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1.
The main objectives of this study were to optimize β-mannanase fermentation conditions by using Response Surface Methodology (RSM) and to model kinetically using the kinetic models. Based on the results, the optimum fermentation conditions were found to be initial sugar concentration of 10°Bx, whey concentration of 0.75% [w/v], and inoculum size of 8% (v/v). Under optimized conditions, β-mannanase activity (P), sugar consumed (ΔS), maximum β-mannanase production rate (QP), and sugar utilization yield (SUY) were 687.89 U/mL, 47.38 g/L, 118.54 U mL–1 day–1, and 69.73%, respectively. Kinetic models were employed to describe the optimum β-mannanase fermentation process. The kinetic analysis of β-mannanase fermentation showed that β-mannanase fermentation is growth associated because the α value (U/mgX) is approximately 330-fold higher than the β value (U/mgX·hr). Nevertheless, maintenance value (Z) was lower than γ value, thus showing that Aspergillus niger mainly utilizes the sugars for β-mannanase production and fungal growth. Consequently, carob extract and whey powder could be used to be cost-effective carbon and organic nitrogen sources, respectively. It was clearly indicated that the suggested kinetic models can successfully describe the fungal growth, β-mannanase production, and substrate consumption.  相似文献   

2.
Summary The kinetics of growth and the chemical composition ofFusarium moniliforme cultivated on aqueous carob pod extract were investigated. The extract was adjusted to provide 0.5, 1.0, 2.0 and 4.0% carob sugars supplemented with inorganic salts at the ratio: carob sugar: NH4H2PO4: MgSO4.7H2O=1:0.6:0.012. The extract contained 16 mg tannic acid (Folin-Dennis) per g of carob sugar.The phase of vigorous growth was exponential. Tannins were not observed to depress growth. The maximum value of 0.22 h–1 for a specific growth rate corresponding to a generation time of 3.15 h was obtained when the fungus was cultivated on a 4% carob sugar medium. The dry mycelium produced per g of consumed carob sugar was then 0.515 g.The protein and purine content was affected by the composition of the growth medium. Protein values up to 37.7% true (Lowry) and 53.1% crude (NX6.25) of dry mycelium were recorded. Mean purine contents were 89 and 116 mol/g, corresponding to nucleic acid levels of 5.7 and 7.5% for mycelium grown on 0.5 and 4.0% carob sugar respectively.These findings linked with those previously reported regarding the good appearance and nutritional quality ofF. moniliforme (Drouliscos et al., 1976) make this fungus worthy of consideration for the production of protein.  相似文献   

3.
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   

4.
Summary Inulinase activity produced by a mixed culture of Aspergillus niger and Kluyveromyces marxianus growing on Jerusalem artichoke powder was investigated. Inulinase produced by this mixed culture had a higher invertase-type activity than inulinase from respective monocultures. When hydrolysis was carried out at 50°C with Jerusalem artichoke exctract (total sugar 16% w/v) at pH 5.0, 90% hydrolysis was achieved after 4 h with 5% v/v of crude cell free enzyme preparation.  相似文献   

5.
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   

6.
Sugarcane-pressmud, a by-product of cane-sugar manufacture, was used as a substrate for production of citric acid by Aspergillus niger CFTRI 30, in a solid-state fermentation system. Of the 170 g of sugar supplied, 131 g were consumed, with a 79% yield of citric acid over 120 h. Potassium ferrocyanide improved the conversion to about 88% and lowered the fermentation time by 24 h. Enrichment with sugar and NH4NO3 was essential to improve productivity. About 174 g citric acid/kg dry sugarcane-pressmud were produced after 120 h in ferrocyanid-treated medium which initially contained 12.5% (w/w) effective sugar and 0.1% (w/w) NH4NO3. About 3% (w/w) of the original sugar present in the sugarcane-pressmud was non-utilizable. This is the first report on the potential of sugarcane-pressmud for citric acid production.V.S. Shankaranand and B.K. Lonsane are with the Fermentation Technology and Bioengineering Discipline, Central Food Technological Research Institute, Mysore-570 013, India  相似文献   

