共查询到20条相似文献,搜索用时 31 毫秒
1.
Jiang L Wang J Liang S Wang X Cen P Xu Z 《Applied biochemistry and biotechnology》2010,160(2):350-359
Butyric acid has many applications in chemical, food, and pharmaceutical industries. In the present study, Clostridium tyrobutyricum ATCC 25755 was immobilized in a fibrous-bed bioreactor to evaluate the performance of butyrate production from glucose and
xylose. The results showed that the final concentration and yield of butyric acid were 13.70 and 0.46 g g−1, respectively, in batch fermentation when 30 g L−1 glucose was introduced into the bioreactor. Furthermore, high concentration 10.10 g L−1 and yield 0.40 g g−1 of butyric acid were obtained with 25 g L−1 xylose as the carbon source. The immobilized cells of C. tyrobutyricum ensured similar productivity and yield from repeated batch fermentation. In the fed-batch fermentation, the final concentration
of butyric acid was further improved to 24.88 g L−1 with one suitable glucose feeding in the fibrous-bed bioreactor. C. tyrobutyricum immobilized in the fibrous-bed bioreactor would provide an economically viable fermentation process to convert the reducing
sugars derived from plant biomass into the final bulk chemical (butyric acid). 相似文献
2.
A fed-batch culture system with constant feeding (glucose 80 g L−1, 0.25 ml min−1) was used to study the influence of glucose on cell dry weight and exopolysaccharides production from submerged Tremella fuciformis spores in a 5-L stirred-tank bioreactor. The results showed that high levels of cell mass (9.80 g L−1) and exopolysaccharides production (3.12 g L−1) in fed-batch fermentation were obtained after 1 h of feeding, where the specific growth rate (μ) and exopolysaccharides yield on substrate consumed (YP/S) were 0.267 d−1 and 0.14 g g−1. Unlike batch fermentation, maximal cell mass and exopolysaccharides production merely reached 7.11 and 2.08 g L−1; the specific growth rate (μ) and exopolysaccharides yield on substrate consumed (YP/S) were 0.194 d−1 and 0.093 g g−1, respectively. It is concluded that the synthesis of exopolysaccharides can be promoted effectively when feeding glucose
at a late exponential phase. 相似文献
3.
Continuous Production of Ethanol from Starch Using Glucoamylase and Yeast Co-Immobilized in Pectin Gel 总被引:1,自引:0,他引:1
This work presents a continuous simultaneous saccharification and fermentation (SSF) process to produce ethanol from starch
using glucoamylase and Saccharomyces cerevisiae co-immobilized in pectin gel. The enzyme was immobilized on macroporous silica, after silanization and activation of the
support with glutaraldehyde. The silica–enzyme derivative was co-immobilized with yeast in pectin gel. This biocatalyst was
used to produce ethanol from liquefied manioc root flour syrup, in three fixed bed reactors. The initial reactor yeast load
was 0.05 g wet yeast/ml of reactor (0.1 g wet yeast/g gel), used in all SSF experiments. The enzyme concentration in the reactor
was defined by running SSF batch assays, using different amount of silica–enzyme derivative, co-immobilized with yeast in
pectin gel. The chosen reactor enzyme concentration, 3.77 U/ml, allowed fermentation to be the rate-limiting step in the batch
experiment. In this condition, using initial substrate concentration of 166.0 g/l of total reducing sugars (TRS), 1 ml gel/1 ml
of medium, ethanol productivity of 8.3 g/l/h was achieved, for total conversion of starch to ethanol and 91% of the theoretical
yield. In the continuous runs, feeding 163.0 g/l of TRS and using the same enzyme and yeast concentrations used in the batch
run, ethanol productivity was 5.9 g ethanol/l/h, with 97% of substrate conversion and 81% of the ethanol theoretical yield.
Diffusion effects in the extra-biocatalyst film seemed to be reduced when operating at superficial velocities above 3.7 × 10−4 cm/s. 相似文献
4.
