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1.
Submerged culture fermentation studies were carried out in batch mode for optimizing the environmental parameters and carbon
source requirement by Pseudomonas elodea for the production of gellan gum. The maximum production of gellan gum was obtained with 16-h-old culture and 8% inoculum
at 30°C and pH 7.0 after 52 h of incubation (6.0 g/L). Of the various carbon sources tested, 2% sucrose, glucose, and soluble
starch yielded considerably high amounts of gellan. Studies on the concentration of various carbohydrates on gellan gum production
indicated that the optimum concentration of glucose and starch was 3%, whereas for sucrose it was 4%. The addition of glucose
in the medium above 3% had a detrimental effect on gellan yield. The investigation of intermediate two-step addition of glucose
under identical conditions of fermentation showed an enhanced production of gellan (8.12 g/L) as compared with the control
(6.0 g/L). To optimize the recovery of gellan from fermented broth, different solvents were tested for precipitation of gellan
gum. Among the various solvents tested, tetrahydrofuran gave better recovery of gellan (82%) as compared with the conventional
solvent isopropanol (49%). 相似文献
2.
Zsófia Kádár Truus de Vrije Giel E. van Noorden Miriam A. W. Budde Zsolt Szengyel Kati Réczey Pieternel A. M. Claassen 《Applied biochemistry and biotechnology》2004,114(1-3):497-508
This study addressed the utilization of an industrial waste stream, paper sludge, as a renewable cheap feedstock for the fermentative
production of hydrogen by the extreme thermophile Caldicellulosiruptor saccharolyticus. Hydrogen, acetate, and lactate were produced in medium in which paper sludge hydrolysate was added as the sole carbon and
energy source and in control medium with the same concentration of analytical grade glucose and xylose. The hydrogen yield
was dependent on lactate formation and varied between 50 and 94% of the theoretical maximum. The carbon balance in the medium
with glucose and xylose was virtually 100%. The carbon balance was not complete in the paper sludge medium because the measurement
of biomass was impaired owing to interfering components in the paper sludge hydrolysate. Nevertheless, >85% of the carbon
could be accounted for in the products acetate and lactate. The maximal volumetric hydrogen production rate was 5 to 6 mmol/(L·h),
which was lower than the production rate in media with glucose, xylose, or a combination of these sugars (9–11 mmol/[L·h]).
The reduced hydrogen production rate suggests the presence of inhibiting components in paper sludge hydrolysate. 相似文献
3.
Freire Denise M. Teles Elaine M. F. Bon Elba P. S. Anna Geraldo Lippel Sant’ 《Applied biochemistry and biotechnology》1997,(1):409-421
A preliminary screening work selectedPenicillium restrictum as a promising micro-organism for lipase production. The physiological response of the fungus towards cell growth and enzyme
production upon variable carbon and nitrogen nutrition, specific air flow rate (Qa) and agitation (N) was evaluated in a 5-L
bench-scale fermenter. In optimized conditions for lipase production meat peptone at 2% (w/v) and olive oil at 1% (w/v) were
used in a growth medium with a C/N ratio of 9.9. Higher C/N ratios favored cell growth in detriment of enzyme production.
Low extracellular lipase activities were observed using glucose as carbon source suggesting glucose regulation. Final lipase
accumulation of 13,000 U/L was obtained, using optimized specific air flow rate (Qa) of 0.5 wm and an impeller speed (N) of
200 rpm. Agitation showed to be an important parameter to ensure nutrient availability in a growth medium having olive oil
as carbon source. 相似文献
4.
