[Objectives]This study was conducted to optimize the Formulation Process of glucosamine chondroitin sulfate tablets. [Methods] The orthogonal design with three levels was carried out with microcrystalline cellulose, c...[Objectives]This study was conducted to optimize the Formulation Process of glucosamine chondroitin sulfate tablets. [Methods] The orthogonal design with three levels was carried out with microcrystalline cellulose, calcium hydrophosphate and cross-linked polyvinylpyrrolidone as three factors to optimize the preparation process. [Results] When microcrystalline cellulose 200 mg/tablet, calcium hydrophosphate 150 mg/tablet, and cross-linked polyvinylpyrrolidone 80 mg/tablet were added, the angle of repose could meet the requirements of tablet pressing, and the dissolution could reach more than 95% in 30 min. The results of the orthogonal test showed that the dissolution effect of self-made tablets was faster than that of commercial products. [Conclusions] The glucosamine hydrochloride chondroitin sulfate tablets prepared by this prescription have better quality.展开更多
Response surface methodology was used to optimize the medium for antifungal active substance production from Streptomyces lydicus E12 in flask cultivation.Initially,the component factors,which influence antifungal sub...Response surface methodology was used to optimize the medium for antifungal active substance production from Streptomyces lydicus E12 in flask cultivation.Initially,the component factors,which influence antifungal substance production,were studied by varying one factor at a time.Starch,soybean cake powder,K_2HPO_4·3H_2O and MgSO_4·7H_2O were found to have a significant effect on the production of antifungal substances by the traditional design.Then,a Box-Behnken design was applied for further optimization.A quadratic model was found to fit antifungal active substance production.The analysis revealed that the optimum values of the tested variable were starch 84.96 g/L,soybean cake powder 4.13 g/L,glucose 5 g/L,MgSO_4·7H_2O 1.23 g/L,K_2HPO_4·3H_2O2.14 g/L and NaCl 0.5 g/L.The test result of 67.44%antifungal inhibition agreed with the prediction and increased by 14.28%in comparison with the basal medium.展开更多
Yeast strain Y68 producing high level of pullulan was isolated from the phyton collected in Toulouse, France. This strain was identified to be Rhodotorula bacarum by BIOLOG analysis. This is the first report that pull...Yeast strain Y68 producing high level of pullulan was isolated from the phyton collected in Toulouse, France. This strain was identified to be Rhodotorula bacarum by BIOLOG analysis. This is the first report that pullulan was produced by Rhodotorula bacarum. The optimal medium (g L -1) for pullulan production by this strain was 80 glucose, 20 soybean cake hydrolysate, 5 K 2HPO 4, 1 NaCl, 0.2 MgSO 4·7H 2O, 0.6 (NH 4) 2SO 4, pH 7.0. Under this condition, 54 g L -1 pullulan was produced within 60 h at 30 ℃. Pullulan is a better starting material for producing marine prodrugs.展开更多
A sequential statistical approach was applied to optimizing the fermentation medium of epothilones(Epos) production by means of a mutant which was obtained by treating polyangium cellulosum ATCC 15384 with nitrite and...A sequential statistical approach was applied to optimizing the fermentation medium of epothilones(Epos) production by means of a mutant which was obtained by treating polyangium cellulosum ATCC 15384 with nitrite and ultraviolet. The effects of different carbon sources and nitrogen sources on the fermentation medium were tested, and the suitable ones were selected. Then a uniform design was employed to design the experiments. A linear model was developed for identifying the significant components in fermentation medium, while a third degree polynomial model was used for studying the relationship between the concentration of the components in fermentation medium and the yield of Epos(YEPs). A pattern search method was used for searching the optimum fermentation medium in the test space, which was as follows(g/L): potassium nitrate 8.00, soybean peptone 17.60, potassium hydrogen phosphate 1.00, beef extraction 6.46, yeast extraction 1.00, calcium chloride 0.25, sodium chloride 1.00 and ferric chloride 0.02. The optimum fermentation medium was expected to result in a yield of Epos(YEPs) of 2.48 mg/L. The validation experiments with the optimum medium were performed in triplicate and the average yield of Epos was 2.45 mg/L which was 7.78 times higher than that of Epos prepared without optimization.展开更多
[Objectives] This study was conducted to further improve the application of Oenococcus oeni in the wine brewing industry. [Methods] O. oeni was isolated, screened, and identified, and medium optimization was performed...[Objectives] This study was conducted to further improve the application of Oenococcus oeni in the wine brewing industry. [Methods] O. oeni was isolated, screened, and identified, and medium optimization was performed to determine the best medium, temperature and oxygen conditions. [Results] O. oeni grew better in mFT80 medium, and the culture conditions were 25 ℃ and an anaerobic condition. [Conclusions] This study provides a reference for the development of China’s wine industry.展开更多
