Effects of pH and feeding strategy on metabolite profiling of beta-lactamase producing bacillus licheniformis

İler, Nazar
In this study, the effects of pH and different feeding modes on beta-lactamase production and cell metabolism were investigated with Bacillus licheniformis (ATCC 25972). For this purpose, first, the effects of pH on beta-lactamase activity, cell formation, substrate consumption, as well as intracellular sodium, potassium, ammonium ion, amino acid and organic acid concentrations were investigated in V= 3.0 dm3 batch bioreactors consisting of temperature, pH, foam, stirring rate and dissolved oxygen controls. Among the investigated uncontrolled pH operation with pH0=7.5 and controlled pH operations, pHc=6.75 yielded the highest cell concentration and beta-lactamase activity as Cx=0.60 kg/m3 and A= 54 U/cm3, respectively. Next, the production medium was redesigned in terms of initial glucose and phosphate ion concentrations in order to increase the enzyme activity and cell growth rate, and to determine the feeding strategy in laboratory scale batch-bioreactors using shake bioreactors having V=33 ml working volumes. The medium containing (kg/m3), glucose 2.5 (7.0); Na2HPO4, 1.0; K2HPO4 1.0; (NH4)2HPO4, 7.1 and salt solution at pHc=6.75 was accepted as optimized medium for fed-batch (batch) processes. Using this optimized medium the feeding strategy was investigated for linear and exponential feeding profiles and compared with batch operation. Throughout the fermentation, cell, substrate and intracellular and extracellular by-product, sodium, potassium, ammonium ion concentrations, beta-lactamase activity, yield coefficients, specific rates, oxygen uptake rates and liquid phase mass transfer coefficient values were determined. The highest beta-lactamase activity was obtained at fed-batch operation with exponential feeding (FB1) condition as A= 108 U/cm3, which is ca. 1.7-fold higher than that of the batch operation with optimized medium. Finally, to invesitigate the


Effects of antimitotic agents on haploid plant production from unpollinated ovules of sugar beet (beta vulgaris l.)
Gürel, S.; Gürel, E.; Kaya, Zeki; Erdal, M.; Güler, E. (Informa UK Limited, 2003-01-01)
The effects of antimicrotubule agents on haploid embryo formation from unpollinated ovules of sugar beet (Beta vulgaris L.) were investigated. The antimitotic agent colchicine (at 100 and 150 mg/l) and trifluralin (at 5.0 mg/l) increased the frequency of haploid embryo formation whereas pronamide (at 76.9 and 128.2 mg/l) and trifluralin (at 3.4 mg/l) decreased. Ovules that were non-treated with antimicrotuble agents (i.e., ovules of the control treatment) produced higher percentages of haploid embryos (4.25...
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...
Determination of metabolic bottlenecks using reaction engineering principles in serine alkaline protease production by recombinant bacillus sp.
Telli, İlkin Ece; Çalık, Pınar; Department of Chemical Engineering (2004)
In this study, firstly, bioprocess characteristics for Serine Alkaline Protease (SAP) production, using recombinant Bacillus subtilis carrying pHV1431::subC, were examined. The cell concentration, substrate concentration, SAP activity and SAP synthesis rate profiles demonstrated that the system reaches to a steady state in terms of cell growth and SAP synthesis between t=15-25 h, therefore, this time interval is appropriate to employ both metabolic flux analysis and metabolic control analysis, which apply s...
Effects of pH strategy on endo- and exo-metabolome profiles and sodium potassium hydrogen ports of beta-lactamase-producing Bacillus licheniformis
Ileri, N; Çalık, Pınar (Wiley, 2006-03-01)
The effects of pH strategy on endo- and exo-metabolome profiling of beta-lactamase-producing Bacillus licheniformis were investigated at controlled-pH (pH(C) = 6.5, 6.75, 7.0, 7.25, 7.5) and uncontrolled-pH (pH(UC) = 7.5) values using a glucose-based defined medium. The cell concentration profiles were not affected by the pH considerably within the investigated range. The highest enzyme activities were obtained as A = 54 U cm(-3) at pHc = 6.75 among the controlled-pH operations and as A = 57 U cm(-3) at the...
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
N. İler, “Effects of pH and feeding strategy on metabolite profiling of beta-lactamase producing bacillus licheniformis,” M.S. - Master of Science, Middle East Technical University, 2005.