Melissa L. E. Gutarra Elisa D. C. Cavalcanti Leda R. Castilho Denise M. G. Freire Geraldo L. Sant’Anna Jr. 《Applied biochemistry and biotechnology》2005,121(1-3):105-116
The production of lipase by Penicillium simplicissimum in solid-state fermentation was studied using babassu cake as the basal medium. Tray-type and packed-bed bioreactors were employed. In the former, the influence of temperature; content of the medium, and medium supplementation with olive oil, sugarcane molasses, corn steep liquor, and yeast hydrolysate was studied. For all combinations of supplements, a temperature of 30°C, a moisture content of 70%, and a concentration of carbon source of 6.25% (m/m, dry basis) provided optimum conditions for lipase production. When used as single supplements olive oil and molasses also were able to provide high lipase activities (20 U/g). Using packed-bed bioreactors and molasses-supplemented medium, optimum conditions for enzyme production were air superficial velocities above 55 cm/min and temperatures below 28°C. The lower temperature optimum found for these reactors is probably related to radial heat gradient formation inside the packed bed. Maximum lipase activities obtained in these bioreactors (26.4 U/g) were 30% higher than in tray-type reactors. 相似文献
5.
Réczey K. Brumbauer A. Bollók M. Szengyel Zs. Zacchi G. 《Applied biochemistry and biotechnology》1998,(1):225-235
Hydrolysis of cellulose byTrichoderma cellulases often results in a mixture of glucose, cellobiose, and low-mol-wt cellodextrins. Cellobiose is nonfermentable
for most yeasts, and therefore it has to be hydrolyzed to glucose by β-glucosidase prior to ethanol fermentation. In the present
study, the β-glucosidase production of onePenicillium and threeAspergillus strains, which were previously selected out of 24 strains, was investigated on steam pretreated willow. Both steam-pretreated
willow and hemicellulose hydrolysate, released during steam explosion of willow, were used as carbon sources. Reference cultivation
runs were performed using prehydrolyzed Solka Floc and glucose: The four strains were compared withTrichoderma reesei regarding sugar consumption and β-glucosidase production.Aspergillus niger andAspergillus phoenicis proved to be the best enzyme producers on hemicellulose hydrolysate. The maximum β-glucosidase activity, 4.60 IU/mL, was
obtained whenA. phoenicis was cultivated on the mixture of hemicellulose hydrolysate and steam-pretreated willow. The maximum yield of enzyme activity,
502 IU/g total carbohydrate, was obtained whenAspergillus foetidus was cultivated on the hemicellulose hydrolysate. 相似文献
6.
7.
Woiciechowski AL Soccol CR Rocha SN Pandey A 《Applied biochemistry and biotechnology》2004,118(1-3):305-312
Cassava bagasse was hydrolyzed using HCl and the hydrolysate was used for the production of xanthan gum using a bacterial
culture of Xanthomonas campestris. Cassava bagasse hydrolysate with an initial concentration of approx 20 g of glucose/L proved to be the best substrate concentration
for xanthan gum production. Among the organic and inorganic nitrogen sources tested to supplement the medium—urea, yeast extract,
peptone, potassium nitrate, and ammonium sulfate—potassium nitrate was most suitable. Ammonium sulfate was the least effective
for xanthan gum production, and it affected sugar utilization by the bacterial culture. In media with an initial sugar concentration
of 48.6 and 40.4 g/L, at the end of fermentation about 30 g/L of sugars was unused. Maximum xanthan gum (about 14 g/L) was
produced when fermentation was carried out with a medium containing 19.8 g/L of initial reducing sugars supplemented with
potassium nitrate and fermented for 72 h, and it remained almost the same until the end of fermentation (i.e., 96 h). 相似文献
8.
Dilute acid hydrolysate of corn fiber was used as carbon source for the production of succinic acid by Actinobacillus succinogenes NJ113. The optimized hydrolysis conditions were obtained by orthogonal experiments. When corn fiber particles were of 20
mesh in size and treated with 1.0% sulfuric acid at 121 °C for 2 h, the total sugar yield could reach 63.3%. It was found
that CaCO3 neutralization combined with activated carbon adsorption was an effective method to remove fermentation inhibitors especially
furfural that presented in the acid hydrolysate of corn fiber. Only 5.2% of the total sugar was lost, while 91.9% of furfural
was removed. The yield of succinic acid was higher than 72.0% with the detoxified corn fiber hydrolysate as the carbon source
in anaerobic bottles or 7.5 L fermentor cultures. It was proved that the corn fiber hydrolysate could be an alternative to
glucose for the production of succinic acid by A. succinogenes NJ113. 相似文献
9.
