Faculty Publications
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Item Microwave-assisted extraction of chrysin from propolis and its encapsulation feasibility analysis in casein micelles(Elsevier Ltd, 2023) Parappa, K.; Krishnapura, P.R.; Iyyaswami, R.; Belur, P.D.The current study focuses on Microwave-assisted extraction of Chrysin from Propolis samples from different South Indian regions and its potential encapsulation in casein micelles to overcome its limitations in solubility, absorption and bioavailability. The extraction was evaluated using different solvent concentrations, and the highest extraction efficiency was obtained in 80 % (v/v) ethanol. Samples from Karnataka had the highest concentration of chrysin (0.085% of propolis weight), and total phenolic and flavonoid content of 7.25% and 15.86% of propolis weight, respectively. Casein was used to encapsulate chrysin to obtain an encapsulation efficiency of 72.91%. The results establish the suitability of casein for successful encapsulation of chrysin for preserving its stability and bioactivity. © 2024 Elsevier Ltd. All rights reserved.Item A critical review on properties and applications of microbial l-asparaginases(Taylor and Francis Ltd healthcare.enquiries@informa.com, 2016) Krishnapura, P.R.; Belur, P.D.; Subramanya, S.Abstract: l-Asparaginase is one of the main drugs used in the treatment of acute lymphoblastic leukemia (ALL), a commonly diagnosed pediatric cancer. Although several microorganisms are found to produce l-asparaginase, only the purified enzymes from E. coli and Erwinia chrysanthemi are employed in the clinical and therapeutic applications in humans. However, their therapeutic response seldom occurs without some evidence of hypersensitivity and other toxic side effects. l-Asparaginase is also of prospective use in food industry to reduce the formation of acrylamide in fried, roasted or baked food products. This review is an attempt to compile information on the properties of l-asparaginases obtained from different microorganisms. The complications involved with the therapeutic use of the currently available l-asparaginases, and the enzyme’s potential application as a food processing aid to mitigate acrylamide formation have also been reviewed. Further, avenues for searching alternate sources of l-asparaginase have been discussed, highlighting the prospects of endophytic microorganisms as a possible source of l-asparaginases with varied biochemical and pharmacological properties. © 2015 Informa Healthcare USA, Inc.Item Partial purification and characterization of L-asparaginase from an endophytic Talaromyces pinophilus isolated from the rhizomes of Curcuma amada(Elsevier, 2016) Krishnapura, P.R.; Belur, P.D.l-Asparaginase is a commercially significant enzyme. There exists a demand for a broad variety of microbial l-asparaginases with characteristics compatible with its different applications. Endophytic microorganisms, in particular are emerging as potential sources of l-asparaginases. The current work involves partial purification and characterization of l-asparaginase from Talaromyces pinophilus, an endophytic fungus isolated from the rhizomes of Curcuma amada. Maximum enzyme activity could be achieved at pH 8.0 and with temperature 28 °C. The enzyme Exhibits 95 % and 98% of its total activity at physiological pH and temperature, respectively. The enzyme activity is largely unhindered in the presence of metal ions such as Ca2+, Cu2+, Fe2+, Mg2+, Mn2+, Zn2+. Increase in the enzyme activity in the presence of thiol groups and reduction in the same upon addition of thiol blockers indicates the involvement of cysteine in the enzyme's catalytic activity. The enzyme is a heterodimer of 62 kDa and 39 kDa. The enzyme has a Km of 6.4 mM, its turnover number towards l-asparagine is 286.3 s-1. The enzyme has 16% glutaminase activity; its Km towards glutamine is 13.3 mM and turnover number is 54.6 s-1. Our results highlight that l-asparaginase from endophytic Talaromyces pinophilus could be considered as potential candidate for clinical and industrial trials, owing to its efficiency and biochemical properties. To the best of our knowledge, this is the first report on partial purification and characterization of L-asparaginase from an endophyte. © 2015 Elsevier B.V. All rights