7.
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   

8.
Response surface methodology (RSM), employing the fractional factorial design (FFD) was used to optimize the fermentation medium for the production of glucose oxidase (GOD) from a marine isolate (NRC9) of Aspergillus niger under submerged fermentation. The design was employed by selecting glucose, CaCO3, ammonium phosphate and MgSO4 concentrations as model factors by ‘one variable at a time’ experiment. A second-order quadratic model and response surface method showed that the optimum concentrations (g/l) glucose, 100; CaCO3, 25; (NH4)2HPO4, 1.8 and 0.4 of MgSO4, resulted in an improvement of GOD production (170?±?0.88 U/ml) as compared to the initial level (109.81?±?1.38 U/ml) after four days of incubation at 200 rpm and 30 °C, whereas its predicted value obtained by the quadratic model was 164.36 U/ml. Analysis of variance (ANOVA) showed a high coefficient of determination value (R 2) of 0.967, ensuring a satisfactory adjustment of the quadratic model with the experimental data. This is the first report on production of glucose oxidase from a marine fungal isolate, Aspergillus niger NRC9, using statistical experimental design and response surface methodology in optimization of its production under submerged fermentation.  相似文献   

9.
β-mannanase was produced mainly by Aspergillus species and can degrade the β-1,4-mannose linkages of galactomannans. This study was undertaken to enhance mannanase production using talcum and aluminum oxide as the microparticles, which control cell morphology of recombinant Aspergillus sojae in glucose and carob extract medium. Both microparticles improved fungal growth in glucose and carob pod extract medium. Aluminum oxide (1 g/L) was the best agent for glucose medium which resulted in 514.0 U/ml. However, the highest mannanase activity was found as 568.7 U/ml with 5 g/L of talcum in carob extract medium. Increase in microparticle concentration resulted in decreasing the pellet size diameter. Furthermore, more than 10 g/L of talcum addition changed the filamentous fungi growth type from pellet to pellet/mycelium mixture. Results showed that right type and concentration of microparticle in fermentation media improved the mannanase activity and production rate by controlling the growth morphology.  相似文献   

10.
Bioethanol production from carob pods has attracted many researchers due to its high sugar content. Both Zymomonas mobilis and Saccharomyces cerevisiae have been used previously for this purpose in submerged and solid-state fermentation. Since extraction of sugars from the carob pod particles is a costly process, solid-state and solid submerged fermentations, which do not require the sugar extraction step, may be economical processes for bioethanol production. The aim of this study is to evaluate the bioethanol production in solid submerged fermentation from carob pods. The maximum ethanol production of 0.42 g g?1 initial sugar was obtained for Z. mobilis at 30°C, initial pH 5.3, and inoculum size of 5% v/v, 9 g carob powder per 50 mL of culture media, agitation rate 0 rpm, and fermentation time of 40 hr. The maximum ethanol production for S. cerevisiae was 0.40 g g?1 initial sugar under the same condition. The results obtained in this research are comparable to those of Z. mobilis and S. cerevisiae performance in other culture mediums from various agricultural sources. Accordingly, solid submerged fermentation has a potential to be an economical process for bioethanol production from carob pods.  相似文献   

11.
It has been confirmed that Saccharomyces sp. W0 can produce high concentration of ethanol. In this study, the INU1 gene cloned from the marine-derived Pichia guilliermondii was transformed into uracil mutant of Saccharomyces sp. W0. The positive transformant Inu-66 obtained could produce 34.2 U ml−1 of extracellular inulinase within 72 h of cultivation. It was found that 15.2 U of inulinase activity per one gram of inulin was suitable for inulin hydrolysis and ethanol production by the transformant Inu-66. During the small-scale fermentation, 13.7 ml of ethanol in 100 ml of medium was produced and 99.1% of the added inulin was utilized by the transformant. During the 2 l fermentation, 14.9% (v/v) of ethanol was produced from inulin and 99.5% of the added inulin was converted into ethanol, CO2 and cell mass.  相似文献   

