共查询到20条相似文献,搜索用时 421 毫秒
1.
In this study, Streptomyces sp. Al-Dhabi-49 was isolated from the soil sample of Saudi Arabian environment for the simultaneous production of lipase and protease in submerged fermentation. The process parameters were optimized to enhance enzymes production. The production of protease and lipase was found to be maximum after 5 days of incubation (139.2 ± 2.1 U/ml, 253 ± 4.4 U/ml). Proteolytic enzyme increases with the increase in pH up to 9.0 (147.2 ± 3.6 U/ml) and enzyme production depleted significantly at higher pH values. In the case of lipase, production was maximum in the culture medium containing pH 8.0 (166 ± 1.3 U/ml). The maximum production of protease was observed at 40 °C (174 ± 12.1 U/ml) by Streptomyces sp. Lipase activity was found to be optimum at the range of temperatures (30–50 °C) and maximum production was achieved at 35 °C (168 ± 7.8 U/ml). Among the evaluated carbon sources, maltose significantly influenced on protease production (218 ± 12.8 U/ml). Lipase production was maximum when Streptomyces sp. was cultured in the presence of glucose (162 ± 10.8U/ml). Among various concentrations of peptone, 1.0% (w/v) significantly enhanced protease production. The lipase production was very high in the culture medium containing malt extract as nitrogen source (86 ± 10.2 U/ml). Protease production was maximum in the presence of Ca 2+ as ionic source (212 ± 3.8 U/ml) and lipase production was enhanced by the addition of Mg 2+ with the fermentation medium (163.7 ± 6.2 U/ml). 相似文献
2.
In this work, capability of Fusarium solani F-552 of producing lignocellulose-degrading enzymes in submerged fermentation was investigated. The enzyme cocktail includes
hydrolases (cellulases, xylanases, and proteinases) as well as ligninolytic enzymes: manganese-dependent peroxidase (MnP),
lignin peroxidase (LiP), and laccase (Lac). To our knowledge, this is the first report on production of MnP, LiP, and Lac
together by one F. solani strain. The enzyme productions were significantly influenced by application of either lignocellulosic material or chemical
inducers into the fermentation medium. Among them, corn bran significantly enhanced especially productions of cellulases and
xylanases (248 and 170 U/mL, respectively) as compared to control culture (11.7 and 29.2 U/mL, respectively). High MnP activity
(9.43 U/mL, control 0.45 U/mL) was observed when (+)-catechin was applied into the medium, the yield of LiP was maximal (33.06 U/mL,
control 2.69 U/mL) in gallic acid, and Lac was efficiently induced by, 2,2′-azino-bis-[3-ethyltiazoline-6-sulfonate] (6.74 U/mL,
not detected in control). Finally, in order to maximize the ligninolytic enzymes yields, a novel strategy of introduction
of mild oxidative stress conditions caused by hydrogen peroxide into the fermentation broth was tested. Hydrogen peroxide
significantly increased activities of MnP, LiP, and Lac which may indicate that these enzymes could be partially involved
in stress response against H 2O 2. The concentration of H 2O 2 and the time of the stress application were optimized; hence, when 10 mmol/L H 2O 2 was applied at the second and sixth day of cultivation, the MnP, LiP, and Lac yields reached 21.67, 77.42, and 12.04 U/mL,
respectively. 相似文献
3.
The production of extracellular pullulanase by Bacillus licheniformis NRC22 was investigated using different fermentation modes. In batch culture maximal enzyme activity of 18 U/ml was obtained
after 24 h of growth. In continuous fermentation by the free cells, maximal reactor productivity (4.15 KU/l/h) with enzyme
concentration of 14.8 U/ml and specific productivity of 334.9 U/g wet cells/h was attained at a dilution rate of 0.28/h, over
a period of 25 days. B. licheniformis NRC22 cells were immobilized on Ca-alginate. The immobilization conditions with respect to matrix concentration and cell
load was optimized for maximal enzyme production. In repeated batch operation, the activity of the immobilized cells was stable
during the 10 cycles and the activity remained between 9.8 and 7.7 U/ml. Continuous production of pullulanase by the immobilized
cells was investigated in a packed–bed reactor. Maximal reactor productivity (7.0 KU/h) with enzyme concentration of 16.8 U/ml
and specific productivity of 131.64 U/g wet cells/h was attained at dilution rate of 0.42/h. The enzyme activity in the effluent
started to decline gradually to the level of 8.7 U/ml after 25 days of the operation. 相似文献
4.
