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Effect of glucose and galactose on whey lactose hydrolysis and enzyme stability under sonic treatment
Abstracts / Journal of Biotechnology 131S (2007) S211–S241
S217
14. investigation of whey lactose hydrolysis and enzyme stability by a sonifier
15. Effect of glucose and galactose on whey lactose hydrolysis and enzyme stability under sonic treatment
Elcin Demirhan ∗ , Belma Ozbek
Elcin Demirhan ∗ , Belma Ozbek
Chemical Engineering Department, Yildiz Technical University, Davutpasa Campus, Esenler, 34210 Istanbul, Turkey
Chemical Engineering Department, Yildiz Technical University, Davutpasa Campus, Esenler, 34210 Istanbul, Turkey
Lactose is a sugar with a high biochemical oxygen demand (BOD) and has a strong tendency to adsorb flavours and odours compared to its hydrolysis products; glucose and galactose (Pessela et al., 2003; Ladero et al., 2001). The hydrolysis of lactose to glucose and galactose is a promising process in the food industry for the development of new products with no lactose in their composition which permits greater usage of permeate, as a substitute for syrup in soft drinks, fermented beverages and confectionery products (Di Serio et al., 2003; Santos et al., 1998). The hydrolysis of lactose to glucose and galactose is catalysed by enzymes called -galactosidases. In biotechnological processes, ultrasonication method is widely used for laboratory scale and it does not require sophisticated equipment or extensive technical training. The influence of ultrasound waves on the activity and stability of enzymes has shown to be specific for each enzyme and dependent on son¨ ¨ ication parameters (Ozbek and Ulgen, 2000; Liu et al., 2003). Therefore, in the present work, the performance of hydrolysis of lactose recovered from whey was investigated under ultrasonic irradiation using a batch reactor system. The reactions were carried out in 250 ml of 25 mM phosphate buffer solutions containing 5% (w/v) lactose. The effect of sonifier parameters and reaction volume on the hydrolysis and on the enzyme stability was investigated with respect to processing time. The kinetics of lactose hydrolysis reaction and enzyme inactivation were examined at various process conditions, and the mathematical models depending on these process conditions were developed.
The hydrolysis of lactose has found commercial use in the food industry for the preparation of low-lactose dairy products for people suffering lactose intolerance, and for the preparation of new foods and dairy products. The hydrolytic reaction can also be applied in the up-grading of whey and permeates, the major byproducts of cheese manufacturing (Flores et al., 1996). And also, lactose is scarcely biodegradable compared to its hydrolysis products, glucose and galactose, so solutions containing lactose can not dispose of without expensive treatments due to prevent environmental pollution (Ladero et al., 2001). The hydrolysis of lactose to glucose and galactose catalyzed by -galactosidases are widely distributed in nature, appearing in microorganisms, plants and animal tissues (Pessela et al., 2003). The information is required that describing the inhibition mechanisms that affect the process yield. Therefore, in the present study, the effect of hydrolysis products (glucose and galactose) on lactose hydrolysis and maximal efficiency of galactosidase are investigated. The Bandelin Sonicator system was used for the lactose hydrolysis experiments. -galactosidase enzyme used is produced by Kluyveromyces marxianus. The reactions were carried out in 250 mL of 25 mM phosphate buffer solutions containing 5% (w/v) lactose recovered from whey. The amount of -galactosidase enzyme added to this solution was 1 mL/L. The degree of lactose hydrolysis (%) and enzyme activity (%) depending on time were investigated versus glucose (6.25–25 g/L) and galactose (6.25–25 g/L). An evaluation of the experimental data showed that both -galactosidase enzyme activity and lactose concentration after hydrolysis process were affected by addition of these materials under sonic treatment. The mathematical models for each added materials were also derived by using the experimental data of residual lactose concentration and residual enzyme activity.