12.
The influence of some fermentation parameters on the semi-pilot scale (alteration of growth conditions,e.g., sugar concentration, incubation temperature and initial pH) on citrate production was demonstrated in parent and mutant strains ofAspergillus niger. Raw material from sugar industry (cane molasses) was examined as basal fermentation medium in a stirred stainless-steel 15-L fermentor. After growth on medium with 150 g/L sugar, the parent strain produced 51.2 g/L citric acid; the mutant strain achieved production maximum of 96.2 g/L. Comparing the growth, kinetic (volumetric substrate uptake rate, rate of substrate consumption and volumetric productivity rate) and production parameters it was found that the mutant strain grows more rapidly, with slightly changed morphology (intermediate, shiny round pellets with diameter 0.6–0.7 mm), and exhibits a higher citrate production and higher efficiency of sugar utilization.  相似文献   

13.
《Process Biochemistry》2007,42(5):805-811
The marine yeast strain G7a isolated from sediment of China South Sea was found to secrete a large amount of inulinase into the medium. This marine yeast strain was identified to be a strain of Cryptococcus aureus according to the results of routine yeast identification and molecular methods. The crude inulinase produced by this marine yeast showed the highest activity at pH 5.0 and 50 °C. The optimal medium for inulinase production was artificial seawater containing inulin 4.0% (w/v), K2HPO4 0.3% (w/v), yeast extract 0.5% (w/v), KCl 0.5% (w/v), CaCl2 0.12% (w/v), NaCl 4.0% (w/v) and MgCl2·6H2O 0.6% (w/v), while the optimal cultivation conditions for inulinase production were pH 5.0, a temperature of 28 °C and a shaking speed of 170 rpm. Under the optimal conditions, over 85.0 U/ml of inulinase activity was produced within 42 h of fermentation at shake flask level. This is very high level of inulinase activity produced by yeasts. A large amount of monosaccharides and oligosaccharides were detected after inulin hydrolysis by the crude inulinase.  相似文献   

14.
In this work, carob pulp syrup was used as carbon source in C. cohnii fermentations for docosahexaenoic acid production. In preliminary experiments different carob pulp dilutions supplemented with sea salt were tested. The highest biomass productivity (4 mg/lh) and specific growth rate (0.04/h) were observed at the highest carob pulp dilution (1:10.5 (v/v), corresponding to 8.8 g/l glucose). Ammonium chloride and yeast extract were tested as nitrogen sources using different carob pulp syrup dilutions, supplemented with sea salt as growth medium. The best results were observed for yeast extract as nitrogen source. A C. cohnii fed-batch fermentation was carried out using diluted carob pulp syrup (1:10.5 v/v) supplemented with yeast extract and sea salt. The biomass productivity was 420 mg/lh, and the specific growth rate 0.05/h. Under these conditions the DHA concentration and DHA production volumetric rate attained 1.9 g/l and 18.5 mg/lh respectively after 100.4 h. The easy, clean and safe handling of carob pulp syrup makes this feedstock a promising carbon source for large-scale DHA production from C. cohnii. In this way, this carob industry by-product could be usefully disposed of through microbial production of a high value fermentation product.  相似文献   

15.
Inulinase production by Penicillium sp. NFCC 2768 isolated from the rhizosphere soil of dahlia was studied on media containing inulin-rich plant extracts. The maximum inulinase activity (64.54 nkat/ml) was observed with the tuber extract of dahlia (Dahlia pinnata). The fungus produced substantial inulinase activity on asparagus root powder (45.23 nkat/ml) and garlic extracts (41.32 nkat/ml). The apparent molecular weight of the purified inulinase was 68 kDa. The optimum pH and temperature for enzyme activity were 5.0 and 50°C, respectively. Mn2+ and Ca2+ were found to enhance the inulinase activity, while Hg2+ was found to be a strong inhibitor. Inulinase liberated fructose, glucose, sucrose, kestose (GF2), nystose (GF3), and inulooligosaccharides (IOS). This study suggested the use of dahlia tuber extract and asparagus root powder as suitable substrates for inulinase production by the newly isolated Penicillium sp. NFCC 2768, and its application in the generation of fructose and IOS.  相似文献   