Jacqueline Destain Patrick Fickers Frédéric Weekers Benoît Moreau Philippe Thonart 《Applied biochemistry and biotechnology》2005,121(1-3):269-277
In this article, we report the development and optimization of an industrial culture medium for the production of extracellular
lipase in the yeast Yarrowia lipolytica. Until now olive oil in combination with glucose was used as the carbon source and inducer for the production of lipase.
Our results demonstrate that methyloleate, a cheap hydrophobic compound, could efficiently substitute olive oil as the inducer
and carbon source for lipase production. A new process of lipase production was developed yielding a twofold increase in the
level of production compared with the levels in previous reports. 相似文献
10.
Lim JM Kim SW Hwang HJ Joo JH Kim HO Choi JW Yun JW 《Applied biochemistry and biotechnology》2004,119(2):159-170
Optimization of submerged culture conditions for the production of mycelial growth and exopolysaccharides (EPSs) by Collybia maculata was investigated. The optimum temperature and the initial pH for EPS production in a shake-flask culture of C. maculata were found to be 20°C and 5.5, respectively. Among the various medium’s constituents examined, glucose, Martone A-1, K2HPO4, and CaCl2 were the most suitable carbon, nitrogen, and mineral sources for EPS production, respectively. The optimum concentration
of the medium’s ingredients determined using the orthogonal matrix method was as follows: 30 g/L of glucose, 20 g/L of Martone
A-1, 1g/L of K2HPO4, and 1g/L of CaCl2. Under the optimized culture conditions, the maximum concentration of EPSs in a 5-L stirred-tank reactor was 2.4 g/L, which
was approximately five times higher than that in the basal medium. A comparative fermentation result showed that the EPS productivity
in an airlift reactor was higher than that in the stirred-tank reactor despite the lower mycelial growth rate. The specific
productivities and the yield coefficients in the airlift reactor were higher than those in the stirred-tank reactor even though
the volumetric productivities were higher in the stirred-tank reactor than in the airlift reactor. 相似文献
11.
Woo Gi Lee Jin Suk Lee Chul Seung Shin Soon Chul Park Ho Nam Chang Yong Keun Chang 《Applied biochemistry and biotechnology》1999,78(1-3):547-559
Ethanol production from concentrated oak wood hydrolysate was carried out to obtain a high ethanol concentration and a high
ethanol yield. The effect of added inhibitory compounds, which are typically produced in the pretreatment step of steam-explosion
on ethanol fermentation, was also examined. p-Hydroxybenzoic aldehyde, a lignin-degradation product, was the most inhibitory compound tested in this study. Compounds with
additional methyl groups had reduced toxicity and the aromatic acids were less toxic than the corresponding aldehydes. The
lignin-degradation products were more inhibitory than the sugar-derived products, such as furfural and 5-hydroxymethylfurfural
(HMF). Adaptation of yeast cells to the wood hydrolysate and detoxification methods, such as using charcoal and overlime,
had some beneficial effects on ethanol production using the concentrated wood hydrolysate. After treatment with charcoal and
low-temperature sterilization, the yeast cells could utilize the concentrated wood hydrolysate with 170 as well as 140 g/L
glucose, and produce 69.9 and 74.2 g/L ethanol, respectively, with a yield of 0.46–0.48 g ethanol/g glucose. In contrast,
the cells could not completely utilize untreated wood hydrolysate with 100 g/L glucose. Low-temperature sterilization, with
or without charcoal treatment, was very effective for ethanol production when highly concentrated wood hydrolysates were used.
