共查询到20条相似文献,搜索用时 46 毫秒
1.
Claucia Fernanda Volken de Souza Júlio Xandro Heck Marco Antônio Záchia Ayub 《Journal of industrial microbiology & biotechnology》2008,35(12):1677-1685
In this work, we investigated the production of transglutaminase (TGase) by an Amazonian isolated strain of Bacillus circulans by solid-state cultivation (SSC). Several agro-industrial residues, such as untreated corn grits, milled brewers rice, industrial
fibrous soy residue, soy hull, and malt bagasse, were used as substrates for microbial growth and enzyme production. Growth
on industrial fibrous soy residue, which is rich in protein and hemicellulose, produced the highest TGase activity (0.74 U g−1 of dried substrate after 48 h of incubation). A 23 central composite design was applied to determine the optimal conditions of aeration, cultivation temperature and inoculum
cell concentration to TGase production. The best culture conditions were determined as being 0.6 L air min−1, 33 °C and 10 log 10 CFU g−1 of dried substrate, respectively. Under the proposed optimized conditions, the model predicted an enzyme production of 1.16 U g−1 of dried substrate, closely matching the experimental activity of 1.25 U g−1. Results presented in this work point to the use of this newly isolated B. circulans strain as a potential alternative of microbial source for TGase production by SSC, using inexpensive culture media. 相似文献
2.
The objective of this study was to use statistically based experimental designs for the optimization of xylanase production
from Alternaria mali ND-16. Ten components in the medium were screened for nutritional requirements. Three nutritional components, including NH4Cl, urea, and MgSO4, were identified to significantly affect the xylanase production by using the Plackett–Burman experimental design. These
three major components were subsequently optimized using the Doehlert experimental design. By using response surface methodology
and canonical analysis, the optimal concentrations for xylanase production were: NH4Cl 11.34 g L−1, urea 1.26 g L−1, and MgSO4 0.98 g L−1. Under these optimal conditions, the xylanase activity from A. mali ND-16 reached 30.35 U mL−1. Verification of the optimization showed that xylanase production of 31.26 U mL−1 was achieved. 相似文献
3.
Acid phosphatase production by recombinant Arxula adeninivorans was carried out in submerged fermentation. Using the Plackett–Burman design, three fermentation variables (pH, sucrose concentration,
and peptone concentration) were identified to significantly affect acid phosphatase and biomass production, and these were
optimized using response surface methodology of central composite design. The highest enzyme yields were attained in the medium
with 3.9% sucrose and 1.6% peptone at pH 3.8. Because of optimization, 3.86- and 4.19-fold enhancement in enzyme production
was achieved in shake flasks (17,054 U g−1 DYB) and laboratory fermenter (18,465 U g−1 DYB), respectively. 相似文献
4.
A cellulase-free xylanase production by Thermomyces lanuginosus SSBP using bagasse pulp was examined under submerged (SmC) and solid-state cultivation (SSC). Higher level of xylanase activity
(19,320 ± 37 U g−1 dried carbon source) was obtained in SSC cultures than in SmC (1,772 ± 15 U g−1 dried carbon source) after 120 h with 10% inoculum. The biobleaching efficacy of crude xylanase was tested on bagasse pulp,
and the maximum brightness of 46.1 ± 0.06% was observed with 50 U of crude xylanase per gram of pulp, which was 3.8 points
higher than the brightness of untreated samples. Reducing sugars (26 ± 0.1 mg g−1) and UV-absorbing lignin-derived compounds in the pulp filtrates were observed as maximum in 50 U of crude xylanase-treated
samples. T. lanuginosus SSBP has potential applications due to its high productivity of xylanase and its efficiency in pulp bleaching. 相似文献
5.
