Mass flux balance-based model and metabolic pathway engineering analysis for serine alkaline protease synthesis by Bacillus licheniformis

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 sole carbon source citrate, dry cell, organic acids, amino acids, and SAP; variations in the intracellular fluxes were demonstrated for the three periods of the batch bioprocess. The flux distribution maps showed that the cells completed the TCA cycle and utilized the gluconeogenesis; pathway, pentose phosphate pathway, and anaplerotic reactions throughout the fermentation; however the glycolysis pathway was inactive in all the periods of the fermentation. The flux values toward SAP increased throughout the bioprocess and slightly decreased in the last period; however, SRP selectivity values were almost the same in Periods II and III and higher than Period I. The diversions in the pathways and certain metabolic reactions depending on the bioprocess periods are also presented and the results indicated that the intracellular amino acid fluxes played an important role in the SAP fermentation process. (C) 1999 Elsevier Science Inc. All rights reserved.


Oxygen transfer effects in serine alkaline protease fermentation by Bacillus licheniformis: Use of citric acid as the carbon source
Çalık, Pınar (Elsevier BV, 1998-12-01)
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-produ...
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 ...
OZILGEN, M; CELIK, M; BOZOGLU, F (Elsevier BV, 1991-03-01)
Substrate consumption, ethanol production, microbial growth, and temperature increase in a fermentation vessel are metabolically interrelated biological phenomena. In spontaneous wine fermentations, mixed cultures of various microbial species are involved in the fermentation process. Due to the continuously changing species contributing to the microbial population, these metabolically interrelated parameters are treated separately in the enology literature. In the present study, mathematical models are pres...
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...
Citation Formats
P. Çalık, “Mass flux balance-based model and metabolic pathway engineering analysis for serine alkaline protease synthesis by Bacillus licheniformis,” ENZYME AND MICROBIAL TECHNOLOGY, pp. 621–635, 1999, Accessed: 00, 2020. [Online]. Available: