Bioreactor operation parameters as tools for metabolic regulations in fermentation processes: influence of pH conditions

Çalı́k, Pınar; Bilir, Esra; Çalık, Güzide; Özdamar, Tunçer H.

doi:10.1016/s0009-2509(02)00605-x

Cited by 33 publications

(25 citation statements)

References 9 publications

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“…Adsorption experiments were performed for the concentrations of 0.25-1.0 g dm −3 SAP at the pH values of 7.14, 9.08, and 11.06 provided by phosphate buffers. The enzyme concentration range studied was about the one obtained by the fermentation [24] so that the results could be utilisable for the separation of SAP from the production medium. Fermentation medium for SAP production (pH 7.14) that contained (kg m −3 ): glucose, 8; NaH 2 PO 4 , 5.630; Na 2 HPO 4 ·2H 2 O, 0.055; KH 2 PO 4 , 2; (NH 4 ) 2 HPO 4 , 4.710; CaCl 2 , 0.2 [24] was taken into account as a basal medium to find out the effects of ions on adsorption and effective diffusion coefficient of SAP in the membrane.…”

Section: Static Adsorption Experimentsmentioning

confidence: 99%

Effect of ionic environments on the adsorption and diffusion characteristics of serine alkaline protease enzyme in polyethersulfone ultrafiltration membranes

Salgın

Takaç

Özdamar

2006

Journal of Colloid and Interface Science

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Section: Static Adsorption Experimentsmentioning

confidence: 99%

Effect of ionic environments on the adsorption and diffusion characteristics of serine alkaline protease enzyme in polyethersulfone ultrafiltration membranes

Salgın

Takaç

Özdamar

2006

Journal of Colloid and Interface Science

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“…A kind of Damköhler number, Da, defined as maximum possible oxygen utilization rate per maximum mass transfer rate (6,8), and effectiveness factor, η, defined as the oxygen uptake rate per maximum possible oxygen utilization rate values (6,8), can be seen in Table 5.…”

Section: Oxygen Transfer Characteristics and Ratelimiting-mentioning

confidence: 99%

“…In the production of an enzyme the bioreactor operation conditions, i.e., the medium, oxygen-transfer, and pH-operation conditions, are momentous (4)(5)(6)(7)(8) and should be finetuned for industrial production in the bioreactor. In Bacillus, substrate and medium design and bioreactor operation conditions, e.g., oxygen transfer rate and pH, regulate enzyme formation beginning from t ) 0 h (4)(5)(6)(7)(8)(9). In this context, the regulation of the intracellular reaction network toward the synthesis of -lactamase in well-designed medium is indeed important in order to increase the yield and selectivity within the ultimate limit of the production capacity of the cell.…”

Section: Introductionmentioning

confidence: 99%

Bioprocess Parameters and Oxygen Transfer Characteristics in β‐Lactamase Production by Bacillus Species