Phytase is used as a feed additive for degradation of antinutritional phytate, and the enzyme is desired to be highly thermostable
for it to withstand feed formulation conditions. A Bacillus sp. MD2 showing phytase activity was isolated, and the phytase encoding gene was cloned and expressed in Escherichia coli. The recombinant phytase exhibited high stability at temperatures up to 100°C. A higher enzyme activity was obtained when
the gene expression was done in the presence of calcium chloride. Production of the enzyme by batch- and fed-batch cultivation
in a bioreactor was studied. In batch cultivation, maintaining dissolved oxygen at 20–30% saturation and depleting inorganic
phosphate below 1 mM prior to induction by IPTG resulted in over 10 U/ml phytase activity. For fed–batch cultivation, glucose
concentration was maintained at 2–3 g/l, and the phytase expression was increased to 327 U/ml. Induction using lactose during
fed-batch cultivation showed a lag phase of 4 h prior to an increase in the phytase activity to 71 U/ml during the same period
as IPTG-induced production. Up to 90% of the total amount of expressed phytase leaked out from the E. coli cells in both IPTG- and lactose-induced fed-batch cultivations. 相似文献
5.
During the submerged cultivation of Trichoderma sp. 414 on a medium with 2% cellulose containing plant substrats an enzyme system – exocellobiohydrolase (C 1-enzyme), endogluconase (C x-enzyme), β-glucosidase and xylase – catalizing the cellulose hydrolysis was synthesized. The process of enzyme biosynthesis by the microbial strain under the conditions of two-step cultivation in flasks was optimized. The influence of different sources of carbohydrate – avicel, micricel, maize stalk and straw – on the activity of the synthesized enzymes was studied. This activity depends on induction properties and the concentration of the used substrats. During the cultivation of Trichoderma sp. 414 on a medium containing avicel and wheat bran the activity of cellobiohydrolase reaches 40 U/ml and this of endogluconase – 520 U/ml. When the cultivation was performed on a medium containing wheat bran and straw the activity of xylanase reaches 240 U/ml. 相似文献
6.
ObjectiveTo solve the bottleneck of plasmid instability during microbial fermentation of l-DOPA with recombinant Escherichia coli expressing heterologous tyrosine phenol lyase. ResultsThe tyrosine phenol lyase from Fusobacterium nucleatum was constitutively expressed in E. coli and a fed-batch fermentation process with temperature down-shift cultivation was performed. Efficient strategies including replacing the original ampicillin resistance gene, as well as inserting cer site that is active for resolving plasmid multimers were applied. As a result, the plasmid stability was increased. The co-use of cer site on plasmid and kanamycin in culture medium resulted in proportion of plasmid containing cells maintained at 100% after fermentation for 35 h. The specific activity of tyrosine phenol lyase reached 1493 U/g dcw, while the volumetric activity increased from 2943 to 14,408 U/L for l-DOPA biosynthesis. ConclusionsThe established strategies for plasmid stability is not only promoted the applicability of the recombinant cells for l-DOPA production, but also provides important guidance for industrial fermentation with improved microbial productivity. 相似文献
7.