He Jun Yu Bing Zhang Keying Ding Xuemei Chen Daiwen 《Indian journal of microbiology》2009,49(2):188-195
The strain of Trichoderma reesei Rut C-30 was subjected to mutation after treatment with N-methyl-N′-nitro-N-nitrosoguanidine (NG) for 6 h followed by UV irradiation for 15 min. Successive mutants showed enhanced cellulase production,
clear hydrolysis zone and rapid growth on Avicel-containing plate. Particularly, the mutant NU-6 showed approximately two-fold
increases in activity of both FPA and CMCase in shake flask culture when grown on basal medium containing peptone (1%) and
wheat bran (1%). The enzyme production was further optimized using eight different media. When a mixture of lactose and yeast
cream was used as cellulase inducer, the mutant NU-6 yielded the highest enzyme and cell production with a FPase activity
of 6.2 U ml−1, a CMCase activity of 54.2 U ml−1, a β-glucosidase activity of 0.39 U ml−1, and a fungal biomass of 12.6 mg ml−1. It deserved noting that the mutant NU-6 also secreted large amounts of xylanases (291.3 U ml−1). These results suggested that NU-6 should be an attractive producer for both cellulose and xylanase production. 相似文献
6.
A novel phytase gene appA, with upstream and downstream sequences from Citrobacter amalonaticus CGMCC 1696, was cloned by degenerate polymerase chain reaction (PCR), and thermal asymmetric interlaced (TAIL) PCR and was
overexpressed in Pichia pastoris. Sequence analysis revealed one open reading frame that consisted of 1311 bp encoding a 436–amino-acid protein, which had
a deduced molecular mass of 46.3 kDa. The phytase appA belongs to the histidine acid phosphatase family and exhibits the highest
identity (70.1%) with C. braakii phytase. The gene was overexpressed in P. pastoris. The secretion yield of recombinant appA protein was accumulated to approximately 4.2 mg·mL−1, and the enzyme activity level reached 15,000 U·mL−1, which is higher than any previous reports. r-appA was glycosylated, as shown by Endo H treatment. r-appA was purified and
characterized. The specific activity of r-appA for sodium phytate was 3548 U·mg−1. The optimum pH and temperature for enzyme activity were 4.5 and 55°C, respectively. r-appA was highly resistant to pepsin
or trypsin treatment. This enzyme could be an economic and efficient alternative to the phytases currently used in the feed
industry. 相似文献
7.
This work was aimed at producing inulinase by solid-state fermentation of sugarcane bagasse, using factorial design to identify
the effect of corn steep liquor (CSL) and soybean bran concentration, particle size of bagasse and size of inoculum. Maximum
inulinase activity achieved was 250 U per g of dry substrate (gds) at 20% (w/w) of CSL, 5% (w/w) of soybean bran, 1 × 1010 cells mL−1 and particle size of bagasse in the range 9/32 mesh. The use of soybean bran decreased the time to reach maximum activity
from 96 to 24 h and the maximum productivity achieved was 8.87 U gds−1 h−1. The maximum activity was obtained at pH 5.0 and 55.0°C. Within the investigated range, the enzyme extract was more thermostable
at 50.0°C, showing a D-value of 123.1 h and deactivation energy of 343.9 kJ gmol−1. The extract showed highest stability from pH 4.5 to 4.8. Apparent K
m and V
max are 7.1 mM and 17.79 M min−1, respectively. 相似文献
8.
Amit Gupta Babu Joseph Abin Mani George Thomas 《World journal of microbiology & biotechnology》2008,24(2):237-243
In this communication, we report the presence of a newly identified serine alkaline protease producing bacteria, Virgibacillus pantothenticus (MTCC 6729) in the fresh chicken meat samples and the factors affecting biosynthesis as well as characterization of protease.
The strain produced only 14.3 U ml−1 protease in the standard medium after 72 h of incubation, while in optimized culture conditions the production of protease
was increased up to 18.2 U ml−1. The strain was able to produce protease at 40°C at pH 9.0. The addition of dextrose and casein improved protease production.
The protease was partially purified and characterized in terms of pH and temperature stability, effect of metal ions and inhibitors.
The protease was found to be thermostable alkaline by retaining its 100% and 85% stability at pH 10.0 and at 50°C respectively.
The protease was compatible with some of the commercial detergents tested, and was effective in removing protein stains from
cotton fabrics. The V. pantothenticus, MTCC 6729 protease appears to be potentially useful as an additive in detergents as a stain remover and other bio-formulations. 相似文献
9.
