Influence of copper and cadmium salts anions on the diffusion in alginate beads

Wyznaczono efektywne współczynniki dyfuzji w granulkach alginianu wapnia, dla siarczanów i chlorków dwóch metali ciężkich: miedzi oraz kadmu. Na wartość efektywnego współczynnika dyfuzji wpływały: rodzaj metalu, anion z soli metalu oraz zawartość ałginianu w granulkach. Współczynniki dyfuzji obliczono metodą konduktometryczną. Uzyskano dobrą zgodność danych doświadczalnych z modelem matematycznym, o czym świadczyły wysokie wartości współczynnika korelacji. Zarówno w przypadku soli miedzi, jak i kadmu obecność jonów siarczanowych znacząco obniżała wartość efektywnego współczynnika dyfuzji soli tych metali w granulkach alginianowych (w porównaniu do jonów chlorkowych).Effective diffusion coefficients in beads of calcium alginate for two heavy metals - copper and cadmium sulphates and ch lo rides were determined. The values o f these coefficients depended on the metal type, anion from the metal salt, and alginate content in the beads. The diffusion coefficients were calculated using the conductometric method. The experimental da ta were found to be in a good agreement with the mathematical model, confirmed by high values of the correlation coefficient. In both cases of copper and cadmium salts, a presence of sulphate ions significantly decreased the effective diffusion coefficient in the beads in comparison with chloride ions

Diffusion retardation coefficient of different heavy metal salts in calcium alginate beads

Wyznaczono współczynniki spowolnienia dyfuzji w granulkach alginianu wapnia dla 9 różnych soli metali ciężkich: CuCl2, CuSO4, CdCl2, CdSO4, ZnCl2, ZnSO4, Zn(NO3)2, Pb(NO3)2, Cr(NO3)3. Wartość współczynnika spowolnienia dyfuzji zależała od rodzaj metalu (najlepsza dyfuzja dla CuCl2, a najniższe φ dla Cr(NO3)3), anionu soli metalu oraz zawartości alginianu w granulkach. Wzrost zawartości alginianu w granulkach prowadził do obniżenia wartości współczynnika spowolnienia dyfuzji. Obecność jonów siarczanowych znacząco obniżała wartość współczynnika spowolnienia dyfuzji soli tych metali w granulkach alginianowych. Najniższe współczynniki spowolnienia otrzymano dla wszystkich soli siarczanowych.Diffusion retardation coefficients for 9 different heavy metal salts in calcium alginate beads were determined. There were examined: CuCl2, CuSO4, CdCl2, CdSO4, ZnCl2, ZnSO4, Zn(NO3)2, Pb(NO3)2, Cr(NO3)3. Values of diffusion retardation coefficients depended on a metal type, anion from the metal salt, and the alginate content in beads. An increase in the alginate content in beads leads to a decrease of φ values. A presence of sulphate ions significantly decreased diffusion retardation coefficients in the beads. The lowest retardation coefficients were obtained for all sulphate salts

Optimal temperature control in a batch bioreactor with parallel deactivation of enzyme

W niniejszej zatem pracy, dla procesu rozkładu nadtlenku wodoru przez natywną katalazę drożdży Saccharomyces cerevisae, określono optymalne warunki prowadzenia procesu z punktu widzenia czasu jego trwania. W obliczeniach wykorzystano równanie szybkości dezaktywacji katalazy zaprezentowane przez Do i Weilanda. Okazało się, że realizacja procesu musi przebiegać przynajmniej przy aktywnym górnym T- Tmax ograniczeniu temperaturowym, przy czym długość odcinka stacjonarnego jest tym krótsza im wyższe są wartości energii aktywacji zmian stałych Michaelis. Stwierdzono, że spadek ilorazu energii aktywacji E i końcowej aktywności biokatalizatora Cef oraz wzrost stopnia przemiany αf=1- Csf powodują wzrost sumarycznego czasu procesu. W sytuacji, gdy realizacja warunków optymalnych okazała się niemożliwa podano rozwiązanie suboptymalne.Based on the decomposition process of hydrogen peroxide by the native yeast catalase Saccharomyces cerevisae and the equation of its deactivation suggested by Do and Weiland, in the present paper an analysis was performed aimed at the determination of optimal temperature control with respect to the process duration time. Additionally, the effect of temperature on Michaelis constants is expressed by the Arrhenius equation. It was proved that the process accomplishment usually has to be made at least at the active upper Tmas temperature constraint, while the length of stationary section is the shorter, the higher are values of the activation energy of the variation of Michaelis constants. It was found that a jdecrease in the activation energy quotient E and the final catalyst activity CEJ , as well as an increase in conversion αf=1- Csf results in an increase of the overall process duration time tf.opt

Effect of temperature on the kinetics of deactivation of catalase from Aspergillus niger by substrate

