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1.
Summary
Pseudomonas putida (ATCC 111 72) was studied in a continuous culture at various dilution rates with asparagine as the sole carbon source and
limiting factor. Under the experimental conditions applied, a considerable number of the cells became attached to the fermentor
walls and equipment. The viable count of the attached cells was of the same magnitude as those in suspension.
The following steady-state characteristics were obtained: The cell-mass (OD620 and dry weight) versus dilution rate (D) had maxima at 0.63 and 1.1 h−1. The corresponding plot of viable count had a minimum at 0.94 h−1 whereafter it reached a maximum at 1.3 h−1. Largest yield coefficient obtained was 0.44 g dry weight/g asparagine (D=1.1 h−1). The productivity of the culture increased with D up to 1.1 h−1, which is far above the D corresponding to the maximum specific growth rate (μmax) of a batch culture (0.59 h−1). The cell mass was not completly washed-out of the fermentor even at a D of 2.2 h−1.
The influence of attached growth for the steady-state characteristics, and the significance of the results in relation to
chemostate as an instrument for testing environmental factors, are discussed. It is suggested that the attached cells had
a significantly higher (μmax) value than the suspended ones. 相似文献
2.
Kamakshi Gupta P. K. Mishra Pradeep Srivastava 《Biotechnology and Bioprocess Engineering》2009,14(2):207-212
Lovastatin, a hypocholesterolemic agent, is a secondary metabolite produced by filamentous microorganism Aspergillus terreus in submerged batch cultivation. Lovastatin production by pellets and immobilized siran cells was investigated in an airlift
reactor. The process was carried out by submerged cultivation in continuous mode with the objective of increasing productivity
using pellet and siran supported growth of A terreus. The continuous mode of fermentation improves the rate of lovastatin production. The effect of dilution rate and aeration
rate were studied in continuous culture. The optimum dilution rate for pellet was 0.02 h−1 and for siran carrier was 0.025 h−1. Lovastatin productivity using immobilized siran carrier (0.0255 g/L/h) was found to be greater than pellets (0.022 g/L/h).
The productivity by both modes of fermentation was found higher than that of batch process which suggests that continuous
cultivation is a promising strategy for lovastatin production. 相似文献
3.
Woo Jun Kim Woo Gi Lee Kalaimahan Theodore Ho Nam Chang 《Biotechnology and Bioprocess Engineering》2001,6(1):6-10
The production of chitosan from the mycelia ofAbsidia coerulea was studied to improve cell growth and chitosan productivity. Culture conditions were optimized in batch cultivation (pH
4.5 agitator speed of 250 rpm, and aeration rate of, 2 vvm) and the maximum chitosan concentration achieved was 2.3 g/L under
optimized conditions. Continuous culture was carried out successfully by the formation of new growth spots under optimized
conditions, with a chitosan productivity of 0.052 gL−1 h−1, which is the highest value to date, and was obtained at a dilution rate of 0.05 h−1. Cell chitosan concentrations reached about 14% in the steady state, which is similar to that achieved in batch culture.
This study shows that for the continuous culture ofAbsidia coerulea it is vital to control the medium composition. 相似文献
4.
Bifidobacterium longum grew at 65 L pilot scale of the membrane bioreactor (MBR), externally fitted with ceramic membrane (0.7 m2). Cell mass at the MBR reached 22.18 g L−1 as dry cell weight in 12 h, which is 8.44 times higher than cell mass attained at the vial culture. The growth rate in the
vial culture was μ = 0.385 h− and at the batch culture was μ = 1.13 h− in the exponential period and μ = 0.31 h−1 in the stationary period. In the fed-batch mode was μ = 1.102 h−1 for 6 h with inoculation and declined to μ = 0.456 h−1 with feeding of feed medium. The growth rate at the MBR was μ = 0.134 h−1. The number of viable cells was 6.01 × 1012 cfu L−1 at the batch culture, but increased to 1.15 × 1014 cfu L−1 at the MBR culture. The specific growth rate of viable cell number (colony-forming units per liter, per hour) improved by
6.01 times from the batch to the MBR culture. The wall shear stress mainly generated by the pump, and the membrane incorporated
into the MBR was controlled during the cultivation at the MBR. The viability of B. longum declined to under 10% in the first 2 weeks of the 4-week stability test (40°C) as B. longum was exposed to over wall shear stress 713 Pa, but the viability improved to 30–40% in wall shear stress of 260 Pa or STR
culture. The loss in the cell viability can be saved by managing with wall shear stress during the cultivation at the MBR. 相似文献
5.
Production of 1,3-Propanediol by Clostridium butyricum VPI 3266 in continuous cultures with high yield and productivity 总被引:2,自引:0,他引:2
González-Pajuelo M Andrade JC Vasconcelos I 《Journal of industrial microbiology & biotechnology》2005,32(9):391-396
The effects of dilution rate and substrate feed concentration on continuous glycerol fermentation by Clostridium butyricum VPI 3266, a natural 1,3-propanediol producer, were evaluated in this work. A high and constant 1,3-propanediol yield (around
0.65 mol/mol), close to the theoretical value, was obtained irrespective of substrate feed concentration or dilution rate.
Improvement of 1,3-propanediol volumetric productivity was achieved by increasing the dilution rate, at a fixed feed substrate
concentration of 30, 60 or 70 g l−1. Higher 1,3-propanediol final concentrations and volumetric productivities were also obtained when glycerol feed concentration
was increased from 30 to 60 g l−1, at D=0.05–0.3 h−1, and from 60–70 g l−1, at D=0.05 and 0.1 h−1·30 g l−1 of 1,3-propanediol and the highest reported value of productivity, 10.3 g l−1 h−1, was achieved at D=0.30 h−1 and 60 g l−1 of feed glycerol. A switch to an acetate/butyrate ratio higher than one was observed for 60 g l−1 of feed glycerol and a dilution rate higher than 0.10 h−1; moreover, at D=0.30 h−1 3-hydroxypropionaldehyde accumulation was observed for the first time in the fermentation broth of C. butyricum. 相似文献
6.
Jie Chen Heming Chen Xiangchen Zhu Yinghua Lu Shang-Tian Yang Zhinan Xu Peilin Cen 《Applied microbiology and biotechnology》2009,82(2):241-248
The production of recombinant glycoproteins in Dictyostelium discoideum by conventional cell culture methods was limited by low cell density as well as low growth rate. In this work, cotton towel
with a good adsorption capability for D. discoideum cells was used as the immobilization matrix in an external fibrous bed bioreactor (FBB) system. With batch cultures in the
FBB, the concentration of immobilized cells in the cotton fiber carrier increased to 1.37 × 108 cells per milliliter after 110-h cultivation, which was about tenfold higher than the maximal cell density in the conventional
free-cell culture. Correspondingly, a high concentration of soluble human Fas ligand (hFasL; 173.7 μg l−1) was achieved with a high productivity (23 μg l−1 h−1). The FBB system also maintained a high density of viable cells for hFasL production during repeated-batch cultures, achieving
a productivity of 9∼10 μg l−1 h−1 in all three batches studied during 15 days. The repeated-batch culture using immobilized cells of D. discoideum in the FBB system thus provides a good method for long-term and high-level production of hFasL. 相似文献
7.
Shokrollahzadeh S Bonakdarpour B Vahabzadeh F Sanati M 《Journal of industrial microbiology & biotechnology》2007,34(1):17-25
The effect of phosphate (P
i
) concentration on the growth behavior of Saccharomyces cerevisiae strain CEN.PK113-5D in phosphate-limited batch and chemostat cultures was studied. The range of dilution rates used in the present study was 0.08–0.45 h−1. The batch growth of yeast cells followed Monod relationship, but growth of the cells in phosphate-limited chemostat showed change in growth kinetics with increasing dilution rates. The difference in growth kinetics of the yeast cells in phosphate-limited chemostat for dilution rates below and above approximately 0.2 h−1 has been discussed in terms of the batch growth kinetic data and the change in the metabolic activity of the yeast cells. Immunological detection of a C-terminally myc epitope-tagged Pho84 fusion protein indicated derepressive expression of the Pho84 high-affinity P
i
transporter in the entire range of dilution rates employed in this study. Phosphate transport activity mediated by Pho84 transporter was highest at very low dilution rates, i.e. 0.08–0.1 h−1, corresponding to conditions in which the amount of synthesized Pho84 was at its maximum. 相似文献
8.
Extracellular human granulocyte-macrophage colony stimulating factor (hGM-CSF) expression was studied under the control of
the GAP promoter in recombinant Pichia pastoris in a series of continuous culture runs (dilution rates from 0.025 to 0.2 h−1). The inlet feed concentration was also varied and the steady state biomass concentration increased proportionally demonstrating
efficient substrate utilization and constancy of the biomass yield coefficient (Yx/s) for a given dilution rate. The specific product formation rate (qP) showed a strong correlation with dilution rates demonstrating growth associated product formation of hGM-CSF. The volumetric
product concentration achieved at the highest feed concentration (4×) and a dilution rate of 0.2 h−1 was 82 mg l−1 which was 5-fold higher compared to the continuous culture run with 1× feed concentration at the lowest dilution rate thus
translating to a 40 fold increase in the volumetric productivity. The specific product yield (YP/X) increased slightly from 2 to 2.5 mg g−1, with increasing dilution rates, while it remained fairly invariant, for all feed concentrations demonstrating negligible
product degradation or feed back inhibition. The robust nature of this expression system would make it easily amenable to
scale up for industrial production. 相似文献
9.
Candida utiilis NRRL Y-900 was grown on pineapple cannery waste as the sole carbon and energy source in a chemostat at dilution rates ranging
between 0.05 and 0.65 h−1 to determine the growth kinetics. The cell yield coefficient varied with dilution rate and a maximum value of 0.662 ± 0.002
gx/gcarb was obtained at a dilution rate of 0.4 h−1. At steady state, the concentrations of carbohydrate, reducing sugar, and chemical oxygen demand (COD) appeared to follow
Monod kinetics. At maximum specific growth rate (μmax) 0.65 h−1, the saturation constants for carbohydrate, reducing sugar and COD were 0.51 ± 0.02 gcarb/1, 0.046 ± 0.003 grs/1, and 1.036 ± 0.001 gCOD/1, respectively. Maximum biomass productivity (Q
x max) 2.8 ± 0.03 gx/1 h was obtained at a dilution rate of 0.5 h−1. At this dilution rate, only 71.0 ± 0.41% COD was removed whereas at a dilution rate of 0.1 h−1, 98.2 ± 0.35% reduction in COD was achieved. At a dilution rate of 0.4 h−1, the optimal yeast productivity and reduction in COD were 2.7 ± 0.13 gp/1 h, and 84.2 ± 0.42%, respectively.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
10.
Lipid and docosahexaenoic acid (DHA) accumulation into Schizochytrium G13/2S was studied under batch and continuous culture. Different glucose and glutamate concentrations were supplemented in
a defined medium. During batch cultivation, lipid accumulation, 35% total fatty acids (TFA) occurred at the arithmetic growth
phase but ceased when cell growth stopped. When continuous culture was performed under different glutamate concentrations,
nitrogen-growth-limiting conditions induced the accumulation of 30–28% TFA in Schizochytrium. As the dilution rate decreased from 0.08 to 0.02 h−1, both cell dry weight and TFA content of the cell increased. Under a constant dilution rate of 0.04 h−1, carbon-limiting conditions decreased the TFA to 22%. Fatty acid profile was not affected by the different nutrient concentrations
provided during continuous culture. Consequently, lipid accumulation can be induced through the carbon and nitrogen source
concentration in the medium to maximise the TFA and subsequently DHA productivity by this microorganism. 相似文献
11.
Lakkana Laopaiboon Pornthap Thanonkeo Prasit Jaisil Pattana Laopaiboon 《World journal of microbiology & biotechnology》2007,23(10):1497-1501
Sweet sorghum juice supplemented with 0.5% ammonium sulphate was used as a substrate for ethanol production by Saccharomyces cerevisiae TISTR 5048. In batch fermentation, kinetic parameters for ethanol production depended on initial cell and sugar concentrations.
The optimum initial cell and sugar concentrations in the batch fermentation were 1 × 108 cells ml−1 and 24 °Bx respectively. At these conditions, ethanol concentration produced (P), yield (Y
ps) and productivity (Q
p
) were 100 g l−1, 0.42 g g−1 and 1.67 g l−1 h−1 respectively. In fed-batch fermentation, the optimum substrate feeding strategy for ethanol production at the initial sugar
concentration of 24 °Bx was one-time substrate feeding, where P, Y
ps and Q
p
were 120 g l−1, 0.48 g g−1 and 1.11 g l−1 h−1 respectively. These findings suggest that fed-batch fermentation improves the efficiency of ethanol production in terms of
ethanol concentration and product yield. 相似文献
12.
P. Becker I. Abu-Reesh S. Markossian G. Antranikian H. Märkl 《Applied microbiology and biotechnology》1997,48(2):184-190
A thermostable lipase was produced in continuous cultivation of a newly isolated thermophilic Bacillus sp. strain IHI-91 growing optimally at 65 °C. Lipase activity decreased with increasing dilution rate while lipase productivity
showed a maximum of 340 U l−1 h−1 at a dilution rate of 0.4 h−1. Lipase productivity was increased by 50% compared to data from batch fermentations. Up to 70% of the total lipase activity
measured was associated to cells and by-products or residual substrate. Kinetic and stoichiometric parameters for the utilisation
of olive oil were determined. The maximal biomass output method led to a saturation constant K
S of 0.88 g/l. Both batch growth data and a washout experiment yielded a maximal specific growth rate, μmax, of 1.0 h−1. Oxygen uptake rates of up to 2.9 g l−1h−1 were calculated and the yield coefficient, Y
X/O, was determined to be 0.29 g dry cell weight/g O2. From an overall material balance the yield coefficient, Y
X/S, was estimated to be 0.60 g dry cell weight/g olive oil.
Received: 8 January 1997 / Received revision: 30 April 1997 / Accepted: 4 May 1997 相似文献
13.
Continuous production of acetone, n-butanol, and ethanol (ABE) was carried out using immobilized cells of Clostridium acetobutylicum DSM 792 using glucose and sugar mixture as a substrate. Among various lignocellulosic materials screened as a support matrix,
coconut fibers and wood pulp fibers were found to be promising in batch experiments. With a motive of promoting wood-based
bio-refinery concept, wood pulp was used as a cell holding material. Glucose and sugar mixture (glucose, mannose, galactose,
arabinose, and xylose) comparable to lignocellulose hydrolysate was used as a substrate for continuous production of ABE.
We report the best solvent productivity among wild-type strains using column reactor. The maximum total solvent concentration
of 14.32 g L−1 was obtained at a dilution rate of 0.22 h−1 with glucose as a substrate compared to 12.64 g L−1 at 0.5 h−1 dilution rate with sugar mixture. The maximum solvent productivity (13.66 g L−1 h−1) was obtained at a dilution rate of 1.9 h−1 with glucose as a substrate whereas solvent productivity (12.14 g L−1 h−1) was obtained at a dilution rate of 1.5 h−1 with sugar mixture. The immobilized column reactor with wood pulp can become an efficient technology to be integrated with
existing pulp mills to convert them into wood-based bio-refineries. 相似文献
14.
The potential use of spin filter device to retainPropionibacterium acidipropionici in the bioreactor under continuous mode of fermentation and improve propionic acid productivity, was examined. The yield
of propionic acid based on lactose concentration was 51% in batch and 54% in continuous (dilution rate=0.05 h−1) operation. The yield in continuous fermentation with cell retention using spin filter of 10 micron size (dilution rate=0.05
h−1) was even higher at 70% (w/w). The volumetric productivity under batch and continuous mode of operation were 0.312 g L−1 h−1 and 0.718 g L−1 h−1 respectively. Continuous fermentation with cell retention demonstrated even higher volumetric productivities at 0.98 g L−1 h−1 with out clogging problems It could be used for utilization of cheese whey to produce propionic acid at higher yield and
productivities. 相似文献
15.
The continuous production of citric acid from dairy wastewater was investigated using calcium-alginate immobilizedAspergillus niger ATCC 9142. The citric acid productivity and yield were strongly affected by the culture conditions. The optimal pH, temperature,
and dilution rate were 3.0, 30°C, and 0.025 h−1, respectively. Under optimal culture conditions, the maximum productivity, concentration, and yield of citric acid produced
by the calcium-alginate immobilizedAspergillus niger were 160 mg L−1 h−1, 4.5 g/L, and 70.3% respectively. The culture was continuously perfored for 20 days without any apparent loss in citric acid
productivity. Conversely, under the same conditions with a batch shake-flask culture, the maximum productivity, citric acid
concentration, and yield were only 63.3 mg L−1 h−1, 4.7 g/L and 51.4%, respectively. Therefore, the results suggest that the bioreactor used in this study could be potentially
used for continuous citric acid production from dairy wastewater by applying calcium-alginate immobilizedAspergillus niger. 相似文献
16.
Batch cultivation of Ralstonia eutropha NRRL B14690 attained 21 g biomass l−1 and 9.4 g poly(β-hydroxybutyrate) l−1 (0.45 g PHB g−1 dry wt−1) in 60 h. Repeated batch operation (empty-and-fill protocol) to remove 20% (v/v) of the culture broth and to supplement an
equal volume of fresh media resulted in 49 g biomass l−1 and 25 g PHB l−1 (0.51 g PHB g−1 dry wt−1) with an overall productivity of 0.42 g PHB l−1 h−1 in 67 h. In the two cycles of repeated batch fermentation there was a 3-fold increase in productivity as compared to batch. 相似文献
17.
Phimchanok Nakkharat Dietmar Haltrich 《World journal of microbiology & biotechnology》2007,23(6):759-764
The β-galactosidase from Talaromyces thermophilus CBS 236.58 immobilized onto Eupergit C produced galacto-oligosaccharides (GalOS) in batchwise and continuous packed-bed mode
of operation. A maximum yield of GalOS of 12, 39 and 80 g l−1 was obtained for initial lactose concentrations of 50, 100 and 200 g l−1, respectively, for batch conversion experiments. The immobilized enzyme could be re-used for several cycles for lactose hydrolysis
and transformation. The maximum GalOS concentration of approximately 50 g l−1 was obtained with the dilution rate of 0.375 h−1 in a packed-bed reactor, when using an initial lactose concentration of 200 g l−1. Continuous conversion of lactose in the packed-bed reactor resulted in the formation of relatively more trisaccharides than
when employing the immobilized enzyme in discontinuous mode of operation. 相似文献
18.
Li-Ming Liu Guo-Cheng Du Yin Li Hua-Zhong Li Jian Chen 《Biotechnology and Bioprocess Engineering》2005,10(2):136-141
The capability of utilizing a TCA cycle intermediates as the sole carbon source by the multi-vitamin auxotrophic yeastTorulopsis glabrata CCTCC M202019 was demonstrated with plate count method. It is indicated thatT. glabrata could grew on a medium with one of the TCA cycle intermediates as the sole carbon source, but more colonies were observed
when glucose, acetate and one of the TCA cycle intermediates coexisted in the medium. Among the intermediates of the TCA cycle
examined in this study, cell growth was improved by supplementing oxaloacetate. Further investigation showed that the presence
of acetate was necessary when oxaloacetate was supplemented. By supplementing with 10 g/L of oxaloacetate in pyruvate batch
fermentation, dry cell weight increased from 11.8 g/L to 13.6 g/L, and pyruvate productivity was enhanced from 0.96 gL−1h−1 to 1.19 gL−1h−1 after cultivation of 56 h. The yield of pyruvate to glucose was also improved from 0.63 g/g to 0.66 g/g. These results indicate
that under vitamins limitation, the productivity and yield of pyruvate could be enhancedvia an increase of cell growth by the supplementation of oxaloacetate. 相似文献
19.
Tzvetkova Bonka Hristozova Tsonka Angelov Angel Paskaleva Donka 《World journal of microbiology & biotechnology》2004,20(3):219-223
The effects of furfural on the growth of the lactose-utilizing yeast Candida blankii 35 were investigated using the method of continuous cultivation under conditions of carbon limitation and at dilution rates
of 0.1 and 0.25 h−1. The data obtained at dilution rate 0.1 h−1 and 0.04% furfural showed a decrease in the yield of biomass by 6% and in the RNA content, but the synthesis of cell protein
increased with 11.6% compared to the control. Treatment with 0.08% furfural induced significant changes in growth and biosynthesizing
ability. A strong inhibitory effect of furfural was observed: the biomass yield decreased by half at 48 h and the culture
the reached the control level of protein content. The effect of 0.02% furfural at 0.25 h−1 dilution rate caused a significant reduction of biomass yield (34.4%) and the substrate utilization rate reached values higher
by 52.4% at 48 h, but the protein-synthesizing ability of the cells slightly increased. The results showed that a treatment
with 0.04 or 0.08% furfural caused significant disturbances of cell functions, the yields of biomass and protein drastically
decreased and the culture was washed out. Data showed that the inhibitory effect of furfural on the growth and protein-synthesizing
ability of Candida blankii 35 depends on the inhibitor concentration as well as the dilution rate.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
20.
E Parente C Brienza A Ricciardi G Addario 《Journal of industrial microbiology & biotechnology》1997,18(1):62-67
Production of the bacteriocin enterocin 1146 (E1146) by Enterococcus faecium DPC1146 was studied in batch and continuous fermentation. Growth was strongly inhibited by lactic acid. In batch fermentations
maximum E1146 activity (2.8 MBU L−1) was obtained in 9 h with 20 g L−1 glucose. Increase in initial glucose concentration did not lead to a proportional increase in E1146 activity. A simple linear
model was found to be adequate to explain the relationship between specific bacteriocin production rate and specific growth
rate in batch fermentations with initial glucose concentration higher than 20 g L−1. Maximum bacteriocin activity (2.9–3.2 MBU L−1) was obtained in continuous fermentations at dilution rates between 0.12 and 0.17 h−1 and specific bacteriocin production rate increased linearly with dilution rate.
Received 31 July 1996/ Accepted in revised form 01 November 1996 相似文献