics of broiler rabbit in different housing systems. It cited several carcass traits considered including weight at slaughter, weight of head, weight of pelt, and dressing percentage without head. Topics covered include materials and methods used in the study, factors that expand the gap between demand and supply of meat, and a comparison between the slaughter weight in White Giant and Soviet Chinchilla.
- Published
- 2014
22. Weldability of Structural Steels
- Author
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Raghavendran, V., primary, Naganathan, S., additional, and Rao, A. S. N., additional
- Published
- 1974
- Full Text
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23. Trichobezoar in a Sheep.
- Author
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Bharathy, N., Raghavendran, V. B., Jayanthi, D., and Murali, N.
- Abstract
An abstract of the article "Trichobezoar in a Sheep," by N. Bharathy, V. B. Raghavendran, D. Jayanthi and N. Murali is presented.
- Published
- 2013
24. Blocking Mitophagy Does Not Significantly Improve Fuel Ethanol Production in Bioethanol Yeast Saccharomyces cerevisiae.
- Author
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Eliodório KP, de Gois E Cunha GC, White BA, Patel DHM, Zhang F, Hettema EH, Basso TO, Gombert AK, and Raghavendran V
- Subjects
- Alcoholic Beverages, Autophagy-Related Proteins, Ethanol, Fermentation, Industrial Microbiology, Mitophagy, Receptors, Cytoplasmic and Nuclear, Saccharomyces cerevisiae genetics, Saccharomyces cerevisiae Proteins genetics
- Abstract
Ethanolic fermentation is frequently performed under conditions of low nitrogen. In Saccharomyces cerevisiae, nitrogen limitation induces macroautophagy, including the selective removal of mitochondria, also called mitophagy. Previous research showed that blocking mitophagy by deletion of the mitophagy-specific gene ATG32 increased the fermentation performance during the brewing of Ginjo sake. In this study, we tested if a similar strategy could enhance alcoholic fermentation in the context of fuel ethanol production from sugarcane in Brazilian biorefineries. Conditions that mimic the industrial fermentation process indeed induce Atg32-dependent mitophagy in cells of S. cerevisiae PE-2, a strain frequently used in the industry. However, after blocking mitophagy, no significant differences in CO
2 production, final ethanol titers, or cell viability were observed after five rounds of ethanol fermentation, cell recycling, and acid treatment, which is commonly performed in sugarcane biorefineries. To test if S. cerevisiae's strain background influenced this outcome, cultivations were carried out in a synthetic medium with strains PE-2, Ethanol Red (industrial), and BY (laboratory) with and without a functional ATG32 gene and under oxic and oxygen restricted conditions. Despite the clear differences in sugar consumption, cell viability, and ethanol titers, among the three strains, we did not observe any significant improvement in fermentation performance related to the blocking of mitophagy. We concluded, with caution, that the results obtained with Ginjo sake yeast were an exception and cannot be extrapolated to other yeast strains and that more research is needed to ascertain the role of autophagic processes during fermentation. IMPORTANCE Bioethanol is the largest (per volume) ever biobased bulk chemical produced globally. The fermentation process is well established, and industries regularly attain nearly 85% of maximum theoretical yields. However, because of the volume of fuel produced, even a small improvement will have huge economic benefits. To this end, besides already implemented process improvements, various free energy conservation strategies have been successfully exploited at least in laboratory strains to increase ethanol yields and decrease byproduct formation. Cellular housekeeping processes have been an almost unexplored territory in strain improvement. It was previously reported that blocking mitophagy by deletion of the mitophagy receptor gene ATG32 in Saccharomyces cerevisiae led to a 2.1% increase in final ethanol titers during Japanese sake fermentation. We found in two commercially used bioethanol strains (PE-2 and Ethanol Red) that ATG32 deficiency does not lead to a significant improvement in cell viability or ethanol levels during fermentation with molasses or in a synthetic complete medium. More research is required to ascertain the role of autophagic processes during fermentation conditions.- Published