Carbohydrases secreted by marine Vibrio sp. YKW-34 with strong Laminaria cell wall degrading ability were screened, and among them alginate lyase was found to be dominant. The effects of medium composition and culturi...Carbohydrases secreted by marine Vibrio sp. YKW-34 with strong Laminaria cell wall degrading ability were screened, and among them alginate lyase was found to be dominant. The effects of medium composition and culturing condition on the produc- tion of alginate lyase by marine Vibrio sp. YKW-34 in flask were investigated in this study. In the culture medium of marine broth, no alginate lyase was produced. The activity of the alginate lyase, after being induced, reached 5 UmL–1. The best inoculum volume and inoculum age were 10% and 12 h, respectively. The optimal temperature for alginate lyase production was 25℃. The fermentation medium was composed of 0.5% of Laminaria powder and 0.2% of KNO3 with an initial acidity of pH 8.0. Alginate could induce alginate lyase production but not as efficiently as Laminaria powder did. The addition of fucoidan, cellulose and glucose had nega- tive effect on the alginate lyase production. Other kinds of nitrogen sources, such as yeast extract, beef extract and peptone, had posi- tive effect on the growth of the microorganism and negative effect on alginate lyase production. In addition, the time course of algi- nate lyase production under the optimized condition was described. The optimal harvest time was 48 h.展开更多
Response surface methodology (RSM) was used to optimize the fermentation medium for enhancing pyruvic acid production by Torulopsis glabrata TP19. In the first step of optimization, with Plackett-Burman design, ammoni...Response surface methodology (RSM) was used to optimize the fermentation medium for enhancing pyruvic acid production by Torulopsis glabrata TP19. In the first step of optimization, with Plackett-Burman design, ammonium sulfate, glucose and nicotinic acid were found to be the important factors affecting pyruvic acid production significantly. In the second step, a 23 full factorial central composite design and RSM were applied to determine the optimal concentration of each significant variable. A second-order polynomial was determined by the multiple regression analysis of the experimental data. The optimum values for the critical components were obtained as follows: ammonium sulfate 0.7498 (10.75 g/L), glucose 0.9383 (109.38 g/L) and nicotinic acid 0.3633 (7.86 mg/L) with a predicted value of maximum pyruvic acid production of 42.2 g/L. Under the optimal conditions, the practical pyruvic acid production was 42.4 g/L. The determination coefficient (R2) was 0.9483, which ensures adequate credibility of the model. By scaling up fermentation from flask to jar fermentor, we obtained promising results.展开更多
Harmful algal blooms(HABs) have led to extensive ecological and environmental issues and huge economic losses.Various HAB control techniques have been developed,and biological methods have been paid more attention.Alg...Harmful algal blooms(HABs) have led to extensive ecological and environmental issues and huge economic losses.Various HAB control techniques have been developed,and biological methods have been paid more attention.Algicidal bacteria is a general designation for bacteria which inhibit algal growth in a direct or indirect manner,and kill or damage the algal cells.A metabolite which is strongly toxic to the dinoflagellate Alexandrium tamarense was produced by strain DH46 of the alga-lysing bacterium Alteromonas sp.The culture conditions were optimized using a single-factor test method.Factors including carbon source,nitrogen source,temperature,initial pH value,rotational speed and salinity were studied.The results showed that the cultivation of the bacteria at 28℃ and 180 r min-1with initial pH 7 and 30 salt contcentration favored both the cell growth and the lysing effect of strain DH46.The optimal medium composition for strain DH46 was determined by means of uniform design experimentation,and the most important components influencing the cell density were tryptone,yeast extract,soluble starch,NaNO3 and MgSO4.When the following culture medium was used(tryptone 14.0g,yeast extract 1.63g,soluble starch 5.0 g,NaNO3 1.6 g,MgSO4 2.3 g in 1L),the largest bacterial dry weight(7.36 g L-1) was obtained,which was an enhancement of 107% compared to the initial medium;and the algal lysis rate was as high as 98.4% which increased nearly 10% after optimization.展开更多
[Objectives] To study the optimal proportion and formulation process of Jinweng granule,the physicochemical properties of the optimal preparing process was observed. [Methods] Adopting the D-optimal mixture design met...[Objectives] To study the optimal proportion and formulation process of Jinweng granule,the physicochemical properties of the optimal preparing process was observed. [Methods] Adopting the D-optimal mixture design method,selecting the mixing ratio of starch,dextrin,fumei powder and lactose as tested factors,and selecting the most significant factor between hygroscopicity,formability,solubility as the evaluation index,the optimal proportion of filler was examined by system experiments. Granularity,solubility,the angle of repose,and critical relative humidity( CRH) were used to evaluate the optimal proportion and formulation process of Jinweng granule. [Results]The optimal prescription of Jinweng granule is extract∶ starch∶ dextrin∶ lactose∶ fumei powder( 1∶ 0. 5∶ 0. 05∶ 0. 3∶ 0. 15),and the binder was consisted of 1% sodium carboxymethylcellulose( CMC) slurry and 3% starch syrup. The CRH of the optimum formulation process of granule is 72%,and the fluidity,solubility and granularity were qualified. [Conclusions] The process model established by D-optimum mixture design has good predictability,and the granule prepared by the optimal proportion has good repeatability,and the granule proportion and formulation process is stable and reliable.展开更多
