Fermentation Conditions (fermentation + condition)

Distribution by Scientific Domains


Selected Abstracts


Optimization of Fermentation Conditions for Preparation of Polygalacturonic Acid Transeliminase by Erwinia carotovora IFO3830

BIOTECHNOLOGY PROGRESS, Issue 2 2001
Fengping Ding
This paper is concerned with optimization of the fermentation conditions for preparation of alkaline pectin lyase (poly-galacturonic acid trans-eliminase, PATE) by Erwinia carotovoraIFO3830 (E.C.IFO3830). The orthogonal matrix method was adopted as the experimental design method for media. The effects of media composition on the growth rate of E.C.IFO3830 are in the order of pectin > KH2PO4/Na2HPO4 > MgSO4 > (NH4)2SO4 > glucose > L -glutamate sodium, and those on PATE activity are in the order of glucose > pectin > L -glutamate sodium > KH2PO4/Na2HPO4 > MgSO4 > (NH4)2SO4. The strain of E.C.IFO3830 grows quickly and easily near an initial pH of 7.0, and especially at the alkaline range of pH 7.0,8.0. The growth rate profiles indicate that E.C.IFO3830 grows very quickly; its generation time t1/2 is about 0.2 h. The appropriate fermentation period is about 10,20 h for a high level productivity of biomass and 25,35 h for high productivity of PATE enzyme. [source]


Production of indole diterpenes by Aspergillus alliaceus

BIOTECHNOLOGY & BIOENGINEERING, Issue 5 2006
B. Junker
Abstract Production of two related indole diterpenes (differing by a dimethyl leucine side chain) by Aspergillus alliaceus was improved through several pilot scale fermentations. Media were optimized through focus primarily on initial increases, as well as mid-cycle additions, of carbon and nitrogen sources. Fermentation conditions were improved by varying ventilation conditions using various combinations of air flowrate and back-pressure set points. Production improvements were quantified based on total indole diterpene concentration as well as the ratio of the major-to-minor by-product components. Those changes with a positive substantial impact primarily on total indole diterpene concentration included early cycle glycerol shots and enhanced ventilation conditions (high air flowrate, low back-pressure). Those changes with a significant impact primarily on ratio included higher initial cerelose, soybean oil, monosodium glutamate, tryptophan, or ammonium sulfate concentrations, higher broth pH, and enhanced ventilation conditions. A few changes (higher initial glycerol and monosodium glutamate concentrations) resulted in less notable and desirable titer or ratio changes when implemented individually, but they were adopted to more fully realize the impact of other improvements or to simplify processing. Overall, total indole diterpene titers were improved at the 600 L pilot scale from 125,175 mg/L with a ratio of about 2.1 to 200,260 mg/L with a ratio of about 3.3,4.5. Thus, the ability to optimize total indole diterpene titer and/or ratio readily exists for secondary metabolite production using Aspergillus cultures. 2006 Wiley Periodicals, Inc. [source]


Modelling the growth of Weissella cibaria as a function of fermentation conditions

JOURNAL OF APPLIED MICROBIOLOGY, Issue 5 2009
A. Ricciardi
Abstract Aims:, To investigate the effect of pH, water activity (aw) and temperature on the growth of Weissella cibaria DBPZ1006, a lactic acid bacterium isolated from sourdoughs. Methods and Results:, The kinetics of growth of W. cibaria DBPZ1006 was investigated during batch fermentations as a function of pH (40,80), aw (0935,0994) and temperature (10,45C) in a rich medium. The growth curve parameters (lag time, growth rate and asymptote) were estimated using the dynamic model of Baranyi and Roberts (1994. A dynamic approach to predicting bacterial growth in food. Int J Food Microbiol23, 277,294). The effect of pH, aw and temperature on maximum specific growth rate (,max) were estimated by fitting a cardinal model. ,max under optimal conditions (pH = 66, aw = 0994, T = 363C) was estimated to be 093 h,1. Minimum and maximum estimated pH and temperature for growth were 36 and 815, and 90C and 478C, respectively, while minimum aw was 0918 (equivalent to 122% w/v NaCl). Conclusions:,Weissella cibaria DBPZ1006 is a fast-growing heterofermentative strain, which could be used in a mixed starter culture for making bread. Significance and Impact of the Study:, This is the first study reporting the modelling of the growth of W. cibaria, a species that is increasingly being used as a starter in sourdough and vegetable fermentations. [source]


Production of conjugated linoleic acid by probiotic Lactobacillus acidophilus La-5

JOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2009
M. Macouzet
Abstract Aims:, To study the ability of the probiotic culture Lactobacillus acidophilus La-5 to produce conjugated linoleic acid (CLA), which is a potent anti-carcinogenic agent. Methods and Results:, The conversion of linoleic acid to CLA was studied both by fermentation in a synthetic medium and by incubation of washed cells. Accumulation of CLA was monitored by gas chromatography analysis of the biomass and supernatants. While the fermentation conditions applied may not be optimal to observe CLA production in growing La-5 cells, the total CLA surpassed 50% of the original content in the washed cells after 48 h under both aerobic and micro-aerobic conditions. The restriction of oxygen did not increase the yield, but favoured the formation of trans, trans isomers. Conclusions:, The capability of L. acidophilus La-5 to produce CLA is not dependant on the presence of milk fat or anaerobic conditions. Regulation of CLA production in this strain needs to be further investigated to exploit the CLA potential in fermented foods. Significance and Impact of the study:, Knowledge gained through the conditions on the accumulation of CLA would provide further insight into the fermentation of probiotic dairy products. The capacity of the nongrowing cells to produce CLA is also of great relevance for the emerging nonfermented probiotic foods. [source]


The stress response is repressed during fermentation in brewery strains of yeast

JOURNAL OF APPLIED MICROBIOLOGY, Issue 5 2000
M.P. Brosnan
Yeast cells encounter a variety of environmental stresses during brewing and must respond to ensure cell survival. Cells can respond to stress by inducing a Heat Shock Response in which heat shock proteins (Hsps) are synthesized. In laboratory strains of Saccharomyces cerevisiae, the heat shock protein, Hsp104, plays a major role in the acquisition of tolerance to a variety of stresses such as heat, ethanol and sodium arsenite, and as such acts as an excellent stress indicator. The induction of Hsp104 in bottom-and top-fermenting brewery strains was examined when grown under laboratory and industrial fermentation conditions, and it was found that each brewing strain exhibits its own unique pattern of Hsp104 expression. During industrial fermentations, brewery strains are capable of mounting a stress response at the early stages of fermentation. However, as the fermentation proceeds, the response is repressed. The results suggest that conditions experienced in industrial brewing prevent the activation of the stress response. This study increases our understanding of alterations in gene expression patterns during the brewing process, and yields information that will aid in the definition of best practice in yeast management. [source]


Strain isolation and optimization of process parameters for bioconversion of glycerol to lactic acid

JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 10 2009
An-An Hong
Abstract BACKGROUND: The crude glycerol from biodiesel production represents an abundant and inexpensive source which can be used as raw material for lactic acid production. The first aim of this investigation was to select a strain suitable for producing lactic acid from glycerol with a high concentration and productivity. The second aim was to obtain the optimum fermentation conditions, as a basis for large-scale lactate production in the future. RESULTS: Eight bacterial strains, which could aerobically convert glycerol to lactic acid, were screened from soil samples. One of the strains, AC-521, which synthesized lactic acid with a higher concentration, was identified based on its 16S rDNA sequences and physiological characteristics. These results indicated that this strain was a member of Escherichia coli. The optimal fermentation conditions for Escherichia coli AC-521 were 42 C, pH 6.5, 0.85 min,1 (KLa). CONCLUSION:Escherichia coli AC-521 suitable for producing lactic acid from glycerol with high concentration and productivity was identified. After 88 h of fed-batch fermentation, both the lactic acid concentration and glycerol consumption reached maximum, giving 85.8 g L,1 of lactic acid with a productivity of 0.97 g L,1 h,1 and a yield of 0.9 mol mol,1 glycerol. Copyright 2009 Society of Chemical Industry [source]


Performance and population analysis of a non-sterile trickle bed reactor inoculated with Caldicellulosiruptor saccharolyticus, a thermophilic hydrogen producer

BIOTECHNOLOGY & BIOENGINEERING, Issue 5 2009
J.W. van Groenestijn
Abstract Non-axenic operation of a 400 L trickle bed reactor inoculated with the thermophile Caldicellulosiruptor saccharolyticus, yielded 2.8 mol,H2/mol hexose converted. The reactor was fed with a complex medium with sucrose as the main substrate, continuously flushed with nitrogen gas, and operated at 73C. The volumetric productivity was 22 mmol,H2/(L,filterbed,h). Acetic acid and lactic acid were the main by-products in the liquid phase. Production of lactic acid occurred when hydrogen partial pressure was elevated above 2% and during suboptimal fermentation conditions that also resulted in the presence of mono- and disaccharides in the effluent. Methane production was negligible. The microbial community was analyzed at two different time points during operation. Initially, other species related to members of the genera Thermoanaerobacterium and Caldicellulosiruptor were present in the reactor. However, these were out-competed by C. saccharolyticus during a period when sucrose was completely used and no saccharides were discharged with the effluent. In general, the use of pure cultures in non-sterile industrial applications is known to be less useful because of contamination. However, our results show that the applied fermentation conditions resulted in a culture of a single dominant organism with excellent hydrogen production characteristics. Biotechnol. Bioeng. 2009;102: 1361,1367. 2008 Wiley Periodicals, Inc. [source]