Celem pracy było zbadanie wpływu temperatury na kinetykę dezaktywacji katalazę z Aspergillus niger przez nadtlenek wodoru. Wyznaczono wartość energii aktywacji dla procesu dezaktywacji dla stężenia nadtlenku wodoru niższego niż 0,015mol/dm3 oraz temperatury w zakresie 35÷50°C.The aim of this work was to investigate the temperature effect on the kinetics of deactivation of catalase from Aspergillus niger by hygrogen peroxidase. A value of activation energy of catalase deactivation for the hydrogen peroxide concentration lower than 0.015 mol/dm3 and the temperature in a range of 35÷50°C was determined

Determination of effective diffusion coefficient for copper ions in alginate beads using the conductometric method

Opracowano nową metodę wyznaczania efektywnego współczynnika dyfuzji metali ciężkich w granulkach alginianowych, polegającą na pomiarze zawartości jonów metalu w roztworze za pomocą konduktometru. Wzrost zawartości alginianu w granulkach prowadził do zmniejszenia się wartości De jonów miedzi (w zakresie od 0.78 do 0,99-10-9 [m2/s]zgodnie z mechanizmem dyfuzji w porowatych nośnikach.A new method was developed for the determination of effective diffusion coefficient of heavy metal ions in beads of biosorbents. This method is based on conductometric measurements of ions in solution. Its usefulness was confirmed in the determination of effective diffusivity for copper ions in alginate beads. It was found that effective diffusivity De ranged from 0.78-10-9 to 0.99-10-9 [m2/s] and decreased with increased alginate concentration in accordance with a mechanism of diffusion in porous carries

The effect of pH on the sorption of copper ions by alginates

The effect of pH on copper ions sorption by alginates has been investigated. The granules of the sorbent obtained from sodium alginate (type DMF, manufactured by KELCO) have been applied. By using a new method of gelation a biosorbent containing from 11.3 to 20.3% mas. of alginate has been produced. Investigations have been carried out at a constant temperature of 25°C and the pH values ranging from 3 to 5. The obtained experimental results have been described by the Langmuir equation. It has been found that with the increasing pH of the solution the maximum biosorbent sorption capacity increased

An alternative method to determine the diffusion coefficient for the shrinking core model

A new method to determine the effective diffusion coefficient of sorbate in sorbent granule based on the analytical solution of the shrinking core model (SCM) has been proposed. The experimental data presented by Lewandowski and Roe concerning the sorption of copper ions by alginate granules have been applied to compare the analytical and numerical methods. The results obtained by both methods are very close

Determination of the effective diffusivity of cadmium(II) in calcium alginate beads

Effective diffusivity (De) of cadmium compounds was calculated in the beads. The study was carried out using two methods: a shrinking core model (SCM) method and a newly developed method named conductometric. It turned out to be a simple and effective method for the calculation of effective diffusivity of Cd(II) in alginate sorbents. The De values obtained by the two methods depended on the alginate content in the beads. However, SCM, in contrast to the conductometric method, gave De values increasing with increasing alginate levels in the beads and lower than the molecular diffusivity of Cd(II), this being inconsistent with the mechanism of diffusion in porous carriers. Hence, the conductometric method can be considered as one giving more reliable results, compared with the SCM method. Moreover, diffusion retardation coefficients for the alginate beads were calculated. Enhanced content of the biopolymer in the beads caused retardation of Cd(II) diffusion in the beads due to the decreasing calculated retardation coefficients with the increasing alginate contents in the beads

Immobilization of catalase from aspergillus niger in calcium alginate gel

Badano proces pułapkowania katalazy z Aspergillus niger w żelu 2 % i 4 % mas. alginianu wapnia. W przypadku użycia żelu 2% zaobserwowano stopniowy spadek aktywności biokatalizatora, związany z uwalnianiem się katalazy z porów żelu. Stosując 4% żel alginianu wapnia uzyskano stabilny biokatalizator z maksymalną aktywnością w temperaturze 40^(o)C i przy pH 7. Stwierdzono przydatność immobilizowanego biokatalizatora do wielokrotnego użycia przy rozkładzie H2 O2 w reaktorze okresowym.The entrapment of catalase from Aspergillus niger in a gel containing 2% and 4% by weight of calcium alginate was investigated. For the 2% gel, the biocatalyst was observed to gradually lose its activity as catalase was released from the gel pores. A stable biocatalyst with a maximum activity at 40^(o)C and pH 7 was obtained using the gel containing 4% calcium alginate. The immobilized biocatalyst was found to be useful in repeated applications for decomposing H2 O2 in a batch reactor

Effect of temperature, concentration of alcohols and time on baker’s yeast permeabilization process

Baker’s yeast beyond the traditional use in the food industry may be used to carry out biotransformations. The effectiveness of yeast as biocatalysts is based on the presence of large amounts of intracellular enzymes, whose efficiency can be repeatedly increased by permeabilization. It is the process of increasing the permeability of cell walls and membranes in order to facilitate reagents access to the intracellular enzyme. Alcohols permeabilization process allows for approx. 50-fold increase in catalase activity of baker’s yeast. In this paper, the influence of physical and chemical parameters on the effectiveness of permeabilization of baker’s yeast cells using alcohols was analyzed. Research has shown that with increasing temperature of permeabilization process better results are achieved using a lower alcohol concentration. Based on presented response surface graphs, we can also indicate a negligible impact of duration time on the process efficiency