- 2022
- Full Text
- View/download PDF
25. Ethanol yield calculations in biorefineries.
- Author
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Bermejo PM, Badino A, Zamberlan L, Raghavendran V, Basso TO, and Gombert AK
- Subjects
- Brazil, Fermentation, Industrial Microbiology, Ethanol, Saccharum
- Abstract
The ethanol yield on sugar during alcoholic fermentation allows for diverse interpretation in academia and industry. There are several different ways to calculate this parameter, which is the most important one in this industrial bioprocess and the one that should be maximized, as reported by Pereira, Rodrigues, Sonego, Cruz and Badino (A new methodology to calculate the ethanol fermentation efficiency at bench and industrial scales. Ind Eng Chem Res 2018; 57: 16182-91). On the one hand, the various methods currently employed in industry provide dissimilar results, and recent evidence shows that yield has been consistently overestimated in Brazilian sugarcane biorefineries. On the other hand, in academia, researchers often lack information on all the intricate aspects involved in calculating the ethanol yield in industry. Here, we comment on these two aspects, using fuel ethanol production from sugarcane in Brazilian biorefineries as an example, and taking the work of Pereira, Rodrigues, Sonego, Cruz and Badino (A new methodology to calculate the ethanol fermentation efficiency at bench and industrial scales. Ind Eng Chem Res 2018; 57: 16182-91.) as a starting point. Our work is an attempt to demystify some common beliefs and to foster closer interaction between academic and industrial professionals from the fermentation sector. Pereira, Rodrigues, Sonego, Cruz and Badino (A new methodology to calculate the ethanol fermentation efficiency at bench and industrial scales. Ind Eng Chem Res 2018; 57: 16182-91)., (© The Author(s) 2021. Published by Oxford University Press on behalf of FEMS. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
- Published
- 2021
- Full Text
- View/download PDF
26. The protective role of intracellular glutathione in Saccharomyces cerevisiae during lignocellulosic ethanol production.
- Author
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Raghavendran V, Marx C, Olsson L, and Bettiga M
- Abstract
To enhance the competitiveness of industrial lignocellulose ethanol production, robust enzymes and cell factories are vital. Lignocellulose derived streams contain a cocktail of inhibitors that drain the cell of its redox power and ATP, leading to a decrease in overall ethanol productivity. Many studies have attempted to address this issue, and we have shown that increasing the glutathione (GSH) content in yeasts confers tolerance towards lignocellulose inhibitors, subsequently increasing the ethanol titres. However, GSH levels in yeast are limited by feedback inhibition of GSH biosynthesis. Multidomain and dual functional enzymes exist in several bacterial genera and they catalyse the GSH biosynthesis in a single step without the feedback inhibition. To test if even higher intracellular glutathione levels could be achieved and if this might lead to increased tolerance, we overexpressed the genes from two bacterial genera and assessed the recombinants in simultaneous saccharification and fermentation (SSF) with steam pretreated spruce hydrolysate containing 10% solids. Although overexpressing the heterologous genes led to a sixfold increase in maximum glutathione content (18 µmol g
drycellmass -1 ) compared to the control strain, this only led to a threefold increase in final ethanol titres (8.5 g L- 1 ). As our work does not conclusively indicate the cause-effect of increased GSH levels towards ethanol titres, we cautiously conclude that there is a limit to cellular fitness that could be accomplished via increased levels of glutathione.- Published
