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1.
A newly isolated anti-Streptococcus suis bacteriocin-producing strain LPL1-5 was obtained from healthy unweaned piglets' fecal matter, and was designated as Lactobacillus pentosus LPL1-5 based on morphology, biochemical properties, and 16S rDNA sequencing analysis. The medium composition for enhanced bacteriocin production by L. pentosus LPL1-5 was optimized by statistical methodology. Yeast extract, K2HPO4 · 3H2O, and MnSO4 · H2O were identified as significant components influencing pentocin LPL1-5 production using the Plackett–Burman method. Response surface methodology was applied for further optimization. The concentrations of medium components for enhanced pentocin LPL1-5 production were as follows (g/L): lactose 20.00, tryptone 10.00, beef extract 10.00, yeast extract 14.00, MnSO4 · H2O 0.84, K2HPO4 · 3H2O 4.92, triammonium citrate 2.00, Na-acetate 5.00, MgSO4 · 7H2O 0.58, Tween 80 1.00. Under the optimized condition, a value of 3154.65 ± 27.93 IU/mL bacteriocin activity was achieved, which was 4.2-fold that of the original medium.  相似文献   

2.
Pedobacter cryoconitis BG5 are psychrophiles isolated from the cold environment and capable of proliferating and growing well at low temperature regime. Their cellular products have found a broad spectrum of applications, including in food, medicine, and bioremediation. Therefore, it is imperative to develop a high-cell density cultivation strategy coupled with optimized growth medium for P. cryoconitis BG5. To date, there has been no published report on the design and optimization of growth medium for P. cryoconitis, hence the objective of this research project. A preliminary screening of four commercially available media, namely tryptic soy broth, R2A, Luria Bertani broth, and nutrient broth, was conducted to formulate the basal medium. Based on the preliminary screening, tryptone, glucose, NaCl, and K2HPO4 along with three additional nutrients (yeast extract, MgSO4, and NH4Cl) were identified to form the basal medium which was further analyzed by Plackett–Burman experimental design. Central composite experimental design using response surface methodology was adopted to optimize tryptone, yeast extract, and NH4Cl concentrations in the formulated growth medium. Statistical data analysis showed a high regression factor of 0.84 with a predicted optimum optical (600?nm) cell density of 7.5 using 23.7?g/L of tryptone, 8.8?g/L of yeast extract, and 0.7?g/L of NH4Cl. The optimized medium for P. cryoconitis BG5 was tested, and the observed optical density was 7.8. The cost-effectiveness of the optimized medium was determined as 6.25 unit prices per gram of cell produced in a 250-ml Erlenmeyer flask.  相似文献   

3.
In order to overproduce biofungicides agents by Bacillus amyloliquefaciens BLB371, a suitable culture medium was optimized using response surface methodology. Plackett–Burman design and central composite design were employed for experimental design and analysis of the results. Peptone, sucrose, and yeast extract were found to significantly influence antifungal activity production and their optimal concentrations were, respectively, 20 g/L, 25 g/L, and 4.5 g/L. The corresponding biofungicide production was 250 AU/mL, corresponding to 56% improvement in antifungal components production over a previously used medium (160 AU/mL). Moreover, our results indicated that a deficiency of the minerals CuSO4, FeCl3 · 6H2O, Na2MoO4, KI, ZnSO4 · 7H2O, H3BO3, and C6H8O7 in the optimized culture medium was not crucial for biofungicides production by Bacillus amyloliquefaciens BLB371, which is interesting from a practical point of view, particularly for low-cost production and use of the biofungicide for the control of agricultural fungal pests.  相似文献   