reserved.Item Isolation and screening of endophytes from the rhizomes of some Zingiberaceae plants for L-asparaginase production(Taylor and Francis Inc. 325 Chestnut St, Suite 800 Philadelphia PA 19106, 2016) Krishnapura, P.R.; Belur, P.D.Endophytes are described as microorganisms that colonize the internal tissues of healthy plants without causing any disease. Endophytes isolated from medicinal plants have been attracting considerable attention due to their high biodiversity and their predicted potential to produce a plethora of novel compounds. In this study, an attempt was made to isolate endophytes from rhizomes of five medicinal plants of Zingiberaceae family, and to screen the endophytes for L-asparaginase activity. In total, 50 endophytes (14 bacteria, 22 actinomycetes, and 14 fungi) were isolated from Alpinia galanga, Curcuma amada, Curcuma longa, Hedychium coronarium, and Zingiber officinale; of these, 31 endophytes evidenced positive for L-asparaginase production. All the L-asparaginase-positive isolates showed L-asparaginase activity in the range of 54.17–155.93 U/mL in unoptimized medium. An endophytic fungus isolated from Curcuma amada, identified as Talaromyces pinophilus, was used for further experiments involving studies on the effect of certain nutritional and nonnutritional factors on L-asparaginase production in submerged fermentation. Talaromyces pinophilus initially gave an enzyme activity of 108.95 U/mL, but gradually reduced to 80 U/mL due to strain degeneration. Perhaps this is the first report ever on the production of L-asparaginase from endophytes isolated from medicinal plants of Zingiberaceae family. © 2016, Taylor & Francis Group, LLC.Item L-asparaginase production using solid-state fermentation by an endophytic talaromyces pinophilus isolated from rhizomes of curcuma amada(Journal of Pure and Applied Microbiology micro_drkhan@yahoo.com 54, Near Post Office, Thana Street, Shahjahanabad Bhopal 462 001, 2020) Krishnapura, P.R.; Belur, P.D.In recent times, exploration of endophytes for L-asparaginase production is gradually gaining momentum. This work deals with studies on the production of L-asparaginase from Talaromyces pinophilus, an endophytic fungus isolated from the rhizomes of Curcuma amada. L-asparaginase production was carried out by Submerged Fermentation (SmF) followed by Solid-state Fermentation (SSF). A liquid medium was designed and optimized using Plackett-Burman Design and Response Surface Methodology (RSM), under SmF. Additionally, optimal concentrations of various metal salts were incorporated in the optimized liquid medium, by one-factor-at-a-time experiments. To further enhance L-asparaginase production, SSF was carried out using Polyurethane Foam (PUF) as inert support impregnated with the optimized liquid medium. Effects of PUF cube volume, mass of PUF, moisture content, initial medium pH, and incubation temperature on the enzyme production in SSF were optimized by one-factor-at-a-time approach.L-asparaginase production enhanced from 80.8 U/mL in the unoptimized medium to 94.4 U/mL in the optimized medium under SmF. Enzyme production further increased to 120.3 U/mL under SSF by using PUF soaked in the optimized liquid medium. This study highlights the benefits of carrying out SSF with PUF, using the same liquid medium optimized for SmF - a novel approach to enhance the enzyme yield (in our case an increase of about 27% was observed). To the best of our knowledge, this is the first report on the production of L-asparaginase by both SmF and SSF, from an endophyte Talaromyces pinophilus isolated from the rhizomes of Curcuma amada. © The Author(s) 2020. Open Access. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License which permits unrestricted use, sharing, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.Item Development of stable and functional encapsulated chrysin using casein–polysaccharide complexes for food applications(John Wiley and Sons Inc, 2023) Parappa, K.; Krishnapura, P.R.; Iyyaswami, R.; Belur, P.D.Chrysin is a hydrophobic flavonoid with multiple health benefits. The various applications of chrysin are challenged by its poor solubility, instability and loss of bioactivity. Casein–chrysin complex and casein–polysaccharide–chrysin complexes have developed to overcome these limitations. Very