- 2020
- Full Text
- View/download PDF
27. A microbubble-sparged yeast propagation-fermentation process for bioethanol production.
- Author
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Raghavendran V, Webb JP, Cartron ML, Springthorpe V, Larson TR, Hines M, Mohammed H, Zimmerman WB, Poole RK, and Green J
- Abstract
Background: Industrial biotechnology will play an increasing role in creating a more sustainable global economy. For conventional aerobic bioprocesses supplying O
2 can account for 15% of total production costs. Microbubbles (MBs) are micron-sized bubbles that are widely used in industry and medical imaging. Using a fluidic oscillator to generate energy-efficient MBs has the potential to decrease the costs associated with aeration. However, little is understood about the effect of MBs on microbial physiology. To address this gap, a laboratory-scale MB-based Saccharomyces cerevisiae Ethanol Red propagation-fermentation bioethanol process was developed and analysed., Results: Aeration with MBs increased O2 transfer to the propagation cultures. Titres and yields of bioethanol in subsequent anaerobic fermentations were comparable for MB-propagated and conventional, regular bubble (RB)-propagated yeast. However, transcript profiling showed significant changes in gene expression in the MB-propagated yeast compared to those propagated using RB. These changes included up-regulation of genes required for ergosterol biosynthesis. Ergosterol contributes to ethanol tolerance, and so the performance of MB-propagated yeast in fed-batch fermentations sparged with 1% O2 as either RBs or MBs were tested. The MB-sparged yeast retained higher levels of ergosteryl esters during the fermentation phase, but this did not result in enhanced viability or ethanol production compared to ungassed or RB-sparged fermentations., Conclusions: The performance of yeast propagated using energy-efficient MB technology in bioethanol fermentations is comparable to that of those propagated conventionally. This should underpin the future development of MB-based commercial yeast propagation., Competing Interests: Competing interestsPerlemax Ltd holds awarded patents for fluidic oscillation generated microbubbles., (© The Author(s) 2020.)- Published
- 2020
- Full Text
- View/download PDF
28. Neither 1G nor 2G fuel ethanol: setting the ground for a sugarcane-based biorefinery using an iSUCCELL yeast platform.
- Author
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Bermejo PM, Raghavendran V, and Gombert AK
- Subjects
- Brazil, Cellobiose metabolism, Ethanol metabolism, Glucose metabolism, Metabolic Engineering, Saccharomyces cerevisiae metabolism, Saccharum metabolism, Xylose metabolism, Biofuels, Fermentation, Industrial Microbiology methods, Saccharomyces cerevisiae genetics, Saccharum microbiology
- Abstract
First-generation (1G) fuel ethanol production in sugarcane-based biorefineries is an established economic enterprise in Brazil. Second-generation (2G) fuel ethanol from lignocellulosic materials, though extensively investigated, is currently facing severe difficulties to become economically viable. Some of the challenges inherent to these processes could be resolved by efficiently separating and partially hydrolysing the cellulosic fraction of the lignocellulosic materials into the disaccharide cellobiose. Here, we propose an alternative biorefinery, where the sucrose-rich stream from the 1G process is mixed with a cellobiose-rich stream in the fermentation step. The advantages of mixing are 3-fold: (i) decreased concentrations of metabolic inhibitors that are typically produced during pretreatment and hydrolysis of lignocellulosic materials; (ii) decreased cooling times after enzymatic hydrolysis prior to fermentation; and (iii) decreased availability of free glucose for contaminating microorganisms and undesired glucose repression effects. The iSUCCELL platform will be built upon the robust Saccharomyces cerevisiae strains currently present in 1G biorefineries, which offer competitive advantage in non-aseptic environments, and into which intracellular hydrolyses of sucrose and cellobiose will be engineered. It is expected that high yields of ethanol can be achieved in a process with cell recycling, lower contamination levels and decreased antibiotic use, when compared to current 2G technologies., (© FEMS 2020.)