4.
Synthesis of amylase by Aspergillus niger strain UO-01 under solid-state fermentation with sugarcane bagasse was optimized by using response surface methodology and empirical modelling. The process parameters tested were particle size of sugarcane bagasse, incubation temperature and pH, moisture level of solid support material and the concentrations of inoculum, total sugars, nitrogen and phosphorous. The optimum conditions for high amylase production (457.82 EU/g of dry support) were particle size of bagasse in the range of 6–8 mm, incubation temperature and pH: 30.2°C and 6.0, moisture content of bagasse: 75.3%, inoculum concentration: 1 × 107 spores/g of dry support and concentrations of starch, yeast extract and KH2PO4: 70.5, 11.59 and 9.83 mg/g of dry support, respectively. After optimization, enzyme production was assayed at the optimized conditions. The results obtained corroborate the effectiveness and reliability of the empirical models obtained.  相似文献   

5.
The present study explores the production of biodiesel, a sustainable replacement for depleting fossil fuel by utilizing microbial oil, which was procured from Yarrowia lipolytica employing chicken tallow as the carbon substrate. Chicken tallow, yeast extract, and MgSO4·7H2O were screened for biomass production through Plackett–Burman design. Further, Box–Behnken design analysis was performed, and the optimal concentration of the medium variables was found to be 20 g/L of chicken tallow, 7.0 g/L of yeast extract, and 0.45 g/L of MgSO4·7H2O.The various parameters viz., pH (6), temperature (30 °C), RPM (150), inoculum volume (5%, v/v), and C/N ratio (100) were optimized for maximal biomass and lipid yield, and lipid content. Nile red-stained cells were observed for intracellular lipid bodies using fluorescence microscopy, and its fluorescence intensity was measured bythe flow cytometer. The dimorphic transition and substrate assimilation of Y. lipolytica were analyzed using scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FT-IR). Batch kinetic studies revealed the concomitant synthesis of microbial lipid (4.16 g/L), lipase (43 U/mL), and biosurfactant (1.41 g/L). The GC-MS analysis of microbial oil presented the fatty acid profile as oleic acid (49.15%), palmitic acid (29.83%), stearic acid (11.43%), linoleic acid (3.83%), palmitoleic acid (3.77%), and myristic acid (1.32%).  相似文献   

6.
To improve the acetoin-producing ability of Bacillus subtilis SF4-3, isolated from “natto,” a Japanese traditional food, the fermentation medium was optimized in shake-flask fermentation by statistically designed methods. Based on results of the single-factor experiment, orthogonal experiment, and Plackett–Burman design, yeast extract, corn steep liquor, and urea were identified as showing significant influence on the acetoin production. Subsequently, the optimum combination of the three factors was investigated by the Box–Behnken design (BBD) of response surface methodology (RSM) in order to further enhance the acetoin production. The maximum acetoin yield of 45.4 g/L was predicted when the concentrations of yeast extract, corn steep liquor, and urea were 8.5 g/L, 14.6 g/L, and 3.8 g/L, respectively. The results were further confirmed in triplicate experiments using the optimized medium (glucose 160 g/L, yeast extract 8.5 g/L, corn steep liquor 14.6 g/L, urea 3.8 g/L, manganese sulfate 0.05 g/L, ferrous sulfate 0.05 g/L), and an acetoin yield of 46.2 g/L was obtained in the validation experiment, which was in agreement with the prediction. After the optimization of medium components, an increase of 36.28% in acetoin production was achieved in comparison to that at the initial medium levels.  相似文献   

7.
Exploration of novel active anti-tumor compounds from marine microbes for pharmaceutical applications has been a continuously hot spot in natural product research. Bacterial growth and metabolites may greatly vary under different culture conditions. In this study, the effects of different culture conditions and medium components on the growth and bioactive metabolites of Serratia proteamacula 657, an anti-tumor bacterium found in our previous study, were investigated. The results showed that lower temperature, weak acidic condition and solid fermentation favored the bacterial growth and the production of active compounds. Four components in the culture medium, NaCl, peptone, yeast extract and MgSO4, were found important to the bacterial growth and active compounds production in medium optimization. Under the optimized condition of solid state fermentation at pH 6.0–7.0, 23–25 °C, with the MgSO4-free medium containing 10.0 g/L peptone, 1.0 g/L yeast extract and 19.45 g/L NaCl, the antitumor activity of S. proteamacula 657 and the yield of crude extracts increased about 15 times and 6 times than the sample obtained in the original liquid fermentation, respectively. The active components in the metabolites of S. proteamacula 657 were identified as a homolog of prodigiosin, a red bacterial pigment, based on the analysis of the NMR and GC–MS. The bacterium S. proteamacula 657, which is adapted to lower temperature, produced prodigiosin-like pigments with highly antitumor activity, suggesting the bacterium is a potential new source for prodigiosin production.  相似文献   