Inês C. Roberto Ismael M. de Mancilha Sunao Sato 《Applied biochemistry and biotechnology》1999,77(1-3):205-210
The fermentation kinetics for the conversion of rice straw hemicellulosic hydrolysate to xylitol by the yeast Candida guilliermondii was evaluated under batch conditions. The fermentation was accomplished in a 1 L working volume stirred-tank reactor with
aeration of 1.3 vvm and agitation of 300 rpm (kLa=15/h). The maximum specific rate of xylitol formation (0.12 g/g) was achieved when the specific growth rate was lowered
to 1/5 of its highest value. From analysis of the fermentation kinetics, a linear correlation between specific growth rate
(μx) and specific rate of xylitol formation (qp) was evident. Based on the Gaden model, this bioprocess was classified as growth-associated production and the relationship
between μx and qp can be described by the equation qp=6.31μx. 相似文献
5.
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
6.
Beena PS Basheer SM Bhat SG Bahkali AH Chandrasekaran M 《Applied biochemistry and biotechnology》2011,164(5):612-628
Marine Aspergillus awamori BTMFW032, recently reported by us, produce acidophilic tannase as extracellular enzyme. Here, we report the application of
this enzyme for synthesis of propyl gallate by direct transesterification of tannic acid and in tea cream solubilisation besides
the simultaneous production of gallic acid along with tannase under submerged fermentation by this fungus. This acidophilic
tannase enabled synthesis of propyl gallate by direct transesterification of tannic acid using propanol as organic reaction
media under low water conditions. The identity of the product was confirmed with thin layer chromatography and Fourier transform
infrared spectroscopy. It was noted that 699 U/ml of enzyme could give 60% solubilisation of tea cream within 1 h. Enzyme
production medium was optimized adopting Box–Behnken design for simultaneous synthesis of tannase and gallic acid. Process
variables including tannic acid, sodium chloride, ferrous sulphate, dipotassium hydrogen phosphate, incubation period and
agitation were recognized as the critical factors that influenced tannase and gallic acid production. The model obtained predicted
4,824.61 U/ml of tannase and 136.206 μg/ml gallic acid after 48 h of incubation, whereas optimized medium supported 5,085 U/ml
tannase and 372.6 μg/ml of gallic acid production after 36 and 84 h of incubation, respectively, with a 15-fold increase in
both enzyme and gallic acid production. Results indicated scope for utilization of this acidophilic tannase for transesterification
of tannic acid into propyl gallate, tea cream solubilisation and simultaneous production of gallic acid along with tannase. 相似文献
7.
The purpose of this investigation was to study the effect of Streptomyces erumpens cells immobilized in various matrices, i.e., agar–agar, polyacrylamide, and luffa (Luffa cylindrica L.) sponge for production of α-amylase. Luffa sponge was found to be 21% and 51% more effective in enzyme yield than agar–agar
and polyacrylamide, respectively. Response surface methodology was used to evaluate the effect of three main variables, i.e.,
incubation period, pH, and temperature on enzyme production with immobilized luffa cells. The experimental results showed
that the optimum incubation period, pH, and temperature were 36h, 6.0, and 50 °C, respectively. The repeated batch fermentation
of immobilized cells in shake flasks showed that S. erumpens cells were more or less equally physiologically active on the support even after three cycles of fermentation (3,830–3,575
units). The application of S. erumpens crude enzyme in liquefying cassava starch was studied. The maximum hydrolysis of cassava starch (85%) was obtained with the
application of 4ml (15,200 units) of crude enzyme after 5 h of incubation. 相似文献
8.