high encapsulation efficiency of 98.23 ± 0.22% was achieved with casein–inulin–chrysin complex. The chrysin was able to form a stable casein–polysaccharide–chrysin complex suspension with a hydrodynamic diameter of 382.3 nm, zeta potential value of −12.3 mV and a Polydispersity Index (PDI) of 27.7. The antioxidant activity of chrysin increased about threefold after encapsulation. The release of chrysin from its encapsulated complexes to different buffers in the pH range of 3 to 10 was studied at 1:10 ratio. At the end of 48 h, only 6%–8% of chrysin was released in the pH range 3–4, 33%–58% at pH 5–9 and 62% at pH 10. The chrysin encapsulated in casein–inulin–chrysin complex was able to overcome the rapid release of chrysin from the casein–chrysin complex. The results indicate the successful development of a stable encapsulated chrysin complex which can overcome the various limitations of chrysin in its potential applications. © 2023 Institute of Food, Science and Technology (IFSTTF).Item Production of nisin from Lactococcus lactis in acid-whey with nutrient supplementation(Taylor and Francis Ltd., 2024) Vijayakumar, S.; Vishnu, G.; Krishnapura, P.R.; Iyyaswami, R.The production of Nisin, an FDA-approved food preservative, was attempted by Lactococcus lactis subsp. lactis ATCC® 11454 using the underutilized milk industry effluent, acid-whey, as a substrate. Nisin production was further improved by studying the effect of supplementation of nutrients and non-nutritional parameters. The addition of yeast extract (6% w/v) as nitrogen source and sucrose (4% w/v) as carbon source were found to be suitable nutrients for the maximum nisin production. The changes in the medium pH due to lactic acid accumulation during batch fermentation and its influence on the production of nisin were analyzed in the optimized whey medium (OWM). The production characteristics in OWM were further compared with the nisin production in MRS media. The influence of nisin as an inducer for its own production was also studied and found that the addition of nisin at 0.22 mg/ml promote the nisin production. The analysis of consumption of various metal ions present in the OWM during the nisin production was also analyzed, and found that the copper ions are the most consumed ion. The highest nisin yield of 2.6 × 105 AU/mL was obtained with OWM. © 2023 Taylor & Francis Group, LLC.Item Extraction of chrysin from propolis and its selective encapsulation in synthetic/natural surfactant-based micelles(Taylor and Francis Ltd., 2024) Sivanesan, M.; Krishnapura, P.R.; Iyyaswami, R.; Parappa, K.; Belur, P.D.The encapsulation characteristics of chrysin (important flavonoid with potential food, pharmaceutical, and biomedical applications) was studied with nonionic surfactants Triton X-114 (TX) and Quillaja Saponin (QS), individually. The factors influencing the encapsulation efficiency (EE) of standard chrysin that is surfactant concentration, pH, NaCl concentration, and chrysin concentration were analyzed. The maximum EE of standard chrysin was found to be 98.23 ± 1.63% with TX micelles and 83 ± 2.31% with QS micelles under the following conditions: 0.02 mg/mL standard chrysin, 5% NaCl, pH 7, and 4% w/w TX 6% w/w QS. Selective extraction of chrysin from propolis was tried using three extraction techniques namely Maceration, Microwave-assisted Extraction (MAE), and Maceration with Microwave-assisted Extraction (MMAE). MAE, which gave a chrysin yield of 3 mg/g, was deemed the most suitable method for chrysin extraction from propolis. This MAE crude extract was subjected to encapsulation under the conditions previously optimized for standard chrysin. Specific encapsulation of chrysin from the propolis crude extract was achieved, with an EE of 92 ± 0.86% with TX and 84.97 ± 1.34% with QS. The encapsulated chrysin was characterized using particle size analysis and antioxidant activity. TX system was found to be the most suitable for the encapsulation, as it was able to selectively encapsulate chrysin from propolis, despite the presence of other interfering flavonoids in the crude extract. The microwave-assisted extraction combined with surfactant-based micellar encapsulation can be said to be an effective process for the extraction and encapsulation of chrysin from propolis. © 2023 Taylor & Francis Group, LLC.