Critical Medium Components Research Articles

Correction to: Optimization of critical medium components for lipase production by Neurospora crassa in solid state fermentation

Correction to: Optimization of critical medium components for lipase production by Neurospora crassa in solid state fermentation

Optimization of critical medium components for lipase production by Neurospora crassa in solid state fermentation

Optimization of critical medium components for lipase production by Neurospora crassa in solid state fermentation

Xylitol biosynthesis enhancement by Candida tropicalis via medium, process parameter optimization, and co-substrate supplementation

The present study examines the impact of nitrogen sources (yeast extract, ammonium sulfate peptone, ammonium nitrate, urea, and sodium nitrate), salt solution (0.5 g/L MgSO4, 0.5 g/L KH2PO4, 0.3 g/L CaCl2), trace elements solution (0.1 g/L CuSO4, 0.1 g/L FeSO4, 0.02 g/L MnCl2, 0.02 g/L ZnSO4), operational parameters (temperature, aeration, agitation, initial pH and xylose concentration) and co- substrate supplementation (glucose, fructose, maltose, sucrose, and glycerol) on xylitol biosynthesis by Candida tropicalis ATCC 13803 using synthetic xylose. The significant medium components were identified using the Plackett Burman design followed by central composite designs to obtain the optimal concentration for the critical medium components in shaker flasks. Subsequently, the effect of operational parameters was examined using the One Factor At a Time method, followed by the impact of five co-substrates on xylitol biosynthesis in a 1 L bioreactor. The optimal media components and process parameters are as follows: peptone: 12.68 g/L, yeast extract: 6.62 g/L, salt solution (0.5 g/L MgSO4, 0.5 g/L KH2PO4, and 0.3 g/L CaCl2): 1.23 X (0.62 g/L, 0.62 g/L, and 0.37 g/L respectively), temperature: 30 °C, pH: 6, agitation: 400 rpm, aeration: 1 vvm, and xylose: 50 g/L. Optimization studies resulted in xylitol yield and productivity of 0.71 ± 0.004 g/g and 1.48 ± 0.018 g/L/h, respectively. Glycerol supplementation (2 g/L) further improved xylitol yield (0.83 ± 0.009 g/g) and productivity (1.87 ± 0.020 g/L/h) by 1.66 and 3.12 folds, respectively, higher than the unoptimized conditions thus exhibiting the potential of C. tropicalis ATCC 13803 being used for commercial xylitol production.

Modulation of nutrient precursors for controlling metabolic inhibitors by genome-scale flux balance analysis.

Therapeutic protein productivity and glycosylation pattern highly rely on cell metabolism. Cell culture medium composition and feeding strategy are critical to regulate cell metabolism. In this study, the relationship between toxic metabolic inhibitors and their nutrient precursors was explored to identify the critical medium components toward cell growth and generation of metabolic by-products. Generic CHO metabolic model was tailored and integrated with CHO fed-batch metabolomic data to obtain a cell line- and process-specific model. Flux balance analysis study was conducted on toxic metabolites cytidine monophosphate, guanosine monophosphate and n-acetylputrescine-all of which were previously reported to generate from endogenous cell metabolism-by mapping them to a compartmentalized carbon utilization network. Using this approach, the study projected high level of inhibitory metabolites accumulation when comparing three industrially relevant fed-batch feeding conditions one against another, from which the results were validated via a dose-dependent amino acids spiking study. In the end, a medium optimization design was employed to lower the amount of supplemented nutrients, of which improvements in critical process performance were realized at 40% increase in peak viable cell density (VCD), 15% increase in integral VCD, and 37% increase in growth rate. Tight control of toxic by-products was also achieved, as the study measured decreased inhibitory metabolites accumulation across all conditions. Overall, thestudy successfully presented a digital twin approach to investigate the intertwined relationship between supplemented medium constituents and downstream toxic metabolites generated through host cell metabolism, further elucidating different control strategies capable of improving cellular phenotypes and regulating toxic inhibitors.