In course of searching for proteolytic microbes from the gut of Gryllotalpa africana, a potent isolate GAP 12.4 was screened and identified as Kitasatospora cheerisanensis having protease activity 46.8?±?1.52?U/ml. Optimum conditions for the protease production (605.3?±?9.7?U/ml) were 7-d cultivation, 5% inoculum, pH 9.5, 55?°C, 150?rpm, and supplementation with 0.8% glucose and 0.6% ammonium sulfate. Surfactants such as SDS, EDTA, Tween 80 and Triton X-100 showed positive effect on enzyme production. Addition of biotin (50?μg/ml) promotes enzyme production maximally (674.15?±?4.13?U/ml). Further enhancement on addition of casein hydrolysate and molasses to the production medium was 709.20?±?7.53?U/ml and 744.26?±?9.71?U/ml, respectively. The isolate was also able to utilize agro-industries waste, green gram husk in solid-state fermentation for enzyme production (1675.02?±?21.58?U/ml). This thermo-alkaliphilic isolate may be a potent candidate for low cost protease production through management of agro-residues. It is the first report of protease production by a member of actinobacteria under the Kitasatospora genus. 相似文献
8.
In this study, in order to isolate inulinase overproducers from the marine yeast Pichia guilliermondii, its cells were treated by using UV light and LiCl. The mutant M-30 with enhanced inulinase production was obtained and was found to be stable after cultivation for 20 generations. Response surface methodology (RSM) was used to optimize the medium compositions and cultivation conditions for inulinase production by the mutant M-30 in liquid fermentation. Inulin, yeast extract, NaCl, temperature, pH for maximum inulinase production by the mutant M-30 were found to be 20.0 g/l, 5.0 g/l, 20.0 g/l, 28 °C and 6.5, respectively. Under the optimized conditions, 127.7 U/ml of inulinase activity was reached in the liquid culture of the mutant M-30 whereas the predicted maximum inulinase activity of 129.8 U/ml was derived from RSM regression. Under the same conditions, its parent strain only produced 48.1 U/ml of inulinase activity. This is the highest inulinase activity produced by the yeast strains reported so far. We also found that inulin could be actively converted into monosaccharides by the crude inulinase. 相似文献
9.
Parthenium hysterophorus biomass can be used as a non-conventional renewable feedstock for the production of bioethanol. Therefore, the present work was designed to hydrolyze P. hysterophorus biomass using cellulase enzyme produced from an actinomycete, i.e., Streptomyces sp. NAA2 using P. hysterophorus biomass as a substrate. The isolate NAA2 was identified by molecular characterization of 16SrDNA. The enzyme production by strain NAA2 was enhanced by optimization studies conducted under submerged fermentation conditions using P. hysterophorus as a substrate. The crude enzyme produced under optimized conditions was used to hydrolyze alkali-acid pretreated P. hysterophorus biomass. The highest CMCase production was achieved in 4–5 days when steam-pretreated P. hysterophorus biomass was used at 1% (w/v) concentration, using 2 discs (1 disc = 5 × 107 spores/ml) of inoculum, an initial pH 6.5, temperature at 40 °C, an agitation speed of 120–150 rpm, and by supplementing fermentation medium with 1.5% (w/v) carboxymethyl cellulose (CMC) as additional carbon source. Under optimized conditions, the actinomycete strain NAA2 showed production of 0.967 ± 0.016 U/ml CMCase, 0.116 ± 0.08 FPU/ml FPase, and 0.22 ± 0.012 U/ml β-glucosidase enzymes. On utilizing the cellulase enzyme for biomass hydrolysis, maximum 18.2% saccharification yield (of cellulose 0.202 g/g) was achieved in 96 h when enzyme and substrate levels were 30 FPU/100 ml and 2% (w/v) respectively. Parthenium hysterophorus biomass can be hydrolyzed enzymatically yielding considerable amounts of total reducing sugars. It can, therefore, be used as a feedstock for the production of bioethanol. Also, it has the potential to act as a substrate for the production of cellulases. Furthermore, the improved cellulolytic potential of Streptomyces sp. NAA2 can be exploited in various industrial applications. 相似文献
10.