Takagi M Cabrera-Crespo J Baruque-Ramos J Zangirolami TC Raw I Tanizaki MM 《Applied biochemistry and biotechnology》2003,110(2):91-100
Haemophilus influenzae type b (Hib) causes invasive infections in infants and young children. Vaccines consisting of Hib capsular polysaccharide
(polymer of ribosylribitol phosphate [PRP]) conjugated to a protein are effective in the prevention of such infections. The
production of capsular polysaccharide type b was studied in three cultivation conditions: single, glucose pulse, and repeated
batch. Specific polysaccharide production (Y
p/x
) was calculated for all experiments, showing the following values: 67 (single-batch cultivation), 71 (glucose pulse), 75
(repeated-batch cultivation, first batch), and 87 mg of PRP/g of dry cell weight (DCW) (repeated-batch cultivation, second
batch). Biomass concentration reached ∼1.8 g of DCW/L, while polysaccharide concentration was about ∼132 mg/L in the three
fermentation runs. Polysaccharide synthesis is associated with cell growth in all studied conditions as established by Kono's
analysis and Luedeking-Piret's model. 相似文献
9.
Karina B. Hueso Domínguez Ildikó V. Tóth M. Renata S. Souto Filipa Mendes Cándido García De María Isabel Vasconcelos António O. S. S. Rangel 《Applied biochemistry and biotechnology》2010,160(6):1664-1673
A sequential injection system to monitor glycerol in a Saccharomyces cerevisiae fermentation process was developed. The method relies on the rate of formation of nicotinamide adenine dinucleotide in its
reduced form (NADH, measured spectrophotometrically at 340 nm) from the reaction of glycerol with NAD+ cofactor, catalysed by the enzyme glycerol dehydrogenase present in solution. This procedure enables the determination of
glycerol between 0.046 and 0.46 g/l, (corresponding to yeast fermentation samples with concentrations up to 50 g/l) with good
repeatability (relative standard deviation for n = 10 lower than 2.2% for three different samples) at a sampling frequency of 25/h. The detection and quantification limits
using a miniaturised spectrophotometer were 0.13 and 0.44 mM, respectively. Reagent consumption was of 0.45 μmol NAD+ and 1.8 μg enzyme per assay, and the waste production was 2.8 ml per determination. Results obtained for samples were in
agreement with those obtained with a high-performance liquid chromatography method. 相似文献
10.
Xiangzhao Mao Feng Wang Jianguo Zhang Shi Chen Zixin Deng Yaling Shen Dongzhi Wei 《Applied biochemistry and biotechnology》2009,159(3):673-686
CS103, the novel derivative of polyene macrolides antibiotic FR-008/candicidin with lower toxicity has been isolated from
the culture mycelia of the mutant of Streptomyces sp. FR-008, with targeted deletions of the fscP cytochrome P450 gene from its chromosome. To enhance biosynthesis of CS103, pH shift and precursor feeding strategy for fermentation
process by the mutant of Streptomyces sp. FR-008 in a stirred tank bioreactor was developed. According to the process parameters analysis, the effectiveness of
the strategy was examined and confirmed by experiments. A maximal CS103 concentration of 139.98 μg/mL was obtained, 2.05-fold
higher than that in the pH-uncontrolled fermentation. Compared to other three cases as pH-uncontrolled, pH-controlled, and
two-stage pH-controlled batch cultures, the proposed “pH shift and precursor feeding strategy” effectively avoided the scarcity
of the antibiotic precursor, increased the CS103 yield from biomass (Y
P/X) and substrate (Y
P/S) by 110.61% and 48.52%, respectively, and at the time the fermentation time was shortened from 120 to 96 h. The highest CS103
production rate (1.46 μg mL−1 h−1) of the pH shift and precursor feeding strategy was 284.21%, 97.30%, and 58.70% higher than that of pH-uncontrolled, pH-controlled,
and two-stage pH-controlled batch culture cases, respectively. 相似文献
11.