Bioflocculant produced by Bacillusvelezensis and its potential application in brewery wastewater treatment

This study was designed to evaluate the potential of bioflocculant producing strains isolated from wastewater sludge. According to the Plackett–Burman design, the response surface revealed glucose, magnesium sulfate, and ammonium sulfate as critical media components of the nutritional source, whereas the central composite design affirmed an optimum concentration of the critical nutritional source as 16.0 g/l (glucose), 3.5 g/l magnesium sulfate heptahydrate (MgSO4.7H2O), and 1.6 g/l ammonium sulfate ( (NH4)2SO4), yielding an optimal flocculation activity of 96.8%. Fourier Transformer Infrared Spectroscopy (FTIR) analysis confirmed the presence of hydroxyl, carboxyl and methoxyl in the structure of the bioflocculant. Additionally, chemical analysis affirmed the presence of mainly a polysaccharide in the main backbone of the purified bioflocculant with no detection of protein. Energy Dispersive X-ray analysis affirmed the presence of chlorine, phosphorous, oxygen and chlorine as representatives of elemental composition. Thermogravimetric (TGA) analysis revealed over 60% weight was retained at a temperature range of 700 °C. The purified bioflocculant remarkably removed chemical oxygen demand, biological oxygen demand and turbidity in brewery wastewater. This study suggested that the bioflocculant might be an alternate candidate for wastewater treatment.

Cell Metabolic Diagnosis and Control in CHO Fed-batch Process

Therapeutic protein productivity and product quality highly rely on cell metabolism of the fed-batch process, which is a costly, time-consuming and lack of intracellular analytical diagnostic tools. Cell culture medium composition and feeding strategy is critical to regulate cell metabolism. In this study, we present an unorthodox approach to optimize CHO bioprocess by integrating conventional design-of-experiments (DOE) methodology with genome scale model (GEM) flux analysis. Generic CHO-K1 metabolic model was tailored and further integrated with CHO fed-batch metabolomic data to obtain a cell line- and process-specific model. In silico metabolic flux analysis was conducted via GEM to identify the critical medium components toward cellular growth and further evaluate their optimized flux values from thirty five simulated fed-batch DOE conditions. Glucose and valine were projected as the most critical nutrients in the process from the flux simulation analysis. Using this approach, previously identified metabolic inhibitor cytidine monophosphate accumulated in extracellular environment was found to be regulated by glucose, glutamine, aspartate, and alanine and further experimentally validated through dose-dependent amino acid spiking study. A process diagnostic and control model was constructed from network topology modeling constructed through GEM and pathway enrichment analysis, which allowed optimization of medium components utilized in a fed-batch feeding process to better support cell metabolism and mitigate accumulation of metabolic inhibitors.

Detoxification vs. adaptation to inhibitory substances in the production of bioethanol from sugarcane bagasse hydrolysate: A case study

This study was undertaken not only to evaluate detoxification impact vs. adaptation on ethanologenic fermentation but also to optimize the fermentation condition to produce ethanol from Sugarcane Bagasse Hydrolysate (SBH). Detoxification by over-liming significantly improved the fermentability of the Concentrated Sugarcane Bagasse Hydrolysate (CSBH) by a wild strain of Barnettozyma californica. Compared to non-detoxified CSBH, ethanol production by the wild type strain increased from 1.233 g L−1 to 3.8031 g L−1, after 32 h and 24 h fermentation, respectively. Detoxification of SBH and CSBH showed a reverse effect on the adapted yeast. In detoxified CSBH, fermentation time increased to 32 h (3.084 g L−1) by adapted strain, while ethanol production was 3.803 g L−1 after 24 h by the non-adapted strain. Also, it should be noted that the parental yeast's capacity was found to be practicable in SBH without a detoxification and adaptation process. The screening and optimization of process parameters and critical medium components were done using the Plackett–Burman and Box–Behnken experimental design, respectively. (NH4)2SO4, (NH4)2PO4, ZnCl2, hydrolysate concentration, incubation temperature, and flask volume were found to be the main factors affecting ethanol production. Finally, a yield of 0.44 g g−1 was obtained, which is almost twice as high as the non-optimized medium. Taken together, these results indicate that hydrolysate detoxification and yeast adaptation through adaptive evolution and medium optimization are effective methods to overcome the bottleneck of lignocellulosic ethanol production.

Statistical media optimization for the production of clinical uricase from Bacillus subtilis strain SP6

In this study, a potent uricase producing organism was isolated by a thorough screening and identified as Bacillus subtilis strain SP6 by using 16s rDNA sequencing. Response surface methodological optimization was employed for the enhanced production of uricase from newly isolated Bacillus subtilis strain SP6. In media optimization studies, Plackett Burman (PB) design was used for the selection of the critical media components; which were further optimized using central composite design (CCD). Lactose, soya peptone, uric acid and FeSO4.7H2O were found to be the critical factors influencing the enzyme production. Optimum uricase production with these factors was deduced using central composite design. Significant level of the factors were 12.2 g/L of lactose, 12.79 g/L of soya peptone, 2.55 g/L of uric acid and 0.00325 g/L FeSO4.7H2O. Use of statistical optimization upsurges uricase yield from 1.2 U/ml to 15.87 U/ml enhancing the overall production by 13.23 fold; which confirms that the model is effective for process optimization.

