Trigliseridlerin Candida Cylindracea lipazi ile hidrolizinde yüzey ve çözücü etkileri-arayüzey kinetiği /
Yazar: TAMER UÇAR
Danışman: PROF.DR. ARİF ÇAĞLAR
Hacettepe Üniversitesi / Fen Bilimleri Enstitüsü / Kimya Mühendisliği Ana Bilim Dalı
Derece: Doktora, 1984
Konu: Kimya Mühendisliği = Chemical Engineering

Özet:
VX11 tepkime ortamında karışık (triasetin + n-heptan) miselleri ve emülsiyon oluşumundan dolayı olduğu belirlenmiştir. n-Heptanın diğer bir etkisinin, triasetinin kritik misel derişimini, ha cimce, %3. 50-3. 75 aralığından %2. 80-3. 25 aralığına düşürmesi olduğu saptanmıştır. Misel etkilerinin ihmal edilebileceği, hacimce %2 triasetin derişiminde, hidroliz hızının [ (n-heptan)/ (triasetin + su) ] emülsiyonu arayüzeyine tutunan enzim mikta rı ile doğru orantılı olduğu, yüze tutunma ölçümleri sonucunda belirlenmiştir. Tribütirin ve (triasetin + heptan) emülsiyon sistem leri için, hidroliz hızının arayüzeydeki enzim ve tepkiyen de- rişimleri ile orantılı olduğunu ve enzimin emülsiyon arayüzeyi ne tersinir olarak tutunduğunu varsayarak, Hızlı Denge (= Rapid Equilibrium) yaklaşımı ile türetilen hız ve yüze tutunma eşitliklerinin deneysel verilerle uyum içinde olduğu görülmüştür. Sabit tribütirin derişiminde, hacimce %0.5, enzim derişimini değiştirerek yapılan yüze tutunma ölçümleri, ~286 mg/1 enzim derişimine (protein olarak) kadar tektabakalı yüze tutunmanın, bu derişimden sonra ise çoktabakalı yüze tutunmanın önem kazandığını göstermiştir. Yüze tutunma ve hidroliz hızı verilerinin analizi sonucunda, Candida cylindracea lipazı molekülünün (tri- bütirin/su) emülsiyonu arayüzeyinde kapladığı alan, aE, ve görünür Michaelis Sabiti K, hesaplanmıştır. Değişik yöntemlerle hesaplanan a" ve K 'nın ortalama değerleri, sırayla 1.83xl01L cm2/mol ve 0.83 cm2/cm3,tür.XV Michael is constant (KM ) were calculated. The average values Ma 11 2 2 3 of a" and K are 1.83x10 cm /mol and 0.78 cm /cm / respec- h Ma tively. In the adsorption of Candidal lipase at the (n-hep- tane/water) interface induction times, as long as 2.5 hours, are required to attain adsorption equilibrium at the interface. Altough different periods of time are needed to reach steady state at (tributyrin/water) and (n-heptane/water) interfaces, the equilibrium amounts of the enzyme adsorbed per unit area of these surfaces are approximately identical. Using the Cal- derbank' s equation which is proposed for the turbulent systems, the mass transfer coefficient of the Candidal lipase, k", in the (n-heptane/water) system was calculated as 0.19 cm/s. The positive energy barrier to penetration and molecular rearran gement at the (n-heptane/water) interface was decided to be responsible for the observed long induction times. The results of enzyme and total protein adsorption data collected with different techniques, indicate that the commercial lipase pre paration is a mixture of proteins and the lipase of Candida cylin- dracea is selectively adsorbed at (triglyceride/water) in terfaces.VX11 tepkime ortamında karışık (triasetin + n-heptan) miselleri ve emülsiyon oluşumundan dolayı olduğu belirlenmiştir. n-Heptanın diğer bir etkisinin, triasetinin kritik misel derişimini, ha cimce, %3. 50-3. 75 aralığından %2. 80-3. 25 aralığına düşürmesi olduğu saptanmıştır. Misel etkilerinin ihmal edilebileceği, hacimce %2 triasetin derişiminde, hidroliz hızının [ (n-heptan)/ (triasetin + su) ] emülsiyonu arayüzeyine tutunan enzim mikta rı ile doğru orantılı olduğu, yüze tutunma ölçümleri sonucunda belirlenmiştir. Tribütirin ve (triasetin + heptan) emülsiyon sistem leri için, hidroliz hızının arayüzeydeki enzim ve tepkiyen de- rişimleri ile orantılı olduğunu ve enzimin emülsiyon arayüzeyi ne tersinir olarak tutunduğunu varsayarak, Hızlı Denge (= Rapid Equilibrium) yaklaşımı ile türetilen hız ve yüze tutunma eşitliklerinin deneysel verilerle uyum içinde olduğu görülmüştür. Sabit tribütirin derişiminde, hacimce %0.5, enzim derişimini değiştirerek yapılan yüze tutunma ölçümleri, ~286 mg/1 enzim derişimine (protein olarak) kadar tektabakalı yüze tutunmanın, bu derişimden sonra ise çoktabakalı yüze tutunmanın önem kazandığını göstermiştir. Yüze tutunma ve hidroliz