Eleonora Winkelhausen Elena Velickova Samuel A. Amartey Slobodanka Kuzmanova 《Applied biochemistry and biotechnology》2010,162(8):2214-2220
A new lyophilization technique was used for immobilization of Saccharomyces cerevisiae cells in hydroxyethylcellulose (HEC) gels. The suitability of the lyophilized HEC gels to serve as immobilization matrices
for the yeast cells was assessed by calculating the immobilization efficiency and the cell retention in three consecutive
batches, each in duration of 72 h. Throughout the repeated batch fermentation, the immobilization efficiency was almost constant
with an average value of 0.92 (12–216 h). The maximum value of cell retention was 0.24 g immobilized cells/g gel. Both parameters
indicated that lyophilized gels are stable and capable of retaining the immobilized yeast cells. Showing the yeast cells propagation
within the polymeric matrix, the scanning electron microscope images also confirmed that the lyophilization technique for
immobilization of S. cerevisiae cells in the HEC gels was successful. The activity of the immobilized yeast cells was demonstrated by their capacity to convert
glucose to ethanol. Ethanol yield of 0.40, 0.43 and 0.30 g ethanol/g glucose corresponding to 79%, 84% and 60% of the theoretical
yield was attained in the first, second and third batches, respectively. The cell leakage was less than 10% of the average
concentration of the immobilized cells. 相似文献
12.
A feeding technology that was suitable for improving the nisin production by Lactococcus lactis subsp. lactis W28 was established. The effects of initial sucrose concentration (ISC) in the fermentation broth, feeding time, and feeding
rate on the fermentation were studied. It was observed that a fed-batch culture (ISC = 10 g l−1) with 100 ml sucrose solution (190 g l−1) being evenly fed (9–10 ml h−1) into the fermenter after 3-h fermentation gave the best performance in terms of biomass and nisin yield. Under these conditions,
the total biomass and the total nisin yield were approximately 23% and 51% higher than those in batch fermentation, respectively.
When the sucrose concentration was controlled at 5–10 g l−1 in variable volume intermittent fed-batch fermentation (VVIF) with ISC = 10 g l−1, the total biomass and the total nisin yield were 29% and 60% above those in batch fermentation, respectively. The VVIF proved
to be effective to eliminate the substrate inhibition by maintaining sucrose at appropriate levels. It is also easy to be
scaled up, since various parameters involved in industrial production were taken into account. 相似文献
13.
Nikolay Vassilev Almudena Medina Bettina Eichler-Löbermann Elena Flor-Peregrín Maria Vassileva 《Applied biochemistry and biotechnology》2012,168(5):1311-1318
Cells of Aspergillus terreus, free and immobilized in polyurethane foam, were employed in itaconic acid fermentation processes on glycerol-based media. The purpose was to assess their suitability for animal bone char solubilization and the development of a biotechnological alternative to P fertilizers chemically produced from rock phosphate. Animal bones constitute a renewable source of P that can replace the traditionally used finite, nonrenewable rock phosphate as a P source. Glycerol was an excellent substrate for growth (10.2 g biomass L?1) and itaconic acid production (26.9 g?L?1) by free fungal cells after 120-h fermentation. Simultaneously, A. terreus solubilized the insoluble phosphate to a yield of 23 to 50 %, depending on the particle size and concentration. Polyurethane foam cut into cubes of 0.5–0.6 cm per side, with 0.3 mm pore size and applied at 2.0 g?L?1 proved to be an excellent cell carrier. In repeated batch fermentation, the immobilized mycelium showed a high capacity to solubilize animal bone char, which resulted on average in 168.8 mg?L–1 soluble phosphate per 48-h cycle and 59.4 % yield (percent of total phosphate) registered in the fourth batch. 相似文献
14.