On the role of medium components in bio-surfactant production from Achromobacter xylos GSR21

This paper, for the first time, reports the optimization of the critical medium components for bio-surfactant production from achromobacter xylos strain GSR21 using statistical experimental design. Response surface methodology (RSM) was employed to determine the optimal levels of process variables (agar powder, yeast extract, FeSO 4 7H 2 O, and KH 2 PO 4 ). Central composite design (CCD) of RSM was used to study the four variables at five levels, and bio-surfactant concentration was measured as response. Regression coefficients were calculated by regression analysis, and the model equation was determined. R 2 value for bio-surfactant (g/L) was tested to be 0.7222, indicating that the model fitted well with the experimental results. Verification of the mathematical model was conducted by performing the experiment with the predicted optimized values, and bio-surfactant yield was found to be 9.69 g/L. Validation of the predicted model was fitted 96.9% with the experimental results conducted under the optimum conditions. Agar powder and yeast extract was identified as efficient components for bio-surfactant ( achromobacter xylos GSR21) production.

STATISTICAL OPTIMIZATION OF MEDIUM COMPONENTS FOR BIOSURFACTANT PRODUCTION BY ACHROMOBACTER XYLOS GSR21

Introduction: Biosurfactants have picked up an impressive consideration as of late due to their potential uses in an expansive scope of use territories, including environmental remediation, agriculture, biofilm formation, quorum sensing, textile, pharmaceuticals, cosmetics, and the food, oil, and petrochemical industries. Aim: In the present study, optimization of the critical medium components for biosurfactant production by Achromobacter xylos strain GSR21 using statistical experimental design was studied. Materials and Methods: Response surface methodology (RSM) was employed to determine the optimal level of the four medium variables (agar powder, yeast extract, FeSO47H2O, and KH2PO4). Central composite design of RSM was applied to study the four variables at five levels, and biosurfactant concentration was measured as a response. Results: Regression coefficients were calculated by regression analysis and the model equation was determined. R2 value for biosurfactant (g/L) was calculated as 72%, and it indicates that the model was well fitted with the experimental results. Surface plots were made, and the maximum biosurfactant production (A. xylos strain GSR21) (10.20 g/L) was predicted at the optimized values of agar powder 90 g/L, yeast extract 5 g/L, FeSO47H2O 0.05 g/L, and KH2PO4 0.15 g/L. The obtained mathematical model was verified by performing the experiment with the predicted optimized values, and the yield of bio-surfactant was found to be 9.69 g/L. Validation of the predicted model was fitted 96.9% with the experimental results conducted at the optimum conditions. Conclusion: Results of this statistical analysis showed that agar powder and yeast extract had found significant medium components for biosurfactant (A. xylos GSR21) production.

Response Surface Methodology-Genetic Algorithm Based Medium Optimization, Purification, and Characterization of Cholesterol Oxidase from Streptomyces rimosus

The applicability of the statistical tools coupled with artificial intelligence techniques was tested to optimize the critical medium components for the production of extracellular cholesterol oxidase (COD; an enzyme of commercial interest) from Streptomyces rimosus MTCC 10792. The initial medium component screening was performed using Placket-Burman design with yeast extract, dextrose, starch and ammonium carbonate as significant factors. Response surface methodology (RSM) was attempted to develop a statistical model with a significant coefficient of determination (R2 = 0.89847), followed by model optimization using Genetic Algorithm (GA). RSM-GA based optimization approach predicted that the combination of yeast extract, dextrose, starch and ammonium carbonate at concentrations 0.99, 0.8, 0.1, and 0.05 g/100 ml respectively, has resulted in 3.6 folds increase in COD production (5.41 U/ml) in comparison with the un-optimized medium (1.5 U/ml). COD was purified 10.34 folds having specific activity of 12.37 U/mg with molecular mass of 54 kDa. The enzyme was stable at pH 7.0 and 40 °C temperature. The apparent Michaelis constant (Km) and Vmax values of COD were 0.043 mM and 2.21 μmol/min/mg, respectively. This is the first communication reporting RSM-GA based medium optimization, purification and characterization of COD by S. rimosus isolated from the forest soil of eastern India.

Response Surface Methodological Approach to Optimize the Critical Medium Components for Augmented Pectinase Production by Bacillus subtilis BKDS1

Response Surface Methodological Approach to Optimize the Critical Medium Components for Augmented Pectinase Production by Bacillus subtilis BKDS1

Optimisation of critical medium components and culture conditions for enhanced biomass and lipid production in the oleaginous diatom Navicula phyllepta: a statistical approach.