Response surface methodology was applied to optimize medium components for production of recombinant calf chymosin by Kluyveromyces lactis GG799.The previous data indicated that the most suitable carbon source,nitroge...Response surface methodology was applied to optimize medium components for production of recombinant calf chymosin by Kluyveromyces lactis GG799.The previous data indicated that the most suitable carbon source,nitrogen source,salt and vitamin were glucose,yeast extract,KH2PO4 and Ca D-Pantothenate,respectively.The concentration of four media components were optimized by using central composite design of response surface methodology.The optimum medium composition for recombinant calf chymosin production was found to contain glucose 29.84 g· L-1,yeast extract 19.85 g·L-1,KH2PO4 0.1 g·L-1 and Ca D-Pantothenate 4.49 mg·L-1.The enzyme activity of recombinant calf chymosin was 722 U· mL-1,which was in an excellent agreement with the predicted value(723 U·mL-1).The production of recombinant calf chymosin from Kluyveromyces lactis GG799 was effectively increased by response surface methodology.展开更多
In order to screen a high-yield spergualin-production strain and an optimal fermentation medium,large numbers of isolates were selected after ultraviolet(UV)mutation and self-tolerant mutation of Bacillus laterosporus...In order to screen a high-yield spergualin-production strain and an optimal fermentation medium,large numbers of isolates were selected after ultraviolet(UV)mutation and self-tolerant mutation of Bacillus laterosporus A7.A high-yield strain A-94-7 was obtained and the spergualin productivity was 4.1-fold of the parent strain.The genetic stability of the high-yield strain Bacillus laterosporus A-94-7 was very good.After fermentation medium optimization,Bacillus laterosporus A-94-7 was able to produce 380 mg?L-1.The spergualin productivity in Bacillus laterosporus A7 was increased 4.75-fold by mutation and medium optimization.展开更多
Hexanoic acid (HX) is a crucial flavor compound and precursor of ethyl caproate (EA), which determines the quality of Chinese Luzhou-flavor liquor (CLFL). The isolation, purification, identification, and optimization ...Hexanoic acid (HX) is a crucial flavor compound and precursor of ethyl caproate (EA), which determines the quality of Chinese Luzhou-flavor liquor (CLFL). The isolation, purification, identification, and optimization of fermentation conditions of HX-producing bacteria are essential for industrial CLFL production. In this study, one strain of HX-producing bacterium was isolated from six candidate bacterial strains and identified as Clostridium sartagoneforme. Then, the growth characteristics and HX production of C. sartagoneforme were investigated. Sodium acetate medium was identified as the optimal fermentation medium from four candidate media. C. sartagoneforme yielded 800.85 ± 12.87 mg/100mL HX in sodium acetate medium. Then, to further optimize the formula of the fermentation medium, the carbon and nitrogen sources and inorganic salt component of the fermentation medium were investigated using HX yields as an optimization index. Optimization was performed with a single-factor experiment and the Taguchi design method. The single-factor experiment showed that the highest HX outputs were obtained when the sodium acetate medium contained 2.5 g/L yeast extract, 1.8 g/L KCl, 20 g/L sodium acetate, 15 mL/L ethanol, and 1.5 g/L glucose. In the orthogonal experiment designed using the Taguchi design method, HX yields reached 2018.29 ± 46.37 mg/100mL in sodium acetate medium that contained 3.5 g/L yeast extract, 1.8 g/L KCl, 25 g/L sodium acetate, and 15 mL/L ethanol.展开更多
This paper presents a technique for Medium Term Load Forecasting (MTLF) using Particle Swarm Optimization (PSO) algorithm based on Least Squares Regression Methods to forecast the electric loads of the Jordanian grid ...This paper presents a technique for Medium Term Load Forecasting (MTLF) using Particle Swarm Optimization (PSO) algorithm based on Least Squares Regression Methods to forecast the electric loads of the Jordanian grid for year of 2015. Linear, quadratic and exponential forecast models have been examined to perform this study and compared with the Auto Regressive (AR) model. MTLF models were influenced by the weather which should be considered when predicting the future peak load demand in terms of months and weeks. The main contribution for this paper is the conduction of MTLF study for Jordan on weekly and monthly basis using real data obtained from National Electric Power Company NEPCO. This study is aimed to develop practical models and algorithm techniques for MTLF to be used by the operators of Jordan power grid. The results are compared with the actual peak load data to attain minimum percentage error. The value of the forecasted weekly and monthly peak loads obtained from these models is examined using Least Square Error (LSE). Actual reported data from NEPCO are used to analyze the performance of the proposed approach and the results are reported and compared with the results obtained from PSO algorithm and AR model.展开更多