8.
A cane molasses-based medium for the biomass production of biocontrol agent Rhodosporidium paludigenum was statistically optimized. Molasses concentration (after pretreatment), yeast extract, and initial pH were identified by the Plackett–Burman design to show significant influence on the biomass production. The three factors were further optimized by central composite design and response-surface methodology. The statistical analysis indicated the optimum values of the variables were 89.98 g/L for cane molasses, 2.35 g/L for yeast extract and an initial pH of 8.48. The biomass yield at the optimal culture achieved 15.89 g/L in flask fermentation, which was 2.1 times higher than that at the initial NYDB medium. In a 10-L fermenter, 18.97 g/L of biomass was obtained after 36 hr of cultivation. Moreover, the biocontrol efficacy of the yeast was investigated after culture optimization. The results showed the yeast harvested in the optimal medium maintained its initial biocontrol properties by reducing the percentage of decayed apples to below 20%.  相似文献   

9.
Lactic acid is a green chemical that can be used as a raw material for biodegradable polymer. To produce lactic acid through microbial fermentation, we previously screened a novel lactic acid bacterium. In this work, we optimized lactic acid fermentation using a newly isolated and homofermentative lactic acid bacterium. The optimum medium components were found to be glucose, yeast extract, (NH4)2HPO4, and MnSO4. The optimum pH and temperature for a batch culture ofLactobacillus sp. RKY2 was found to be 6.0 and 36°C, respectively. Under the optimized culture conditions, the maximum lactic acid concentration (153.9 g/L) was obtained from 200 g/L of glucose and 15 g/L of yeast extract, and maximum lactic acid productivity (6.21 gL−1h−1) was obtained from 100 g/L of glucose and 20 g/L of yeast extract. In all cases, the lactic acid yields were found to be above 0.91 g/g. This article provides the optimized conditions for a batch culture ofLactobacillus sp. RKY2, which resulted in highest productivity of lactic acid.  相似文献   

10.
Abstract

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%, K2HPO4 0.1%, and MgSO4 0.05%. The suitable fermentation conditions were as follows: initial pH 7.0, temperature 25°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.  相似文献   

11.
Published data supports the neuroprotective effects of several phenolic-containing natural products, including certain fruit, berries, spices, nuts, green tea, and olive oil. However, limited data are available for phenolic-containing plant-derived natural sweeteners including maple syrup. Herein, we investigated the neuroprotective effects of a chemically standardized phenolic-enriched maple syrup extract (MSX) using a combination of biophysical, in vitro, and in vivo studies. Based on biophysical data (Thioflavin T assay, transmission electron microscopy, circular dichroism, dynamic light scattering, and zeta potential), MSX reduced amyloid β1?42 peptide (Aβ1?42) fibrillation in a concentration-dependent manner (50–500 μg/mL) with similar effects as the neuroprotective polyphenol, resveratrol, at its highest test concentration (63.5?% at 500 μg/mL vs. 77.3?% at 50 μg/mL, respectively). MSX (100 μg/mL) decreased H2O2-induced oxidative stress (16.1?% decrease in ROS levels compared to control), and down-regulated the production of lipopolysaccharide (LPS)-stimulated inflammatory markers (22.1, 19.9, 74.8, and 87.6?% decrease in NOS, IL-6, PGE2, and TNFα levels, respectively, compared to control) in murine BV-2 microglial cells. Moreover, in a non-contact co-culture cell model, differentiated human SH-SY5Y neuronal cells were exposed to conditioned media from BV-2 cells treated with MSX (100 μg/mL) and LPS or LPS alone. MSX-BV-2 media increased SH-SY5Y cell viability by 13.8?% compared to media collected from LPS-BV-2 treated cells. Also, MSX (10 μg/mL) showed protective effects against Aβ1?42 induced neurotoxicity and paralysis in Caenorhabditis elegans in vivo. These data support the potential neuroprotective effects of MSX warranting further studies on this natural product.  相似文献   

12.
Dihydrolipohyl dehydrogenase (DLD) is a FAD-dependent enzyme that catalyzes the reversible oxidation of dihydrolipoamide. Herein, we report medium optimization for the production of a recombinant DLD with NADH-dependent diaphorase activity from a strain of Bacillus sphaericus PAD-91. The DLD gene that consisted of 1413 bp was expressed in Escherichia coli BL21 (DE3), and its enzymatic properties were studied. The composition of production medium was optimized using one-variable-at-a-time method followed by response surface methodology (RSM). B. sphaericus DLD catalyzed the reduction of lipoamide by NAD+ and exhibited diaphorase activity. The molecular weight of enzyme was about 50 kDa and determined to be a monomeric protein. Recombinant diaphorase showed its optimal activity at temperature of 30 °C and pH 8.5. K m and V max values with NADH were estimated to be 0.025 mM and 275.8 U/mL, respectively. Recombinant enzyme was optimally produced in fermentation medium containing 10 g/L sucrose, 25 g/L yeast extract, 5 g/L NaCl and 0.25 g/L MgSO4. At these concentrations, the actual diaphorase activity was calculated to be 345.0 ± 4.1 U/mL. By scaling up fermentation from flask to bioreactor, enzyme activity was increased to 486.3 ± 5.5 U/mL. Briefly, a DLD with diaphorase activity from a newly isolated B. sphaericus PAD-91 was characterized and the production of recombinant enzyme was optimized using RSM technique.  相似文献   

13.
Oxidative stress mediates the cell damage in several ailments including neurodegenerative conditions. Ocimum sanctum is widely used in Indian ayurvedic medications to cure various ailments. The present study was carried out to investigate the antioxidant activity and neuroprotective effects of hydroalcoholic extract of O. sanctum (OSE) on hydrogen peroxide (H2O2)-induced oxidative challenge in SH-SY5Y human neuronal cells. The extract exhibited strong antioxidant activity against DPPH, 2,2′-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) radical and hydroxyl radicals with IC50 values of 395 ± 16.2, 241 ± 11.5 and 188.6 ± 12.2 μg/ml respectively, which could be due to high amount of polyphenols and flavonoids. The observed data demonstrates 41.5 % cell survival with 100 μM H2O2 challenge for 24 h, which was restored to 73 % by pre-treatment with OSE for 2 h. It also decreased the lactate dehydrogenase leakage and preserved the cellular morphology. Similarly OSE inhibited lipid peroxidation, DNA damage, reactive oxygen species generation and depolarization of mitochondrial membrane. The extract restored superoxide dismutase and catalase enzyme/protein levels and further downregulated HSP-70 over-expression. These findings suggest that OSE ameliorates H2O2 induced neuronal damage via its antioxidant defence mechanism and might be used to treat oxidative stress mediated neuronal disorders.  相似文献   