Diatoms hold great promise as potential sources of biofuel production. In the present study, the biomass and lipid production in the marine diatom Navicula phyllepta, isolated from Cochin estuary, India and identified as a potential biodiesel feedstock, were optimized using Plackett-Burman (PB) statistical experimental design followed by central composite design (CCD) and response surface methodology (RSM). The growth analyses of the isolate in different nitrogen sources, salinities and five different enriched sea water media showed the best growth in the cheapest medium with minimum components using urea as nitrogen source at salinity between 25 and 40gkg-1. Plackett-Burman experimental analyses for screening urea, sodium metasilicate, sodium dihydrogen phosphate, ferric chloride, salinity, temperature, pH and agitation influencing lipid and biomass production showed that silicate and temperature had a positive coefficient on biomass production, and temperature had a significant positive coefficient, while urea and phosphate showed a negative coefficient on lipid content. A 24 factorial central composite design (FCCD) was used to optimize the concentration of the factors selected. The optimized media resulted in 1.62-fold increase (64%) in biomass (1.2±0.08gL-1) and 1.2-fold increase (22%) in estimated total lipid production (0.11±0.003gL-1) compared to original media within 12days of culturing. A significantly higher biomass and lipid production in the optimized medium demands further development of a two-stage strategy of biomass production followed by induction of high lipid production under nutrient limitation or varying culture conditions for large-scale production of biodiesel from the marine diatom.

Optimization of critical medium components for enhancing antibacterial thiopeptide nocathiacin I production with significantly improved quality

Nocathiacin I, a glycosylated thiopeptide antibiotic, displays excellent antibacterial activities against multidrug resistant bacterial pathogens. Previously, a novel nocathiacin I formulation for intravenous administration has been successfully developed and its aqueous solubility is greatly enhanced for clinical application. The purpose of the present study was to increase the fermentation titer of nocathiacin I and reduce or eliminate analogous impurities by screening the medium ingredients using response surface methodology. After a sysmatic optimization, a water-soluble medium containing quality-controllable components was developed and validated, resulting in an increase in the production of nocathiacin I from 150 to 405.8 mg·L−1 at 150-L scale. Meanwhile, the analogous impurities existed in reported processes were greatly reduced or eliminated. Using optimized medium for fermentation, nocathiacin I with pharmaceutically acceptable quality was easily obtained with a recovery of 67%. In conclusion, the results from the present study offer a practical and efficient fermentation process for the production of nocathiacin I as a therapeutic agent.

CFD modeling of hydrodynamics and optimization of photofermentative hydrogen production by Rhodopseudomonas palustris DSM 123 in annular photobioreactor

H2 has the highest energy density among the other known fuels (143 GJ tonne−1). The present study is focused on spatial aspects of light patterns. Here, Rhodopseudomonas palustris strain DSM 123 was used for biohydrogen production in the triple jacketed photobioreactor (working volume 1 L) with light intensity (15 ± 1.1 W m−2), temperature (33 ± 1) °C, initial pH (6.7 ± 0.1), inoculum volume 10% (v/v), and 250 rpm stirring. Three factor three level full factorial designs was used to optimize the concentration of three critical medium components DL malic acid, L glutamic acid and FeCl3 having high impacts on H2 production. Surface and contour plots of the regression models revealed optimum H2 production rate of 6.885 mL H2 L−1 h−1 showing correlation with experimental optimum H2 production rate of 7.0 mL H2 L−1 h−1. In photobioreactors, turbulent flow conditions and light gradients may occur. CFD simulation study confirmed the advantages of designed annular PBR towards uniform fluid dynamics and heat transfer throughout the reactor. Mathematical modeling on substrate utilization for biomass and kinetics of substrate consumption for H2 production by PNS bacteria gave good simulated results. Modified Gompertz equation yielded good simulated fitting with experimental value for H2 production by Rhodopseudomonas palustris DSM 123.

Combinatorial biosynthesis of Synechocystis PCC6803 phycocyanin holo-α-subunit (CpcA) in Escherichia coli and its activities.

