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1.
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
2.
Treichel H Mazutti MA Maugeri Filho F Rodrigues MI 《Bioprocess and biosystems engineering》2009,32(4):425-433
The present work aimed to study the viability of the use of sugarcane molasses and corn steep liquor (CSL) in a sequential
inulinase production performing an up-stream pretreatment of these agroindustrial residues. A sequential strategy was used
applying three central composite rotatable designs (CCRDs) to optimise medium composition, followed by a down-stream step.
The medium containing 150 g L−1 molasses, 50 g L−1 CSL and 6 g L−1 yeast extract, yielded a maximum inulinase production of 1,294 ± 7 U mL−1, after 72 h of fermentation. A down-stream evaluation was carried out using an expanded bed of Streamline DAE resin (Pharmacia),
with and without the up-stream treatment. The results showed that the enzyme could not be recovered from the non-pretreated
medium, whereas a yield of 91% was obtained in the adsorption stage from the medium prepared with the up-stream treatment,
showing the viability of producing the enzyme inulinase from agroindustrial residues using the integrated process. 相似文献
3.
Inulinase production by a marine yeast <Emphasis Type="Italic">Pichia guilliermondii</Emphasis> and inulin hydrolysis by the crude inulinase 总被引:1,自引:0,他引:1
Marine yeast strain 1, isolated from the surface of a marine alga, was found to secrete a large amount of inulinase into the
medium. This marine yeast was identified as a strain of Pichia guilliermondii according to the results of routine yeast identification and molecular methods. The crude inulinase produced by this marine
yeast worked optimally at pH 6.0 and 60°C. The optimal medium for inulinase production was seawater containing 4.0% (w/v)
inulin and 0.5% (w/v) yeast extract, while the optimal cultivation conditions for inulinase production were pH 8.0, 28°C and
170 rpm. Under the optimal conditions, over 60 U ml−1 of inulinase activity was produced within 48 h of fermentation in shake flasks. A large amount of monosaccharides and a trace
amount of oligosaccharides were detected after the hydrolysis, indicating that the crude inulinase had a high exoinulinase
activity. 相似文献
4.
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
5.
Liu Y Sha Q Wu S Wang J Yang L Sun W 《Journal of industrial microbiology & biotechnology》2006,33(4):274-282
A microorganism with the ability to catalyze the resolution of racemic phenyloxirane was isolated and identified as Aspergillus niger SQ-6. Chiral capillary electrophoresis was successfully applied to separate both phenyloxirane and phenylethanediol. The
epoxide hydrolase (EH) involved in this resolution process was (R)-stereospecific and constitutively expressed. When whole cells were used during the biotransformation process, the optimum
temperature and pH for stereospecific vicinal diol production were 35°C and 7.0, respectively. After a 24-h conversion, the
enantiomer excess of (R)-phenylethanediol produced was found to be >99%, with a conversion rate of 56%. In fed-batch fermentations at 30°C for 44 h,
glycerol (20 g L−1) and corn steep liquor (CSL) (30 g L−1) were chosen as the best initial carbon and nitrogen sources, and EH production was markedly improved by pulsed feeding of
sucrose (2 g L−1 h−1) and continuous feeding of CSL (1 g L−1 h−1) at a fermentation time of 28 h. After optimization, the maximum dry cell weight achieved was 24.5±0.8 g L−1; maximum EH production was 351.2±13.1 U L−1 with a specific activity of 14.3±0.5 U g−1. Partially purified EH exhibited a temperature optimum at 37°C and pH optimum at 7.5 in 0.1 M phosphate buffer. This study
presents the first evidence for the existence of a predicted epoxide racemase, which might be important in the synthesis of
epoxide intermediates. 相似文献
6.