An efficient culture medium producing a bacterial elastase with high yields was developed further following preliminary studies by means of response surface method. Central composite design (CCD) and response surface ...An efficient culture medium producing a bacterial elastase with high yields was developed further following preliminary studies by means of response surface method. Central composite design (CCD) and response surface methodology were applied to optimize the medium constituents. A central composite design was used to explain the combined effect of three medium constituents, viz, glucose, K2HPO4, MgSO4·7H2O. The strain produced more elastase in the completely optimized medium, as compared with the partially optimized medium. The fitted model of the second model, as per RSM, showed that glucose was 7.4 g/100 ml, casein 1.13 g/100 ml, corn steep flour 0.616 g/100 ml, KEHPO4 0.206 g/100 ml and MgSO4·7H2O 0.034 g/100 ml. The fermentation kinetics of these two culture media in the flask experiments were analyzed. It was found that the highest elastase productivity occurred at 54 hours. Higher glucose concentration had inhibitory effect on elastase production. At the same time, we observed that the glucose consumption rate was slow in the completely optimized medium, which can explain the lag period of the highest elastase production. Some metal ions and surfactant additives also affected elastase production and cell growth.展开更多
Traditional small current grounding system has many advantages. Pilot operation shows that optimized one has even better operation characteristics. It has proven to be a geenrallly properand relatively perfect neutyal...Traditional small current grounding system has many advantages. Pilot operation shows that optimized one has even better operation characteristics. It has proven to be a geenrallly properand relatively perfect neutyal grounding method in urban MV network.展开更多
<span style="font-family:Verdana;">Venturi tubes are widely used in manufacture and chemical industry and at</span><span style="font-family:Verdana;"><span style="font-fam...<span style="font-family:Verdana;">Venturi tubes are widely used in manufacture and chemical industry and at</span><span style="font-family:Verdana;"><span style="font-family:Verdana;">t</span></span><span style="font-family:Verdana;">ract broad attention. To improve the transmission efficiency, the optimization of Venturi tube has been carried out, the transport substances involved in either liquid, solid, gas or two of them. The Venturi tubes that used for conveying of three-phase flow, which is consisted of solid, liquid and gas, are poorly investigated. In this paper, a Venturi tube employed in one surface treatment equipment was proposed. The velocity and pressure distribution in the flow field of Venturi tube with different key geometric parameters including diameter ratio, convergence angle and diffuser angle have been studied. One optimal solution has been selected. The negative pressure of suction port can reach a value as high as -</span><span style="font-family:Verdana;">1550 Pa to -</span><span style="font-family:Verdana;">1600 Pa. Such negative pressure offers the opportunities for transporting mixed abrasive.</span>展开更多
[Objective] T his study aimed to investigate the protective effects of proteins,salts,sugars and trace elements on soybean rhizobium strain HW-05 by response surface methodology. [Method]Different types,combinations,r...[Objective] T his study aimed to investigate the protective effects of proteins,salts,sugars and trace elements on soybean rhizobium strain HW-05 by response surface methodology. [Method]Different types,combinations,ratios and concentrations of protective agents were designed. Under simulated conditions,the optimal protective agent formulation was screened for improving the survival rate and survival time of soybean rhizobium strain HW-05. The optimal combination of significant factors was determined by Box-Behnken central composite design. [Result] T hree significant factors affecting effective number of viable cells were screened,including peptone,xanthan gum and Na Cl. The final concentration of each compound was optimized: 0. 13% peptone,0. 011% xanthan gum,0. 30%Na Cl. [Conclusion] After addition of protective agent and preservation at room temperature for six months,effective number of viable cells of soybean rhizobium strain HW-05 reached 3.185 × 10~8 CFU / ml. The survival rate of HW-05 cells was improved by more than 25% compared with the control group(2.458×10~8 CFU / ml).展开更多
Anti-lipopolysaccharide factors (ALFs) are important antimicrobial peptides that are isolated from some aquatic species. In a previous study, we isolated ALF genes from Chinese mitten crab, Eriocheir sinensis. In this...Anti-lipopolysaccharide factors (ALFs) are important antimicrobial peptides that are isolated from some aquatic species. In a previous study, we isolated ALF genes from Chinese mitten crab, Eriocheir sinensis. In this study, we optimized the production of a recombinant ALF by expressing E. sinensis ALF genes in Escherichia coli maintained in shake-flasks. In particular, we focused on optimization of both the medium composition and the culture condition. Various medium components were analyzed by the Plackett-Burman design, and two significant screened factors, (NH4)2SO4 and KH2PO4, were further optimized via the central composite design (CCD). Based on the CCD analysis, we investigated the induction start-up time, the isopropylthio-D-galactoside (IPTG) concentration, the post-induction time, and the temperature by response surface methodology. We found that the highest level of ALF fusion protein was achieved in the medium containing 1.89 g/L (NH4)2SO4 and 3.18 g/L KH2PO4, with a cell optical density of 0.8 at 600 nm before induction, an IPTG concentration of 0.5 mmol/L, a post-induction temperature of 32.7°C, and a post-induction time of 4 h. Applying the whole optimization strategy using all optimal factors improved the target protein content from 6.1% (without optimization) to 13.2%. We further applied the optimized medium and conditions in high cell density cultivation, and determined that the soluble target protein constituted 10.5% of the total protein. Our identification of the economic medium composition, optimal culture conditions, and details of the fermentation process should facilitate the potential application of ALF for further research.展开更多