Durban MA Silbersack J Schweder T Schauer F Bornscheuer UT 《Applied microbiology and biotechnology》2007,74(3):634-639
Twenty-two Bacillus cereus strains were screened for phospholipase C (PLC, EC 3.1.4.3) activity using p-nitrophenyl phosphorylcholine as a substrate. Two strains (B. cereus SBUG 318 and SBUG 516) showed high activity at elevated temperatures (>70°C) at acidic pH (pH 3.5–6) and were selected for
cloning and functional expression using Bacillus subtilis. The genes were amplified from B. cereus DNA using primers based on a known PLC sequence and cloned into the expression vector pMSE3 followed by transformation into
B. subtilis WB800. On the amino acid level, one protein (PLC318) was identical to a PLC described from B. cereus, whereas PLC516 contained an amino acid substitution (E173D). PLC production using the recombinant strains was performed
by an acetoin-controlled expression system. For PLC516, 13.7 U g−1 wet cell weight was determined in the culture supernatant after 30 h cultivation time. Three purification steps resulted
in pure PLC516 with a specific activity of 13,190 U mg−1 protein. 相似文献
10.
11.
Cui Fengjie Li Yin Liu Zhiqiang Zhao Hui Ping Lifeng Ping Liying Yang Yinan Xue Yaping Yan Lijiao 《World journal of microbiology & biotechnology》2009,25(4):721-725
The objective of this study was to maximize production of xylanase by a newly isolated strain Penicillium thiersii ZH-19. Response surface methodology was employed to study the effects of significant factors such as pH, temperature, xylan
concentration, and cultivation time, on the production of xylanase by Penicillium thiersii ZH-19. The optimal fermentation parameters for enhanced xylanase production were found to be pH 7.72, temperature 24.8°C, xylan
13.2 g l−1 and the fermentation time 125.8 h. The model predicted a xylanase activity of 75.24 U ml−1. Verification of the optimization showed that the maximum xylanase production reached 73.50 U mL−1 in the flask experiments and 80.23 U mL−1 in the scale of 15-L fermenter under the optimal condition. 相似文献
12.
The optimization of process parameters for high inulinase production by the marine yeast strain Cryptococcus aureus G7a in solid-state fermentation (SSF) was carried out using central composite design (CCD), one of the response surface methodologies
(RSMs). We found that moisture, inoculation size, the amount ratio of wheat bran to rice husk, temperature and pH had great
influence on inulinase production by strain G7a. Therefore, the CCD was used to evaluate the influence of the five factors
on the inulinase production by strain G7a. Then, five levels of the five factors above were further optimized using the CCD.
Finally, the optimal parameters obtained with the RSM were the initial moisture 61.5%, inoculum 2.75%, the amount ratio of
wheat bran to rice husk 0.42, temperature 29 °C, pH 5.5. Under the optimized conditions, 420.9 U g−1 of dry substrate of inulinase activity was reached in the solid-state fermentation culture of strain G7a within 120 h whereas
the predicted maximum inulinase activity of 436.2 U g−1 of inulinase activity of 436.2 U g−1 of dry weight was derived from the RSM regression. This is the highest inulinase activity produced by the yeast strain reported
so far. A large amount of monosaccharides and oligosaccharides were detected after inulin hydrolysis by the crude inulinase. 相似文献
13.
Kameshnee Naidoo Manimaran Ayyachamy Kugen Permaul Suren Singh 《Bioprocess and biosystems engineering》2009,32(5):689-695
Xanthomonas campestris pv phaseoli produced an extracellular endoinulinase (9.24 ± 0.03 U mL−1) in an optimized medium comprising of 3% sucrose and 2.5% tryptone. X. campestris pv. phaseoli was further subjected to ethylmethanesulfonate mutagenesis and the resulting mutant, X. campestris pv. phaseoli KM 24 demonstrated inulinase production of 22.09 ± 0.03 U mL−1 after 18 h, which was 2.4-fold higher than that of the wild type. Inulinase production by this mutant was scaled up using
sucrose as a carbon source in a 5-L fermenter yielding maximum volumetric (21,865 U L−1 h−1) and specific (119,025 U g−1 h−1) productivities of inulinase after 18 h with an inulinase/invertase ratio of 2.6. A maximum FOS production of 11.9 g L−1 h−1 and specific productivity of 72 g g−1 h−1 FOS from inulin were observed in a fermenter, when the mutant was grown on medium containing 3% inulin and 2.5% tryptone.