G. Pratap Kumar A. Kunamneni T. Prabhakar P. Ellaiah 《World journal of microbiology & biotechnology》2005,21(8-9):1359-1361
Summary Fifty strains were isolated from different soil samples on synthetic medium containing inulin as a sole carbon source for
the production of extracellular inulinase. Of them, five isolates showed high inulinase activity and one of them was selected
for identification and medium optimization studies. The isolate was identified as Aspergillus niger. Various physical and chemical parameters were optimized for inulinase production. Maximum productivity of inulinase (176 U ml−1) was achieved by employing medium containing 5% (w/v) inulin, galactose as additional carbon source, corn steep liquor and
(NH4)H2PO4 as nitrogen sources, incubation period of 72 h, incubation temperature of 28 °C, pH 6.5, inoculum load at 10% (v/v) level
and medium volume to flask volume ratio of 1:20 (v/v) with indented flasks. 相似文献
7.
Bhanja T Rout S Banerjee R Bhattacharyya BC 《Bioprocess and biosystems engineering》2007,30(5):369-376
GROWTEK bioreactor was used as modified solid-state fermentor to circumvent many of the problems associated with the conventional
tray reactors for solid-state fermentation (SSF). Aspergillus oryzae IFO-30103 produced very high levels of α-amylase by modified solid-state fermentation (mSSF) compared to SSF carried out
in enamel coated metallic trays utilizing wheat bran as substrate. High α-amylase yield of 15,833 U g−1 dry solid in mSSF were obtained when the fungus were cultivated at an initial pH of 6.0 at 32°C for 54 h whereas α-amylase
production in SSF reached its maxima (12,899 U g−1 dry solid ) at 30°C after 66 h of incubation. With the supplementation of 1% NaNO3, the maximum activity obtained was 19,665 U g−1 dry solid (24% higher than control) in mSSF, whereas, in SSF maximum activity was 15,480 U g−1 dry solid in presence of 0.1% Triton X-100 (20% higher than the control). 相似文献
8.
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
9.
Ning Guo Fang Gong Zhenming Chi Jun Sheng Jing Li 《Journal of industrial microbiology & biotechnology》2009,36(4):499-507
In order to isolate inulinase overproducers of the marine yeast Pichia guilliermondii, strain 1, cells were mutated by using UV light and LiCl2. 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
10.
Growth and sporulation of Verticillium lecanii on inert and organic carriers (sugar-cane bagasse, corncob, rice straw, polyurethane foam and activated carbon) in a solid-state
fermentation process was studied. Sugar-cane bagasse and polyurethane foam produced 1010 spores g−1 dry carrier whereas corncob, rice straw, and activated carbon yielded, respectively 8 × 109, 4 × 109, and 3 × 108 spores g−1. Chitinase activity of the conidia was in the following order: sugar-cane bagasse (3.3 U mg−1) > wheat bran (3.0 U mg−1) > polyurethane foam (2.7 U mg−1). There was no significant difference (2.5–2.7 U mg−1) in the proteinase activity among the conidia from the three cultures. Scanning electron microscopy shows that aerial mycelium
freely penetrated into the internal area of polyurethane foam. Sugar-cane bagasse provided enough area for vegetative hyphae
to attach. Of the carriers analyzed, polyurethane foams and sugar-cane bagasse were the best carriers for V. lecanii growth and spore production. 相似文献
11.
Jeyagowri Kiddinamoorthy Alfredo J. Anceno Gulelat D. Haki Sudip K. Rakshit 《World journal of microbiology & biotechnology》2008,24(5):605-612
Production of extracellular xylanase from Bacillus sp. GRE7 using a bench-top bioreactor and solid-state fermentation (SSF) was attempted. SSF using wheat bran as substrate
and submerged cultivation using oat-spelt xylan as substrate resulted in an enzyme productivity of 3,950 IU g−1 bran and 180 IU ml−1, respectively. The purified enzyme had an apparent molecular weight of 42 kDa and showed optimum activity at 70°C and pH
7. The enzyme was stable at 60–80°C at pH 7 and pH 5–11 at 37°C. Metal ions Mn2+ and Co2+ increased activity by twofold, while Cu2+ and Fe2+ reduced activity by fivefold as compared to the control. At 60°C and pH 6, the K
m for oat-spelt xylan was 2.23 mg ml−1 and V
max was 296.8 IU mg−1 protein. In the enzymatic prebleaching of eucalyptus Kraft pulp, the release of chromophores, formation of reducing sugars
and brightness was higher while the Kappa number was lower than the control with increased enzyme dosage at 30% reduction
of the original chlorine dioxide usage. The thermostability, alkali-tolerance, negligible presence of cellulolytic activity,
ability to improve brightness and capacity to reduce chlorine dioxide usage demonstrates the high potential of the enzyme
for application in the biobleaching of Kraft pulp. 相似文献
12.
