title: Statistical investigation of Kluyveromyces lactis cells permeabilization with ethanol by response surface methodology.
abstract: The aim of our study was to select the optimal operating conditions to permeabilize Kluyveromyces lactis cells using ethanol as a solvent as an alternative to cell disruption and extraction. Cell permeabilization was carried out by a non-mechanical method consisting of chemical treatment with ethanol, and the results were expressed as β-galactosidase activity. Experiments were conducted under different conditions of ethanol concentration, treatment time and temperature according to a central composite rotatable design (CCRD), and the collected results were then worked out by response surface methodology (RSM). Cell permeabilization was improved by an increase in ethanol concentration and simultaneous decreases in the incubation temperature and treatment time. Such an approach allowed us to identify an optimal range of the independent variables within which the β-galactosidase activity was optimized. A maximum permeabilization of 2,816 mmol L(-1) oNP min(-1) g(-1) was obtained by treating cells with 75.0% v/v of ethanol at 20.0 °C for 15.0 min. The proposed methodology resulted to be effective and suited for K. lactis cells permeabilization at a lab-scale and promises to be of possible interest for future applications mainly in the food industry.
authors.affiliation: Departamento de Tecnologia de Alimentos, Universidade Federal de Viçosa, Viçosa, MG, Brazil.
authors.forename: Janaína T
authors.initials: JT
authors.lastname: de Faria
authors.affiliation: Departamento de Farmácia, Universidade Federal dos Vales do Jequitinhonha e Mucuri, Diamantina, MG, Brazil.
authors.forename: Pollyana F
authors.initials: PF
authors.lastname: Rocha
authors.affiliation: Department of Civil, Chemical and Environmental Engineering, University of Genoa, Genoa, Italy.
authors.forename: Attilio
authors.initials: A
authors.lastname: Converti
authors.affiliation: Departamento de Microbiologia, Universidade Federal de Viçosa, Viçosa, MG, Brazil.
authors.forename: Flávia M L
authors.initials: FM
authors.lastname: Passos
authors.affiliation: Departamento de Tecnologia de Alimentos, Universidade Federal de Viçosa, Viçosa, MG, Brazil.
authors.forename: Luis A
authors.initials: LA
authors.lastname: Minim
authors.affiliation: Departamento de Farmácia, Universidade Federal dos Vales do Jequitinhonha e Mucuri, Diamantina, MG, Brazil.
authors.forename: Fábio C
authors.initials: FC
authors.lastname: Sampaio
mesh_terms: D002462:Cell Membrane / Q000187:drug effects* / Q000502:physiology; D000431:Ethanol / Q000633:toxicity*; D007716:Kluyveromyces / Q000187:drug effects* / Q000502:physiology; D015233:Models, Statistical; D010539:Permeability / Q000187:drug effects*; D013696:Temperature; D013997:Time Factors; D001616:beta-Galactosidase / Q000032:analysis
chemical_list: D000431:Ethanol; D001616:beta-Galactosidase
keywords: cheese whey; ethanol; permeabilization; yeast; β-galactosidase