Production and Stability of Protease from Candida buinensis

Abstract

Cow raw milk from dairy cooperatives was examined for its microbial composition. Among the isolates identified, 17.6% were yeasts. The most frequent genus was Candida, although members belonging to the genera Brettanomyces, Dekkera, and Geotricum were also identified. Although qualitative and quantitative tests for extracellular proteolytic activity were positive for all the species isolated, Candida buinensis showed the highest response (23.5 U/mg); therefore, it was selected for subsequent investigation. The results of fermentations carried out at variable temperature, pH, and soybean flour concentration, according to a 2(3) full factorial design, demonstrated that this yeast ensured the highest production of extracellular proteases (573 U/mL) when cultivated at 35 degrees C, pH 6.5, and using soybean flour concentrations in the range 0.1-0.5% (w/v). The cell-free supernatants showed the highest activity at 25 degrees C and pH 7.0, and satisfactory stability in the ranges 25-30 degrees C and pH 7-9. The first-order rate constants of protease inactivation in the cell-free supernatants were calculated at different temperatures from semi-log plots of the residual activity versus time and then used in Arrhenius and Eyring plots to estimate the main thermodynamic parameters of thermoinactivation (E* = 40.0 kJ/mol; DeltaH* = 37.3 kJ/mol; DeltaS* = -197.5 J/mol K; DeltaG* = 101 kJ/mol).

Molecular identification of yeasts from Turkish traditional cheeses: Extracellular enzyme activities and physiological properties important for dairy industry

“…The extracellular enzyme activities of yeast species can show variations between the strains of the same species. For example, the production of proteases is affected by growth conditions (such as components of medium, inoculum size and dissolved oxygen) and environmental factors (such as pH, temperature and incubation time) (de Araújo et al 2010;Molnárová et al 2014). In this study, it was observed that the proteolytic and lipolytic activities were strain-specific as previously stated.…”

“…The extracellular enzyme properties of yeast species may differ between strains of the same species. They can also be different depending on growth conditions and environmental factors (de Araújo et al 2010;Molnárová et al 2014;Delgado-Ospina et al 2020).…”

Phytochemical analysis, antioxidant and in vitro β-galactosidase inhibition activities of Juniperus phoenicea and Calicotome villosa methanolic extracts

“…Variations in activation enthalpy (∆H), activation entropy (∆S), and Gibbs free energy (∆G) were calculated for the different temperatures as listed in Table 7. Positive ΔH values indicate that enzyme inactivation is an endothermic process [ 70 ]. The high values of ∆H° resulted from the thermal inactivation of β-galactosidase which indicates that the enzymatic activity undergoes a considerable change in conformation during denaturation [ 71 ].…”

Extracellular enzymatic activities and physiological profiles of yeasts colonizing fruit trees

“…Several yeast strains belonging to the species A. pullulans , Y. lipolytica , and the genera Candida and Kluyveromyces have been described as protease producers. The production of proteases is strain specific and influenced by media components, physical factors such as pH and temperature, inoculum size, dissolved oxygen, and incubation time .…”