The thermoalkalophilic Bacillus halodurans JB 99 cells known for production of novel thermostable alkaline keratinolytic protease were immobilized in calcium alginate
matrix. Batch and repeated batch cultivation using calcium alginate immobilized cells were studied for alkaline protease production
in submerged fermentation. Immobilized cells with 2.5% alginate and 350 beads/flask of initial cell loading showed enhanced
production of alkaline protease by 23.2% (5,275 ± 39.4 U/ml) as compared to free cells (4,280 ± 35.4 U/ml) after 24 h. In
the semicontinuous mode of cultivation, immobilized cells under optimized conditions produced an appreciable level of alkaline
protease in up to nine cycles and reached a maximal value of 5,975 U/ml after the seventh cycle. The enzyme produced from
immobilized cells efficiently degraded chicken feathers in the presence of a reducing agent which can help the poultry industry
in the management of keratin-rich waste and obtaining value-added products. 相似文献
11.
Ligninolytic enzyme production and polyphenolic compound extraction by liquid-state culture of Phanerochaete chrysosporium ATCC 24275 was investigated by employing apple pomace sludge and synthetic medium. Different physico-chemical and biological parameters namely viscosity, zeta potential and particle size, viability and enzyme production were investigated. The ligninolytic enzyme production was higher in apple pomace sludge (45 U/l of laccase, 220 U/l of MnP and 6.5 U/l of LiP) than in synthetic medium (17 U/l of laccase, 37 U/l of MnP and 6 U/l). These maximal activities were found during the stationary and decline phase. It was also found that enzyme production was strongly correlated with P. chrysoporium viability in both synthetic medium and apple pomace sludge. Moreover, physico-chemical parameters, such as particle size, zeta potential and viscosity were strongly correlated to the viability of P. chrysosporium and to the ligninolytic enzyme production. An increase in polyphenol content extracted by acetone (383–720 mg GAE/l) was observed during fermentation of apple pomace and it was found that the polyphenol content extracted by ethanol increased ~1.5 fold until 67 h of fermentation and later it decreased. It was found that antioxidant activity increased to 35% and eventually decreased based on the change in the polyphenol content. 相似文献
12.
Lipase production by Bacillus subtilis CICC20034 was assessed by metabolic flux distribution analysis. Lipase production was tested under various oxygen supply conditions in a synthetic medium to obtain the optimal oxygen supply profile. Based on the metabolic flux analysis, a two-stage oxygen supply strategy (TOS) that maintained high oxygen supply conditions during early fermentation phase, and then step-wisely reduced aeration to keep a stable, smooth, and adequate changing dissolved oxygen (DO) level profile throughout the production phases was carried out. With the proposed control strategy, the final lipase activity in batch fermentation significantly increased and reached a high level at 0.56 U/ml, corresponding to a 51% increase. The relevant metabolic flux analysis verified the effectiveness of the proposed control strategy. By applying TOS in composite medium, the final lipase activity reached 5.0 U/ml. 相似文献
13.
An alkaline endoglucanase from Bacillus akibai III-3A was successfully expressed in Escherichia coli in active form, and secretion was greatly enhanced by addition of 5 g/l ethylenediamine tetraacetic acid (EDTA) to the culture
medium at the induction time of 12 h. Under the optimal culture conditions, extracellular and total endoglucanase activities
were 18.5 and 31.2 U/ml, respectively. Both the recombinant and native enzymes exhibited similar properties with respect to
broad pH stability, good thermostability, and resistibility to various metal ions and reagents examined. However, unlike the
native endoglucanase that was partly inhibited by sodium dodecyl sulfate (SDS), the recombinant enzyme had good resistibility
to SDS, being very stable in the commercial detergents, and no decrease in residual activity was observed in 0.2% (w/v) laundry
detergent, indicating that it was suitable for application in detergents industry. 相似文献
14.