The detection of mono- and oligosaccharides in inulin hydrolysates by TLC analysis indicated the presence of an endoinulinase.
This mutant has potential for large-scale production of inulinase and fructooligosaccharides. 相似文献
14.
The hemolytic activity of the cell-free culture supernatant of Anabaena variabilis OL S1 was investigated using the hemolysis of rabbit erythrocytes as an assay. The culture medium of A. variabilis started to exhibit hemolytic activity at the late exponential growth phase, and maximized at the stationary phase. The hemolytic
toxin is heat-stable and can be extracted in dichloromethane. The hemolytic activities under different temperature, light
intensity and pH showed a high correlation with the cell densities (r=0.965, 0.951, 0.865, respectively), and the optimum condition is 28~30°C, pH 7.5~8.0, light intensity 120 μmol photons m−2s−1. The addition of 10~20 μg mL−1 chloramphenicol, an inhibitor of protein synthesis, exhibited no marked suppression on the hemolytic activity. The supplement
of 1~20 μg mL−1 glycerol increased the hemolytic activity significantly, suggesting that synthesis of hemolysin was dependent on carbohydrate
and lipid metabolism. The spectrum of erythrocyte sensitivity to the hemolysin indicated that rabbit erythrocytes were more
sensitive to the hemolysin than were rat and human erythrocytes. Goldfish and cat erythrocytes were, however, insensitive
to the hemolytic toxin of A. variabilis. 相似文献
15.
Anjali Madhavan Sriappareddy Tamalampudi Aradhana Srivastava Hideki Fukuda Virendra S. Bisaria Akihiko Kondo 《Applied microbiology and biotechnology》2009,82(6):1037-1047
Previously, a Saccharomyces cerevisiae strain was engineered for xylose assimilation by the constitutive overexpression of the Orpinomyces xylose isomerase, the S. cerevisiae xylulokinase, and the Pichia stipitis SUT1 sugar transporter genes. The recombinant strain exhibited growth on xylose, under aerobic conditions, with a specific growth
rate of 0.025 h−1, while ethanol production from xylose was achieved anaerobically. In the present study, the developed recombinant yeast was
adapted for enhanced growth on xylose by serial transfer in xylose-containing minimal medium under aerobic conditions. After
repeated batch cultivations, a strain was isolated which grew with a specific growth rate of 0.133 h−1. The adapted strain could ferment 20 g l−1 of xylose to ethanol with a yield of 0.37 g g−1 and production rate of 0.026 g l−1 h−1. Raising the fermentation temperature from 30°C to 35°C resulted in a substantial increase in the ethanol yield (0.43 g g−1) and production rate (0.07 g l−1 h−1) as well as a significant reduction in the xylitol yield. By the addition of a sugar complexing agent, such as sodium tetraborate,
significant improvement in ethanol production and reduction in xylitol accumulation was achieved. Furthermore, ethanol production
from xylose and a mixture of glucose and xylose was also demonstrated in complex medium containing yeast extract, peptone,
and borate with a considerably high yield of 0.48 g g−1. 相似文献
16.
A phytase with high activity at neutral pH and typical water temperatures (∼25°C) could effectively hydrolyze phytate in aquaculture.
In this study, a phytase-producing strain, Pedobacter nyackensis MJ11 CGMCC 2503, was isolated from glacier soil, and the relevant gene, PhyP, was cloned using degenerate PCR and thermal asymmetric interlaced PCR. To our knowledge, this is the first report of detection
of phytase activity and cloning of phytase gene from Pedobacter. PhyP belongs to beta-propeller phytase family and shares very low identity (∼28.5%) with Bacillus subtilis phytase. The purified recombinant enzyme (r-PhyP) from Escherichia coli displayed high specific activity for sodium phytate of 24.4 U mg−1. The optimum pH was 7.0, and the optimum temperature was 45°C. The K
m, V
max, and k
cat values were 1.28 mM, 71.9 μmol min−1 mg−1, and 45.1 s−1, respectively. Compared with Bacillus phytases, r-PhyP had higher relative activity at 25°C (r-PhyP (>50%), B. subtilis phytase (<8%)) and hydrolyzed phytate from soybean with greater efficacy at neutral pH. These characteristics suggest that
r-PhyP might be a good candidate for an aquatic feed additive in the aquaculture industry. 相似文献
17.