hızı verilerinin analizi sonucunda, Candida cylindracea lipazı molekülünün (tri- bütirin/su) emülsiyonu arayüzeyinde kapladığı alan, aE, ve görünür Michaelis Sabiti K, hesaplanmıştır. Değişik yöntemlerle hesaplanan a" ve K 'nın ortalama değerleri, sırayla 1.83xl01L cm2/mol ve 0.83 cm2/cm3,tür.XV Michael is constant (KM ) were calculated. The average values Ma 11 2 2 3 of a" and K are 1.83x10 cm /mol and 0.78 cm /cm / respec- h Ma tively. In the adsorption of Candidal lipase at the (n-hep- tane/water) interface induction times, as long as 2.5 hours, are required to attain adsorption equilibrium at the interface. Altough different periods of time are needed to reach steady state at (tributyrin/water) and (n-heptane/water) interfaces, the equilibrium amounts of the enzyme adsorbed per unit area of these surfaces are approximately identical. Using the Cal- derbank' s equation which is proposed for the turbulent systems, the mass transfer coefficient of the Candidal lipase, k", in the (n-heptane/water) system was calculated as 0.19 cm/s. The positive energy barrier to penetration and molecular rearran gement at the (n-heptane/water) interface was decided to be responsible for the observed long induction times. The results of enzyme and total protein adsorption data collected with different techniques, indicate that the commercial lipase pre paration is a mixture of proteins and the lipase of Candida cylin- dracea is selectively adsorbed at (triglyceride/water) in terfaces.VX11 tepkime ortamında karışık (triasetin + n-heptan) miselleri ve emülsiyon oluşumundan dolayı olduğu belirlenmiştir. n-Heptanın diğer bir etkisinin, triasetinin kritik misel derişimini, ha cimce, %3. 50-3. 75 aralığından %2. 80-3. 25 aralığına düşürmesi olduğu saptanmıştır. Misel etkilerinin ihmal edilebileceği, hacimce %2 triasetin derişiminde, hidroliz hızının [ (n-heptan)/ (triasetin + su) ] emülsiyonu arayüzeyine tutunan enzim mikta rı ile doğru orantılı olduğu, yüze tutunma ölçümleri sonucunda belirlenmiştir. Tribütirin ve (triasetin + heptan) emülsiyon sistem leri için, hidroliz hızının arayüzeydeki enzim ve tepkiyen de- rişimleri ile orantılı olduğunu ve enzimin emülsiyon arayüzeyi ne tersinir olarak tutunduğunu varsayarak, Hızlı Denge (= Rapid Equilibrium) yaklaşımı ile türetilen hız ve yüze tutunma eşitliklerinin deneysel verilerle uyum içinde olduğu görülmüştür. Sabit tribütirin derişiminde, hacimce %0.5, enzim derişimini değiştirerek yapılan yüze tutunma ölçümleri, ~286 mg/1 enzim derişimine (protein olarak) kadar tektabakalı yüze tutunmanın, bu derişimden sonra ise çoktabakalı yüze tutunmanın önem kazandığını göstermiştir. Yüze tutunma ve hidroliz hızı verilerinin analizi sonucunda, Candida cylindracea lipazı molekülünün (tri- bütirin/su) emülsiyonu arayüzeyinde kapladığı alan, aE, ve görünür Michaelis Sabiti K, hesaplanmıştır. Değişik yöntemlerle hesaplanan a" ve K 'nın ortalama değerleri, sırayla 1.83xl01L cm2/mol ve 0.83 cm2/cm3,tür.XV Michael is constant (KM ) were calculated. The average values Ma 11 2 2 3 of a" and K are 1.83x10 cm /mol and 0.78 cm /cm / respec- h Ma tively. In the adsorption of Candidal lipase at the (n-hep- tane/water) interface induction times, as long as 2.5 hours, are required to attain adsorption equilibrium at the interface. Altough different periods of time are needed to reach steady state at (tributyrin/water) and (n-heptane/water) interfaces, the equilibrium amounts of the enzyme adsorbed per unit area of these surfaces are approximately identical. Using the Cal- derbank' s equation which is proposed for the turbulent systems, the mass transfer coefficient of the Candidal lipase, k", in the (n-heptane/water) system was calculated as 0.19 cm/s. The positive energy barrier to penetration and molecular rearran gement at the (n-heptane/water) interface was decided to be responsible for the observed long induction times. The results of enzyme and total protein adsorption data collected with different techniques, indicate that the commercial lipase pre paration is a mixture of proteins and the lipase of Candida cylin- dracea is selectively adsorbed at (triglyceride/water) in terfaces.