The fungus Aspergillus japonicus ATCC 20236 was immobilized in vegetal fiber and used in repeated batch fermentations of sucrose (200 g/l) for the production
of β-fructofuranosidases (FFase). The assays were performed during eight consecutive cycles that were completed in a total
period of 216 h. After each 24-h cycle of fermentation (except for the first cycle, which lasted 48 h), the fermented broth
was replaced by fresh medium, and the FFase activity was determined in the replaced medium. The average value of FFase activity
was a constant 40.6 U/ml at the end of the initial seven cycles, but had decreased by 22% at the end of the eighth cycle.
Concurrent with these high and constant FFase values, the hydrolyzing activity of this enzyme increased during the cycles,
while the transfructosylating activity decreased. As a consequence, the maximum production of fructooligosaccharides of 134.60 g/l
observed in the initial 30 h of fermentation (first cycle) had gradually decreased by the end of the subsequent cycles, reaching
approximately 23% of this value during cycles 4–8. Based on these results, we conclude that the present immobilization system
has a great potential for application in a semi-continuous process for the production of FFase, but further studies are necessary
to maintain the FFase transfructosylation activity at high levels during the overall process. 相似文献
15.
To develop an economical industrial medium, untreated cane molasses (UCM) was tested as a carbon source for fermentation culturing
of Escherichia coli. To test the industrial application of this medium, we chose a strain co-expressing a carbonyl reductase (PsCR) and a glucose
dehydrogenase (BmGDH). Although corn steep liquor (CSL) could be used as an inexpensive nitrogen source to replace peptone,
yeast extract could not be replaced in E. coli media. In a volume of 40 ml per 1-l flask, a cell concentration of optical density (OD 600) 15.1 and enzyme activities of 6.51 U/ml PsCR and 3.32 U/ml BmGDH were obtained in an optimized medium containing 25.66 g/l
yeast extract, 3.88 g/l UCM, and 7.1% ( v/ v) CSL. When 3.88 g/l UCM was added to the medium at 6 h in a fed-batch process, the E. coli concentration increased to OD 600 of 24, and expression of both PsCR and BmGDH were twofold higher than that of a batch process. Recombinant cells from batch
or fed-batch cultures were assayed for recombinant enzyme activity by testing the reduction of ethyl 4-chloro-3-oxobutanoate
to ethyl ( S)-4-chloro-3-hydroxybutanoate (CHBE). Compared to cells from batch cultures, fed-batch cultured cells showed higher recombinant
enzyme expression, producing 560 mM CHBE in the organic phase with a molar yield of 92% and an optical purity of the ( S)-isomer of >99% enantiomeric excess. 相似文献
16.
In order to isolate inulinase overproducers of the marine yeast Pichia guilliermondii, strain 1, cells were mutated by using UV light and LiCl 2. One mutant (M-30) with enhanced inulinase production was obtained. Response surface methodology (RSM) was used to optimize
the medium compositions and cultivation conditions for inulinase production by the mutant in solid-state fermentation. The
initial moisture, inoculum, the amount ratio of wheat bran to rice bran, temperature, pH for the maximum inulinase production
by the mutant M-30 were found to be 60.5%, 2.5%, 0.42, 30°C and 6.50, respectively. Under the optimized conditions, 455.9 U/grams
of dry substrate (gds) of inulinase activity was reached in the solid state fermentation culture of the mutant M-30 whereas
the predicted maximum inulinase activity of 459.2 U/gds was derived from RSM regression. Under the same conditions, its parent
strain only produced 291.0 U/gds of inulinase activity. This is the highest inulinase activity produced by the yeast strains
reported so far. 相似文献
17.