Low-temperature sterilization has advantages over traditional detoxification methods, such as using overlime, ion exchange,
and charcoal, because of the reduction in the total cost of ethanol production. 相似文献
12.
A bacterial strain isolated from spoiled coconut and identified as Bacillus cereus was found capable of producing alkaline thermostable extracellular lipase. Optimum temperature, time, and pH for enzyme substrate
reaction were found to be 60 °C, 10 min, and 8.0 respectively. Common surfactants except Triton X 100 and cetyltrimethylammonium
bromide have no or very little inhibitory effects on enzyme activity. The enzyme was found to be stable in presence of oxidizing
agents and protease enzyme. The maximum lipase production was achieved at 30–33 °C, pH 8.0 on 24 h of fermentation using 50 ml
medium in a 250-ml Erlenmeyer flask. The superior carbon and nitrogen sources for lipase production were starch (2%) and ammonium
sulfate (nitrogen level 21.2 mg/100 ml), peptone (nitrogen level 297 mg/100 ml), and urea (nitrogen level 46.62 mg/100 ml)
in combination, respectively. The maximum enzyme activity obtained was 33 ± 0.567 IU/ml. 相似文献
13.
M. C. B. Pimentel N. Krieger L. C. C. B. Coelho J. O. Fontana E. H. M. Melo W. M. Ledingham J. L. Lima Filho 《Applied biochemistry and biotechnology》1994,49(1):59-74
A lipases (glycerol ester hydrolases E. C. 3.1.1.3) from a brazilian strain ofPenicillium citrinum has been investigated. When the microorganism was cultured in the simple medium (1.0% olive oil and 0.5% yeast extract),
using olive oil in as carbon source in the inocula, the enzyme extracted showed maximum activity (409 IU/mL). In addition,
decrease of yeast extract concentration also reduces the lipase activity. Nevertheless, when yeast extract was replaced by
ammonium sulfate, no activity was detected. Purification by precipitation with ammonium sulfate showed best activity in the
40–60% fraction. The optimum temperature for enzyme activity was found in the range of 34–37°C. However, after 30 min at 60°C,
the enzyme was completely inactivated. The enzyme showed optimum at pH 8.0. The dried concentrated fraction (after dialysis
and lyophilization) maintained its lipase activity at room temperature (28°C) for 8 mo. This result in lipase stability suggests
an application of lipases fromP. citrinum in detergents and other products that require a high stability at room temperature. 相似文献
14.
Production of an extracellular lipase from Serratia marcescens ECU1010, which is an industrially important biocatalyst for the stereospecific synthesis of Diltiazem precusor, was carefully
optimized in both shake flasks and a fermenter, using Tween-80 as the enzyme inducer. Dextrin and beef extract combined with
ammonium sulfate were indicated to be the best carbon and nitrogen sources, respectively. With the increase of Tween-80 from
0 to 10 g l−1, the lipase production was greatly enhanced from merely 250 U l−1 to a maximum of 3,340 U l−1, giving the highest lipase yield of ca 640 U g−1 dry cell mass (DCW), although the maximum biomass (6.0 g DCW l−1) was achieved at 15 g l−1 of Tween-80. When the medium loading in shake flasks was reduced from 20 to 10% (v / v), the lipase production was significantly enhanced. The increase in shaking speed also resulted in an improvement of the
lipase production, although the cell growth was slightly repressed, suggesting that the increase of dissolved oxygen (DO)
concentration contributed to the enhancements of lipase yield. When the lipase fermentation was carried out in a 5-l fermenter,
the lipase production reached a new maximum of 11,060 U l−1 by simply raising the aeration rate from 0.5 to 1.0 vvm, while keeping the dissolved oxygen above 20% saturation via intermittent
adjustment of the agitation speed (≥400 rpm), in the presence of a relatively low concentration (2 g l−1) of Tween-80 to prevent a potential foaming problem, which is easy to occur in the intensively aerated fermenter. 相似文献
15.