On-line size measurement of yeast aggregates using image analysis

BIOTECHNOLOGY & BIOENGINEERING, Issue 2 2001
Sandrine Mas
Abstract Alcohol fermentation productivity can be strongly improved using a flocculation-based yeast recycle. However, the efficiency of the biomass retention system depends strongly on the yeast particle size. Accordingly, the monitoring and control of yeast floc diameter are of primary importance. The on-line measurement of mean floc diameter has been achieved using on-line image analysis, based on the evaluation of image texture. The texture analysis method consisted in the building of a co-occurrence matrix from which the so-called "Energy parameter" was extracted. While image texture is usually used for classification purposes, it has been used here as a quantitative descriptor: a correlation has been found between this statistical image feature and off-line manual floc-size determinations. In the floc-size range investigated (|bu 0.5,4.3 mm), the evaluated mean diameter was in good agreement with the actual particle size, with a determination coefficient equal to 0.980. In contrast with manual measurements, slow and tedious, this method gave the value of the mean particle diameter in real-time, without sampling. This novel tool has been used to investigate the behavior of yeast aggregates as a function of fermentation conditions. While biomass concentration was kept constant, step increases of the feed rate led to a decrease of the mean floc diameter. Image analysis showed that the particle-size reduction could occur within a few minutes after modification of the medium dilution rate, demonstrating the disruptive effect of the CO2 efflux. The kinetic of aggregate formation was dependent on the gas-phase composition. Instead of recycling fermentation gas, sparging the fermentor with nitrogen, to reduce dissolved CO2 concentration, increased the rate of floc-size growth. 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 76: 91,98, 2001. [source]


High-throughput system for determining dissolution kinetics of inclusion bodies

BIOTECHNOLOGY JOURNAL, Issue 5 2009
Astrid Drauer Dr.
Abstract Efficient solubilization is a crucial step during inclusion body processing and dissolving conditions were usually empirically established. Here we describe a new methodology for rapid screening of solubilization conditions and evaluation of dissolution kinetics in microtiter plates. Increase of protein in solution over time was directly related to decrease of turbidity measured by absorbance at 600 nm. Dissolution kinetics of inclusion bodies were described by a first-order reaction kinetics, which was used for drug dissolution modeling. Reaction constants were in the range of 0.01,0.03 s,1 for buffer conditions providing sufficient solubilization power. This method is not limited to the screening of optimal buffer conditions for solubilization and can be applied for studying other parameters involved in the solubility of IBs, such as pI of the protein, influence of fermentation conditions, influence of initial protein concentration, and more. [source]


Enhancing the Production of Fc Fusion Protein in Fed-Batch Fermentation of Pichia pastoris by Design of Experiments

BIOTECHNOLOGY PROGRESS, Issue 3 2007
Henry Lin
This study focuses on the feasibility of producing a therapeutic Fc fusion protein in Pichia pastoris (P. pastoris) and presents an optimization design of experiment (DOE) strategy in a well-defined experimental space. The parameters examined in this study include pH, temperature, salt supplementation, and batch glycerol concentration. The effects of these process conditions were captured by statistical analysis focusing on growth rate and titer responses. Batch medium and fermentation conditions were also investigated prior to the DOE study in order to provide a favorable condition to enable the production of this Fc fusion protein. The results showed that approximately 373 mg/L of the Fc fusion protein could be produced. The pH was found to be particularly critical for the production of this Fc fusion protein. It was significantly higher than the conventional, recommended pH for P. pastoris fermentation. The development of this process shows that protein production in P. pastoris is protein specific, and there is not a set of pre-defined conditions that can work well for all types of proteins. Thorough process development would need to be performed for every type of protein in order for large-scale production in P. pastoris to be feasible. [source]


Optimization of Fermentation Conditions for Preparation of Polygalacturonic Acid Transeliminase by Erwinia carotovora IFO3830

BIOTECHNOLOGY PROGRESS, Issue 2 2001
Fengping Ding
This paper is concerned with optimization of the fermentation conditions for preparation of alkaline pectin lyase (poly-galacturonic acid trans-eliminase, PATE) by Erwinia carotovoraIFO3830 (E.C.IFO3830). The orthogonal matrix method was adopted as the experimental design method for media. The effects of media composition on the growth rate of E.C.IFO3830 are in the order of pectin > KH2PO4/Na2HPO4 > MgSO4 > (NH4)2SO4 > glucose > L -glutamate sodium, and those on PATE activity are in the order of glucose > pectin > L -glutamate sodium > KH2PO4/Na2HPO4 > MgSO4 > (NH4)2SO4. The strain of E.C.IFO3830 grows quickly and easily near an initial pH of 7.0, and especially at the alkaline range of pH 7.0,8.0. The growth rate profiles indicate that E.C.IFO3830 grows very quickly; its generation time t1/2 is about 0.2 h. The appropriate fermentation period is about 10,20 h for a high level productivity of biomass and 25,35 h for high productivity of PATE enzyme. [source]