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
13.
Kuhad Ramesh Chander Kapoor Mukesh Rustagi Renuka 《World journal of microbiology & biotechnology》2004,20(3):257-263
An alkalophilic Streptomyces sp. RCK-SC, which produced a thermostable alkaline pectinase, was isolated from soil samples. Pectinase production at 45
°C in shaking conditions (200 rev min−1) was optimal (76,000 IU l−1) when a combination of glucose (0.25% w/v) and citrus pectin (0.25% w/v) was added along with urea (0.25% w/v) in the basal
medium devoid of yeast extract and peptone. All the tested amino acids and vitamins greatly induced pectinase production and
increased the specific productivity of pectinase up to 550%. In an immobilized cell system containing polyurethane foam (PUF),
the pectinase production was enhanced by 32% (101,000 IU l−1) compared to shake flask cultures. In solid-state cultivation (SSC) conditions, using wheat bran as solid substrate, pectinase
yield of 4857 IU g−1 dry substrate was obtained at substrate-to-moisture ratio of 1:5 after 72 h of incubation. The partially purified pectinase
was optimally active at 60 °C and retained 80% of its activity at 50 °C after 2 h of incubation. The half life of pectinase
was 3 h at 70 °C. Pectinase was stable at alkaline pH ranging from 6.0 to 9.0 for more than 8 h at room temperature retaining
more than 50% of its activity.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
14.
Haiyan Sun Xiangyang Ge Weiguo Zhang 《World journal of microbiology & biotechnology》2007,23(5):603-613
Penicillium sp. X−1, isolated from decayed raw corn, produced high level of raw-starch-digesting glucoamylase (RSDG) under solid state
fermentation (SSF). Maximum enzyme yield of 306.2 U g−1 dry mouldy bran (DMB) was obtained after 36 h of culture upon optimized production. The enzyme could hydrolyse both small
and large granule starches but did not adsorb on raw starch. The enzyme exhibited maximum activity at 65°C and pH 6.5, which
provided an opportunity of synergism with α-amylase. It significantly hydrolysed 15% (w/v) raw corn starch slurry in synergism
with the commercial α-amylase and a degree of hydrolysis of 92.4% was obtained after 2 h of incubation. 相似文献
15.
Two new effective microbial producers of inulinases were isolated from Jerusalem artichoke tubers grown in Thailand and identified
as Aspergillus niger TISTR 3570 and Candida
guilliermondii TISTR 5844. The inulinases produced by both these microorganisms were appropriate for hydrolysing inulin to fructose as the
principal product. An initial inulin concentration of ∼100 g l−1 and the enzyme concentration of 0.2 U g−1 of substrate, yielded 37.5 g l−1 of fructose in 20 h at 40°C when A. niger TISTR 3570 inulinase was the biocatalyst. The yield of fructose on inulin was 0.39 g g−1. Under identical conditions, the yeast inulinase afforded 35.3 g l−1 of fructose in 25 h. The fructose yield was 0.35 g g−1 of substrate. The fructose productivities were 1.9 g l−1 h−1 and 1.4 g l−1 h−1 for the mold and yeast enzymes, respectively. After 20 h of reaction, the mold enzyme hydrolysate contained 53% fructose
and more than 41% of initial inulin had been hydrolysed. Using the yeast enzymes, the hydrolysate contained nearly 38% fructose
at 25 h and nearly 36% of initial inulin had been hydrolysed. The A. niger TISTR 3570 inulinases exhibited both endo-inulinase and exo-inulinase activities. In contrast, the yeast inulinases displayed
mainly exo-inulinase activity. The mold and yeast crude inulinases mixed in the activity ratio of 5:1 proved superior to individual
crude inulinases in hydrolysing inulin to fructose. The enzyme mixture provided a better combination of endo- and exo-inulinase
activities than did the crude extracts of either the mold or the yeast individually. 相似文献
16.