References Di Serio, M., Maturo, C., De Alteriis, E., Parascandola, P., Tesser, R., Santacesaria, E., 2003. Lactose hydrolysis by immobilized -galactosidase: the effect of the supports and the kinetics. Catal. Today 79–80, 333–339. Ladero, M., Santos, A., Garcia, J.L., Garcia, F., 2001. Activity over lactose and ONPG of a genetically engineered -galactosidase from Escherichia coli in solution and immobilized: kinetic modelling. Enzyme Microbial Technol. 29, 181–193. Liu, Y., Takatsuki, H., Yoshikoshi, A., Wang, B., Sakanishi, A., 2003. Effects of ultrasound on the growth and vacuolar H+ -ATPase activity of aloe arborescens callus cells. Colloids Surf. B: Biointerf. 32, 105–116. ¨ ¨ Ozbek, B., Ulgen, K., 2000. The stability of enzymes after sonication. Process Biochem. 35 (9), 1037–1043. Pessela, B., Mateo, C., Fuentes, M., Vian, A., Garcia, J.L., Carrascosa, A.V., Guisan, J.M., Lafuente, R.F., 2003. The immobilization of a thermophilic -galactosidase on sepabeads supports decreases product inhibition complete hydrolysis of lactose in dairy products. Enzyme Microbial Technol. 33, 199–205. Santos, A., Ladero, M., Garcia, F., 1998. Kinetic modeling of lactose hydrolysis by -galactosidase from Kluyveromices fragilis. Enzyme Microbial Technol. 22, 558–567.
References Flores, M.V., Ertola, R.J., Voget, C.E., 1996. Effect of monovalent cations on the stability and activity of Kluyveromyces lactis -galactosidase. Lebensm. -Wiss. u. -Technol. 29, 503–506. Ladero, M., Santos, A., Garcia, J.L., Garcia, F., 2001. Activity over lactose and ONPG of a genetically engineered -galactosidase from Escherichia coli in solution and immobilized: kinetic modelling. Enzyme Microbial Technol. 29, 181–193. Pessela, B., Mateo, C., Fuentes, M., Vian, A., Garcia, J.L., Carrascosa, A.V., Guisan, J.M., Lafuente, R.F., 2003. The Immobilization of a thermophilic -galactosidase on sepabeads supports decreases product inhibition complete hydrolysis of lactose in dairy products. Enzyme Microbial Technol. 33, 199–205.
doi:10.1016/j.jbiotec.2007.07.392 doi:10.1016/j.jbiotec.2007.07.391
S217
14. investigation of whey lactose hydrolysis and enzyme stability by a sonifier
15. Effect of glucose and galactose on whey lactose hydrolysis and enzyme stability under sonic treatment
Elcin Demirhan ∗ , Belma Ozbek
Elcin Demirhan ∗ , Belma Ozbek
Chemical Engineering Department, Yildiz Technical University, Davutpasa Campus, Esenler, 34210 Istanbul, Turkey
Chemical Engineering Department, Yildiz Technical University, Davutpasa Campus, Esenler, 34210 Istanbul, Turkey
Lactose is a sugar with a high biochemical oxygen demand (BOD) and has a strong tendency to adsorb flavours and odours compared to its hydrolysis products; glucose and galactose (Pessela et al., 2003; Ladero et al., 2001). The hydrolysis of lactose to glucose and galactose is a promising process in the food industry for the development of new products with no lactose in their composition which permits greater usage of permeate, as a substitute for syrup in soft drinks, fermented beverages and confectionery products (Di Serio et al., 2003; Santos et al., 1998). The hydrolysis of lactose to glucose and galactose is catalysed by enzymes called -galactosidases. In biotechnological processes, ultrasonication method is widely used for laboratory scale and it does not require sophisticated equipment or extensive technical training. The influence of ultrasound waves on the activity and stability of enzymes has shown to be specific for each enzyme and dependent on son¨ ¨ ication parameters (Ozbek and Ulgen, 2000; Liu et al., 2003). Therefore, in the present work, the performance of hydrolysis of lactose recovered from whey was investigated under ultrasonic irradiation using a batch reactor system. The reactions were carried out in 250 ml of 25 mM phosphate buffer solutions containing 5% (w/v) lactose. The effect of sonifier parameters and reaction volume on the hydrolysis and on the enzyme stability was investigated with respect to processing time. The kinetics of lactose hydrolysis reaction and enzyme inactivation were examined at various process conditions, and the mathematical models depending on these process conditions were developed.