- Published
- 2020
- Full Text
- View/download PDF
29. Commentary on the Benefits of US Pharmacopeial Standards: A Generic Pharmaceutical Industry Survey.
- Author
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Warthin IK, Berik J, Podolsky D, Raghavendran V, Reddy R, Chang J, Porter N, and Garito N
- Subjects
- Drug Industry, Surveys and Questionnaires, United States, United States Food and Drug Administration, Drugs, Generic, Pharmaceutical Preparations
- Abstract
Pharmacopeial quality standards for medicines are associated with ensuring quality, but they can also facilitate innovation and competition in pharmaceutical markets. Unpublished data suggest that pharmacopeial quality standards, while not associated with increasing the likelihood of a first generic entrant in the market, are associated with increasing the overall number of generic entrants. This commentary describes an online survey of finished-dose generic drug manufacturers in the United States and India that explores whether using pharmacopeial documentary standards and physical reference standards (RSs) such as those developed by the US Pharmacopeial Convention, accelerate generic drug development and reduce the duration, cost, and risk involved in bringing generic drugs to the US market. The survey provides new evidence that using pharmacopeial documentary standards and physical RSs (1) saves generic drug companies 19% of the time spent on generic product development overall and 31% of time spent on analytical method development and (2) provides clear guidance on quality, thereby reducing the perceived risk of Abbreviated New Drug Application rejection by the US Food and Drug Administration. Ninety percent of respondents agreed that the use of pharmacopeial documentary standards accelerated product development compared with 85% for physical RSs; and 92% of respondents agreed that the use of documentary standards and physical RSs reduced the risk that their Abbreviated New Drug Application would be rejected. Owing to the relatively small sample size of the survey, the results should be viewed as entirely directional for use in trends analysis on the finished-dose generic pharmaceutical industry. The margin of error for all results is 8%-14% at a 95% confidence interval., (Copyright © 2020 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.)
- Published
- 2020
- Full Text
- View/download PDF
30. Bacterial cellulose: Biosynthesis, production, and applications.
- Author
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Raghavendran V, Asare E, and Roy I
- Abstract
Bacterial cellulose (BC) is a natural polymer produced by the acetic acid producing bacterium and has gathered much interest over the last decade for its biomedical and biotechnological applications. Unlike the plant derived cellulose nanofibres, which require pretreatment to deconstruct the recalcitrant lignocellulosic network, BC are 100% pure, and are extruded by cells as nanofibrils. Moreover, these nanofibrils can be converted to macrofibers that possess excellent material properties, surpassing even the strength of steel, and can be used as substitutes for fossil fuel derived synthetic fibers. The focus of the review is to present the fundamental long-term research on the influence of environmental factors on the organism's BC production capabilities, the production methods that are available for scaling up/scaled-up processes, and its use as a bulk commodity or for biomedical applications., (© 2020 Elsevier Ltd. All rights reserved.)
- Published
- 2020
- Full Text
- View/download PDF
31. Forever panting and forever growing: physiology of Saccharomyces cerevisiae at extremely low oxygen availability in the absence of ergosterol and unsaturated fatty acids.
- Author
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da Costa BLV, Raghavendran V, Franco LFM, Chaves Filho AB, Yoshinaga MY, Miyamoto S, Basso TO, and Gombert AK
- Subjects
- Anaerobiosis, Biomass, Cell Survival, Ethanol metabolism, Fatty Acids isolation & purification, Glucose metabolism, Hydrogen-Ion Concentration, Lipid Metabolism, Lipids isolation & purification, Saccharomyces cerevisiae growth & development, Ergosterol metabolism, Fatty Acids analysis, Fatty Acids, Unsaturated deficiency, Lipids analysis, Oxygen metabolism, Saccharomyces cerevisiae physiology
- Abstract
We sought to investigate how far the growth of Saccharomyces cerevisiae under full anaerobiosis is dependent on the widely used anaerobic growth factors (AGF) ergosterol and oleic acid. A continuous cultivation setup was employed and, even forcing ultrapure N2 gas through an O2 trap upstream of the bioreactor, neither cells from S. cerevisiae CEN.PK113-7D (a lab strain) nor from PE-2 (an industrial strain) washed out after an aerobic-to-anaerobic switch in the absence of AGF. S. cerevisiae PE-2 seemed to cope better than the laboratory strain with this extremely low O2 availability, since it presented higher biomass yield, lower specific rates of glucose consumption and CO2 formation, and higher survival at low pH. Lipid (fatty acid and sterol) composition dramatically altered when cells were grown anaerobically without AGF: saturated fatty acid, squalene and lanosterol contents increased, when compared to either cells grown aerobically or anaerobically with AGF. We concluded that these lipid alterations negatively affect cell viability during exposure to low pH or high ethanol titers., (© FEMS 2019.)
