Faculty Publications
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Item Anionic surfactant based reverse micellar extraction of l-asparaginase synthesized by Azotobacter vinelandii(Springer Verlag, 2017) Murugesan, S.; Iyyaswami, R.; Kumar, S.V.; Surendran, A.Abstract: l-Asparaginase synthesized by Azotobacter vinelandii via submerged fermentation in the presence of sucrose was successfully extracted using Reverse micellar extraction. Single step enzyme purification process was developed by varying the process variables which resulted in maximum specificity and extraction of l-asparaginase. The effect of different variables, including broth pH, addition of alcohol during the forward extraction and pH of the fresh stripping aqueous phase, addition of alcohol and electrolyte during backward extraction process were studied. Lower concentration of butanol resulted in maximum activity of the enzyme during forward extraction while enzyme activity was found to increase further with the addition of higher concentrations of ammonium sulphate during backward extraction. Chromatographic analysis of l-asparaginase peak at ~7.65 min was intense for the back extracted sample confirming the maximum purity of l-asparaginase obtained. Purity of l-asparaginase was increased to about 379.68 fold. Graphical abstract: [Figure not available: see fulltext.]. © 2017, Springer-Verlag Berlin Heidelberg.Item Low frequency sonic waves assisted cloud point extraction of polyhydroxyalkanoate from Cupriavidus necator(Elsevier B.V., 2017) Murugesan, S.; Iyyaswami, R.Low frequency sonic waves, less than 10 kHz were introduced to assist cloud point extraction of polyhydroxyalkanoate from Cupriavidus necator present within the crude broth. Process parameters including surfactant system variables and sonication parameters were studied for their effect on extraction efficiency. Introduction of low frequency sonic waves assists in the dissolution of microbial cell wall by the surfactant micelles and release of cellular content, polyhydroxyalkanoate granules released were encapsulated by the micelle core which was confirmed by crotonic acid assay. In addition, sonic waves resulted in the separation of homogeneous surfactant and broth mixture into two distinct phases, top aqueous phase and polyhydroxyalkanoate enriched bottom surfactant rich phase. Mixed surfactant systems showed higher extraction efficiency compared to that of individual Triton X-100 concentrations, owing to increase in the hydrophobicity of the micellar core and its interaction with polyhydroxyalkanoate. Addition of salts to the mixed surfactant system induces screening of charged surfactant head groups and reduces inter-micellar repulsion, presence of ammonium ions lead to electrostatic repulsion and weaker cation sodium enhances the formation of micellar network. Addition of polyethylene glycol 8000 resulted in increasing interaction with the surfactant tails of the micelle core there by reducing the purity of polyhydroxyalkanoate. © 2017 Elsevier B.V.Item Lipase mediated synthesis of rutin fatty ester: Study of its process parameters and solvent polarity(Elsevier Ltd, 2017) Chandrasekar, C.; Belur, P.D.; Iyyaswami, R.Lipophilization of antioxidants is recognized as an effective strategy to enhance solubility and thus effectiveness in lipid based food. In this study, an effort was made to optimize rutin fatty ester synthesis in two different solvent systems to understand the influence of reaction system hydrophobicity on the optimum conditions using immobilised Candida antartica lipase. Under unoptimized conditions, 52.14% and 13.02% conversion was achieved in acetone and tert-butanol solvent systems, respectively. Among all the process parameters, water activity of the system was found to show highest influence on the conversion in each reaction system. In the presence of molecular sieves, the ester production increased to 62.9% in tert-butanol system, unlike acetone system. Under optimal conditions, conversion increased to 60.74% and 65.73% in acetone and tert-butanol system, respectively. This study shows, maintaining optimal water activity is crucial in reaction systems having polar solvents compared to more non-polar solvents. © 2017 Elsevier LtdItem Enhancement of n-3 polyunsaturated fatty acid glycerides in Sardine oil by a bioimprinted cross-linked Candida rugosa lipase(Elsevier Inc. usjcs@elsevier.com, 2018) Sampath, C.; Belur, P.D.; Iyyaswami, R.Considering the advantages of bioimprinting and carrier free immobilization, cross-linked enzyme aggregates (CLEA) were prepared by using bioimprinted Candida rugosa lipase (CRL) with Bovine serum albumin (BSA), Polyethyleneimine and glutaraldehyde. Effect of various factors such as CRL-Oleic acid ratio, CRL-BSA ratio, CRL- Polyethyleneimine ratio, glutaraldehyde loading, cross-linking time etc., on lipase activity recovery and aggregate yield were studied and optimized. This immobilized lipase (CRL-CLEA) was used for the selective hydrolysis of ester linkages of non-PUFA glycerides, with an aim to concentrate EPA and DHA glycerides in the Sardine oil. Imprinting with oleic acid in the presence of ethanol and Tween 60, and further immobilization with co-aggregates and cross-linking agent showed 10.4 times higher degree of hydrolysis compared to free enzyme. As result, 2.83-fold increase of n-3 PUFA content in deacidified oil was obtained by using CRL-CLEA. The resultant oil had negligible di- and triglycerides content, proving higher efficiency in hydrolysing ester bonds of fatty acids, other than n-3 PUFA. Reusability studies showed CRL-CLEA could be reused up to 5 runs without a substantial reduction in its performance. Improvement in degree of hydrolysis, thermostability, efficiency of hydrolysis and reusability were achieved due to bioimprinting and subsequent immobilization of CRL in the form of CLEA. © 2017 Elsevier Inc.Item Preparation, characterization and stability evaluation of ionic liquid blended chitosan tripolyphosphate