Surface-engineered yeast Saccharomyces cerevisiae codisplaying Rhizopus oryzae glucoamylase and Streptococcus bovis α-amylase on the cell surface was used for direct production of ethanol from uncooked raw starch. By using 50 g/L cells during
batch fermentation, ethanol concentration could reach 53 g/L in 7 days. During repeated batch fermentation, the production
of ethanol could be maintained for seven consecutive cycles. For cells immobilized in loofa sponge, the concentration of ethanol
could reach 42 g/L in 3 days in a circulating packed-bed bioreactor. However, the production of ethanol stopped thereafter
because of limited contact between cells and starch. The bioreactor could be operated for repeated batch production of ethanol,
but ethanol concentration dropped to 55% of its initial value after five cycles because of a decrease in cell mass and cell
viability in the bioreactor. Adding cells to the bioreactor could partially restore ethanol production to 75% of its initial
value. 相似文献
15.
The effects of oxygen limitation on xylose fermentation of Neurospora crassa AS3.1602 were studied using batch cultures. The maximum yield of ethanol was 0.34 g/g at oxygen transfer rate (OTR) of 8.4 mmol/L·h.
The maximum yield of xylitol was 0.33 g/g at OTR of 5.1 mmol/L·h. Oxygen limitation greatly affected mycelia growth and xylitol
and ethanol productions. The specific growth rate (μ) decreased 82% from 0.045 to 0.008 h−1 when OTR changed from 12.6 to 8.4 mmol/L·h. Intracellular metabolites of the pentose phosphate pathway, glycolysis, and tricarboxylic
acid cycle were determined at various OTRs. Concentrations of most intracellular metabolites decreased with the increase in
oxygen limitation. Intracellular enzyme activities of xylose reductase, xylitol dehydrogenase, and xylulokinase, the first
three enzymes in xylose metabolic pathway, decreased with the increase in oxygen limitation, resulting in the decreased xylose
uptake rate. Under all tested conditions, transaldolase and transketolase activities always maintained at low levels, indicating
a great control on xylose metabolism. The enzyme of glucose-6-phosphate dehydrogenase played a major role in NADPH regeneration,
and its activity decreased remarkably with the increase in oxygen limitation. 相似文献
16.
Clostridium acetobutylicum strains used in most Chinese ABE (acetone–butanol–ethanol) plants favorably ferment starchy materials like corn, cassava,
etc., rather than sugar materials. This is one major problem of ABE industry in China and significantly limits the exploitation
of cheap waste sugar materials. In this work, cane molasses were utilized as substrate in ABE production by Clostridium saccharobutylicum DSM 13864. Under optimum conditions, total solvent of 19.80 g/L (13.40 g/L butanol) was reached after 72 h of fermentation
in an Erlenmeyer flask. In a 5-L bioreactor, total solvent of 17.88 g/L was attained after 36 h of fermentation, and the productivity
and yield were 0.50 g/L/h and 0.33 g ABE/g sugar consumption, respectively. To further enhance the productivity, a two-stage
semicontinuous fermentation process was steadily operated for over 8 days (205 h, 26 cycles) with average productivity (stage
II) of 1.05 g/L/h and cell concentration (stage I) of 7.43 OD660, respectively. The average batch fermentation time (stage I and II) was reduced to 21−25 h with average solvent of 15.27 g/L.
This study provides valuable process data for the development of industrial ABE fermentation process using cane molasses as
substrate. 相似文献
17.
In this study, we evaluated the feasibility of solid-state fermentation (SSF) on polyurethane foam (PUF) for xanthan production.
The effects of air pressure pulsation (APP) on biomass accumulation and final xanthan concentration were also studied. Under
suitable conditions (15% inoculum, 0.5-cm (side length) PUF cubes, 15 mL medium per gram cubes and 4.5 cm bed depth), the
broth was dispersed on the PUF as a film. When the initial glucose concentration in the media was low (20 and 40 g L−1), there was no significant difference between the final xanthan concentration in static SSF and submerged fermentation (SMF).