The optimization of nutrient levels for the production of recombinant hyperthermophilic esterase by E.coli was carried out with response surface methodology(RSM) based on the central composite rotatable design(CCRD). ...The optimization of nutrient levels for the production of recombinant hyperthermophilic esterase by E.coli was carried out with response surface methodology(RSM) based on the central composite rotatable design(CCRD). A 2 4 central composite rotatable design was used to study the combined effect of the nutritional constituents like yeast extract, peptone, mineral salt and trace metals. The P-value of the coefficient for the linear effect of peptone concentration was 0.0081 and trace metals solution was less than 0.0001, suggesting that these were the principal variables with significant effect on the hyperthermophilic esterase production. The predicted optimal hyperthermophilic esterase yield was 269.17 U/mL, whereas an actual experimental value of 284.58 U/mL was obtained.展开更多
基金Supported by School-level High-level Talent Project (XGY2021A022)Doctoral Research Startup Fund of Department of Science&Technology of Liaoning Province (2021-BS-252)。
文摘[Objectives]This study was conducted to optimize the Formulation Process of glucosamine chondroitin sulfate tablets. [Methods] The orthogonal design with three levels was carried out with microcrystalline cellulose, calcium hydrophosphate and cross-linked polyvinylpyrrolidone as three factors to optimize the preparation process. [Results] When microcrystalline cellulose 200 mg/tablet, calcium hydrophosphate 150 mg/tablet, and cross-linked polyvinylpyrrolidone 80 mg/tablet were added, the angle of repose could meet the requirements of tablet pressing, and the dissolution could reach more than 95% in 30 min. The results of the orthogonal test showed that the dissolution effect of self-made tablets was faster than that of commercial products. [Conclusions] The glucosamine hydrochloride chondroitin sulfate tablets prepared by this prescription have better quality.
基金Supported by the National Basic Research Program of China (‘‘973’’ Program:2014CB745100)the National Natural Science Foundation of China (No.21576201 and No.21176183)
文摘Response surface methodology was used to optimize the medium for antifungal active substance production from Streptomyces lydicus E12 in flask cultivation.Initially,the component factors,which influence antifungal substance production,were studied by varying one factor at a time.Starch,soybean cake powder,K_2HPO_4·3H_2O and MgSO_4·7H_2O were found to have a significant effect on the production of antifungal substances by the traditional design.Then,a Box-Behnken design was applied for further optimization.A quadratic model was found to fit antifungal active substance production.The analysis revealed that the optimum values of the tested variable were starch 84.96 g/L,soybean cake powder 4.13 g/L,glucose 5 g/L,MgSO_4·7H_2O 1.23 g/L,K_2HPO_4·3H_2O2.14 g/L and NaCl 0.5 g/L.The test result of 67.44%antifungal inhibition agreed with the prediction and increased by 14.28%in comparison with the basal medium.
基金National Natural Science Foundation of China(Grant No.39970005)for its financial support
文摘Yeast strain Y68 producing high level of pullulan was isolated from the phyton collected in Toulouse, France. This strain was identified to be Rhodotorula bacarum by BIOLOG analysis. This is the first report that pullulan was produced by Rhodotorula bacarum. The optimal medium (g L -1) for pullulan production by this strain was 80 glucose, 20 soybean cake hydrolysate, 5 K 2HPO 4, 1 NaCl, 0.2 MgSO 4·7H 2O, 0.6 (NH 4) 2SO 4, pH 7.0. Under this condition, 54 g L -1 pullulan was produced within 60 h at 30 ℃. Pullulan is a better starting material for producing marine prodrugs.
基金Supported by the Science Technology Development Project of Jilin Province,China(No.20020503-2)
文摘A sequential statistical approach was applied to optimizing the fermentation medium of epothilones(Epos) production by means of a mutant which was obtained by treating polyangium cellulosum ATCC 15384 with nitrite and ultraviolet. The effects of different carbon sources and nitrogen sources on the fermentation medium were tested, and the suitable ones were selected. Then a uniform design was employed to design the experiments. A linear model was developed for identifying the significant components in fermentation medium, while a third degree polynomial model was used for studying the relationship between the concentration of the components in fermentation medium and the yield of Epos(YEPs). A pattern search method was used for searching the optimum fermentation medium in the test space, which was as follows(g/L): potassium nitrate 8.00, soybean peptone 17.60, potassium hydrogen phosphate 1.00, beef extraction 6.46, yeast extraction 1.00, calcium chloride 0.25, sodium chloride 1.00 and ferric chloride 0.02. The optimum fermentation medium was expected to result in a yield of Epos(YEPs) of 2.48 mg/L. The validation experiments with the optimum medium were performed in triplicate and the average yield of Epos was 2.45 mg/L which was 7.78 times higher than that of Epos prepared without optimization.