- Published
- 2019
- Full Text
- View/download PDF
32. Lignin-first biomass fractionation using a hybrid organosolv - Steam explosion pretreatment technology improves the saccharification and fermentability of spruce biomass.
- Author
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Matsakas L, Raghavendran V, Yakimenko O, Persson G, Olsson E, Rova U, Olsson L, and Christakopoulos P
- Subjects
- Bioreactors, Cellulose metabolism, Ethanol metabolism, Explosions, Fermentation, Hydrolysis, Polysaccharides metabolism, Steam, Biomass, Lignin metabolism
- Abstract
For a transition to a sustainable society, fuels, chemicals, and materials should be produced from renewable resources. Lignocellulosic biomass constitutes an abundant and renewable feedstock; however, its successful application in a biorefinery requires efficient fractionation into its components; cellulose, hemicellulose and lignin. Here, we demonstrate that a newly established hybrid organosolv - steam explosion pretreatment can effectively fractionate spruce biomass to yield pretreated solids with high cellulose (72% w/w) and low lignin (delignification up to 79.4% w/w) content. The cellulose-rich pretreated solids present high saccharification yields (up to 61% w/w) making them ideal for subsequent bioconversion processes. Moreover, under high-gravity conditions (22% w/w) we obtained an ethanol titer of 61.7 g/L, the highest so far reported for spruce biomass. Finally, the obtained high-purity lignin is suitable for various advanced applications. In conclusion, hybrid organosolv pretreatment could offer a closed-loop biorefinery while simultaneously adding value to all biomass components., (Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.)
- Published
- 2019
- Full Text
- View/download PDF
33. A comparative study of the enzymatic hydrolysis of batch organosolv-pretreated birch and spruce biomass.
- Author
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Raghavendran V, Nitsos C, Matsakas L, Rova U, Christakopoulos P, and Olsson L
- Abstract
A shift towards a sustainable and green society is vital to reduce the negative effects of climate change associated with increased CO
2 emissions. Lignocellulosic biomass is both renewable and abundant, but is recalcitrant to deconstruction. Among the methods of pretreatment available, organosolv (OS) delignifies cellulose efficiently, significantly improving its digestibility by enzymes. We have assessed the hydrolysability of the cellulose-rich solid fractions from OS-pretreated spruce and birch at 2% w/v loading (dry matter). Almost complete saccharification of birch was possible with 80 mg enzyme preparation/gsolids (12 FPU/gsolids ), while the saccharification yield for spruce was only 70%, even when applying 60 FPU/gsolids . As the cellulose content is enriched by OS, the yield of glucose was higher than in their steam-exploded counterparts. The hydrolysate was a transparent liquid due to the absence of phenolics and was also free from inhibitors. OS pretreatment holds potential for use in a large-scale, closed-loop biorefinery producing fuels from the cellulose fraction and platform chemicals from the hemicellulose and lignin fractions respectively.- Published
- 2018
- Full Text
- View/download PDF
34. Correction to: Anaerobiosis revisited: growth of Saccharomyces cerevisiae under extremely low oxygen availability.
- Author
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da Costa BLV, Basso TO, Raghavendran V, and Gombert AK
- Abstract
The published online version contains mistake in Figure1. In the x-axis, instead of "1000", the number should be "100".