Nisha V. Ramadas Carlos R. Soccol Ashok Pandey 《Applied biochemistry and biotechnology》2010,162(4):996-1007
The aim of this work was to statistically optimize the cultural and nutritional parameters for the production of polyhydroxybutyrate (PHB) under submerged fermentation using jackfruit seed hydrolysate as the sole carbon source. On the basis of results obtained from “one variable at a time” experiment, inoculum age, jackfruit seed hydrolysate concentration, and pH were selected for response surface methodology studies. A central composite design (CCD) was employed to get the optimum level of these three factors to maximize the PHB production. The CCD results predicted that jackfruit seed hydrolysates containing 2.5% reducing sugar, inoculum age of 18 h, and initial medium pH 6 could enhance the production of PHB to reach 49% of the biomass (biomass 4.5 g/l and PHB concentration 2.2 g/l). Analysis of variance exhibited a high coefficient of determination (R 2) value of 0.910 and 0.928 for biomass and PHB concentration, respectively, and ensured that the quadratic model with the experimental data was a satisfactory one. This is the first report on PHB production by Bacillus sphaericus using statistical experimental design and RSM in submerged fermentation with jackfruit seed hydrolysate as the sole source of carbon. 相似文献
16.
In scale-up, the potential of ethanol production by dilute sulfuric acid pretreatment using corncob was investigated. Pretreatments were performed at 170 °C with various acid concentrations ranging from 0% to 1.656% based on oven dry weight. Following pretreatment, pretreated biomass yield ranged from 59% to 67%. More than 90% of xylan was removed at 0.828% of sulfuric acid. At same pretreatment condition, the highest glucose yield obtained from pretreated biomass by enzymatic hydrolysis was about 76%, based on a glucan content of 37/100 g. In hydrolysate obtained by pretreatment, glucose concentration was low, while xylose concentration was significantly increased above 0.368% of sulfuric acid. At 1.656% of sulfuric acid, xylose and glucose concentration was highest. In subsequent, fermentation with hydrolysate, maximal ethanol yield was attained after 24 h with 0.368% of sulfuric acid. The fermentation efficiency of hydrolysate obtained by enzymatic hydrolysis reached a maximum of 75% at an acid charge of 0.368%. 相似文献
17.
Silva NL Betancur GJ Vasquez MP Gomes Ede B Pereira N 《Applied biochemistry and biotechnology》2011,163(7):928-936
Current research indicates the ethanol fuel production from lignocellulosic materials, such as residual wood chips from the
cellulose industry, as new emerging technology. This work aimed at evaluating the ethanol production from hemicellulose of
eucalyptus chips by diluted acid pretreatment and the subsequent fermentation of the generated hydrolysate by a flocculating
strain of Pichia stipitis. The remaining solid fraction generated after pretreatment was subjected to enzymatic hydrolysis, which was carried out simultaneously
with glucose fermentation [saccharification and fermentation (SSF) process] using a strain of Saccharomyces cerevisiae. The acid pretreatment was evaluated using a central composite design for sulfuric acid concentration (1.0–4.0 v/v) and solid to liquid ratio (1:2–1:4, grams to milliliter) as independent variables. A maximum xylose concentration of 50 g/L
was obtained in the hemicellulosic hydrolysate. The fermentation of hemicellulosic hydrolysate and the SSF process were performed
in bioreactors and the final ethanol concentrations of 15.3 g/L and 28.7 g/L were obtained, respectively. 相似文献
18.