In order to investigate the feasibility for the biosynthetic pathway of CpcA conjugated protein to be reconstituted in Escherichia coli and its antioxidant ability and protective effect on the growth of E. coli, the minimal biosynthetic pathway in cyanobacteria leading from heme to the formation of the cysteinyl residue of phycocyanobilin with deprosthetic CpcA was reconstituted in E. coli using a relatively simple and effective method. When the constructed plasmid pETDuet-6 bearing five genes involved in the biosynthesis of CpcA was transformed into E. coli, the screened transformant acquired a pronounced blue color. Visualization of proteins on SDS-PAGE gel showed a 29kDa distinct band, corresponding to the theoretically calculated molecular weight of CpcA. Upon exposure to Zn(2+) and UV illumination, the CpcA band was fluorescent. Western blot analysis using His-tag monoclonal antibody confirmed the expression of CpcA in the recombinant E. coli. After the optimization of critical medium components by response surface methodology, the recombinant cells produced 22.29mg/l of CpcA. The recombinant CpcA displayed a strong ability to scavenge three free radicals ·OH, ·DPPH, and O2 (-) to protect against the oxidation of linoleic acid and to restore the growth of E. coli cells injured by DPPH and H2O2 at a relatively low concentration. These results lay a good foundation for the production and future use of CpcA.

Statistical media optimization for enhanced production of fibrinolytic enzyme from newly isolated Proteus penneri SP-20

Abstract Thrombolytic enzymes are invaluable for combating cardiovascular diseases. In this study a thorough isolation resulted, a potent fibrinolytic enzyme producer which was identified as Proteus penneri SP-20 using 16S rRNA sequencing. It secretes extracellular protease possesing fibrinolytic activity which was confirmed through the analysis of fibrin degradation by SDS-PAGE, phase contrast microscopy and fibrin zymography. Response surface methodology is used for media optimization using newly isolated P. penneri SP-20. Plackett Burman (PB) design was employed for selection of critical media constituents while; further optimization was carried out using Central composite rotatable design (CCRD). Casein, yeast extract, maltose and MnCl2·4H2O were critical medium components selected on the basis of PB design. Optimized media components obtained by CCRD were casein; 12.58 g l−1, yeast extract; 17.27 g l−1, maltose; 1.65 g l−1, MnCl2·4H2O; 0.564 g l−1. As compared with initial enzyme activity of 38.19 Units CCRD yielded 796.82 Unit activity, increasing the overall production of fibrinolytic protease by 20.86 fold. Hence the model is reliable for process optimization.

Optimization of Critical Medium Components for Protein Production by Nostoc ellipsosporum Using Response Surface Methodology

Nostoc ellipsosporum is a pharmaceutically important cyanobacteria known for the production of anti-HIV drug called cyanovirin. A five-level four factor central composite design of response surface methodology (RSM) was performed to identify the optimal level for maximum protein production. Four medium variables, PHA extract, glucose, Fe-EDTA and micronutrients, were chosen for RSM optimization study. Experimental data were analyzed by regression, and model equation was constructed. Maximum protein production was expected at the predicted optimal level of PHA extract, 2.50 % (v/v), glucose, 0.05 % (w/v), Fe-EDTA, 0.125 % (v/v) and micronutrients, 0.125 % (v/v). Validation experiment results were in good agreement with the results predicted by RSM. Results of this study showed that optimization by RSM approach improves the protein production, and also PHA extract was found to be a significant medium component for enhancing the protein synthesis.

Ethanol production from hot-water sugar maple wood extract hydrolyzate: fermentation media optimization for <em>Escherichia coli </em>FBWHR

We report the first time statistical study of the optimization for ethanol production from hot-water sugar maple hemicellulosic wood hydrolyzate by Escherichia coli FBWHR. Response surface methodology was employed to investigate the effect of fermentation media on the ethanol production from concentrated hot-water sugar maple hemicellulosic wood extract hydrolyzate by Escherichia coli FBWHR. The critical media components were firstly selected according to Plackett–Burman design and further optimized by central composite design. Based on the response surface analysis, the optimum concentrations of the significant components were obtained: yeast extract, 10.19 g/L; tryptone, 14.55 g/L; Na2HPO4·7H2O, 23.21 g/L; KH2PO4, 5 g/L and NH4Cl, 2 g/L. An ethanol concentration of 15.23 ± 0.21 g/L was achieved under the optimized media, which agreed with the predicted value. Ethanol production was enhanced to 22.18 ± 0.13 g/L by scaling up the fermentation from shaker flask to 1.3 L bioreactor.

Effect of critical medium components and culture conditions on antitubercular pigment production from novel Streptomyces sp D25 isolated from Thar desert, Rajasthan

Antifungal activity of 3-methylcarbazoles from Streptomyces sp. LJK109; an endophyte in Alpinia galangalThongchai Taechowisan, Srisakul Chanaphat, Wanwikar Ruensamran, Waya S. Phutdhawong