- Published
- 2018
- Full Text
- View/download PDF
35. Anaerobiosis revisited: growth of Saccharomyces cerevisiae under extremely low oxygen availability.
- Author
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da Costa BLV, Basso TO, Raghavendran V, and Gombert AK
- Subjects
- Anaerobiosis, Bioreactors microbiology, Ethanol analysis, Ethanol metabolism, Oxygen analysis, Saccharomyces cerevisiae genetics, Oxygen metabolism, Saccharomyces cerevisiae growth & development, Saccharomyces cerevisiae metabolism
- Abstract
The budding yeast Saccharomyces cerevisiae plays an important role in biotechnological applications, ranging from fuel ethanol to recombinant protein production. It is also a model organism for studies on cell physiology and genetic regulation. Its ability to grow under anaerobic conditions is of interest in many industrial applications. Unlike industrial bioreactors with their low surface area relative to volume, ensuring a complete anaerobic atmosphere during microbial cultivations in the laboratory is rather difficult. Tiny amounts of O
2 that enter the system can vastly influence product yields and microbial physiology. A common procedure in the laboratory is to sparge the culture vessel with ultrapure N2 gas; together with the use of butyl rubber stoppers and norprene tubing, O2 diffusion into the system can be strongly minimized. With insights from some studies conducted in our laboratory, we explore the question 'how anaerobic is anaerobiosis?'. We briefly discuss the role of O2 in non-respiratory pathways in S. cerevisiae and provide a systematic survey of the attempts made thus far to cultivate yeast under anaerobic conditions. We conclude that very few data exist on the physiology of S. cerevisiae under anaerobiosis in the absence of the anaerobic growth factors ergosterol and unsaturated fatty acids. Anaerobicity should be treated as a relative condition since complete anaerobiosis is hardly achievable in the laboratory. Ideally, researchers should provide all the details of their anaerobic set-up, to ensure reproducibility of results among different laboratories.- Published
- 2018
- Full Text
- View/download PDF
36. A simple scaled down system to mimic the industrial production of first generation fuel ethanol in Brazil.
- Author
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Raghavendran V, Basso TP, da Silva JB, Basso LC, and Gombert AK
- Subjects
- Brazil, Fermentation, Ethanol metabolism, Industrial Microbiology, Saccharomyces cerevisiae metabolism
- Abstract
Although first-generation fuel ethanol is produced in Brazil from sugarcane-based raw materials with high efficiency, there is still little knowledge about the microbiology, the biochemistry and the molecular mechanisms prevalent in the non-aseptic fermentation environment. Learning-by-doing has hitherto been the strategy to improve the process so far, with further improvements requiring breakthrough technologies. Performing experiments at an industrial scale are often expensive, complicated to set up and difficult to reproduce. Thus, developing an appropriate scaled down system for this process has become a necessity. In this paper, we present the design and demonstration of a simple and effective laboratory-scale system mimicking the industrial process used for first generation (1G) fuel ethanol production in the Brazilian sugarcane mills. We benchmarked this system via the superior phenotype of the Saccharomyces cerevisiae PE-2 strain, compared to other strains from the same species: S288c, baker's yeast, and CEN.PK113-7D. We trust that such a system can be easily implemented in different laboratories worldwide, and will allow a better understanding of the S. cerevisiae strains that can persist and dominate in this industrial, non-aseptic and peculiar environment.
