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1.
Silva Daniel Pereira Pessoa Adalberto Roberto Inês-Conceição Vitolo Michele 《Applied biochemistry and biotechnology》2001,91(1-9):605-613
A batch culture of Saccharomyces cerevisiae for the production of hexokinase was carried out in a 5-L fermentor containing 3 L of culture medium, which was in oculated
with cell suspension (about 0.7 g/L), and left ferm entingat 35°C and pH 4.0. The aeration and agitation were adjusted to
attain k
La values of 15, 60, 135, and 230 h−1. The highest hexokinase productivity (754.6 U/[L h]) and substrate-cell conversion yield (0.21 g/g) occurred for a k
La of 60 h−1. Moreover, the formation of hexokinase and cell growth are coupled events, which is in accordance with the constitutive character
of this enzyme. Hexokinase formation for k
La>60 h−1 was not enhanced probably owing to saturation of the respiratory pathway by oxygen. 相似文献
2.
Continuous production of lactic acid in a cell recycle reactor 总被引:3,自引:0,他引:3
Eric Ohleyer Harvey W. Blanch Charles R. Wilke 《Applied biochemistry and biotechnology》1985,11(4):317-332
The production of lactic acid from glucose has been demonstrated using a CSTR (continuous stirred-tank reactor) with cell
recycle. Studies were conducted withLactobacillus delbrueckii at a fermentation temperature of 42°C and a pH of 6.25. A cell density of 140 g dry weight/L and a volumetric productivity
of 150 g/L.h, with complete glucose consumption, were obtained. It was not possible to obtain a lactic acid concentration
above 60 g/L because of product inhibition. A cell purge was not necessary to maintain high viability bacteria culture or
to obtain a steady state. At steady state the net cell growth appeared to be negligible. The specific glucose consumption
for cell maintenance was 0.33 g glucose/g cells-h. 相似文献
3.
H. Moon S. W. Kim J. Lee S. K. Rhee E. S. Choi H. A. Kang I. H. Kim S. I. Hong 《Applied biochemistry and biotechnology》2003,111(2):65-79
As a novel feeding strategy for aptomizing human epidermal growth factor (hEGF) production with a recombinant Hansenula polymorpha DL-1 using the methanol oxidase (MOX) promoter in H. polymorpha DL-1, independent exponential feeding of two substrates was used. A simple kinetic model considering the cell growth on two
substrates was established and used to calculate the respective feeding rates of glycerol and methanol. In the fedbatch culture
with methanol-only feeding, the optimal set point of specific growth rate on methanol was found to be 0.10 h−1. When the fed-batch cultures were conducted by the independent feeding of glycerol and methanol, the actual specific growth
rate on glycerol and methanol was slightly lower than the set point of specific growth rate. By the uncoupled feeding of glycerol
and methanol the volumetric productivity of hEGF increased from 6.4 to 8.0 mg/(L·h), compared with methanol-only feeding. 相似文献
4.
Hugh G. Lawford 《Applied biochemistry and biotechnology》1988,17(1-3):203-219
Although most fermentation ethanol is currently produced in traditional batch processes with yeast, the ethanologenic bacteriumZymomonas mobilis is recognized as an alternative process organism for fuel alcohol production. Different strategies for improving the productivity
of ethanol fermentations are reviewed. In batch and open-type continuous fermentations the advantage of replacing yeast byZymomonas relates principally to the 10% higher fermentation efficiency (product yield), whereas in high cell density, closed-type
continuous systems (operating with cell recycle or retention) the superior kinetic properties ofZymomonas can be exploited to affect about a five-fold improvement in volumetric productivity. Unlike yeast, the rate of energy supply
(conversion of glucose to ethanol) inZymomonas is not strictly regulated by the energy demand and a nongrowing culture exhibits a maintenance energy coefficient that is
at least 25 times higher than yeast. As an alternative to process improvement through genetic engineering of the process organism
this investigation has taken a biochemical and physiological approach to increasing the kinetic performance ofZ. mobilis through manipulation and control of the chemical environment. Energetically “uncoupled” phenotypes with markedly increased
specific rates of ethanol production were generated under conditions of nutritional limitation (nitrogen, phosphate, or potassium)
in steady-state continuous culture. The pH was shown to influence energy coupling inZymomonas affecting the maintenance coefficient (m
e
) rather than the max growth yield coefficient (Y
x
sάx
). Whereas the pH for optimal growth ofZ. mobilis (ATCC 29191) in a complex medium was 6.0–6.5, the specific rate of ethanol production in continuous fermentations was maximal
in the range 4.0–4.5. Fermentation conditions are specified for maximizing the specific productivity of aZymomonas-based continuous ethanol fermentation where the potential exists for improving the volumetric productivity in dense culture
fermentations with an associated 35–40% reduction in capital costs of fermentation equipment and an estimated savings of 10–15%
on cost of product recovery (distillation), and 3–7% on overall production costs based on the projected use of inexpensive
feedstocks. 相似文献
5.
Beker M. J. Shvinka J. E. Pankova L. M. Laivenieks M. G. Mezhbarde I. N. 《Applied biochemistry and biotechnology》1990,(1):265-274
Two biotechnological systems were developed for sucrose conversion into levan and ethanol withZymomonas mobilis, ensuring a 66.7% transfer of substrate carbon in a batch and 61% carbon transfer in a continuous culture. The effect of
glucose, ethanol, and medium pH on sucrose conversion byZ. mobilis was studied. The addition of ethanol to the fermentation medium, in the final conc. of 100 g/L, uncoupled levan synthesis
from ethanol fermentation. For a continuous culture, the most efficient conversion of substrate carbon into levan was reached
at pH 4.8, giving 64.2 g/L levan, with the levan yield of 0.22 g/g and the productivity of 3.2 g/L/h. 相似文献
6.
Agar-immobilized alkaliphilic Bacillus sp. AR-009 cells were used for xylanase production using batch and continuous culture. In a batch culture, maximum enzyme
production was observed after 48 h and remained high up to 72 h. In repeated batch cultivation, immobilized cells produced
an appreciable level of xylanase activity in seven consecutive batches without any significant decline in productivity. For
continuous xylanase production, immobilized cells were packed in a jacketed glass column and sterile medium was continuously
pumped. A stable continuous production of xylanase was observed over a period of 1 mo. The volumetric productivity of the
continuous culture was 17-fold higher than the batch culture using free cells. 相似文献
7.
Wee Young-Jung Yun Jong-Sun Kang Kui-Hyun Ryu Hwa-Won 《Applied biochemistry and biotechnology》2002,98(1-9):1093-1104
Enterococcus faecalis RKY1, a fumarate-reducing bacterium, was immobilized in an asymmetric hollow-fiber bioreactor (HFBR) for the continuous production
of succinic acid. The cells were inoculated into the shell side of the HFBR, which was operated in transverse mode. Since
the pH values in the HFBR declined during continuous operation to about 5.7, it was necessary to change the feed pH from 7.0
to 8.0 after 24 h of operation in order to enhance production of succinic acid. During continuous operation with a medium
containing fumarate and glycerol, the productivity of succinate was 3.0–10.9 g/(L·h) with an initial concentration of 30 g/L
of fumarate, 4.9–14.9 g/(L·h) with 50 g/L of fumarate, and 7.2–17.1 g/(L·h) with 80 g/L of fumarate for dilution rates between
0.1 and 0.4 h−1. The maximum productivity of succinate obtained by the HFBR (17.1 g of succinate /[L·h]) was 1.7 times higher than that of
the batch bioconversions (9.9 g of succinate /[L·h]) with 80 g/L of fumarate. Furthermore, the long-term stability of the
HFBR was demonstrated with a continuously efficient production of succinate for more than 15 d (360 h). 相似文献
8.
Thaddeus C. Ezeji Marisa Groberg Nasib Qureshi Hans P. Blaschek 《Applied biochemistry and biotechnology》2003,106(1-3):375-382
Acetone, butanol, ethanol (ABE, or solvents) were produced from starch-based packing peanuts in batch and continuous reactors.
In a batch reactor, 18.9 g/L of total ABE was produced from 80 g/L packing peanuts in 110 h of fermentation. The initial and
final starch concentrations were 69.6 and 11.1 g/L, respectively. In this fermentation, ABE yield and productivity of 0.32
and 0.17 g/(L·h) were obtained, respectively. Compared to the batch fermentation, continuous fermentation of 40 g/L of starch-based
packing peanuts in P2 medium resulted in a maximum solvent production of 8.4 g/L at a dilution rate of 0.033 h−1. This resulted in a productivity of 0.27 g/(L·h). However, the reactor was not stable and fermentation deteriorated with
time. Continuous fermentation of 35 g/L of starch solution resulted in a similar performance. These studies were performed
in a vertical column reactor using Clostridium beijerinckii BA101 and P2 medium. It is anticipated that prolonged exposure of culture to acrylamide, which is formed during boiling/autoclaving
of starch, affects the fermentation negatively. 相似文献
9.
Ernesto Acosta Martínez Silvio S. Silva Maria G. A. Felipe 《Applied biochemistry and biotechnology》1999,77(1-3):347-354
The biocon version of xylose intoxylitol using pH values of 4.0, 5.5 and 7.0 and tetracycline concentrations of 20 and 40
mg/L was carried out to verify the influence of these parameters on Candida guilliermondii metabolism for xylitol production. Experiments were performed with sugarcane bagasse hemicellulosi chydrolysate (48.5 g/L
of xylose) in 125-mL Erlenmeyer flasks, at 30°C, 200 rpm, during 88 h. The results demostrated that the bioconversion of xylose
into xylitol was significantly influenced by the pH. On the other hand, in media containing 20 or 40 mg/L of tetracycline,
this bioconversion was not significantly affected. The best results of xylitol production were obtained in hemicellulosic
hydrolysate without tetracycline, at pH 7.0 In these conditions, the maxim um specific growth rate was 0.014/h and the yield
factor of xylitol and volumetric productivity were 0.85g/g and 0.70g/L/h respectively. Xylitol and cell growth occureed simultaneously. 相似文献
10.
The effect of carbon source and its concentration, inoculum size, yeast extract concentration, nitrogen source, pH of the
fermentation medium, and fermentation temperature on β-glucosidase production by Kluyveromyces marxianus in shake-flask culture was investigated. These were the independent variables that directly regulated the specific growth
and β-glucosidase production rate. The highest product yield, specific product yield, and productivity of β-glucosidase occurred
in the medium (pH 5.5) inoculated with 10% (v/v) inoculum of the culture. Cellobiose (20 g/L) significantly improved β-glucosidase
production measured as product yield (Y
P/S
) and volumetric productivity (Q
P
) followed by sucrose, lactose, and xylose. The highest levels of productivity (144 IU/[L·h]) of β-glucosidase occurred on
cellobiose in the presence of CSL at 35°C and are significantly higher than the values reported by other researchers on almost
all other organisms. The thermodynamics and kinetics of β-glucosidase production and its deactivation are also reported. The
enzyme was substantially stable at 60°C and may find application in some industrial processes. 相似文献
11.
Duran-Paramo Enrique Garcia-Kirchner Oscar Hervagault Jean-Franç ois Thomas Daniel Barbotin Jean-Noël 《Applied biochemistry and biotechnology》2000,84(1-9):479-485
The effect of glucose on the α-amylase production by Bacillus subtilis ATCC-21556 was studied. Initial glucose concentrations up to 20 g/L were found to be directly proportional to the specific
α-amylase production in an immobilized-cell batch system, whereas a free-cell batch system presented an inversely proportional
relationship with the initial glucose concentration. This might be owing to the α-amylase repression by the glucose present
in the culture medium. Three hundred eighty-five percent of the specific α-amylase production with the free-cell system was
produced by the immobilized-cell batch culture. 相似文献
12.
Dae Haeng Cho Hee Jeong Chae Eui Yong Kim 《Applied biochemistry and biotechnology》2001,95(3):183-193
The aim of this work was to characterize an exopolysaccharide by Rhodotorula glutinis KCTC 7989 and to investigate the effect of the culture conditions on the production of this polymer. The extracellular polysaccharide
(EPS) produced from this strain was a novel acidic heteropolysaccharide composed of neutral sugars (85%) and uronic acid (15%).
The neutral sugar composition was identified by gas chromatography as mannose, fucose, glucose, and galactose in a 6.7:0.2:0.1:0.1
ratio. The molecular weight of purified EPS was estimated to be 1.0−3.8×105 Dalton, and the distribution of the molecular weight was very homogeneous (polydispersity index =1.32). The EPS solution
showed a characteristic of pseudoplastic non-Newtonian fluid at a concentration >2.0% in distilled water. The maximum EPS
production was obtained when the strain was grown on glucose (30 g/L). Ammonium sulfate was the best suitable nitrogen source
for EPS production. The highest yield of EPS was obtained at a carbon to nitrogen ratio of 15. The EPS synthesis was activated
at the acidic range of pH 3.0–5.0 and increased when the pH of the culture broth decreased naturally to <2.0 during the fermentation.
When the yeast was grown on glucose (30 g/L) and ammonium sulfate (2 g/L) at 22°C at an initial pH of 4.0, EPS production
was maximized (4.0 g/L), and the glucose-based production yield coefficient and carbon-based production yield coefficient
were 0.30 g of EPS/g of glucose and 0.34 g (carbon of EPS)/g (carbon of glucose), respectively. 相似文献
13.
Ali Mohagheghi Karel Grohmann Charles E. Wyman 《Applied biochemistry and biotechnology》1988,17(1-3):263-277
Cellulase production by the RUT-C30 mutant of the fungusTrichoderma reesei was studied on mixtures of xylose and cellulose. In mixed substrates, the lag phase of the growth cycle was shorter and reached
the maximum of total productivity in a shorter time compared to growth on the single substrate, cellulose. A diauxic pattern
of utilization of the two carbon sources was observed as well: Xylose was utilized first to support growth, followed by cellulose
to induce the cellulase enzyme production and provide an additional carbon source for cellular metabolism. Of the various
mixtures of xylose and cellulose used in batch enzyme production, a ratio of 30∶30 g/L of xylose to cellulose was optimal.
This mixture produced the highest maximal enzyme productivity of 122 IFPU/L h, and its total productivity reached a maximum
value of 55 IFPU/L h in less time than others. However, similar total productivities and higher enzyme titers were observed
for growth on cellulose alone. 相似文献
14.
Silvana T. Silveira Melissa S. Oliveira Jorge A. V. Costa Susana J. Kalil 《Applied biochemistry and biotechnology》2006,128(2):131-139
Glucoamylase production by Aspergillus niger in solid-state fermentation was optimized using factorial design and response surface techniques. The variables evaluated
were pH and bed thickness in tray, having as response enzyme production and productivity. The bed thickness in tray was the
most significant variable for both responses. The highest values for glucoamylase production occurred using pH 4.5 and bed
thickness in the inferior limits at 2.0–4.2 cm. For productivity, the optimal conditions were at pH 4.5 as well and bed thickness
from 4.4 to 7.5 cm. The optimal conditions for glucoamylase production while obtaining high activity without loss of productivity
were pH 4.5 and bed thickness in tray from 4.0 to 4.5 cm, which resulted in an enzyme production of 695 U/g and productivity
of 5791 U/h. 相似文献
15.
Citric acid is finding new areas of use each year and the demand for the acid is constantly increasing. Being a bulk chemical,
the continuous production of citric acid would be advantageous. The paper presents the results from ammonia limited batch
and continuous fermentations using the yeast strainSaccharomycopsis (Candida) lipolytica (NRRL Y-7576). Mathematical models were developed for growth and glucose utilization in batch and continuous culture. Cell
and acid yields appeared to be almost the same in batch and continuous culture. The specific production rates were found to
be constant, equal to 0.053 g/g h, in the batch fermentations but varied in the continuous experiments from 0 to 0.11 g/g
h depending on the fermentation conditions. Continuous production in a single stage CSTR was studied for over 1,000 hours
without shutdown. 相似文献
16.
Yoshiharu Yamane Yozo Nakamura Hiroyuki Okamoto Hiroshi Ooshima Jyoji Kato 《Applied biochemistry and biotechnology》1995,50(3):317-322
Effects of pH and dissolved oxygen concentration on batchwise riboflavin production by a 5-fluorouracil (5-FU)-resistant mutant
ofArthrobacter sp. were investigated. The reaction was carried out in a jar fermentor. The optimal pH of culture medium was around 7.3.
Dissolved oxygen concentration was almost constant during fermentation at 600 rpm of agitation rate. Production of riboflavin
reached a maximum of 160 mg/L after 70 h fermentation under the agitation rate of 600 rpm, aeration rate of 1.0 L/min, and
pH 7.0. 相似文献
17.
R. R. Gataullin T. V. Kazhanova F. F. Minnigulov A. A. Fatykhov L. V. Spirikhin I. B. Abdrakhmanov 《Russian Chemical Bulletin》2000,49(10):1767-1770
When reacting with I2, 2-(cyclopent-2-enyl)anilines undergo cyclization into 3-iodo-1,2,3,3a,4,8b-hexahydrocyclopenta[b]indoles in high yields. The minor reaction products were 3,5- or 3,7-diiodoindolines. Ammonolysis of 3-iodo-5-methyl-1,2,3,3a,4,8b-hexahydro-cyclopenta[b]indole or itsN-chloroacetyl derivative results in 3-amino-5-methyl-1,2,3,3a,48b-hexahydro- and 5-methyl-1,3a,4,8b-tetrahydrocyclopenta[b]indoles.
Published inIzvestiya Akademii Nauk. Seriya Khimischeskaya, No. 10, pp. 1789–1793, October, 2000. 相似文献
18.
R. P. Tengerdy J. E. Johnson J. Holló J. Tóth 《Applied biochemistry and biotechnology》1981,6(1):3-13
Pseudomonas fluorescens, immobilized on soft polyvinyl chloride granules containing up to 35% softeners as carbon source, was used for simultaneous
removal of nitrate and heavy metals. In typical continuous column operation, a 100 mg/L nitrate input solution was reduced
to a 20 mg/L output at a feeding rate of 1500 mL/h, with a capacity of 14 kg/day/m3, and with an efficiency of 79%. In the same column, Pb(NO3)2 concentration was reduced from 1.0 to 0.05−0.1 mg/L and ZnSO4 concentration was reduced from 10 to 5 mg/L.Pseudomonas aeruginosa immobilized on an O2 plasma-treated melt blown polypropylene web was used for removing 95% of a 1.7 nCi PuCl4 activity from a nuclear plant waste water in a batch operation. 相似文献
19.
Chattopadhyay S Srivastava AK Bisaria VS 《Applied biochemistry and biotechnology》2002,102(1-6):381-393
The root explants of the germinated seedlings of Podophyllum hexandrum were grown in MS medium supplemented with indole acetic acid (IAA) (2 mg/L) and activated charcoal (0.5%), and healthy callus
culture was obtained after incubation for 3 wk at 20°C. The cultivation of plant cells in shake flask was associated with
problems such as clumping of cells and browning of media, which were solved by the addition of pectinase and polyvinylpyrrolidone.
The effect of major media components and carbon source was studied on the growth and podophyllotoxin production in suspension
culture. It was found that glucose was a better carbon source than sucrose and that NH4
+:NO3
− ratio (total nitrogen concentration of 60 mM) and PO4
3− did not have much effect on the growth and product formation. The relative effect of culture parameters (inoculum level,
pH, IAA, glucose, NH4
+:NO3
− ratio, and PO4
3−) on the overall growth and product response of the plant cell suspension culture was further investigated by Plackett-Burman
design. This indicated that inoculum level, glucose, IAA, and pH had significant effects on growth and production of podophyllotoxin.
To identify the exact optimum concentrations of these parameters on culture growth and podophyllotoxin production, central
composite design experiments were formulated. The overall response equations with respect to growth and podophyllotoxin production
as a function of these culture parameters were developed and used to determine the optimum concentrations of these parameters,
which were pH 6.0, 1.25 mg/L of IAA, 72 g/L of glucose, and inoculum level of 8 g/L. 相似文献
20.
Valduga E Valério A Treichel H Furigo Júnior A Di Luccio M 《Applied biochemistry and biotechnology》2009,157(1):61-69
With the objective of determining the kinetic behavior (growth, substrate, pH, and carotenoid production) and obtain the stoichiometric
parameters of the fermentative process by Sporidiobolus salmonicolor in synthetic and agroindustrial media, fermentations were carried out in shaken flasks at 25°C, 180 rpm, and initial pH of
4.0 for 120 h in the dark, sampling every 6 h. The maximum concentrations of total carotenoids in synthetic (913 μg/L) and
agroindustrial (502 μg/L) media were attained approximately 100 h after the start of the fermentative process. Carotenoid
bioproduction is associated with cell growth and the ratio between carotenoid production and cell growth (Y
P/X) is 176 and 163 μg/g in the synthetic and agroindustrial media, respectively. The pH of the agroindustrial fermentation medium
varied from 4.2 to 8.5 during the fermentation. The specific growth rate (μ
X) for S. salmonicolor in synthetic and agroindustrial media was 0.07 and 0.04 h−1, respectively. The synthetic medium allowed for greater productivity, obtaining maximum cell productivity (P
x) of 0.08 g L−1 h−1 and maximum total carotenoid productivity (P
car) of 14.2 μg L−1 h−1. Knowledge of the kinetics of a fermentative process is of extreme importance when transposing a laboratory experiment to
an industrial scale, as well as making a quantitative comparison between different culture conditions. 相似文献