Mantzouridou F Roukasa T Kotzekidoua P Liakopoulou M 《Applied biochemistry and biotechnology》2002,101(2):153-175
The effect of inoculum, pH, carbon and nitrogen source, natural oils, fatty acids, antioxidant, and precursors on beta-carotene production by Blakeslea trispora in shake-flask culture was investigated. The highest concentration of beta-carotene was obtained in the medium (pH 7.0) inoculated with one loop of each culture. Sucrose, glycerol, cornmeal, soy protein acid hydrolysate, and distiller's solubles did not improve the production of beta-carotene. By contrast, glucose, corn steep liquor, antioxidant, olive oil, soybean oil, cottonseed oil, oleic and linoleic acids, and kerosene significantly increased the beta-carotene production. A central composite design was employed to determine the maximum beta-carotene production at optimum values for the process variables (linoleic acid, kerosene, and antioxidant). The fit of the model was found to be good. Linoleic acid, kerosene, and antioxidant had a strong linear effect on beta-carotene production. The concentration of beta-carotene was significantly affected by linoleic acid-kerosene and linoleic acid-antioxidant interactions as well as by the negative quadratic effects of these variables. The interaction between kerosene and antioxidant had no significant linear effect. The maximum beta-carotene concentration (2.88 g/L) was obtained at concentrations of 17.15 g/L of linoleic acid, 39.25 g/L of kerosene, and 9.04 g/L of antioxidant. 相似文献
19.
Xiaofeng Wang Yongchuan Sun Feng Ke Heyun Zhao Tao Liu Li Xu Yun Liu Yunjun Yan 《Applied biochemistry and biotechnology》2012,166(5):1355-1367
A gene encoding Yarrowia lipolytica lipase LIP2 (YlLIP2) was cloned into a constitutive expression vector pGAPZαA and electrotransformed into the Pichia pastoris X-33 strain. The high-yield clones obtained by high copy and enzyme activity screening were chosen as the host strains for
shaking flask and fermentor culture. The results showed that glucose was the optimum carbon source for YlLIP2 production,
and the maximum hydrolytic activity of recombinant YlLIP2 reached 1,315 U/ml under the flask culture at 28 °C, pH 7.0, for
48 h. The fed-batch fermentation was carried out in 3- and 10-l bioreactors by continuously feeding glucose into the growing
medium for achieving high cell density and YlLIP2 yields. The maximum hydrolytic activity of YlLIP2 and cell density obtained
in the 3-l bioreactor were 10,300 U/ml and 116 g dry cell weight (DCW)/l, respectively. The peak hydrolytic activity of YlLIP2
and cell density were further improved in the 10-l fermentor where the values respectively attained were 13,500 U/ml and 120 g
DCW/l. The total protein concentration in the supernatant reached 3.3 g/l and the cell viability remained approximately 99%
after 80 h of culture. Furthermore, the recombinant YlLIP2 produced in P. pastoris pGAP and pAOX1 systems have similar content of sugar (about 12%) and biochemical characteristics. The above results suggest
that the GAP promoter-derived expression system of P. pastoris is effective for the expression of YlLIP2 by high cell density culture and is probably an alternative to the conventional
AOX1 promoter expression system in large-scale production of industrial lipases. 相似文献
20.
Jeong Gwi-Taek Park Don-Hee Ryu Hwa-Won Lee Woo-Tai Park Kyungmoon Kang Choon-Hyoung Hwang Baik Woo Je-Chang 《Applied biochemistry and biotechnology》2002,98(1-9):1129-1139
Panax ginseng hairy roots were transformed by Agrobacterium rhizogenes KTCT 2744. They showed an active branching pattern and fast growth in hormone-free medium, and good growth at 23°C, pH 5.8,
1/2 MS medium, and 3% sucrose. Sucrose provided the highest growth among seven carbon sources tested. Six complex media were
also tested. In the combined sugar study, hairy roots grew better on sucrose without glucose or fructose than with glucose
or fructose. In the 1/2 MS basal medium, 30 mM in nitrogen and 0.62 mM phosphate salt concentration was the optimum. The growth ratio was maximal at an inoculum size of 0.4% (w/v). Crude saponin
and polysaccharide levels were also measured. 相似文献