Abstract:
XIV triacetin both in soluble and insoluble regions. The formation of mixed micelles of (triacetin + n-heptane) and emulsion for mation were found to be responsible for the observed rate en hancements. In the mixed micelle, n-heptane molecules act as the solubilizate and incorporate in the hydrocarbon interior of the micelle. Solubilization of n-heptane by surface active triacetin has the effect of lowering the critical micelle con centration from 3.50-3.75 % triacetin concentration (by volume) to 2.8-3.25 %. In the presence of 2% triacetin (by volume), at which micellar effects may be neglected, the initial rate of triacetin hydrolysis has been shown to be linearly proportional to the amount of enzyme present at the (n-heptane) /triacetin + water) interface. Kinetic equations interrelating the initial rates and adsorbtion at the oil/water interfaces have been developed using the Rapid Equilibrium approach for both tributyrin and (triacetin + n-heptane) systems. Application of experimental data has proven the validity of the assumptions made in deriving these kinetic equations. At constant tributyrin concentration, 0.5 % by volume, the variation of the amount of enzyme adsorbed with enzyme concentration indicates that monolayer adsorbtion is predominant up to 286 mg/1 enzyme concentration (as protein) after which multilayer formation starts. From the analysis of experimental data using the model equations developed, the mole cular area occupied by the lipase of Candida cylindracea at (tributyrin/ water) interface, aE, and value of apparentXV Michael is constant (KM ) were calculated. The average values Ma 11 2 2 3 of a" and K are 1.83x10 cm /mol and 0.78 cm /cm / respec- h Ma tively. In the adsorption of Candidal lipase at the (n-hep- tane/water) interface induction times, as long as 2.5 hours, are required to attain adsorption equilibrium at the interface. Altough different periods of time are needed to reach steady state at (tributyrin/water) and (n-heptane/water) interfaces, the equilibrium amounts of the enzyme adsorbed per unit area of these surfaces are approximately identical. Using the Cal- derbank' s equation which is proposed for the turbulent systems, the mass transfer coefficient of the Candidal lipase, k", in the (n-heptane/water) system was calculated as 0.19 cm/s. The positive energy barrier to penetration and molecular rearran gement at the (n-heptane/water) interface was decided to be responsible for the observed long induction times. The results of enzyme and total protein adsorption data collected with different techniques, indicate that the commercial lipase pre paration is a mixture of proteins and the lipase of Candida cylin- dracea is selectively adsorbed at (triglyceride/water) in terfaces.XIV triacetin both in soluble and insoluble regions. The formation of mixed micelles of (triacetin + n-heptane) and emulsion for mation were found to be responsible for the observed rate en hancements. In the mixed micelle, n-heptane molecules act as the solubilizate and incorporate in the hydrocarbon interior of the micelle. Solubilization of n-heptane by surface active triacetin has the effect of lowering the critical micelle con centration from 3.50-3.75 % triacetin concentration (by volume) to 2.8-3.25 %. In the presence of 2% triacetin (by volume), at which micellar effects may be neglected, the initial rate of triacetin hydrolysis has been shown to be linearly proportional to the amount of enzyme present at the (n-heptane) /triacetin + water) interface. Kinetic equations interrelating the initial rates and adsorbtion at the oil/water interfaces have been developed using the Rapid Equilibrium approach for both tributyrin and (triacetin + n-heptane) systems. Application of experimental data has proven the validity of the assumptions made in deriving these kinetic equations. At constant tributyrin concentration, 0.5 % by volume, the variation of the amount of enzyme adsorbed with enzyme concentration indicates that monolayer adsorbtion is predominant up to 286 mg/1 enzyme concentration (as protein) after which multilayer formation starts. From the