14.
The Doehlert experimental design was used to optimize the production of mycelial biomass and exopolymer from Hericium erinaceus CZ-2 in this study. Statistical analysis showed that the linear and quadric terms of 3 variables: corn flour, yeast extract, and corn steep liquor had significant effects. The optimized combination of these 3 variables was confirmed through validation experiments. The optimal conditions for higher production of mycelial biomass (19.92 g/L) were estimated when the media composition concentrations were set as: 30.85 g/L, corn flour; 2.81 g/L, yeast extract; 16.9 mL/L, corn steep liquor; 10 g/L, glucose; 1 g/L, KH2PO4; and 0.5 g/L, MgSO4·7H2O; while a maximal exo-polymer yield (1.653 g/L) could be achieved when setting concentrations of: 32.71 g/L, corn flour; 2.35 g/L, Yeast extract; 14.42 mL/L, Corn steep liquor; 10 g/L, glucose; 1 g/L, KH2PO4; and 0.5 g/L, MgSO4·7H2O. The upscale production was also investigated using a 15 L fermentor using the optimized medium.  相似文献   

15.
This study aimed to improve microbial flocculant production by optimizing the components of a Bacillus subtilis CZ1003 culture medium. Using the flocculation rate as the dependent variable, single-factor experiments were performed and beef extract at a concentration of 9 g/L was found to be the optimal nitrogen source, while glucose at a concentration of 20 g/L was the optimal carbon source. KCl, MgCl2, NaCl, and CaCl2 at concentrations of 0.75, 2.5, 0.5, and 5.0 g/L, respectively, were the optimum inorganic salts, in order of flocculant production activity. Orthogonal experimental demonstrated that KCl played a dominant role for Bacillus subtilis production of bioflocculants, followed by NaCl and CaCl2. Optimization experiments demonstrated that the optimal combination of the two salts was 0.75 g/L KCl and 0.5 g/L NaCl, resulting in a flocculation rate of 36.2% when included together at these concentrations. The final optimized medium consisted of 20 g/L glucose, 9 g/L beef extract, 0.75 g/L KCl, and 0.5 g/L NaCl. Compared with the initial medium, the optimized medium enhanced the flocculation activity from 12.1 to 36.2%, which equates to an increase of 199.17%. Meanwhile, the flocculant yield was increased from 0.058 g/L to 0.134/L, an increase of 131.03%. The optimized medium could be used to improve microbial flocculant production and provides a basis for further exploration.  相似文献   

16.
Methanolysis of sunflower oil catalyzed by immobilized Aspergillus niger mycelium was studied in a packed-bed reactor. The optimal cultivation parameters for A. niger were determined using full factorial and steepest ascent experimental designs. Sunflower oil, yeast extract and soybean meal were selected as the best carbon and nitrogen sources and were used in the subsequent experiments. Intracellular lipase activity and cell mass concentration were respectively 3.2 and 2.4 times greater and cultivation period decreased by 24 h compared with the initial medium. The optimum values of these most significant parameters were as follows: sunflower oil (13.2 g/L), yeast extract (6.2 g/L), soybean meal (7.4 g/L) and incubation period (72 h) at 30 °C. With A. niger biocatalyst grown in optimized conditions, the biodiesel fuel yield reached 23.1% after sixth pass of recycled reaction mixture through the reactor.  相似文献   

17.
Carbonic anhydrase (CA) was produced from the polyextremophilic (halotolerant, moderately thermophilic and alkaliphilic) bacterium Aeribacillus pallidus TSHB1 isolated from water and sediment samples of Choti Anhoni hot spring of Pipariya, Madhya Pradesh (India), is being reported to be suitable for carbon sequestration. Growth and CA production were inhibited at higher CO2 concentration (5–10 %). Under optimized culture variables (tryptone 0.8 %, yeast extract 0.08 %, glucose 1 %, micronutrient solution 1 %, inoculums size 1.10 %, agitation 200 at pH 8, and temperature 55 °C), 3.7-fold higher CA production was attained than that under unoptimized conditions. The zymogram analysis of the partially purified CA revealed an activity band corresponding to 32 kDa. The enzyme is stable in the pH range between 8.0 and 11.0 with T 1/2 of 40, 15, and 8 min at 60, 70, and 80 °C, respectively. The CA of A. pallidus displayed a marked enhancement in the rate of CaCO3 precipitation from aqueous CO2. The CA-aided formation of CaCO3 was 42.5 mg mg?1 protein. Scanning electron microscopy revealed the formation of rhomboid calcite crystals. This is the first report on the production and applicability of CA from the polyextremophilic A. pallidus in carbon sequestration.  相似文献   