- Published
- 2017
- Full Text
- View/download PDF
37. Sucrose and Saccharomyces cerevisiae: a relationship most sweet.
- Author
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Marques WL, Raghavendran V, Stambuk BU, and Gombert AK
- Subjects
- Biotechnology methods, Brazil, Ethanol metabolism, Humans, Industrial Microbiology methods, Metabolic Engineering methods, Saccharomyces cerevisiae growth & development, Saccharomyces cerevisiae metabolism, Metabolic Networks and Pathways genetics, Saccharomyces cerevisiae physiology, Sucrose metabolism
- Abstract
Sucrose is an abundant, readily available and inexpensive substrate for industrial biotechnology processes and its use is demonstrated with much success in the production of fuel ethanol in Brazil. Saccharomyces cerevisiae, which naturally evolved to efficiently consume sugars such as sucrose, is one of the most important cell factories due to its robustness, stress tolerance, genetic accessibility, simple nutrient requirements and long history as an industrial workhorse. This minireview is focused on sucrose metabolism in S. cerevisiae, a rather unexplored subject in the scientific literature. An analysis of sucrose availability in nature and yeast sugar metabolism was performed, in order to understand the molecular background that makes S. cerevisiae consume this sugar efficiently. A historical overview on the use of sucrose and S. cerevisiae by humans is also presented considering sugarcane and sugarbeet as the main sources of this carbohydrate. Physiological aspects of sucrose consumption are compared with those concerning other economically relevant sugars. Also, metabolic engineering efforts to alter sucrose catabolism are presented in a chronological manner. In spite of its extensive use in yeast-based industries, a lot of basic and applied research on sucrose metabolism is imperative, mainly in fields such as genetics, physiology and metabolic engineering., (© FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
- Published
- 2016
- Full Text
- View/download PDF
38. Mitochondrial import and accumulation of alpha-synuclein impair complex I in human dopaminergic neuronal cultures and Parkinson disease brain.
- Author
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Devi L, Raghavendran V, Prabhu BM, Avadhani NG, and Anandatheerthavarada HK
- Subjects
- Aged, Aged, 80 and over, Amino Acid Substitution, Dopamine metabolism, Electron Transport Complex I genetics, Female, Humans, Male, Middle Aged, Mitochondria ultrastructure, Mitochondrial Membranes ultrastructure, Mutation, Missense, Neurons pathology, Organ Specificity genetics, Parkinson Disease genetics, Parkinson Disease pathology, Protein Sorting Signals genetics, Protein Transport genetics, Reactive Oxygen Species metabolism, alpha-Synuclein genetics, Electron Transport Complex I metabolism, Mitochondria metabolism, Mitochondrial Membranes metabolism, Neurons metabolism, Parkinson Disease metabolism, alpha-Synuclein metabolism
- Abstract
Alpha-synuclein, a protein implicated in the pathogenesis of Parkinson disease (PD), is thought to affect mitochondrial functions, although the mechanisms of its action remain unclear. In this study we show that the N-terminal 32 amino acids of human alpha-synuclein contain cryptic mitochondrial targeting signal, which is important for mitochondrial targeting of alpha-synuclein. Mitochondrial imported alpha-synuclein is predominantly associated with the inner membrane. Accumulation of wild-type alpha-synuclein in the mitochondria of human dopaminergic neurons caused reduced mitochondrial complex I activity and increased production of reactive oxygen species. However, these defects occurred at an early time point in dopaminergic neurons expressing familial alpha-synuclein with A53T mutation as compared with wild-type alpha-synuclein. Importantly, alpha-synuclein that lacks mitochondrial targeting signal failed to target to the mitochondria and showed no detectable effect on complex I function. The PD relevance of these results was investigated using mitochondria of substantia nigra, striatum, and cerebellum of postmortem late-onset PD and normal human brains. Results showed the constitutive presence of approximately 14-kDa alpha-synuclein in the mitochondria of all three brain regions of normal subjects. Mitochondria of PD-vulnerable substantia nigra and striatum but not cerebellum from PD subjects showed significant accumulation of alpha-synuclein and decreased complex I activity. Analysis of mitochondria from PD brain and alpha-synuclein expressing dopaminergic neuronal cultures using blue native gel electrophoresis and immunocapture technique showed the association of alpha-synuclein with complex I. These results provide evidence that mitochondrial accumulated alpha-synuclein may interact with complex I and interfere with its functions.
- Published
- 2008
- Full Text
- View/download PDF
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