microparticles(Editions de Sante editions.de.sante@wanadoo.fr, 2019) Safdar, R.; Francisco Nirmala, N.; Iyyaswami, R.; Arunagiri, A.; Papadimitriou, S.; Murugesan, M.Recently, drug delivery systems are facing several shortcomings which demand for the development of new formulations. A new drug–solvent systems may improve the characteristics and sustained release of drugs. Investigations in this domain revealed the significance of Ionic Liquids (ILs) as active pharmaceutical ingredients for pharmaceutical applications. ILs–drug assisted carriers exhibit many unique and attractive properties which are lacking in their conventional counterparts. In this work, Chitosan (CS), a natural polymer was blended with an ammonium based IL, Tetramethylammonium hydroxide (TMAOH), and microparticles (MPs) of CS–TMAOH–TPP were synthesized by cross–linking with sodium tripolyphosphate (TPP) using ionic gelation method. The addition of TMAOH to CS enhanced the stability of MPs without affecting the particle size. FTIR analysis confirmed the structural changes whereas the FE-SEM analysis showed almost similar sizes of freeze–dried MPs as determined by Zetasizer. The morphology of the CS–TMAOH–TPP MPs was mostly similar to CS–TPP MPs. The Thermogravimetric analysis indicated that these MPs exhibit good thermal resistance. Moreover, the DSC and XRD analysis of the prepared MPs were conducted to analyze thermograms and crystallographic structure respectively. Overall, the present synthesized CS–TMAOH–TPP MPs are more stable than CS–TPP MPs, which will be useful for drug delivery applications. © 2019Item Aqueous two phase based selective extraction of mannose/glucose specific lectin from Indian cultivar of Pisum sativum seed(Elsevier B.V., 2019) Rashmi, B.S.; Iyyaswami, R.Pisum sativum lectin (Psl) being a high-value protein has marked its application in the biomedical and therapeutic field. Aqueous two phase extraction (ATPE) was implemented as a selective partitioning technique for the partial purification of Psl from its seeds. PEG/citrate based biodegradable aqueous two phase system (ATPS) was screened and the factors such as the type and concentration of citrate salts, molar mass and concentration of polyethylene glycol (PEG), tie line length (TLL) and additive (NaCl) concentration, pH, crude load and volume ratio were studied for the selective partition of Psl. The Psl was successfully extracted to the top phase in the ATPS formed with 18% PEG 6000/16% sodium citrate at 41.01% TLL, 2% NaCl and pH of 7.5. A volume ratio of 0.76 and a crude load of 20% showed maximum activity yield of 122.12% with the purification factor of 16.26. The subunits of Psl namely ? and ? were identified with a molecular weight of 6 and 18 kDa respectively during the purity analysis using SDS PAGE and HPLC. © 2019 Elsevier B.V.Item Designing of A Synergistic Mixture of Natural Antioxidants Through Statistical Approaches for Enhancing the Oxidative Stability of Sardine Oil(Enviro Research Publishers, 2023) Mishra, S.K.; Belur, P.D.; Chandrasekar, V.; Iyyaswami, R.Given the diverse routes of oxidation and a variety of oxidation products, the right combination of antioxidants is expected to exhibit synergistic effects in retarding refined sardine oil oxidation. In this study, a full factorial design (24) was utilized to choose a combination of natural antioxidants which exhibit interactive effect and response surface modelling (RSM) was used to identify the optimal concentration of the selected antioxidant mixture which exhibit synergistic effect. Catechin and resveratrol showed a strong interactive effect among the four natural antioxidants (sinapic acid, vanillic acid, catechin, and resveratrol) studied in sardine oil stored for 50 days at 25ºC under darkness. Two optimal concentrations of interactive antioxidants were found through RSM. Catechin and resveratrol at 0.5 mM and 0.625 mM respectively, exhibited a strong synergistic effect whereas, at 0.5 mM and 3.7 mM respectively, showed prooxidant effect. This is the first of its kind report on the formulation of a synergistic antioxidant mixture for retarding oxidation using statistical approaches. © 2023 The Author(s).Item Assessment of Arsenic, Vanadium, Mercury, and Cadmium in Food and Drug Packaging(F1000 Research Ltd, 2024) Mukhi, S.; Rukmini, M.S.; Manjrekar, P.; Iyyaswami, R.; Sindhu, H.Background: Food and drug packaging materials are an integral part of our everyday life. Noxious elements can inadvertently be included in packaging materials in various stages of their production. Adulterants, adhesives, colorants and heavy metal interference are the common sources of contamination in food packaging materials. Heavy metal toxicity has far-reaching ill effects on living organisms. The present study aimed at qualitatively and quantitatively analysing heavy metal content of various materials that are used for food and drug packaging in India. Methods: The qualitative detection was done by rapid assay and heavy metals were quantified with the help of inductively coupled plasma-optical emission spectrometry (ICP-OES). A total of thirteen types of food and drug packaging materials were procured from local market and analysed for four heavy metals viz. arsenic (As), vanadium (V), mercury (Hg) and cadmium (Cd). The concentration of each heavy metal in the samples was compared with the permissible values published by the European Council. Results: Heavy metals were qualitatively detected in ten out of thirteen samples. Among the ten samples mercury and arsenic were detected the most followed by cadmium and vanadium. Quantitative estimation by ICP-OES showed presence of vanadium and cadmium in ten samples and arsenic and mercury in all the thirteen samples above the permissible range. Conclusions: The notable elevation in mercury concentration, followed by cadmium, arsenic and vanadium registering the least, presents a potential health hazard to consumers and compromises the food quality. ©: © 2024 Mukhi S et al.