Influence of controlled-pH and uncontrolled-pH operations on recombinant benzaldehyde lyase production by Escherichia coli

Çalık, Pınar
Demir, AS
To select the host microorganism having the highest benzaldehyde lyase (BAL) production capacity, pUC 18::bal gene was transferred into four Escherichia coli strains. As the highest enzyme activity was obtained with E. coli K12 (ATCC 10798) carrying pUC18::bal gene, BAL production medium was designed for K 12. Using the designed medium containing 8.0 kg m(-3) glucose, 5.0 kg m(-3) (NH4)(2)HPO4 and the salt solution, the effects of uncontrolled-pH and controlled-pH operations were investigated at uncontrolled-pH pH(UC) 7.2 and controlled-pH values pH(C) 5.0, 6.4, 6.7, 7.0 7.2 and 7.8 in 3.0 dm(3) bioreactor systems with a V-R = 1.65 dm(3) working volume at the air inlet rate of Q(o)/V-R = 0.5 vvm and agitation rate of N= 500 min(-1). The uncontrolled-pH (pHuc 7.2) operation produced the highest cell concentration and BAL activity as C-X = 2.3 kg m(-3) and A = 860 U cm(-3). respectively. Among the controlled-pH operations, the highest cell concentration and enzyme activity were obtained at pH(C) 7.0 operation, respectively, as C-X = 2. 1 kg m(-3) and A = 775 U cm(-3). The accumulation of the metabolic by-product acetic acid and the total organic acid concentrations were the highest at pHc 7.2 and 7.8 operations. On the other hand, there was no significant difference in the acetic acid concentration profiles of pHc 5.0. 6.4, 6.7 and 7.0 operations; however, the highest total organic acid concentration was attained at pHC 5.0 because of the lactic acid excretion, and the lowest total organic acid was obtained at pH(C) 6.7. K(L)a values varied between 0.01 and 0.03 s(-1). To compare the mass transfer and biochemical reaction rates, the maximum possible oxygen utilization rate, possible mass transfer rate, Damkohler number, and effectiveness factor, were also calculated. Damkohler number increased with the cultivation time indicating that mass transfer resistances were becoming more effective than biochemical reaction resistances. The yield and maintenance coefficients as well as the kinetic constants for BAL production process were also reported. (c) 2005 Elsevier Inc. All rights reserved.


Influence of oxygen transfer on benzaldehyde lyase production by recombinant Escherichia coli BL21(DE3) pLySs
Angardi, Vahideh; Çalık, Pınar; Department of Chemical Engineering (2007)
In this study, the effects of oxygen transfer conditions on the synthesis of the enzyme benzaldehyde lyase as intracellular in recombinant E. coli BL21 (DE3) pLysS was investigated sistematically and a comprehensive model was developed to determine benzaldehyde lyase activity. For this purpose, the research program was carried out in mainly two parts. In the first part of study, the effects of oxygen transfer together with the mass transfer coefficient (KLa), enhancement factor E (=KLa/KLao), volumetric oxy...
Effects of pulse feeding of beet molasses on recombinant benzaldehyde lyase production by Escherichia coli BL21(DE3)
Çalık, Pınar (Springer Science and Business Media LLC, 2009-11-01)
The effect of fed-batch operation (FBO) strategy was investigated using pretreated-beet molasses, containing galactose that induces the lac promoter, on benzaldehyde lyase (BAL) production by recombinant Escherichia coli BL21(DE3)pLySs. After batch cultivation with 30 g l(-1) pretreated-beet molasses consisting of 7.5 g l(-1) glucose and 7.5 g l(-1) fructose, three FBO strategies were applied at dissolved oxygen (=40%) cascade to air-flow rate. In FBO1 when air-flow rate decreased considerably, feed was giv...
Role of the cmcH-ccaR intergenic region and ccaR overexpression in cephamycin C biosynthesis in Streptomyces clavuligerus
Kurt, Aslihan; Alvarez-Alvarez, Ruben; Liras, Paloma; Özcengiz, Gülay (Springer Science and Business Media LLC, 2013-07-01)
The effect of the CcaR regulatory protein on expression of the cephamycin C gene cluster is studied. Quantitative reverse transcription PCR (qRT-PCR) expression analysis of the cephamycin biosynthesis genes in the ccaR-disrupted strain, S. clavuligerus ccaR::aph, revealed that in the absence of CcaR, the lat and cmcI genes expression was reduced 2,200-and 1,087-fold compared with the wild type. Expression of pcbAB-pcbC-cefD-cefE-cmcJ-cmcH and blp was 225- to 359-fold lower, while expression of pcbR-pbpA-bla...
Overexpression of serine alkaline protease encoding gene in Bacillus species: performance analyses
Çalık, Pınar; Ozdamar, TH (Elsevier BV, 2003-12-02)
Bacillus species carrying subC gene encoding serine alkaline protease (SAP) enzyme were developed in order to increase the yield and selectivity in the bioprocess for SAP production. For this aim, subC gene was cloned into pHV1431 Escherichia coli-Bacillus shuttle vector, and transferred into nine host Bacillus species, i.e. B. alvei, B. amyloliquefaciens, B. badius, B. cereus, B. coagulans, B. firmus, B. licheniformis, B. sphaericus and B. subtilis. The influence of the host Bacillus species on SAP product...
Comparison of benzaldehyde lyase production capacity in recombinant Escherichia coli and recombinant Bacillus species
Kaya, Hande; Çalık, Pınar; Department of Chemical Engineering (2006)
In this study, the benzaldehyde lyase (BAL, EC production in E. coli BL21 (DE3) pLySs as intracellular and in Bacillus species as extracellular were investigated, and comparison of the production capacity of the enzyme in the developed recombinant microorganisms were compared. For this purpose, firstly, PCR amplified bal gene was cloned into pRSETA vector which is under the control of strong T7 promoter and expressed in E. coli BL21 (DE3) pLysS strain. With developed recombinant E. coli BL21 (DE3)...
Citation Formats
P. Çalık and A. Demir, “Influence of controlled-pH and uncontrolled-pH operations on recombinant benzaldehyde lyase production by Escherichia coli,” ENZYME AND MICROBIAL TECHNOLOGY, pp. 617–627, 2006, Accessed: 00, 2020. [Online]. Available: