Artificial intelligence based optimization of exocellular glucansucrase production from Leuconostoc dextranicum NRRL B-1146

Two different artificial intelligence techniques namely artificial neural network (ANN) and genetic algorithm (GA) were integrated for optimizing fermentation medium for the production of glucansucrase. The experimental data reported in a previous study were used to build the neural network. The ANN was trained using the back propagation algorithm. The ANN predicted values showed good agreement with the experimentally reported ones from a response surface based experiment. The concentrations of three medium components: viz Tween 80, sucrose and K(2)HPO(4) served as inputs to the neural network model and the enzyme activity as the output of the model. A model was generated with a coefficient of correlation (R(2)) of 1.0 for the training set and 0.90 for the test data. A genetic algorithm was used to optimize the input space of the neural network model to find the optimum settings for maximum enzyme activity. This artificial neural network supported genetic algorithm predicted a maximum glucansucrase activity of 6.92U/ml at medium composition of 0.54% (v/v) Tween 80, 5.98% (w/v) sucrose and 1.01% (w/v) K(2)HPO(4). ANN-GA predicted model gave a 6.0% increase of enzyme activity over the regression based prediction for optimized enzyme activity. The maximum enzyme activity experimentally obtained using the ANN-GA designed medium was 6.75+/-0.09U/ml which was in good agreement with the predicted value.     

Screening and optimization of nutritional factors for higher dextransucrase production by Leuconostocmesenteroides NRRL B-640 using statistical approach

To improve dextransucrase production from Leuconostocmesenteroides NRRL B-640 culture medium was screened and optimized using the statistical design techniques of Plackett-Burman and response surface methodology (RSM). Plackett-Burman design with six variables viz. sucrose, yeast extract, K2HPO4, peptone, beef extract and Tween 80 was performed to screen the nutrients that were significantly affecting dextransucrase production. The variables sucrose, K2HPO4, yeast extract and beef extract showed above 90% confidence levels for dextransucrase production and were considered as significant factors for optimization using response surface methodology. 2(4)-central composite design was used for RSM optimization. The experimental results were fitted to a second-order polynomial model which gave a coefficient of determination R2=0.95. The optimized composition of 30g/l sucrose, 18.9g/l yeast extract, 19.4g/l K2HPO4 and 15g/l beef extract gave an experimental value of dextransucrase activity of 10.7U/ml which corresponded well with the predicted value of 10.9U/ml by the model.     

Optimization of culture variables for improving glucoamylase production by alginate-entrapped Thermomucor indicae-seudaticae using statistical methods

Alginate-entrapped sporangiospores of Thermomucor indicae-seudaticae were used for the production of glucoamylase. The critical variables that affected glucoamylase production were identified by Plackett-Burman design (sucrose, yeast-extract, K(2)HPO(4) and asparagine) and further optimized by using a four factor central composite design (CCD) of response surface methodology (RSM). Immobilized sporangiospores secreted 41% and 60% higher glucoamylase titers in shake flasks and airlift fermenter, respectively, when the variables were used at their optimum levels (sucrose 3.0%, yeast-extract 0.2%, K(2)HPO(4) 0.1% and asparagine 0.35%). Glucoamylase production (26.3 U ml(-1)) in the optimized medium was in good agreement with the values predicted by the quadratic model (26.7 U ml(-1)), thereby confirming its validity. The enzyme production was sustainable in flasks of higher volume and also airlift fermenter, and attained a peak within 32 h in the fermenter as compared to that of 48 h in shake flasks.     

Optimization of medium for lipase production by Acinetobacter haemolyticus from healthy human skin

A lipase producing Acinetobacter haemolyticus TA106 was isolated from healthy human skin of tribal population. The maximum activity of 55 U/ml was observed after medium optimization using the "one variable at a time" and the statistical approaches. The optimal composition of the medium was determined as (% w/v or v/v): tryptone--1, yeast extract--0.5, sodium chloride-1, olive oil-1, Tween-80 1, manganese sulphate--5 mM, sucrose--1, pH-7. It was found that maximum production occurred in late log phase, i.e., after 72 h and at 200 rpm. From factorial design and statistical analysis, it was found that pH, temperature, salt, inoculum density and aeration significantly affected the lipase production. It was also noted that inoculum density of 3% (v/v), sucrose (1% w/v) and manganese sulphate (5 mM) displayed maximum lipase activity of 55 U/ml by conventional as well as statistical method. Optimization studies also indicated the increase in specific activity from 0.2 U/mg to 6.7 U/mg.     

Production of beta-fructofuranosidase with transfructosylating activity for fructooligosaccharides synthesis by Aspergillus japonicus NTU-1249.

Microbial beta-fructofuranosidases with transfructosylating activity can catalyze the transfructosylation of sucrose and synthesize fructooligosaccharides. Aspergillus japonicus NTU-1249 isolated from natural habitat was found to produce a significant amount of beta-fructofuranosidase with high transfructosylating activity and to have the potential for industrial production of fructooligosaccharides. In order to improve it's enzyme productivity, the medium composition and the cultivation conditions for A. japonicus NTU-1249 were studied. A. japonicus NTU-1249 can produce 83.5 units of transfructosylating activity per ml broth when cultivated in a shaking flask at 28 degrees C for 72 hours with a modified medium containing 80 g/l sucrose, 15 g/l soybean flour, 5 g/l yeast extract and 5 g/l NaCl at an initial pH of 6.0. The enzyme productivity was also optimized by submerged cultivation in a 5-litre jar fermentor with aeration at 1.5 vvm and agitation at 500 rpm. Under these operating conditions, the productivity of transfructosylating activity increased to 185.6 U/ml. Furthermore, the transfructosylating activity was improved to 256.1 U/ml in 1,000-litre pilot-scale fermentor. Enzymatic synthesis of fructooligosaccharides by beta-fructofuranosidase from A. japonicus NTU-1249 was performed in batch type by adding 5.6 units of transfructosylating activity per gram of sucrose to a 50% (w/v) sucrose solution at pH 5.0 and 50 degrees C. The yield of fructooligosaccharides was about 60% after reaction for 24 hours, and the syrup produced contained 29.8% (w/v) fructooligosaccharides, 15.2% (w/v) glucose and 5.0% (w/v) sucrose.     

Production of amylase by newly isolated moderate halophile,Halobacillus sp. strain MA-2

Production of extracellular amylase was demonstrated under stress conditions of high temperature and high salinity in aerobically cultivated culture of a newly isolated moderately halophilic bacterium of spore-forming Halobacillus sp. strain MA-2 in medium containing starch, peptone, beef extract, and NaCl. The maximum amylase production was secreted in the presence of 15% (w/v) Na(2)SO(4) (3.2 U ml(-1)). The isolate was capable of producing amylase in the presence of NaCl, NaCH(3)COOH, or KCl, with the results NaCl>NaCH(3)COOH>KCl. Maximum amylase activity was exhibited in the medium containing 5% (w/v) NaCl (2.4 U ml(-1)). Various carbon sources induced enzyme production. The potential of different carbohydrates in the amylase production was in the order: dextrin>starch>maltose>lactose>glucose>sucrose. In the presence of sodium arsenate (100 mM), maximum production of the enzyme was observed at 3.0 U ml(-1). Copper sulfate (0.1 mM) decreased the amylase production considerately, while lead nitrate had no significant enhancement on amylase production (p<0.05). The pH, temperature, and aeration optima for enzyme production were 7.8, 30 degrees C, and 200 rpm, respectively, while the optimum pH and temperature for enzyme activity was 7.5-8.5 and 50 degrees C, respectively.     

Improvement of xylanase production in solid state fermentation by alkali-tolerant Aspergillus fumigatus MKU1 using a fractional factorial design

Optimization of media for the maximum production of xylanase by Aspergillus fumigatus MKUI was carried out using De Meo's fractional factorial design with seven components such as NaNO3, K2HPO4, MgSO4, FeSO4. KCl, peptone and yeast extract. A. fumigatus produced a maximum of 700 U/gds of enzyme after 48 hr of incubation (before optimization). After two steps of optimization, the medium designed favoured a 2.8 fold (1950 U/gds) increase in xylanase production by A. fumigatus. Optimized medium for Aspergillus fumigatus contained (g/l) NaNO3, 15; K2HPO4, 15; MgSO4, 5; FeSO4, 0.009; KCI, 0.5; peptone, 20; and yeast extract, 10.     

Optimization of fermentation medium and conditions for mycelial growth and water-soluble exo-polysaccharides production by Isaria farinosa B05

The optimal fermentation medium and conditions for mycelial growth and water-soluble exo-polysaccharides production by Isaria farinosa B05 were investigated. The medium components and fermentation conditions were optimized according to the one at a time method, while the concentration of medium components was determined by the orthogonal matrix method. The results showed that the optimal fermentation medium was as follows: sucrose 3.5% (w/v), peptone 0.5%, yeast extract 0.2%, K(2)HPO(4) 0.1%, and MgSO(4) 0.05%. The suitable fermentation conditions were as follows: initial pH 7.0, temperature 25 degrees C, medium volume 75 mL/250 mL, inoculum volume 5% (v/v), time 5d. In such optimal nutrition and environmental conditions, the maximal mycelial yield was 2.124 g/100 mL after 4 day's fermentation, while maximal water-soluble exo-polysaccharides production reached 2.144 g/L after 5 day's fermentation.     

Medium optimization of a hydrophilic solvent‐stable protease from Serratia sp. SYBC H

Two statistical methods were used for medium optimization for a hydrophilic solvent‐stable protease production by Serratia sp. SYBC H with duckweed as the nitrogen source. Orthogonal design was applied to find the significant variables, then response surface methodology (RSM), including Box–Behnken central composite experiments, was used to determine the optimal concentrations and interaction of the significant variables. Results demonstrated that duckweed powder, wheat flour, Tween 80, sodium chloride had significant effects on the solvent‐stable protease production. The interaction between duckweed and wheat flour was significant. The optimal level of the variables for the maximum protease production was duckweed 43.9 g/L, wheat flour 20 g/L, sodium chloride 0.08 M, Tween 80 1% v/v, initial pH 11.0, and inoculum size 7% v/v. The maximum protease activity reached 1922.8 U/mL in the optimized medium, with about 18.3‐fold higher than that in the unoptimized medium. Most importantly, the protease from Serratia sp. SYBC H has successfully catalyzed the specific acylation of sucrose in a two‐solvent medium consisting of pyridine and n‐hexane (1:1, v/v), and non‐specific acylation of sucrose in anhydrous DMSO. These results demonstrated that the protease from Serratia sp. SYBC H is a solvent‐stable protease and it could be an ideal biocatalyst for sugar esters syntheses in non‐aqueous media.     

Optimization of bacteriocin production by Lactobacillus plantarum ST13BR, a strain isolated from barley beer

