Oxygen transfer effects in serine alkaline protease fermentation by Bacillus licheniformis: Use of citric acid as the carbon source

The effects of oxygen transfer on serine alkaline protease (SAP) production by Bacillus licheniformis on a defined medium with C-c = 9.0 kg m(-3) citric acid as sole carbon source were investigated in 3.5 dm(3) batch bioreactor systems. The concentrations of the product (SAP) and by-products, i.e., neutral protease, amylase, amino acids, and organic acids were determined in addition to SAP activities. Ar Q(o)/V = 1 vvm airflow rate, the effect of agitation rate on DO concentration, pH, product, and by-product concentrations and SAP activity were investigated at N = 150, 500, and 750 min(-1); these are named as low-(LOT), medium-(MOT), and high oxygen transfer (HOT) conditions. LOT conditions favor biomass concentration; however, substrate consumption was highest at HOT conditions. MOT was optimum for maximum SAP activity which was 441 U cm(-3) at t = 37 h. The total amino acid concentration was maximum in LOT and minimum in MOT conditions; lysine had the highest concentration under all oxygen transfer conditions. Among organic acids, acetic acid had the highest concentration and its concentration increased with oxygen transfer rate. The oxygen transfer coefficient increases with the agitation rate and the oxygen consumption rate increased almost linearly with the biomass concentration. (C) 1998 Elsevier Science Inc.


Mass flux balance-based model and metabolic pathway engineering analysis for serine alkaline protease synthesis by Bacillus licheniformis
Çalık, Pınar (Elsevier BV, 1999-07-01)
A mass flux balance-based stoichiometric model of Bacillus licheniformis for the serine alkaline protease (SAP) fermentation process has been established. The model considers 147 reaction fluxes, and there are 105 metabolites that are assumed to be in pseudo-steady state. Metabolic flux distributions were obtained from the solution of the model based on the minimum SAP accumulation rate assumption in B. licheniformis in combination with the off-line extracellular analyses of the metabolites that were the so...
Substrate interactions during the biodegradation of benzene, toluene and phenol mixtures
Abu Hamed, T; Bayraktar, E; Mehmetoglu, T; Mehmetoglu, U (Elsevier BV, 2003-09-30)
Benzene, toluene and phenol were degraded completely at high initial concentrations by Pseudomonas putida F I ATCC 700007. Two hundred and fifty milligram per litre benzene, 225 mg/l toluene and 200 mg/l phenol were degraded individually in 19, 14 and 3 5 h, respectively. The biodegradation times increased on increasing the substrate concentration. The maximum biodegradation rates were 149 mg benzene/g dry cell h for 60 mg/l benzene, 44 mg toluene/g dry cell h for 110 mg/l toluene and 102 mg phenol/g dry ce...
Kinetic analyses of the effects of temperature and light intensity on growth, hydrogenm production and organic acid utilization by rhodobacter capsulatus
Sevinç, Pelin; Gündüz, Ufuk; Department of Biotechnology (2010)
Effects of temperature and light intensity on photofermentative hydrogen production by Rhodobacter capsulatus DSM1710 by use of acetic and lactic acids as substrates were studied. Experiments were conducted at 20, 30 and 38oC incubator temperatures under light intensities in the 1500 – 7000 lux range. pH of the medium and quantity of hydrogen forming together with quantity of biomass, and concentrations of acetic, lactic, formic, butyric and propionic acids in the medium were determined periodically. Growth...
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...
Protein-based complex medium design for recombinant serine alkaline protease production
Çalık, Pınar; Telli, IE; Oktar, C; Ozdemir, E (Elsevier BV, 2003-12-02)
This work reports on the design of a complex medium based on simple and complex carbon sources, i.e. glucose, sucrose, molasses, and defatted-soybean, and simple and complex nitrogen sources, i.e. (NH4)(2)HPO4, casein, and defatted-soybean, for serine alkaline protease (SAP) production by recombinant Bacillus subtilis carrying pHV1431::subC gene. SAP activity was obtained as 3050 U cm(-3) with the initial defatted-soybean concentration C-soybean(o) = 20 kg m(-3) and initial glucose concentration C-G(o) = 8 ...
Citation Formats
P. Çalık, “Oxygen transfer effects in serine alkaline protease fermentation by Bacillus licheniformis: Use of citric acid as the carbon source,” ENZYME AND MICROBIAL TECHNOLOGY, pp. 451–461, 1998, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/53144.