M. Salam N. Dahiya R. Sharma S. K. Soni G. S. Hoondal R. Tewari 《Indian journal of microbiology》2008,48(3):358-364
A chitinase producing bacterium Enterobacter sp. NRG4, previously isolated in our laboratory, has been reported to have a wide range of applications such as anti-fungal
activity, generation of fungal protoplasts and production of chitobiose and N-acetyl D-glucosamine from swollen chitin. In
this paper, the gene coding for Enterobacter chitinase has been cloned and expressed in Escherichia coli BL21(DE3). The structural portion of the chitinase gene comprised of 1686 bp. The deduced amino acid sequence of chitinase
has high degree of homology (99.0%) with chitinase from Serratia marcescens. The recombinant chitinase was purified to near homogeneity using His-Tag affinity chromatography. The purified recombinant
chitinase had a specific activity of 2041.6 U mg−1. It exhibited similar properties pH and temperature optima of 5.5 and 45°C respectively as that of native chitinase. Using
swollen chitin as a substrate, the Km, kcat and catalytic efficiency (kcat/Km) values of recombinant chitinase were found to be 1.27 mg ml−1, 0.69 s−1 and 0.54 s−1M−1 respectively. Like native chitinase, the recombinant chitinase produced medicinally important N-acetyl D-glucosamine and
chitobiose from swollen chitin and also inhibited the growth of many fungi. 相似文献
18.
H. Li W. Q. Liang Z. Y. Wang N. Luo X. Y. Wu J. M. Hu J. Q. Lu X. Y. Zhang P. C. Wu Y. H. Liu 《World journal of microbiology & biotechnology》2006,22(1):1-7
Summary Response surface methodology was applied to optimize medium components for maximum production of a thermostable α-galactosidase by thermotolerant Absidia sp. WL511. First, the Plackett-Burman screening design was used to evaluate the effects of variables on enzyme production. Among
these variables, MgSO4 and soybean meal were identified as having the significant effects (with confidence level (90%). Subsequently, the concentrations
of MgSO4 and soybean meal were further optimized using central composite designs. The optimal parameters were determined by response
surface and numerical analyses as 0.0503% (g/g) MgSO4 and 0.406% (g/g) soybean meal and allowed α-galactosidase production to be increased from 4.4 IU g−1 to 117.8 IU g−1. The subsequent verification experiments confirmed the validity of the model. The optimum pH of enzymatic activity was 7.5
and the enzyme was stable at pH values ranging from 5.0 to 9.0. The optimum temperature was 73 °С. The enzyme was fairly stable
at temperatures up to 60 °С and had 87% of its full activity at 65 °С after 2 h of incubation. 相似文献
19.
An extracellular raw-starch-digesting α-amylase was isolated from Geobacillus thermodenitrificans HRO10. The culture conditions for the production of α-amylase by G. thermodenitrificans HRO10 was optimized in 1.2–l bioreactor using full 24 and 32 factorial designs. From the optimal reaction conditions, a model (Y = − 594.206 − 0.178T2 − 8.448pH2 + 6.020TpH − 0.005T2pH2) was predicted, which was then used for α-amylase production. In the bioreactor studies, the enzyme yield under optimized
conditions (pH 7.1, 49°C) was 30.20 U/ml, a 51% improvement over the results (19.97 U/ml) obtained when the traditional one-factor-at-a-time
method was employed. This α-amylase does not require extraneous calcium ions for activity, which may be a commercially important
observation. 相似文献
20.
Production of Alkaline Protease with <Emphasis Type="Italic">Teredinobacter turnirae</Emphasis> in Controlled Fed-batch Fermentation 总被引:2,自引:0,他引:2
By using our previously optimized media and a fed-batch operation controlled by LabVIEW Software, the key parameter for a
high production of alkaline protease using the marine bacterium, Teredinobacter turnirae, was to maintain a low concentration of C and N-sources ( < 2 g sucrose l−1 and < 0.2 g NH4C l l−1) using an appropriate fed-batch culture system. A maximum protease activity of 8250 U ml−1 was thus achieved. 相似文献