analysis of experimental data using the model equations developed, the mole cular area occupied by the lipase of Candida cylindracea at (tributyrin/ water) interface, aE, and value of apparentXV Michael is constant (KM ) were calculated. The average values Ma 11 2 2 3 of a" and K are 1.83x10 cm /mol and 0.78 cm /cm / respec- h Ma tively. In the adsorption of Candidal lipase at the (n-hep- tane/water) interface induction times, as long as 2.5 hours, are required to attain adsorption equilibrium at the interface. Altough different periods of time are needed to reach steady state at (tributyrin/water) and (n-heptane/water) interfaces, the equilibrium amounts of the enzyme adsorbed per unit area of these surfaces are approximately identical. Using the Cal- derbank' s equation which is proposed for the turbulent systems, the mass transfer coefficient of the Candidal lipase, k", in the (n-heptane/water) system was calculated as 0.19 cm/s. The positive energy barrier to penetration and molecular rearran gement at the (n-heptane/water) interface was decided to be responsible for the observed long induction times. The results of enzyme and total protein adsorption data collected with different techniques, indicate that the commercial lipase pre paration is a mixture of proteins and the lipase of Candida cylin- dracea is selectively adsorbed at (triglyceride/water) in terfaces.XIV triacetin both in soluble and insoluble regions. The formation of mixed micelles of (triacetin + n-heptane) and emulsion for mation were found to be responsible for the observed rate en hancements. In the mixed micelle, n-heptane molecules act as the solubilizate and incorporate in the hydrocarbon interior of the micelle. Solubilization of n-heptane by surface active triacetin has the effect of lowering the critical micelle con centration from 3.50-3.75 % triacetin concentration (by volume) to 2.8-3.25 %. In the presence of 2% triacetin (by volume), at which micellar effects may be neglected, the initial rate of triacetin hydrolysis has been shown to be linearly proportional to the amount of enzyme present at the (n-heptane) /triacetin + water) interface. Kinetic equations interrelating the initial rates and adsorbtion at the oil/water interfaces have been developed using the Rapid Equilibrium approach for both tributyrin and (triacetin + n-heptane) systems. Application of experimental data has proven the validity of the assumptions made in deriving these kinetic equations. At constant tributyrin concentration, 0.5 % by volume, the variation of the amount of enzyme adsorbed with enzyme concentration indicates that monolayer adsorbtion is predominant up to 286 mg/1 enzyme concentration (as protein) after which multilayer formation starts. From the analysis of experimental data using the model equations developed, the mole cular area occupied by the lipase of Candida cylindracea at (tributyrin/ water) interface, aE, and value of apparentXV Michael is constant (KM ) were calculated. The average values Ma 11 2 2 3 of a" and K are 1.83x10 cm /mol and 0.78 cm /cm / respec- h Ma tively. In the adsorption of Candidal lipase at the (n-hep- tane/water) interface induction times, as long as 2.5 hours, are required to attain adsorption equilibrium at the interface. Altough different periods of time are needed to reach steady state at (tributyrin/water) and (n-heptane/water) interfaces, the equilibrium amounts of the enzyme adsorbed per unit area of these surfaces are approximately identical. Using the Cal- derbank' s equation which is proposed for the turbulent systems, the mass transfer coefficient of the Candidal lipase, k", in the (n-heptane/water) system was calculated as 0.19 cm/s. The positive energy barrier to penetration and molecular rearran gement at the (n-heptane/water) interface was decided to be responsible for the observed long induction times. The results of enzyme and total protein adsorption data collected with different techniques, indicate that the commercial lipase pre paration is a mixture of proteins and the lipase of Candida cylin- dracea is selectively adsorbed at (triglyceride/water) in terfaces.