Dasagrandhi Chakradhar Saleem Javeed Avinash P. Sattur 《Journal of industrial microbiology & biotechnology》2009,36(9):1179-1187
Nigerloxin, a new and potent lipoxygenase inhibitor, was discovered in our laboratory through solid-state fermentation of
wheat bran by Aspergillus niger V. Teigh (MTCC-5166). The aim of this study is to investigate the possibility of using different agro-industrial residues
as nutritional supplements along with wheat bran to enhance the production of nigerloxin. Nigerloxin produced by SSF was quantified
spectrophotometrically at 292 nm. The results indicate that the inhibitor production was influenced by the type of solid substrate
supplemented, moisture content, pH and size of the inoculum. Individually optimized supplements were tested in different combinations
to determine their effects on nigerloxin production. A twofold increase in the production of nigerloxin (4.9 ± 0.3 mg gds−1) was achieved by supplementing wheat bran with 10% w/w sweet lemon peel and 5% v/w methanol at optimized process parameters,
that is, an initial moisture content of 65% v/w and incubation period of 6 days with an initial inoculum size of 2 ml (8 × 105 spores gds−1). Nigerloxin production was stable between pH of 4 and 5. 相似文献
17.
M. I. Rajoka Tayyaba Huma A. M. Khalid F. Latif 《World journal of microbiology & biotechnology》2005,21(6-7):869-876
Summary Industrial byproducts namely canola meal, rice bran, sunflower meal, and wheat straw were used as substrates for endo-xylanase
production by Humicola lanuginosemutant TH1 through solid substrate fermentation. The enzyme was secreted extracellularly by both wild and mutant cultures.
Rice bran supported the maximum production of endo-xylanase followed by wheat straw, canola meal and sunflower meal. The highest
activity was achieved after 72 h of culture and the highest yields from the above substrates were 842, 840, 610 and 608 IU
per g substrate consumed respectively. The highest productivity (281 IU flask−1 h−1 corresponding to 5620 l−1 h-1) of endo-xylanase by the mutant of H. lanuginosa was 1.6-fold more than that produced by the parental organism in solid-state fermentation of rice bran at 45 °C. Maximum
specific activity (180 IU mg−1 protein) and substrate consumption rates were significantly more than those reported by previous researchers on Humicola sp. The mutant possessed markedly low accompanying cellulase activity. Thermodynamic studies revealed that the mutant required
significantly lower activation energy for enzyme production and higher for thermal inactivation which signified that the endogenous
metabolic machinery of mutant cells exerted more protection against thermal inactivation during product formation than that
needed by its parental cultures. 相似文献
18.