Because of the crucial role of ligninolytic enzymes in a variety of industrial processes, the demand for a new effective producer has been constantly increasing. Furthermore, information on enzyme synthesis by autochthonous fungal strains is very seldom found. Two fungal strains producing ligninolytic enzymes were isolated from Bulgarian forest soil. They were identified as being Trametes trogii and T. hirsuta. These two strains were assessed for their enzyme activities, laccase (Lac), lignin peroxidase (LiP) and Mn‐dependent peroxidase (MnP) in culture filtrate depending on the temperature and the type of nutrient medium. T. trogii was selected as the better producer of ligninolytic enzymes. The production process was further improved by optimizing a number of parameters such as incubation time, type of cultivation, volume ratio of medium/air, inoculum size and the addition of inducers. The maximum activities of enzymes synthesized by T. trogii was detected as 11100 U/L for Lac, 2.5 U/L for LiP and 4.5 U/L for MnP after 14 days of incubation at 25°C under static conditions, volume ratio of medium/air 1:6, and 3 plugs as inoculum. Among the supplements tested, 5% glycerol increased Lac activity to a significant extent. The addition of 1% veratryl alcohol had a positive effect on MnP. 相似文献
18.
The exploration of seven physiologically different white rot fungi potential to produce cellulase, xylanase, laccase, and
manganese peroxidase (MnP) showed that the enzyme yield and their ratio in enzyme preparations significantly depends on the
fungus species, lignocellulosic growth substrate, and cultivation method. The fruit residues were appropriate growth substrates
for the production of hydrolytic enzymes and laccase. The highest endoglucanase (111 U ml −1) and xylanase (135 U ml −1) activities were revealed in submerged fermentation (SF) of banana peels by Pycnoporus coccineus. In the same cultivation conditions Cerrena maxima accumulated the highest level of laccase activity (7,620 U l −1). The lignified materials (wheat straw and tree leaves) appeared to be appropriate for the MnP secretion by majority basidiomycetes.
With few exceptions, SF favored to hydrolases and laccase production by fungi tested whereas SSF was appropriate for the MnP
accumulation. Thus, the Coriolopsis polyzona hydrolases activity increased more than threefold, while laccase yield increased 15-fold when tree leaves were undergone
to SF instead SSF. The supplementation of nitrogen to the control medium seemed to have a negative effect on all enzyme production
in SSF of wheat straw and tree leaves by Pleurotus ostreatus. In SF peptone and ammonium containing salts significantly increased C. polyzona and Trametes versicolor hydrolases and laccase yields. However, in most cases the supplementation of media with additional nitrogen lowered the fungi
specific enzyme activities. Especially strong repression of T. versicolor MnP production was revealed. 相似文献
19.
The objective of this study was to determine the potential of Thermus thermophilus HB8 for accumulating a high level of extracellular, thermostable amylolytic enzyme. Initial production tests indicated clearly that only very low levels of amylolytic activity could be detected, solely from cells after extraction using the mild, non-ionic detergent Triton X-100. A sequential optimization strategy, based on statistical designs, was used to enhance greatly the production of extracellular amylolytic activity to achieve industrially attractive enzyme titers. Focus was placed on the optimal level of initial biomass concentration, culture medium composition and temperature for maximizing extracellular amylolytic enzyme accumulation. Empirical models were then developed describing the effects of the experimental parameters and their interactions on extracellular amylolytic enzyme production. Following such efforts, extracellular amylolytic enzyme accumulation was increased more than 70-fold, with enzyme titers in the 76 U/mL range. The crude extracellular enzyme was thereafter partially characterized. The optimal temperature and pH values were found to be 80 °C and 9.0, respectively. 100% of the initial enzyme activity could be recovered after incubation for 24 h at 80 °C, therefore, proving the very high thermostability of the enzyme preparation. 相似文献
20.
Optimization of the growth conditions for maximum β-mannanase production in shake flasks by using recombinant Aspergillus sojae ATCC11906 (AsT1) was carried out by Box–Behnken design of response surface methodology. The highest β-mannanase activity on the fourth day of cultivation at 30 °C was obtained as 363 U/ml in the optimized medium consisting of 7% sugar beet molasses, 0.43% NH 4NO 3, 0.1% K 2HPO 4 and 0.05% MgSO 4 (by weight per volume) at 207 rpm. On the sixth day of cultivation under the optimized conditions, the highest β-mannanase activity was achieved as 482 U/ml which is 1.4-fold of 352 U/ml activity found on glucose medium previously. 相似文献
|