Çelik

Çalı́k

2004

Biotechnology Progress

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After screening potential beta-lactamase producers in a medium containing penicillin G, an inducible (Bacillus subtilis NRS 1125) and a constitutive (Bacillus licheniformis 749/C ATCC 25972) beta-lactamase producer were selected. As the highest enzyme activity was obtained with B. licheniformis 749/C, the effects of the concentration of carbon sources, i.e., glucose, fructose, sucrose, citric acid, and glycerol, and nitrogen sources, i.e., (NH(4))(2)HPO(4), NH(4)Cl, yeast extract, casamino acids and peptone, pH, and temperature on beta-lactamase production were investigated with B. licheniformis 749/C in laboratory scale bioreactors. Among the investigated media, the highest volumetric activity was obtained as 270 U cm(-)(3) in the medium containing 10.0 kg m(-)(3) glucose, 1.18 kg m(-)(3) (NH(4))(2)HPO(4), 8.0 kg m(-)(3) yeast extract, and the salt solution at 32 degrees C and pH(0) = 6.0. By using the designed medium, fermentation and oxygen transfer characteristics of the bioprocess were investigated at V = 3.0 dm(3) bioreactor systems with a V(R) = 1.65 dm(3) working volume at Q(O)/V(R) = 0.5 vvm and N = 500 min(-1). At the beginning of the process the Damköhler number was <1, indicating that the process was at biochemical reaction limited condition; at t = 2-5 h both mass-transfer and biochemical reaction resistances were effective; and at t = 6-10 h (Da >>1) the bioprocess was at mass transfer limited condition. Overall oxygen transfer coefficients (K(L)a) varied between 0.01 and 0.03 s(-)(1), enhancement factor (K(L)a/K(L)a(O)) varied between 1.2 and 2.3, and volumetric oxygen uptake rate varied between 0.001 and 0.003 mol m(-)(3) s(-)(1) throughout the bioprocess. The specific oxygen uptake and the specific substrate consumption rates were the highest at t = 2 h and then decreased with the cultivation. The maximum yield of cells on substrate and the maximum yield of cells on oxygen values were obtained, respectively, as Y(X/S) = 0.34 and Y(X/O) = 1.40, at t = 5 h, whereas the highest yield of substrate on oxygen was obtained as Y(S/O) = 6.94 at t = 3.5 h. The rate of oxygen consumption for maintenance and the rate of substrate consumption for maintenance values were found, respectively, as m(O) = 0.13 kg kg(-)(1) h(-)(1) and m(S) = 3.02 kg kg(-)(1) h(-)(1).

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“…The production of extracellular protease in microorganisms is influenced significantly by physical factors such as pH, temperature, dissolved oxygen, incubation time, inoculum level, aeration and agitation and medium constituents (Hanlon et al, 1982;McKeller and Cholette, 1984;Kole et al, 1988;Calik et al, 2002Calik et al, , 2003Shafee et al, 2006;Potumarthi et al, 2007). Response surface methodology (RSM) is a collection of statistical techniques for designing experiments, building models, evaluating the effects of factors and searching optimum levels of parameters for desirable responses (Myers and Montgomery, 2002).…”

Section: Introductionmentioning

confidence: 99%

Effect of physical parameters, carbon and nitrogen sources on the production of alkaline protease from a newly isolatedBacillus pseudofirmus SVB1

2009

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-The effect of process physical parameters (initial pH of the medium, temperature and rpm of the shaking incubator) on the production of alkaline protease from a newly isolated Bacillus pseudofirmus SVB1 was studied using central composite design technique. The individual optimum levels of initial pH of the medium, temperature and rpm of the shaking incubator were found to be 9.2, 27.3 °C and 195, respectively for the production of alkaline protease (specific activity, U/mg of protein) and 11, 28.9 °C and 210, respectively for cell growth. By applying multiresponse analysis method of generalized distance approach for production and growth, the optimal levels were found to be 9.9, 28.1 °C and 202, for initial pH of the medium, temperature and rpm of the shaking incubator, respectively. After optimization, the production of alkaline protease and cell growth were enhanced by 36.23 and 44.29%, respectively. Also, the various nutritional parameters, which have significant effect on the production of alkaline protease, are delineated in the present study. Alkaline protease production was found to be influenced by media components, viz., types of C/N source and presence of metal ions. Finally an overall 6.2 fold increase in the production was achieved using casein as both carbon and nitrogen source.

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Bioreactor operation parameters as tools for metabolic regulations in fermentation processes: influence of pH conditions

Cited by 33 publications

References 9 publications

Effect of ionic environments on the adsorption and diffusion characteristics of serine alkaline protease enzyme in polyethersulfone ultrafiltration membranes

Effect of ionic environments on the adsorption and diffusion characteristics of serine alkaline protease enzyme in polyethersulfone ultrafiltration membranes

Bioprocess Parameters and Oxygen Transfer Characteristics in β‐Lactamase Production by Bacillus Species

Effect of physical parameters, carbon and nitrogen sources on the production of alkaline protease from a newly isolatedBacillus pseudofirmus SVB1

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