文摘[Objectives] This study was conducted to further improve the application of Oenococcus oeni in the wine brewing industry. [Methods] O. oeni was isolated, screened, and identified, and medium optimization was performed to determine the best medium, temperature and oxygen conditions. [Results] O. oeni grew better in mFT80 medium, and the culture conditions were 25 ℃ and an anaerobic condition. [Conclusions] This study provides a reference for the development of China’s wine industry.
文摘Carbohydrases secreted by marine Vibrio sp. YKW-34 with strong Laminaria cell wall degrading ability were screened, and among them alginate lyase was found to be dominant. The effects of medium composition and culturing condition on the produc- tion of alginate lyase by marine Vibrio sp. YKW-34 in flask were investigated in this study. In the culture medium of marine broth, no alginate lyase was produced. The activity of the alginate lyase, after being induced, reached 5 UmL–1. The best inoculum volume and inoculum age were 10% and 12 h, respectively. The optimal temperature for alginate lyase production was 25℃. The fermentation medium was composed of 0.5% of Laminaria powder and 0.2% of KNO3 with an initial acidity of pH 8.0. Alginate could induce alginate lyase production but not as efficiently as Laminaria powder did. The addition of fucoidan, cellulose and glucose had nega- tive effect on the alginate lyase production. Other kinds of nitrogen sources, such as yeast extract, beef extract and peptone, had posi- tive effect on the growth of the microorganism and negative effect on alginate lyase production. In addition, the time course of algi- nate lyase production under the optimized condition was described. The optimal harvest time was 48 h.
文摘Response surface methodology (RSM) was used to optimize the fermentation medium for enhancing pyruvic acid production by Torulopsis glabrata TP19. In the first step of optimization, with Plackett-Burman design, ammonium sulfate, glucose and nicotinic acid were found to be the important factors affecting pyruvic acid production significantly. In the second step, a 23 full factorial central composite design and RSM were applied to determine the optimal concentration of each significant variable. A second-order polynomial was determined by the multiple regression analysis of the experimental data. The optimum values for the critical components were obtained as follows: ammonium sulfate 0.7498 (10.75 g/L), glucose 0.9383 (109.38 g/L) and nicotinic acid 0.3633 (7.86 mg/L) with a predicted value of maximum pyruvic acid production of 42.2 g/L. Under the optimal conditions, the practical pyruvic acid production was 42.4 g/L. The determination coefficient (R2) was 0.9483, which ensures adequate credibility of the model. By scaling up fermentation from flask to jar fermentor, we obtained promising results.
基金financially supported by the National Natural Science Foundation(40930847,31070442)the Natural Science Foundation of Fujian Province(2012J01150)Public science and technology research funds projects of ocean(201305016,201305041,201305022) and MELRI1003
文摘Harmful algal blooms(HABs) have led to extensive ecological and environmental issues and huge economic losses.Various HAB control techniques have been developed,and biological methods have been paid more attention.Algicidal bacteria is a general designation for bacteria which inhibit algal growth in a direct or indirect manner,and kill or damage the algal cells.A metabolite which is strongly toxic to the dinoflagellate Alexandrium tamarense was produced by strain DH46 of the alga-lysing bacterium Alteromonas sp.The culture conditions were optimized using a single-factor test method.Factors including carbon source,nitrogen source,temperature,initial pH value,rotational speed and salinity were studied.The results showed that the cultivation of the bacteria at 28℃ and 180 r min-1with initial pH 7 and 30 salt contcentration favored both the cell growth and the lysing effect of strain DH46.The optimal medium composition for strain DH46 was determined by means of uniform design experimentation,and the most important components influencing the cell density were tryptone,yeast extract,soluble starch,NaNO3 and MgSO4.When the following culture medium was used(tryptone 14.0g,yeast extract 1.63g,soluble starch 5.0 g,NaNO3 1.6 g,MgSO4 2.3 g in 1L),the largest bacterial dry weight(7.36 g L-1) was obtained,which was an enhancement of 107% compared to the initial medium;and the algal lysis rate was as high as 98.4% which increased nearly 10% after optimization.
基金Supported by Public Welfare and Industry Special Fund Project of the Ministry of Agriculture(201303040-05)Natural Science Foundation Project of CQCSTC(2013FYF110600)
文摘[Objectives] To study the optimal proportion and formulation process of Jinweng granule,the physicochemical properties of the optimal preparing process was observed. [Methods] Adopting the D-optimal mixture design method,selecting the mixing ratio of starch,dextrin,fumei powder and lactose as tested factors,and selecting the most significant factor between hygroscopicity,formability,solubility as the evaluation index,the optimal proportion of filler was examined by system experiments. Granularity,solubility,the angle of repose,and critical relative humidity( CRH) were used to evaluate the optimal proportion and formulation process of Jinweng granule. [Results]The optimal prescription of Jinweng granule is extract∶ starch∶ dextrin∶ lactose∶ fumei powder( 1∶ 0. 5∶ 0. 05∶ 0. 3∶ 0. 15),and the binder was consisted of 1% sodium carboxymethylcellulose( CMC) slurry and 3% starch syrup. The CRH of the optimum formulation process of granule is 72%,and the fluidity,solubility and granularity were qualified. [Conclusions] The process model established by D-optimum mixture design has good predictability,and the granule prepared by the optimal proportion has good repeatability,and the granule proportion and formulation process is stable and reliable.
