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1.
The effects of cultivation medium compositions including soybean meal, peptone, soybean oil and cornstarch for actinomycin X2 production by Streptomyces spp JAU4234 were accessed by using response surface methodology. The 2(4) full factorial designs and the paths of steepest ascent were effective in searching for the major factors of actinomycin X2 production. In this study, cornstarch and soybean oil showed negative effect on actinomycin X2 production based on the first-order regression coefficients derived from MINITAB software. Subsequently, a central composite design for optimization was further investigated. Preliminary studies showed that soybean meal and peptone were believed to be the major factors for actinomycin X2 production. Estimated optimum compositions for the production of actionmycin X2 were as follows (g/l): soybean meal 21.65 and peptone 9.41, and result in a maximum actionmycin X2 production of 617.4 mg/l. This value was closed to the 612 mg/l actionmycin X2 production from actual experimental observations. The yield of actionmycin X2 was increased by 36.9% by culturing the strain Streptomyces spp JAU4234 in the nutritionally optimized fermentation medium. 相似文献
2.
Genetic differences among Agaricus blazei strains were investigated using somatic incompatibility testing, isozyme analysis, restriction fragment length polymorphism (RFLP) analysis of mitochondrial DNA (mtDNA), and random amplified polymorphic DNA (RAPD) analysis. Eight strains, one cultivated strain from Brazil and seven from Japan, were used in this study. Somatic incompatibility interactions were observed between the Brazilian cultivated strain and the Japanese strains. The Brazilian cultivated strain had its own distinct patterns of esterase isozyme and mtDNA RFLP, but all seven Japanese cultivated strains showed identical patterns. When the RAPD patterns, obtained using eight primers, were compared the eight strains had their own distinct RAPD profiles. Distance values were calculated between all pairs of the strains based on presence or absence of individual RAPD bands, and a dendrogram was constructed by unweighted pair-group method with arithmetic clustering (UPGMA) analysis. Seven Japanese cultivated strains were grouped to each other, and this group was finally linked to the Brazilian cultivated strain. Based on these results, the degree of genetic variation among the A. blazei strains used is discussed. 相似文献
3.
Optimization of riboflavin production by recombinant <Emphasis Type="Italic">Bacillus subtilis</Emphasis> RH44 using statistical designs 总被引:3,自引:0,他引:3
A sequential optimization strategy, based on statistical experimental designs, was used to enhance the production of riboflavin
by recombinant Bacillus subtilis RH44. In the first instance, the medium components were optimized in shake flask cultures. After preliminary experiments
of nitrogen source selection, the two-level Plackett–Burman (PB) design was implemented to screen medium components that significantly
influence riboflavin production. Among the 15 variables tested, glucose, NaNO3, K2HPO4, ZnSO4, and MnCl2 were identified as the most significant factors (confidence levels above 95%) for riboflavin production. The optimal values
of these five variables were determined by response surface methodology (RSM) based on the central composite design (CCD).
The validity of the model developed was verified, and the optimum medium led to a maximum riboflavin concentration of 6.65 g/l,
which was 44.3 and 76.4% higher than the improved medium and the basal medium, respectively. A glucose-limited fed-batch culture
profile in a 5-l fermentor was consequently designed according to the above optimum medium in shake flasks. A final riboflavin
concentration of 16.36 g/l was obtained in 48 h, which further verified the practicability of this optimum strategy. 相似文献
4.
Lovastatin, an inhibitor of HMG-CoA reductase, was produced by submerged fermentation using Monascus purpureus MTCC 369. Five nutritional parameters screened using Plackett–Burman experimental design were optimized by Box–Behnken factorial
design of response surface methodology for lovastatin production in shake flask cultures. Maximum lovastatin production of
351 mg/l were predicted in medium containing 29.59 g/l dextrose, 3.86 g/l NH4Cl, 1.73 g/l KH2PO4, 0.86 g/l MgSO4·7H2O, and 0.19 g/l MnSO4·H2O using response surface plots and point prediction tool of DESIGN EXPERT 7.0 (Statease, USA) software. 相似文献
5.
Statistical experimental design was used to optimize medium constituents for emulsan production by Acinetobacter venetianus RAG-1 in batch cultivation. The factors affecting emulsan production were screened by a two-level factorial design, and the
optimal concentration of medium constituents for emulsan production were determined by the method of steepest path ascent
and central composite experimental design. Experimental results showed that the optimal medium constituents were 9.16 g/L
ethanol, 8.2 g/L KH2PO4, 23.32 g/L K2HPO4, 5.77 g/L (NH4)2SO4 and 0.354 g/L MgSO4•7H2O. Under this optimal composition, the predicted emulsan production was 72.198 mg/L, and experimental value was 73.312 mg/L
for 80 h culture in the shake flasks, and the emulsan yield by A. venetianus RAG-1 was enhanced nearly 1.48-fold (from 49.5 to 73.312 mg/L). Based on the results, we identify the optimal medium constituents
for emulsan production and could take advantage of strategy for scale up the fermentation of emulsan production. 相似文献
6.
The nutritional requirements for phenazine-1-carboxylic acid (PCA) production using Pseudomonas sp. M18G, a gacA chromosomal-inactivated mutant of the strain M18, with a high PCA yield, were optimized statistically in shake flask experiments.
Based on a single-factor experiment design, we implemented the two-level Plackett–Burman (PB) design with 11 variables to
screen medium components that significantly influence PCA production. Soybean meal, glucose, soy peptone, and ethanol were
identified as the most important significant factors (P < 0.05). Response surface methodology based on the Center Composite Design (CCD) was applied to determine these factors’
optimal levels and their mutual interactions between components for PCA production. The predicted results showed that 1.89 g
l−1 of PCA production was obtained after a 60-h fermentation period, with optimal concentrations of soybean meal powder (33.4 g
l−1), glucose (12.7 g l−1), soy peptone (10.9 g l−1), and ethanol (13.8 ml l−1) in the flask fermentations. The validity of the model developed was verified, and the optimum medium led to a maximum PCA
concentration of 2.0 g l−1, a nearly threefold increase compared to that in the basal medium. Furthermore, the experiment was scaled up in the 10 l
fermentor and 2 g l−1 PCA productions were achieved in 48 h based on optimization mediums which further verified the practicability of this optimum
strategy. 相似文献
7.
Spore production of Bacillus subtilis from distillery effluent was optimized using statistically-based experimental designs. The two-level Plackett–Burman design
was applied to choose the nutrient supplements significantly influencing spore production. Among the seven variables we tested,
the most significant variables influencing spore production were statistically elucidated for optimization, and included (NH4)2SO4, corn flour and MgSO4. The optimum concentration of each significant variable was then predicted using Box–Behnken design. A second-order polynomial
was determined by the multiple regression analysis of this experimental data. The optimum values for the critical nutrient
supplements for the maximum were obtained as followed: (NH4)2SO4, 4.54%; corn flour, 1.2%; MgSO4, 0.56% with the corresponding value of maximum spore production of 7.24 × 108 spores/ml. A verification experiment performed under the optimum conditions resulted in 6.95 × 108 spores/ml. The determination coefficient (R
2) was 0.98, which ensure an adequate credibility of the model. 相似文献
8.
Bhalchandra K. Vaidya Snehal R. Mutalik Renuka M. Joshi Sanjay N. Nene Bhaskar D. Kulkarni 《Journal of industrial microbiology & biotechnology》2009,36(5):671-678
In the present work, statistical experimental methodology was used to enhance the production of amidase from Rhodococcus erythropolis MTCC 1526. R.
erythropolis MTCC 1526 was selected through screening of seven strains of Rhodococcus species. The Placket–Burman screening experiments suggested that sorbitol as carbon source, yeast extract and meat peptone
as nitrogen sources, and acetamide as amidase inducer are the most influential media components. The concentrations of these
four media components were optimised using a face-centred design of response surface methodology (RSM). The optimum medium
composition for amidase production was found to contain sorbitol (5 g/L), yeast extract (4 g/L), meat peptone (2.5 g/L), and
acetamide (12.25 mM). Amidase activities before and after optimisation were 157.85 units/g dry cells and 1,086.57 units/g
dry cells, respectively. Thus, use of RSM increased production of amidase from R.
erythropolis MTCC 1526 by 6.88-fold. 相似文献
9.
To screen stimulators from Chinese medicinal insects for mycelial growth and polysaccharides production of Ganoderma lucidum, G. lucidum was inoculated into the media with and without supplementation of medicinal insect extracts. The ethyl acetate extract of
Eupolyphaga sinensis at 55 mg l−1 lead to significant increase in both biomass and intracellular polysaccharides (IPS) concentration from 8.53 ± 0.41 to 14.16 ± 0.43
and 1.28 ± 0.09 to 2.13 ± 0.11 g l−1, respectively. In addition, the ethyl acetate extract of Catharsius molossus at 55 mg l−1 significantly enhanced extracellular polysaccharides (EPS) production; the EPS yield increased from 350.9 ± 14.1 to 475.1 ± 15.3 mg
l−1. There were no new components in the two types of polysaccharides obtained by the addition of the insect extracts. 相似文献
10.
Iturin A, a lipopeptide antibiotic produced by Bacillus subtilis RB14-CS, suppresses the growth of various plant pathogens. Here, enhancement of iturin A production in solid-state fermentation
(SSF) on okara, a soybean curd residue produced during tofu manufacturing, was accomplished using statistical experimental
design. Primary experiments showed that the concentrations of carbon and nitrogen sources were the main factors capable of
enhancing iturin A production, whereas initial pH, initial water content, temperature, relative humidity, and volume of inoculum
were only minor factors. Glucose and soybean meal were the most effective among tested carbon and nitrogen sources, respectively.
Based on these preliminary findings, response surface methodology was applied to predict the optimum amounts of the carbon
and nitrogen sources in the medium. The maximum iturin A concentration was 5,591 μg/g initial wet okara under optimized condition.
Subsequent experiments confirmed that iturin A production was significantly improved under the predicted optimal medium conditions.
The SSF product generated under the optimized conditions exhibited significantly higher suppressive effect on the damping-off
of tomato caused by Rhizoctonia solani K-1 compared with the product generated under the non-optimized conditions. 相似文献
11.
Medium composition and culture conditions for the bleaching stable alkaline protease production by Aspergillus clavatus ES1 were optimized. Two statistical methods were used. Plackett-Burman design was applied to find the key ingredients and conditions for the best yield. Response surface methodology (RSM) including full factorial design was used to determine the optimal concentrations and conditions. Results indicated that Mirabilis jalapa tubers powder (MJTP), culture temperature, and initial medium pH had significant effects on the production. Under the proposed optimized conditions, the protease experimental yield (770.66 U/ml) closely matched the yield predicted by the statistical model (749.94 U/ml) with R (2)=0.98. The optimum operating conditions obtained from the RSM were MJTP concentration of 10 g/l, pH 8.0, and temperature of 30 degrees C, Sardinella heads and viscera flour (SHVF) and other salts were used at low level. The medium optimization contributed an about 14.0-fold higher yield than that of the unoptimized medium (starch 5 g/l, yeast extract 2 g/l, temperature 30 degrees C, and pH 6.0; 56 U/ml). More interestingly, the optimization was carried out with the by-product sources, which may result in cost-effective production of alkaline protease by the strain. 相似文献
12.
Summary Spore production of Coniothyrium minitans was optimized by using response surface methodology (RSM), which is a powerful mathematical approach widely applied in the optimization of fermentation process. In the first step of optimization, with Plackett–Burman design, soluble starch, urea and KH2PO4 were found to be the important factors affecting C. minitans spore 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 for the maximum were obtained as follows: soluble starch 0.643 (36.43 g. l−1), urea −0.544 (3.91 g l−1) and KH2PO4 0.049 (1.02 g l−1) with a predicted value of maximum spore production of 9.94 × 109 spores/g IDM. Under the optimal conditions, the practical spore production was 1.04 × 1010 spores/g IDM. The determination coefficient (R2) was 0.923, which ensure an adequate credibility of the model. 相似文献
13.
Baek-Rock Oh Jeong-Woo Seo Min Ho Choi Chul Ho Kim 《Biotechnology and Bioprocess Engineering》2008,13(6):666-670
To produce 1,3-propanediol (1,3-PD) from crude glycerol, cultivation conditions were optimized by response surface methodology
(RSM) based on a 25 factorial central composite design (CCD). RSM was adopted to derive a statistical model for the individual and interactive
effects of crude glycerol, (NH4)2SO4, pH, cultivation time and temperature on the production of 1,3-PD. Optimal conditions for maximum 1,3-PD production were
as follows: crude glycerol, 35 g/L; (NH4)2SO4, 8 g/L; pH, 7.37; cultivation time, 10.8 h; temperature, 36.88°C. Under these optimal conditions, the design expert presented
the maximal numerical solution with a predicted 1,3-PD production level of up to 13.74 g/L. The experimental production of
1,3-PD yielded 13.8 g/L, which was in close agreement with the model prediction. 相似文献
14.
Fermentation conditions were statistically optimized for producing extracellular xylanase by Aspergillus niger SL-05 using apple pomace and cotton seed meal. The primary study shows that culture medium with a 1:1 ratio of apple pomace and cotton seed meal (carbon and nitrogen sources) yielded maximal xylanase activity. Three significant factors influencing xylanase production were identified as urea, KH(2)PO(4), and initial moisture content using Plackett-Burman design study. The effects of these three factors were further investigated using a design of rotation-regression-orthogonal combination. The optimized conditions by response surface analysis were 2.5% Urea, 0.09% KH(2)PO(4), and 62% initial moisture content. The analysis of variance indicated that the established model was significant (P < 0.05), "while" or "and" the lack of fit was not significant. Under the optimized conditions, the model predicted 4,998 IU/g dry content, whereas validation experiments produced an enzymatic activity of xylanase at 5,662 IU/g dry content after 60 h fermentation. This study innovatively developed a fermentation medium and process to utilize inexpensive agro-industrial wastes to produce a high yield of xylanase. 相似文献
15.
Chu WH 《Journal of industrial microbiology & biotechnology》2007,34(3):241-245
Thirty-five strains capable of secreting extracellular alkaline proteases were isolated from the soil and waste water near
the milk processing plant, slaughterhouse. Strain APP1 with the highest-yield alkaline proteases was identified as Bacillus sp. The cultural conditions were optimized for maximum enzyme production. When the initial pH of the medium was 9.0, the
culture maintained maximum proteolytic activity for 2,560 U ml−1 at 50°C for 48 h under the optimized conditions containing (g−1): soyabean meal, 15; wheat flour, 30; K2HPO4, 4; Na2HPO4, 1; MgSO4·7H2O, 0.1; Na2CO3, 6. The alkaline protease showed extreme stability toward SDS and oxidizing agents, which retained its activity above 73
and 110% on treatment for 72 h with 5% SDS and 5% H2O2, respectively. 相似文献
16.
José Miguel Müller Ranulfo Monte Alegre 《World journal of microbiology & biotechnology》2007,23(5):691-695
In this study alginate production by Pseudomonas mendocina in a laboratory-scale fermenter was investigated. In the experiments the effect of temperature (25–31°C) and agitation (500–620 rev min−1) at a constant air flow of 10 v/v/h were evaluated in relation to the rate of glucose bioconversion to alginate using response
surface methodology (RSM). The fermenter configuration was also adapted to a system with a screw mixer and draft tube, due
to the change in rheological characteristics of the fermentation broth. The adjusted model indicates a temperature of 29.1°C
and agitation of 553 rev min−1 for optimum alginate synthesis. In this fermentation system a Y
p/s
of 44.8% was achieved. The alginate synthesized by P. mendocina showed a partially acetylated pattern as previously reported for alginates obtained from other Pseudomonas spp and Azotobacter vinelandii. 相似文献
17.
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
18.
Verticillium lecanii is an entomopathogen with high potential in biological control of pests. We developed a solid-state fermentation with sugarcane
bagasse as carrier absorbing liquid medium to propagate V. lecanii spores. Using statistical experimental design, we optimized the medium composition for spore production. We first used one-factor-at-a-time
design to identify corn flour and yeast extract as the best carbon and nitrogen sources for the spore production of V. lecanii. Then, we used two-level fractional factorial design to confirm corn flour, yeast extract, and KH2PO4 as important factors significantly affecting V. lecanii spore production. Finally, we optimized these selected variables using a central composite design and response surface method.
The optimal medium composition was (grams per liter): corn flour 35.79, yeast 8.69, KH2PO4 1.63, K2HPO4 0.325, and MgSO4 0.325. Under optimal conditions, spore production reached 1.1 × 1010 spores/g dried carrier, much higher than that on wheat bran (1.7 × 109 spores/g initial dry matter). 相似文献
19.
Amplified fragment length polymorphism (AFLP) analysis was used to examine genetic differences in Agaricus blazei cultivated strains and their single-spore isolates (SSIs). AFLP analysis with five primer combinations identified a total
of 267 AFLP bands from nine cultivated strains (one from Brazil and eight from Japan), of which 165 were polymorphic between
the nine strains. An AFLP data dendrogram grouped the eight Japanese strains, with the Brazilian strain acting as an outlier,
suggesting that the Brazilian and Japanese strains are genetically quite different. Twelve SSIs derived from each of four
cultivated strains were subjected to AFLP analysis. All the AFLP bands detected in the cultivated strains were also found
in at least one SSI, but some unique bands were detected in SSIs. The total number of AFLP bands from individual SSIs was
clearly less than those from their parental strains, and many of polymorphic AFLP bands from the parental strains segregated
in SSIs at a ratio of 1 : 1, suggesting that the SSIs are homokaryotic. Distance values based on presence or absence of individual
AFLP bands among SSIs from different strains were clearly higher than those among SSIs from a single strain. In addition,
AFLP analysis was shown to be useful in confirming hybrid formation in crosses between SSIs. 相似文献
20.
The P transposable element invaded the Drosophila melanogaster genome in the middle of the twentieth century, probably from D. willistoni in the Caribbean or southeastern North America. P elements then spread rapidly and became ubiquitous worldwide in wild populations of D. melanogaster by 1980. To study the dynamics and long-term fate of transposable genetic elements, we examined the molecular profile of genomic P elements and the phenotype in the P-M system of the current North American natural populations collected in 2001-2003. We found that full-size P and KP elements were the two major size classes of P elements present in the genomes of all populations ("FP + KP predominance") and that the P-related phenotypes had largely not changed since the 1980s. Both FP + KP predominance and phenotypic stability were also seen in other populations from other continents. As North American populations did not show many KP elements in earlier samples, we hypothesize that KP elements have spread and multiplied in the last 20 years in North America. We suggest that this may be due to a transpositional advantage of KP elements, rather than to a role in P-element regulation. 相似文献