Fermentation of biomass derived synthesis gas to ethanol is a sustainable approach that can provide more usable energy and
environmental benefits than food-based biofuels. The effects of various medium components on ethanol production by Clostridium ragsdalei utilizing syngas components (CO:CO2) were investigated, and corn steep liquor (CSL) was used as an inexpensive nutrient source for ethanol production by C. ragsdalei. Elimination of Mg2+, NH4
+ and PO4
3− decreased ethanol production from 38 to 3.7, 23 and 5.93 mM, respectively. Eliminating Na+, Ca2+, and K+ or increasing Ca2+, Mg2+, K+, NH4
+ and PO4
3− concentrations had no effect on ethanol production. However, increased Na+ concentration (171 mM) inhibited growth and ethanol production. Yeast extract (0.5 g l−1) and trace metals were necessary for growth of C. ragsdalei. CSL alone did not support growth and ethanol production. Nutrients limiting in CSL were trace metals, NH4
+ and reducing agent (Cys: cysteine sulfide). Supplementation of trace metals, NH4
+ and CyS to CSL (20 g l−1, wet weight basis) yielded better growth and similar ethanol production as compared to control medium. Using 10 g l−1, the nutritional limitation led to reduced ethanol production. Higher concentrations of CSL (50 and 100 g l−1) were inhibitory for cell growth and ethanol production. The CSL could replace yeast extract, vitamins and minerals (excluding
NH4
+). The optimized CSL medium produced 120 and 50 mM of ethanol and acetate, respectively. The CSL could provide as an inexpensive
source of most of the nutrients required for the syngas fermentation, and thus could improve the economics of ethanol production
from biomass derived synthesis gas by C. ragsdalei. 相似文献
19.
Hydrolysis of organic phosphates by corn and soybean roots 总被引:1,自引:0,他引:1
Because of the importance of organic phosphates as sources of P for plants, this work was performed to study the hydrolysis
of nine organic phosphates by sterile, intact corn (Zea mays L.) and soybean (Glycine max L.) roots. Results showed that the rates of hydrolysis ofp-nitrophenyl phosphate (PNP) in buffered solutions by roots of three varieties of corn and three varieties of soybean ranged
from 13 to 22 μmol PO4−P g−1 root h−1 and from 2.1 to 2.2 μmol PO4−P 0.1 g−1 root h−1, respectively. The average rate of hydrolysis of PNP in nonbuffered solutions was 2- to 3-fold lower for corn roots and 6-
to 10-fold lower for soybean roots as compared with those obtained with buffered solutions. The orthophosphate released from
hydrolysis of organic P compounds in buffered solutions during a 48-h incubation of corn roots showed that the maximum rate
of hydrolysis of PNP was 4 to 6 times greater than the commonly used substrates: α- and β-glycerophosphates, phenolphthalein
diphosphate, and glucose-6-phosphate. The rates of hydrolysis of glucose-6-phosphate and glucose-1-phosphate were similar
and about 6- to 12-fold lower than that of PNP. Phosphoethanolamine and phosphocholine were hydrolyzed slightly, ando-carboxyphenyl phosphate was not hydrolyzed. The rates of hydrolysis of organic P compounds in nonbuffered solutions by corn
and soybean roots were 1 to 3 and 1 to 10 times lower than those in buffered solutions, respectively. The trends in rates
of hydrolysis by soybean roots of buffered organic P substrates were similar to those observed with corn roots, with the exception
of glucose-1-phosphate and phosphoethanolamine. 相似文献
20.
Isolation and characterization of dihydromonacolin-MV from <Emphasis Type="Italic">Monascus purpureus</Emphasis> for antioxidant properties 总被引:4,自引:0,他引:4
Dhale MA Divakar S Kumar SU Vijayalakshmi G 《Applied microbiology and biotechnology》2007,73(5):1197-1202
The methanolic extract of Monascus purpureus cultivated by solid-state fermentation on rice showed strong 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity
and better yield as compared to other polarity based extracted fractions. It was selected for further purification of the
antioxidant. The activity-guided repeated fractionation of methanolic extract on a silica gel column chromatography yielded
a compound that exhibited strong antioxidant activity. Based on the spectroscopic analysis by UV, IR, 1H NMR, 13C NMR, 2D-HSQCT NMR, and MS, the antioxidant isolated was elucidated as a derivative of dihydromonacolin-K, where the ester
group is 2-methyl propionate, designated as dihydromonacolin-MV. The DPPH radical was significantly scavenged by the dihydromonacolin-MV
(IC50 20±1 μg ml−1). The dihydromonacolin-MV showed strong inhibition of lipid peroxidation in a liposome model with an IC50 value of 5.71±0.38 μg ml−1 and superoxide radical scavenging activity with an IC50 value of 163.97±2.68 μg ml−1. 相似文献