18.
In an attempt to obtain a microbial strain with higher yield of folate for industrial applications, we mutated the wild strain Candida utilis Y1.0 using a novel mutagenic process, i.e., irradiation by a helium–neon (He-Ne) laser with an output power of 20 mW and an exposure time of 20 min. The yield of folate in the mutated cells reached 1,102 ng/mL, which was 20.4-fold that of the wild strain. The mutant strain Y3.636 was relatively stable in terms of folate production through eight successive transfers of cultures and batch fermentation in a 3.7-L stirred-tank fermenter. Optimization further increased the yield of the mutant by 110 %, i.e., to 2,314?±?13 ng/mL. The optimal culture conditions for folate production were: cultivation in fermentation culture medium composed of 62.5 g/L glucose, 15 g/L corn liquor, 3 g/L (NH4)2SO4, 3 g/L MgSO4, and 1 g/L glutamic acid; inoculum size of 9 %; incubation at 28 °C and 196 rpm for 36 h. A time-course study of cell growth and folate production by mutant strain Y3.636 strongly suggested that folate production in C. utilis is growth-associated.  相似文献   

19.
The present work was conducted to investigate the antioxidant activity and neuroprotective effects of Tripterygium regelii extract (TRE) on H2O2-induced apoptosis in human dopaminergic cells, SH-SY5Y. TRE possessed considerable amounts of phenolics (282.73 mg tannic acid equivalents/g of extract) and flavonoids (101.43 mg naringin equivalents/g of extract). IC50 values for reducing power and DPPH radical scavenging activity were 52.51 and 47.83 μg, respectively. The H2O2 scavenging capacity of TRE was found to be 57.68 μM × μg−1 min−1. By examining the effects of TRE on SH-SY5Y cells injured by H2O2, we found that after incubation of cells with TRE prior to H2O2 exposure, the H2O2 induced cytotoxicity was significantly reversed and the apoptotic features such as change in cellular morphology, nuclear condensation and DNA fragmentation was inhibited. Moreover, TRE was very effective attenuating the disruption of mitochondrial membrane potential and apoptotic cell death induced by H2O2. TRE extract effectively suppressed the up-regulation of Bax, Caspase-3 and -9, and down-regulation of Bcl-2. Moreover, TRE pretreatment evidently increased the tyrosine hydroxylase (TH) and brain-derived neurotrophic factor (BDNF) in SH-SY5Y cells. These findings demonstrate that TRE protects SH-SY5Y cells against H2O2-induced injury and antioxidant properties may account for its neuroprotective actions and suggest that TRE might potentially serve as an agent for prevention of neurodegenerative disease associated with oxidative stress.  相似文献   

20.
In order to obtain a high ethanol yield from the Jerusalem artichoke raw extract and reduce the fermentation cost, we have engineered a new recombinant Saccharomyces cerevisiae strain that could produce ex-inulinase. The response surface methodology based on Plackett–Burman and Box–Behnken design was used to optimize the medium for the ethanol production from the Jerusalem artichoke raw extracts by the recombinant strain. In the first optimization step, Plackett–Burman design was employed to select significant factors, including concentrations of yeast extract, inoculum, and MgSO4·7H2O. In the second step, the steepest ascent experiment was carried out to determine the center point with the three significant factors; the selected combinations were further optimized using the Box–Behnken design. The maximum ethanol production rate was predicted at 91.1 g/l, which was based on a medium consisting of yeast extract 9.24 g/l, inoculum 39.8 ml/l, and MgSO4·7H2O 0.45 g/l. In the validating experiment, the ethanol fermentation rate reached 102.1 g/l, closely matching the predicted rate.  相似文献   

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