The cell-free supernatant containing bacteriocin ST13BR, produced by Lactobacillus plantarum ST13BR, inhibits the growth of L. casei, Pseudomonas aeruginosa, Enterococcus faecalis, Klebsiella pneumoniae and Escherichia coli. Based on tricine-SDS-PAGE, bacteriocin ST13BR is 10 kDa in size. Complete inactivation or significant reduction in bacteriocin activity was observed after treatment with Proteinase K, trypsin and pronase, but not with catalase or alpha-amylase. Low bacteriocin activity (200 AU/ml) was recorded in BHI medium, M17 broth, 10% (w/v) soy milk, and 2% and 10% (w/v) molasses, despite good growth. Maximal bacteriocin activity (6,400 AU/ml) was recorded after 23 h in MRS broth, but only at 30 degrees C. Tween 80 in MRS broth increased bacteriocin production by more than 50%. Meat extract or yeast extract as sole nitrogen source, or a combination of the two (1 : 1) in MRS broth, stimulated bacteriocin production (6,400 AU/ml). Only 50% activity (3,200 AU/ml) was recorded with tryptone as sole nitrogen source, whereas a combination of tryptone, meat extract and yeast extract yielded 6,400 AU/ml. Bacteriocin production was not stimulated by the addition of glucose at 2.0% w/v (3,200 AU/ml), nor 2% (w/v) fructose, sucrose, lactose or mannose, respectively (800 AU/ml). Activity levels less than 200 AU/ml were recorded in the presence of 0.05% to 0.5% (w/v) maltose. Maximal bacteriocin production (6,400 AU/ml) was recorded in the presence of 2% (w/v) maltose. Maltose at 4.0% (w/v) led to a 50% reduction of bacteriocin activity. The presence of 1.0% (w/v) and higher KH(2)PO(4), or glycerol at 0.2% (w/v) suppressed bacteriocin production.     

Optimization of a fermentation medium for the production of Penicillin G acylase from Bacillus sp

AIMS: Optimization of Penicillin G acylase (PAC) production from a novel isolate of Bacillus sp. METHODS: Fermentation medium for PAC production was optimized using a two-level fractional factorial design with seven components. RESULTS: A maximum production of 9.5 U ml(-1) of PAC was obtained in an optimized medium containing (g l(-1): K2HPO4, 1.0; MgSO4.7H2O, 0.1; CaCl2.2H2O, 0.1; PAA, 2.0; tryptone, 5.0; yeast extract, 3.0; and sucrose, 50.0. SIGNIFICANCE AND IMPACT OF THE STUDY: The two-step medium optimization resulted in a twofold increase in PAC production. Since the strain Bacillus sp. PGS10 produces a high level of PAC, it could be a potential candidate for industrial production of PAC.     

Isomaltulose production using free cells: optimisation of a culture medium containing agricultural wastes and conversion in repeated-batch processes

The enzyme glucosyltransferase is an industrially important enzyme since it produces non-cariogenic isomaltulose (6-O-alpha-D-glucopyronosyl-1-6-D-fructofuranose) from sucrose by intramolecular transglucosylation. The experimental designs and response surface methodology (RSM) were applied for the optimisation of the nutrient concentrations in the culture medium for the production of glucosyltransferase by Erwinia sp. D12 in shaken flasks at 200 rpm and 30 degrees C. A statistical analysis of the results showed that, in the range studied, the factors had a significant effect (P < 0.05) on glucosyltransferase production and the highest enzyme activity (10.84 U/ml) was observed in culture medium containing sugar cane molasses (150 g l(-1)), corn steep liquor (20 g l(-1)), yeast extract Prodex Lac SD (15 g l(-1)) and K2HPO4 (0.5 g l(-1)) after 8 h at 30 degrees C. The production of cell biomass by the strain of Erwinia sp. D12 was carried out in a 6.6-l fermenter with a mixing rate of 200 rpm and an aeration rate of 1 vvm. Fermentation time, cellular growth, medium pH and glucosyltransferase production were observed. The greatest glucosyltransferase activity was 22.49 U/ml, obtained after 8 h of fermentation. The isomaltulose production from sucrose was performed using free Erwinia sp. D12 cells in a batch process using an orbital shaker. The influence of the parameters sucrose concentration, temperature, pH, and cell concentration on the conversion of sucrose into isomaltulose was studied. The free cells showed a high conversion rate of sucrose into isomaltulose using batch fermentation, obtaining an isomaltulose yield of 72.11% from sucrose solution 35% at 35 degrees C.     

Production of penicillic acid by Aspergillus sclerotiorum CGF

The production of penicillic acid by Aspergillus sclerotiorum CGF for the biocontrol of Phytophthora disease was investigated in submerged fermentation using media composed of different nutrients. Soluble starch was found to be the most effective substrate among the carbon sources used, and produced the highest penicillic acid concentration of 2.98 mg ml(-1). When organic nitrogen sources were used, pharmamedia, yeast extract, and polypeptone-S were found to be suitable organic nitrogen sources (2.46-2.71 mg ml(-1)). The production of penicillic acid was not detected in when inorganic nitrogen sources were used. Only Na2HPO4, among the metal ions and phosphate salts tested, increased the production of penicillic acid (approximately 20%). When A. sclerotiorum CGF was cultured in optimal medium [8.0% (w/v) soluble starch, 0.6% (w/v) yeast extract, and 0.3% (w/v) Na2HPO4], maximum penicillic acid concentration (approximately 9.40 mg ml(-1)) and cell mass (approximately 17.4 g l(-1)) were obtained after 12 days.     

Impact of Extraction Parameters on the Recovery of Lipolytic Activity from Fermented Babassu Cake

Enzyme extraction from solid matrix is as important step in solid-state fermentation to obtain soluble enzymes for further immobilization and application in biocatalysis. A method for the recovery of a pool of lipases from Penicillium simplicissimum produced by solid-state fermentation was developed. For lipase recovery different extraction solution was used and phosphate buffer containing Tween 80 and NaCl showed the best results, yielding lipase activity of 85.7 U/g and 65.7 U/g, respectively. The parameters with great impacts on enzyme extraction detected by the Plackett-Burman analysis were studied by Central Composite Rotatable experimental designs where a quadratic model was built showing maximum predicted lipase activity (160 U/g) at 25°C, Tween 80 0.5% (w/v), pH 8.0 and extraction solution 7 mL/g, maintaining constant buffer molarity of 0.1 M and 200 rpm. After the optimization process a 2.5 fold increase in lipase activity in the crude extract was obtained, comparing the intial value (64 U/g) with the experimental design (160 U/g), thus improving the overall productivity of the process.     

Optimization and purification of glucansucrase produced by Leuconostoc mesenteroides DRP2-19 isolated from Chinese Sauerkraut

Abstract

Strain DRP2-19 was detected to produce high yield of glucansucrase in MRS broth, which was identified to be Leuconostoc mesenteroides. In order for industrial glucansucrase production of L. mesenteroides DRP2-19, a one-factor test was conducted, then response surface method was applied to optimize its yield and discover the best production condition. Based on Plackett–Burman (PB) experiment, sucrose, Ca²⁺, and initial pH were found to be the most significant factors for glucansucrase production. Afterwards, effects of the three main factors on glucansucrase activity were further investigated by central composite design and the optimum composition was sucrose 35.87?g/L, Ca²⁺ 0.21?mmol/L, and initial pH 5.56. Optimum results showed that glucansucrase activity was increased to 3.94?±?0.43?U/mL in 24?hr fermentation, 2.66-fold higher than before. In addition, the crude enzyme was purified using ammonium sulfate precipitation, ion-exchange chromatography, and gel filtration. The molecular weight of glucansucrase was determined as approximately 170?kDa by Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The enzyme was purified 15.77-fold and showed a final specific activity of 338.56?U/mg protein.     

The effect of cultural conditions on the production of lipase by Acremonium strictum

Summary The optimum cultural conditions for the production of lipase byA. strictum under stationary condition are: period of incubation, 7 days; temperature, 30°C; xylose at a concentration of 2% (w/v) and 3.5% (w/v) soyabean meal as carbon and nitrogen sources respectively. Incorporation of 1% (v/v) of Tween 80 in culture medium enhanced enzyme production while the presence of fatty acids reduced both fungal growth and lipase production. The enzyme showed broad substrate specificity.     

低温脂肪酶产生菌的筛选、产酶发酵及粗酶性质研究

利用含有Tween 80的琼脂平板和摇瓶发酵法,从若尔盖高原土壤中筛选产脂肪酶菌株.通过菌落形态和菌体特征观察初步对菌种进行鉴定,得到一株产低温脂肪酶的适冷菌Pseudomonassp.DL-B,并设计正交试验对该菌株的产酶发酵培养条件进行了优化.摇瓶实验表明,该菌株最适产酶发酵培养基为:蔗糖10 g/L,蛋白胨20 ...     

Statistical optimization of production conditions of alkaline pectin lyase from Bacillus cereus using response surface methodology

Alkaline pectin lyase finds applications in the degumming and retting of plant fibres, textile industry and pectic wastewater treatment where it degrades highly methylesterified pectin without prior action of any other pectinase. Response surface methodology (RSM) has been frequently utilized for the optimization of production process of industrially important enzymes from microbes. In the present work, fermentation conditions for the production of pectin lyase from Bacillus cereus were optimized using the factorial and central composite design of RSM. The cubic order polynomial regression model was found to be adequate and significant with a determination coefficient R² of 0.9505 (p?相似文献   

Production of Bacteriocin ST33LD, Produced by Leuconostoc mesenteroides subsp. mesenteroides, as Recorded in the Presence of Different Medium Components

Summary Bacteriocin ST33LD, produced by Leuconostoc mesenteroides subsp. mesenteroides, is approximately 2.7 kDa in size and inhibits Enterococcus faecalis, Escherichia coli, Lactobacillus casei and Pseudomonas aeruginosa. Good growth was recorded in the presence of 10% (w/v) soy milk or 10% (w/v) molasses, but there was no bacteriocin production. Growth in MRS broth adjusted to pH 4.5 yielded low bacteriocin levels (800 AU/ml). However, the same medium adjusted to pH 5.0, 5.5 and 6.5, respectively, yielded 3200 AU/ml. Tween 80 decreased bacteriocin production by more than 50%. Growth in the presence of tryptone yielded maximal activity (12,800 AU/ml), whereas different combinations of tryptone, meat extract and yeast extract produced activity levels of 1600 AU/ml and less. Growth in the presence of 2.0% (w/v) sucrose, or maltose, yielded much higher levels of bacteriocin activity (12,800 AU/ml) compared to growth in the presence of 2.0% (w/v) glucose or lactose (6400 AU/ml). Lower yields were also recorded in the presence of fructose and mannose. KH₂PO₄ at 10.0% (w/v) stimulated bacteriocin production. Glycerol concentrations of 0.5% (w/v) and higher (up to 5.0%, w/v) repressed bacteriocin production by 50%. The addition of cyanocobalamin, thiamine and L-ascorbic acid to MRS broth (1.0 ppm) yielded 12,800 AU/ml bacteriocin, whereas the addition of DL-6,8-thioctic acid yielded only 6 400 AU/ml.     

Production, purification and characterization of thermophilic lipase from Bacillus sp. THL027

A low-cost medium, MGRS, has been developed for growth and lipase production from Bacillus THL027 at 65 degrees C and pH 7.0. MGRS was composed of 2% (v/v) buffer solution (7.3% (w/v) Na(2)HPO(4), 3.2% (w/v) KH(2)PO(4), pH 7.2), 40 microg ml(-1) FeSO(4) and 40 microg ml(-1) MgSO(4), 0.1% (w/v) (NH(4))(2)SO(4) supplemented with 3% NaCl, 0.1% glucose, 1.0% rice bran oil and 0.5% (w/v) rice bran. The lipase was purified 2.6-fold to apparent homogeneity by ultrafiltration and gel filtration chromatography. Its molecular mass was 69 kDa. The purified enzyme was characterized for its general physical properties.