基金Supported by Science and Technology Fund of Heilongjiang Province Education Department (11541018)
文摘Response surface methodology was applied to optimize medium components for production of recombinant calf chymosin by Kluyveromyces lactis GG799.The previous data indicated that the most suitable carbon source,nitrogen source,salt and vitamin were glucose,yeast extract,KH2PO4 and Ca D-Pantothenate,respectively.The concentration of four media components were optimized by using central composite design of response surface methodology.The optimum medium composition for recombinant calf chymosin production was found to contain glucose 29.84 g· L-1,yeast extract 19.85 g·L-1,KH2PO4 0.1 g·L-1 and Ca D-Pantothenate 4.49 mg·L-1.The enzyme activity of recombinant calf chymosin was 722 U· mL-1,which was in an excellent agreement with the predicted value(723 U·mL-1).The production of recombinant calf chymosin from Kluyveromyces lactis GG799 was effectively increased by response surface methodology.
基金Supported by Program for Innovative Research Team of Northeast Agricultural University
文摘In order to screen a high-yield spergualin-production strain and an optimal fermentation medium,large numbers of isolates were selected after ultraviolet(UV)mutation and self-tolerant mutation of Bacillus laterosporus A7.A high-yield strain A-94-7 was obtained and the spergualin productivity was 4.1-fold of the parent strain.The genetic stability of the high-yield strain Bacillus laterosporus A-94-7 was very good.After fermentation medium optimization,Bacillus laterosporus A-94-7 was able to produce 380 mg?L-1.The spergualin productivity in Bacillus laterosporus A7 was increased 4.75-fold by mutation and medium optimization.
文摘Hexanoic acid (HX) is a crucial flavor compound and precursor of ethyl caproate (EA), which determines the quality of Chinese Luzhou-flavor liquor (CLFL). The isolation, purification, identification, and optimization of fermentation conditions of HX-producing bacteria are essential for industrial CLFL production. In this study, one strain of HX-producing bacterium was isolated from six candidate bacterial strains and identified as Clostridium sartagoneforme. Then, the growth characteristics and HX production of C. sartagoneforme were investigated. Sodium acetate medium was identified as the optimal fermentation medium from four candidate media. C. sartagoneforme yielded 800.85 ± 12.87 mg/100mL HX in sodium acetate medium. Then, to further optimize the formula of the fermentation medium, the carbon and nitrogen sources and inorganic salt component of the fermentation medium were investigated using HX yields as an optimization index. Optimization was performed with a single-factor experiment and the Taguchi design method. The single-factor experiment showed that the highest HX outputs were obtained when the sodium acetate medium contained 2.5 g/L yeast extract, 1.8 g/L KCl, 20 g/L sodium acetate, 15 mL/L ethanol, and 1.5 g/L glucose. In the orthogonal experiment designed using the Taguchi design method, HX yields reached 2018.29 ± 46.37 mg/100mL in sodium acetate medium that contained 3.5 g/L yeast extract, 1.8 g/L KCl, 25 g/L sodium acetate, and 15 mL/L ethanol.
文摘This paper presents a technique for Medium Term Load Forecasting (MTLF) using Particle Swarm Optimization (PSO) algorithm based on Least Squares Regression Methods to forecast the electric loads of the Jordanian grid for year of 2015. Linear, quadratic and exponential forecast models have been examined to perform this study and compared with the Auto Regressive (AR) model. MTLF models were influenced by the weather which should be considered when predicting the future peak load demand in terms of months and weeks. The main contribution for this paper is the conduction of MTLF study for Jordan on weekly and monthly basis using real data obtained from National Electric Power Company NEPCO. This study is aimed to develop practical models and algorithm techniques for MTLF to be used by the operators of Jordan power grid. The results are compared with the actual peak load data to attain minimum percentage error. The value of the forecasted weekly and monthly peak loads obtained from these models is examined using Least Square Error (LSE). Actual reported data from NEPCO are used to analyze the performance of the proposed approach and the results are reported and compared with the results obtained from PSO algorithm and AR model.
