Kinetic Modelling and Optimization of Ultrasonication-Induced Protein and βgalactosidase Release from Kefir Grains
XX. International Conference on Pharmacy and Chemical Engineering , London, England, 18 - 19 May 2026, pp.6, (Summary Text)
- Publication Type: Conference Paper / Summary Text
- City: London
- Country: England
- Page Numbers: pp.6
- Yıldız Technical University Affiliated: Yes
Abstract
β-galactosidase (EC 3.2.1.23), is a valuable biocatalyst that hydrolyses lactose, the main sugar found in milk, into glucose and galactose; as such, it is one of the key enzymes used in the dairy industry for the production of lactose-free or low-lactose milk products. Commercial βgalactosidases are commonly produced from yeasts such as Kluyveromyces lactis and molds such as Aspergillus niger, depending on the intended application and operating pH conditions. Kefir is a fermented dairy beverage produced using starter culture termed “kefir grains” and the grains are a gelatinous clump, commonly white or yellow in colour and are approximately 1-6 mm in diameter, surrounded by a polysaccharide matrix called kefiran. Kefiran is highly branched heteropolysaccharide composed of roughly equal proportions of D-glucose and Dgalactose. Kefir grains are composed of a complex symbiotic matrix, typically consisting of 60–80% lactic acid bacteria, 10–30% yeast, and 8–20% acetic acid bacteria. Dominated by Lactobacillus, Lactococcus, Leuconostoc, and yeasts like Kluyveromyces and Saccharomyces. They are highly diverse and vary with geographic origin. In this study, protein and the intracellular β-galactosidase enzyme release from kefir grains were investigated by using ultrasonication method. The effects of acoustic power, duty cycle % of a sonicator, medium pH and kefir biomass concentration on protein and β-galactosidase release kinetics were examined. The kinetics of protein and β-galactosidase release were characterized through comprehensive modelling studies. Moreover, a Response Surface Methodology-based optimization was performed to identify the ideal process parameters to achieve high βgalactosidase enzyme activity.
Keywords: β- galactosidase, kefir, kinetics, optimization, protein, ultrasonication. **This work was supported by Research Fund of the Yildiz Technical University. Project Number: FDK-2024-6196.