The hydrolysis of lactose has found commercial use in the food industry for the preparation of low-lactose dairy products for people suffering lactose intolerance, and for the preparation of new foods and dairy products. The hydrolytic reaction can also be applied in the up-grading of whey and permeates, the major byproducts of cheese manufacturing (Flores et al., 1996). And also, lactose is scarcely biodegradable compared to its hydrolysis products, glucose and galactose, so solutions containing lactose can not dispose of without expensive treatments due to prevent environmental pollution (Ladero et al., 2001). The hydrolysis of lactose to glucose and galactose catalyzed by -galactosidases are widely distributed in nature, appearing in microorganisms, plants and animal tissues (Pessela et al., 2003). The information is required that describing the inhibition mechanisms that affect the process yield. Therefore, in the present study, the effect of hydrolysis products (glucose and galactose) on lactose hydrolysis and maximal efficiency of galactosidase are investigated. The Bandelin Sonicator system was used for the lactose hydrolysis experiments. -galactosidase enzyme used is produced by Kluyveromyces marxianus. The reactions were carried out in 250 mL of 25 mM phosphate buffer solutions containing 5% (w/v) lactose recovered from whey. The amount of -galactosidase enzyme added to this solution was 1 mL/L. The degree of lactose hydrolysis (%) and enzyme activity (%) depending on time were investigated versus glucose (6.25–25 g/L) and galactose (6.25–25 g/L). An evaluation of the experimental data showed that both -galactosidase enzyme activity and lactose concentration after hydrolysis process were affected by addition of these materials under sonic treatment. The mathematical models for each added materials were also derived by using the experimental data of residual lactose concentration and residual enzyme activity.
References Di Serio, M., Maturo, C., De Alteriis, E., Parascandola, P., Tesser, R., Santacesaria, E., 2003. Lactose hydrolysis by immobilized -galactosidase: the effect of the supports and the kinetics. Catal. Today 79–80, 333–339. Ladero, M., Santos, A., Garcia, J.L., Garcia, F., 2001. Activity over lactose and ONPG of a genetically engineered -galactosidase from Escherichia coli in solution and immobilized: kinetic modelling. Enzyme Microbial Technol. 29, 181–193. Liu, Y., Takatsuki, H., Yoshikoshi, A., Wang, B., Sakanishi, A., 2003. Effects of ultrasound on the growth and vacuolar H+ -ATPase activity of aloe arborescens callus cells. Colloids Surf. B: Biointerf. 32, 105–116. ¨ ¨ Ozbek, B., Ulgen, K., 2000. The stability of enzymes after sonication. Process Biochem. 35 (9), 1037–1043. Pessela, B., Mateo, C., Fuentes, M., Vian, A., Garcia, J.L., Carrascosa, A.V., Guisan, J.M., Lafuente, R.F., 2003. The immobilization of a thermophilic -galactosidase on sepabeads supports decreases product inhibition complete hydrolysis of lactose in dairy products. Enzyme Microbial Technol. 33, 199–205. Santos, A., Ladero, M., Garcia, F., 1998. Kinetic modeling of lactose hydrolysis by -galactosidase from Kluyveromices fragilis. Enzyme Microbial Technol. 22, 558–567.
References Flores, M.V., Ertola, R.J., Voget, C.E., 1996. Effect of monovalent cations on the stability and activity of Kluyveromyces lactis -galactosidase. Lebensm. -Wiss. u. -Technol. 29, 503–506. Ladero, M., Santos, A., Garcia, J.L., Garcia, F., 2001. Activity over lactose and ONPG of a genetically engineered -galactosidase from Escherichia coli in solution and immobilized: kinetic modelling. Enzyme Microbial Technol. 29, 181–193. Pessela, B., Mateo, C., Fuentes, M., Vian, A., Garcia, J.L., Carrascosa, A.V., Guisan, J.M., Lafuente, R.F., 2003. The Immobilization of a thermophilic -galactosidase on sepabeads supports decreases product inhibition complete hydrolysis of lactose in dairy products. Enzyme Microbial Technol. 33, 199–205.
doi:10.1016/j.jbiotec.2007.07.392 doi:10.1016/j.jbiotec.2007.07.391