文摘An efficient culture medium producing a bacterial elastase with high yields was developed further following preliminary studies by means of response surface method. Central composite design (CCD) and response surface methodology were applied to optimize the medium constituents. A central composite design was used to explain the combined effect of three medium constituents, viz, glucose, K2HPO4, MgSO4·7H2O. The strain produced more elastase in the completely optimized medium, as compared with the partially optimized medium. The fitted model of the second model, as per RSM, showed that glucose was 7.4 g/100 ml, casein 1.13 g/100 ml, corn steep flour 0.616 g/100 ml, KEHPO4 0.206 g/100 ml and MgSO4·7H2O 0.034 g/100 ml. The fermentation kinetics of these two culture media in the flask experiments were analyzed. It was found that the highest elastase productivity occurred at 54 hours. Higher glucose concentration had inhibitory effect on elastase production. At the same time, we observed that the glucose consumption rate was slow in the completely optimized medium, which can explain the lag period of the highest elastase production. Some metal ions and surfactant additives also affected elastase production and cell growth.
文摘Traditional small current grounding system has many advantages. Pilot operation shows that optimized one has even better operation characteristics. It has proven to be a geenrallly properand relatively perfect neutyal grounding method in urban MV network.
文摘<span style="font-family:Verdana;">Venturi tubes are widely used in manufacture and chemical industry and at</span><span style="font-family:Verdana;"><span style="font-family:Verdana;">t</span></span><span style="font-family:Verdana;">ract broad attention. To improve the transmission efficiency, the optimization of Venturi tube has been carried out, the transport substances involved in either liquid, solid, gas or two of them. The Venturi tubes that used for conveying of three-phase flow, which is consisted of solid, liquid and gas, are poorly investigated. In this paper, a Venturi tube employed in one surface treatment equipment was proposed. The velocity and pressure distribution in the flow field of Venturi tube with different key geometric parameters including diameter ratio, convergence angle and diffuser angle have been studied. One optimal solution has been selected. The negative pressure of suction port can reach a value as high as -</span><span style="font-family:Verdana;">1550 Pa to -</span><span style="font-family:Verdana;">1600 Pa. Such negative pressure offers the opportunities for transporting mixed abrasive.</span>
基金Supported by Fund of Heilongjiang Academy of Sciences
文摘[Objective] T his study aimed to investigate the protective effects of proteins,salts,sugars and trace elements on soybean rhizobium strain HW-05 by response surface methodology. [Method]Different types,combinations,ratios and concentrations of protective agents were designed. Under simulated conditions,the optimal protective agent formulation was screened for improving the survival rate and survival time of soybean rhizobium strain HW-05. The optimal combination of significant factors was determined by Box-Behnken central composite design. [Result] T hree significant factors affecting effective number of viable cells were screened,including peptone,xanthan gum and Na Cl. The final concentration of each compound was optimized: 0. 13% peptone,0. 011% xanthan gum,0. 30%Na Cl. [Conclusion] After addition of protective agent and preservation at room temperature for six months,effective number of viable cells of soybean rhizobium strain HW-05 reached 3.185 × 10~8 CFU / ml. The survival rate of HW-05 cells was improved by more than 25% compared with the control group(2.458×10~8 CFU / ml).
基金Supported by the National High Technology Research and Development Program of China(863 Program)(No.2006AA100311)
文摘Anti-lipopolysaccharide factors (ALFs) are important antimicrobial peptides that are isolated from some aquatic species. In a previous study, we isolated ALF genes from Chinese mitten crab, Eriocheir sinensis. In this study, we optimized the production of a recombinant ALF by expressing E. sinensis ALF genes in Escherichia coli maintained in shake-flasks. In particular, we focused on optimization of both the medium composition and the culture condition. Various medium components were analyzed by the Plackett-Burman design, and two significant screened factors, (NH4)2SO4 and KH2PO4, were further optimized via the central composite design (CCD). Based on the CCD analysis, we investigated the induction start-up time, the isopropylthio-D-galactoside (IPTG) concentration, the post-induction time, and the temperature by response surface methodology. We found that the highest level of ALF fusion protein was achieved in the medium containing 1.89 g/L (NH4)2SO4 and 3.18 g/L KH2PO4, with a cell optical density of 0.8 at 600 nm before induction, an IPTG concentration of 0.5 mmol/L, a post-induction temperature of 32.7°C, and a post-induction time of 4 h. Applying the whole optimization strategy using all optimal factors improved the target protein content from 6.1% (without optimization) to 13.2%. We further applied the optimized medium and conditions in high cell density cultivation, and determined that the soluble target protein constituted 10.5% of the total protein. Our identification of the economic medium composition, optimal culture conditions, and details of the fermentation process should facilitate the potential application of ALF for further research.
文摘The optimization of nutrient levels for the production of recombinant hyperthermophilic esterase by E.coli was carried out with response surface methodology(RSM) based on the central composite rotatable design(CCRD). A 2 4 central composite rotatable design was used to study the combined effect of the nutritional constituents like yeast extract, peptone, mineral salt and trace metals. The P-value of the coefficient for the linear effect of peptone concentration was 0.0081 and trace metals solution was less than 0.0001, suggesting that these were the principal variables with significant effect on the hyperthermophilic esterase production. The predicted optimal hyperthermophilic esterase yield was 269.17 U/mL, whereas an actual experimental value of 284.58 U/mL was obtained.