16.
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   

17.
The waste materials from the carob processing industry are a potential resource for second-generation bioethanol production. These by-products are small carob kibbles with a high content of soluble sugars (45–50%). Batch and fed-batch Saccharomyces cerevisiae fermentations of high density sugar from carob pods were analyzed in terms of the kinetics of sugars consumption and ethanol inhibition. In all the batch runs, 90–95% of the total sugar was consumed and transformed into ethanol with a yield close to the theoretical maximum (0.47–0.50 g/g), and a final ethanol concentration of 100–110 g/l. In fed-batch runs, fresh carob extract was added when glucose had been consumed. This addition and the subsequent decrease of ethanol concentrations by dilution increased the final ethanol production up to 130 g/l. It seems that invertase activity and yeast tolerance to ethanol are the main factors to be controlled in carob fermentations. The efficiency of highly concentrated carob fermentation makes it a very promising process for use in a second-generation ethanol biorefinery.  相似文献   

18.
Direct fermentation of gelatinized sago starch into solvent (acetone–butanol–ethanol) by Clostridium acetobutylicum P262 was studied using a 250 ml Schott bottle anaerobic fermentation system. Total solvent production from fermentation using 30 g sago starch/l (11.03g/l) was comparable to fermentation using corn starch and about 2-fold higher than fermentation using potato or tapioca starch. At the range of sago starch concentration investigated (10–80 g/l), the highest total solvent production (18.82 g/l) was obtained at 50 g/l. The use of a mixture of organic and inorganic nitrogen source (yeast extract + NH4NO3) enhanced growth of C. acetobutylicum, starch hydrolysis and solvent production (24.47 g/l) compared to the use of yeast extract alone. This gave the yield based on sugar consumed of 0.45 g/g. Result from this study also showed that the individual concentrations of nitrogen and carbon influenced solvent production to a greater extent than did carbon to nitrogen (C/N) ratio.  相似文献   

19.
The inulinase gene cloned from the marine-derived yeast Pichia guilliermondii strain 1 was expressed in Pichia pastoris X-33 and the conditions for overexpression of the inulinase were optimized. After the optimization of the conditions for production of the recombinant inulinase, 286.8 ± 5.4 U/ml and 8873 ± 55.3 U/mg of the recombinanat inulinase in the supernatant of the culture of 2-l fermentor were attained at 120 h of the fermentation and fermentation efficiency was 13.04 μg ± 0.4 of protein/ml/d. The recombinant inulinase was purified and characterized. The molecular weight of the purified recombinant inulinase was 57.6 kDa, which was higher than that of the native iunlinase. The optimal pH and temperature of the purified recombinant inulinase were 6.0 and 60 °C, respectively. Other biochemical characteristics of the purified recombinant inulinase were the same as those of the native inulinase produced by the marine-derived P. guilliermondii strain 1. The purified recombinant inulinase also had high exoinulinase activity. Therefore, the recombinant inulinase may have highly potential applications in food and pharmaceutical industies.  相似文献   

20.
Summary The effect of the addition of octadecanoylsucrose esters to the growth medium on the production of inulinase by Aspergillus niger SL-09 was studied in batch culture using shake flasks. The activities of inulinase in vitro and in vivo formed by Aspergillus niger SL-09 was enhanced dramatically by the addition of sucrose ester S-770 to the medium, and it was confirmed that sucrose ester acted as a very efficient inducer for inulinase production. As a result, with the addition of 6 g sucrose ester l−1 at the beginning of the culture, the enzyme activities were enhanced near 7-fold higher than that obtained in the basal medium.  相似文献   

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