Faculty Publications
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Item Analysis of ionic and nonionic surfactants blends used for the reverse micellar extraction of Lactoperoxidase from whey(John Wiley and Sons Ltd, 2021) Karanth, S.; Iyyaswami, I.Bovine Lactoperoxidase (LP), a minor whey protein, is used as an antimicrobial in cosmetic, food, and pharmaceutical preparations. Industries are in pursuit of reliable, cheap, and scalable purification methods as the conventional techniques for LP purification like chromatography and membrane separation suffer from several drawbacks. The present work investigates the selective reverse micellar extraction of LP using the reverse micellar system formed by mixing food grade nonionic (Tween, Span, and Triton series) and ionic (AOT) surfactant blends. The analysis of LP extraction efficiency was performed by varying the concentration of nonionic surfactants with a constant AOT concentration of 100 mM and the initial pH of the system. Complete LP solubilization was achieved with reverse micelles formed by 100 mM AOT and 20 mM Tween 80 at pH 8. It was found that the extraction efficiency was dependent on the chain length or the number of ethylene oxide units in the Triton surfactant tail and the carbon–carbon double bond in Tween 80 tail, that is, on oleic acid. Span series however showed poor extraction in the organic phase substantiating the lesser water content. The forward extracted LP was successfully back-extracted into a fresh aqueous phase containing 1 M KCl at pH 10.5. The aqueous phase (whey) from the forward transfer can be further used to fractionate other whey proteins. © 2020 Curtin University and John Wiley & Sons, Ltd.Item Mixed Surfactant-Based Reverse Micellar Extraction Studies of Bovine Lactoperoxidase(John Wiley and Sons Inc, 2021) Karanth, S.; Iyyaswami, I.The suitability of reverse micellar extraction for recovery of bovine lactoperoxidase (LP) from aqueous solution was evaluated using systems formed by ionic and nonionic surfactant mixtures. The influence of ionic surfactant concentration, organic solvent, and pH on the extraction of LP into the reverse micellar phase was studied. The Tween® series surfactants with Aerosol-OT (bis-(2-ethylhexyl) sulfosuccinate) showed better extraction of LP in the reverse micelles (RM) compared to the Triton® and Span® series of surfactants. Complete extraction of LP from an aqueous phase of initial concentration 25 mg L?1 occurred with the RM formed by 90 mM Aerosol-OT/8 mM Tween® 80 in isooctane. The optimal pH, ionic strength, and positively charged ionic surfactant concentration for back extraction were also studied and a maximum of 95.5% back extraction efficiency and 66% LP activity recovery was obtained for a pH of 10.5,1 M KCl and 60 mM cetyltrimethylammonium bromide system. © 2021 AOCSItem Lactoperoxidase partitioning from whey using the reverse micelles of non-ionic/ionic mixed surfactants: Improvement of back extraction(John Wiley and Sons Inc, 2022) Karanth, S.; Iyyaswami, R.The reverse micellar system formed with a mixture of ionic and non-ionic surfactants, AOT (Sodium bis[2-ethyl hexyl] sulfosuccinate)/Tween 80 in isooctane, was studied for the selective extraction of Bovine Lactoperoxidase (LP) from acid whey. The effect of pH and ionic strength of acid whey and surfactant concentrations were studied and a maximum of 86% LP was extracted from acid whey at pH 9.5 with the addition of 0.2 M KCl to the reverse micelles formed with AOT (115 mM)/Tween 80 (23 mM). The back extraction of LP was studied at different aqueous stripping phase pH, ionic strength and concentration of counter-ionic surfactant Cetyltrimethylammonium bromide (CTAB). The back extraction of 112% with 80% LP recovery was achieved when the stripping phase pH was 10.5 with 1.5 M KCl and 60 mM CTAB. The antimicrobial activity of the extracted LP showed reduction in colony-forming units of S. aureus. Novelty impact statement: The reverse micelles formed with AOT/Tween 80 surfactant mixture minimize the pH-dependent denaturation of LP and widen the pH window (7.5–9.5) for LP extraction. The back extraction of LP from the reverse micellar phase to aqueous stripping phase was improved by the addition of CTAB as counter-ionic surfactant. A purification fold of 11.26 achieved with minimal loss in activity of LP by retaining the native Antimicrobial characteristic. © 2022 Wiley Periodicals LLC.Item Biosurfactant Based Reverse Micellar Extraction of Lactoperoxidase from Whey: Exploitation of Rhamnolipid Characteristics for Back Extraction(Taylor and Francis Ltd., 2023) Karanth, S.; Iyyaswami, R.; Raj, N.T.Biosurfactant-based reverse micellar extraction of Lactoperoxidase (LP) was studied using Rhamnolipid (RL) as a biosurfactant. Different solvents were considered to select a suitable organic phase for forming reverse micelles (RM) to varying concentrations of RL for the extraction of LP from its synthetic aqueous solution. The effect of addition of nonionic surfactant as lipophilic linker, whey pH, and ionic strength of the whey was studied to improve the forward extraction of LP from acid whey. About 96.65% LP was extracted to the RM phase during forward extraction. Further, a new back extraction strategy was developed by harnessing the biosurfactant properties. The pH-specific protonation–deprotonation characteristic of the RL headgroups was exploited to overcome the back extraction of LP, which is the rate-limiting step. The back extraction in citrate buffer at pH 5 using 0.75 M KCl resulted in 85.71% active LP recovery with 8.4-fold purification. The effect of the extraction process on the antimicrobial activity of LP was further examined with S. aureus, and the multiplication of the organism was almost arrested even after 24 hr at 9°C. © 2023 Taylor & Francis Group, LLC.