When high initial glucose concentrations (60 and 80 g L−1) were used, the final gum concentrations in SSF were much higher than those in SMF. When the APP technique was applied in
xanthan production with a medium containing a high glucose concentration (80 g L−1), the oxygen consumption rate of Xanthomonas campestris was significantly enhanced at the later stages of fermentation, and both the biomass and xanthan concentration were improved.
The results indicated that SSF on PUF is suitable for xanthan preparation, especially when the initial glucose concentration
ranged from 60 to 80 g L−1. Those results also demonstrated that APP technology can be used to enhance xanthan yields. 相似文献
18.
Screening of a growing cell immobilization procedure for the biosynthesis of thermostable α-amylases
V. Ivanova M. Stefanova A. Tonkova E. Dobreva D. Spassova 《Applied biochemistry and biotechnology》1995,50(3):305-316
Studies were carried out on α-amylase production with immobilized cells of twoBacillus strains. High yields of thermostable αamylases were obtained byBacillus licheniformis 44MB82-G, resistant to glucose catabolite repression and a thermophileBacillus brevis 174, after repeated batch cultivation (270–600 h) of the immobilized biocatalysts. Various cell immobilization techniques
were compared, including entrapment in gel matrices (Ca-alginate,x-carrageenan, agar, and their combinations with polyethylene oxide), adsorption on cut disks of polymerized polyethylene oxide,
and fixation on formaldehyde activated acrylonitrile-acrylamide membranes. The optimal immobilization parameters (gel and
biocatalyst concentration, initial cell quantity) were determined. Among the gels and supports tested, agar,x-carrageenan, agar/polyethylene oxide gels, and the membranes were found to be suitable for immobilization and biocatalysts
with high operational stabilities were obtained. An enzyme yield of 2750 U/mL culture medium was reached in the fifth repeated
batch run with membrane-immobilizedBacillus licheniformis cells. This activity represented 176% of the corresponding yield obtained in batch fermentation with free cells. Higher amylase
yields than the activity of the control were reached in all experiments and repeated batch runs with immobilizedBacillus brevis cells. 相似文献
19.
Isomaltulose was obtained from sucrose solution by immobilized cells of Erwinia sp. D12 using a batch and a continuous process. Parameters for sucrose conversion into isomaltulose were evaluated using
both experimental design and response surface methodology. Erwinia sp. D12 cells were immobilized in different alginates, and the influence of substrate flow rate and concentration parameters
to produce isomaltulose from sucrose were observed. Response surface methodology demonstrated that packed bed columns containing
cells immobilized in low-viscosity sodium alginate (250 cP) presented a mean isomaltulose conversion rate of 47%. In a continuous
process, both sucrose substrate concentration and substrate flow rate parameters had a significant effect (p < 0.05) and influenced the conversion of sucrose into isomaltulose. Higher conversion rates of sucrose into isomaltulose,
from 53–75% were obtained using 75 g of immobilized cells at a substrate flow rate of 0.6 mL/min. 相似文献
20.
The production of propionic acid by Propionibacterium freudenreichii CCTCC M207015 was investigated in a 7.5-l stirred-tank fermentor. Batch fermentations by P. freudenreichii CCTCC M207015 at various pH values ranging from 5.5 to 7.0 were studied. Based on the analysis of the time course of specific
cell growth rate (μ
x) and specific propionic acid formation rate (μ
p), a two-stage pH-shift control strategy was proposed. At first 48 h, pH was controlled at 6.5 to obtain the maximal μ
x, subsequently pH 6.0 was used to maintain high μ
p to enhance the production of propionic acid. By applying this pH-shift control strategy in propionic acid fermentation, the
maximal propionic acid and glucose conversion efficiency had a significant improvement and reached 19.21 g/l and 48.03%, respectively,
compared with those of constant pH operation (14.58 g/l and 36.45%). Fed-batch fermentation with pH-shift control strategy
was also applied to produce propionic acid; the maximal propionic acid yield and glucose conversion efficiency reached 25.23 g/l
and 47.76%, respectively. 相似文献