Optimization of batch fermentation conditions for dextran production
TL;DR: The nutrient medium, temperature and initial pH conditions were optimised for batch dextran production in shake flask fermentations using a strain of Leuconostoc mesenteroides NRRL B 512 (F) and the optimal values of tested variables were found to be sucrose, yeast extract and K2HPO4.
Abstract: The nutrient medium (containing sucrose, yeast extract and K2HPO4), temperature and initial pH conditions were optimised for batch dextran production in shake flask fermentations using a strain of Leuconostoc mesenteroides NRRL B 512 (F). A 25−1 fractional factorial central composite experimental design was attempted. Multistage Monte Carlo optimization program was used to maximize the multiple regression equation obtained. The optimal values of tested variables for maximal dextran production were found to be: sucrose, 300 g/l; yeast extract, 10 g/l; K2HPO4, 30 g/l; temperature, 23°C and initial pH 8.3 with a predicted dextran yield of 154 g/l.
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TL;DR: In this paper, dextran was produced using Saccharum officinarum juice (SOJ) as a low-carbon source by Leuconostoc mesenteroides MTCC 7337.
Abstract: Dextrans are exo-polysaccharides prominently used as biomaterial on the grounds of their biodegradability and biocompatibility characteristics. There is an increasing interest and need to identify alternative cost-effective and renewable carbon source for dextran to reduce the production cost and to improve the overall economy of dextran production. In this work, dextran was produced using Saccharum officinarum juice (SOJ) as a low-carbon source by Leuconostoc mesenteroides MTCC 7337. The suitable condition/parameter for the production of dextran was found to be medium pH, 7; shaking speed, 150 rpm; inoculum size, 5% v/v; and nitrogen source, yeast extract. The different downstream factors including screening of solvent, supernatant to solvent ratio and precipitation time on the recovery of dextran, were studied. The organic solvent, ethanol with volume ratio of 1:4 (supernatant to solvent ratio), and precipitation time of 16 h were selected based on the maximum recovery of dextran from SOJ medium. The purified dextran was characterized by proton nuclear magnetic resonance spectroscopy (1H-NMR), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA) analysis. The results of rheological studies indicate that dextran solution behaves like a pseudoplastic fluid at higher concentrations of dextran solution. Based on the results, it was found that SOJ could be used as an alternate substrate for the production of dextran.
4 citations
TL;DR: Response surface methodology was employed in optimizing the nutrient levels needed towards the optimal production of phosphatidylinositol-specific phospholipase C enzyme by Bacillus thuringiensis serovar.
Abstract: Response surface methodology was employed in optimizing the nutrient levels needed towards the optimal production of phosphatidylinositol-specific phospholipase C enzyme by Bacillus thuringiensis serovar. kurstaki. A 23 factorial central composite experimental design was used. The multiple regression equation, relating the enzyme activity to the nutrient medium, was used to find the optimum values of glucose, peptone and dipotassium hydrogen phosphate. The optimum values of these variables for maximal enzyme production were found to be: glucose, 6.5 g l−1; peptone, 5.38 g l−1 and dipotassium hydrogen phosphate, 6.36 g l−1 with the predicted enzyme activity of 0.96 U ml−1.
3 citations
Cites methods from "Optimization of batch fermentation ..."
...The Design-Expert package (Stat-Ease Inc, Minneapolis, MN, USA) (Karthikeyan et al. 1996) was used for regression and graphical analysis of the data obtained....
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TL;DR: In this paper , the authors compared the yield of microbial dextran using treated sugarcane molasses (SCM) as a feed stock from different treatment methods, and found that the maximum yield of dextrans was obtained to be 17.18 ± 0.08 g L-1 using the conventional optimization.
3 citations
DOI•
09 Nov 2021
TL;DR: Dextran is an extracellular bacterial polysaccharide for which industrial applications have been found in different areas as discussed by the authors. Several researchers have optimized the fermentation conditions to maximize the yield of Dextran.
Abstract: Dextran is an extracellular bacterial polysaccharide for which industrial applications have been found in different areas. Several researchers have optimized the fermentation conditions to maximize...
3 citations
24 Jul 2006
TL;DR: In this article, a polynomial regression model was developed using the experimental data including the effects of linear, quadratic and interaction of the factors involved were substrate (POME) and co-substrate (wheat flour) concentrations, temperature, pH, inoculum and agitation.
Abstract: The filamentous fungus Trichoderma harzianum was used for liquid state bioconversion of POME for cellulase production. Statistical optimization was carried out to evaluate the physico-chemical parameters (factors) for maximum cellulase production by 2-level fractional factorial design with six central points. The polynomial regression model was developed using the experimental data including the effects of linear, quadratic and interaction of the factors. The factors involved were substrate (POME) and co-substrate (wheat flour) concentrations, temperature, pH, inoculum and agitation. Statistical analysis showed that the optimum conditions were: temperature of 300C, substrate concentration of 2%, wheat flour concentration of 3%, pH of 4, inoculum of 3% and agitation of 200 rpm. Under these conditions, the model predicted the enzyme production to be about 14 FPU/ml. Analysis of variance (ANOVA) of the design showed a high coefficient of determination (R2) value of 0.99, thus ensuring a high satisfactory adjustment of the quadratic model with the experimental data.
2 citations
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01 Jan 2003
TL;DR: In this article, the authors present a survey of the properties of polymers and their application in the field of chemical engineering, including the following: Coextrusion, Injection Molding, Flexible Packaging, Fibers, Polymer-Clay, and Plasticizers.
Abstract: VOLUME 1. Acetylenic Polymers, Substituted. Acrylamide Polymers. Acrylic (and Methacrylic) Acid Polymers. Acrylic Ester Polymers. Acrylonitrile and Acrylonitrile Polymers. Acrylonitrile-Butadiene-Styrene Polymers. Additives. Adhesion. Adhesive Compounds. Aging, Physical. Alkyd Resins. Am,ino Resins and Plastics. Antifoaming Agents. Atomic Force Microscopy. Biotechnology Applications. Bloack Copolymers. Bloack Copolymers, Ternary Triblock. Blow Molding. Chitin and Chitosan. Chromatography, Affinity. Chromatography, HPLC. Chromatography, Size Exclusion. Coating Methods, Survey. Coatings. VOLUME 2 Coextrusion. Colorants. Coloring Processes. Composites, Fabrication. Conformation and Configuration. Critical Phase Polymerizations. Cyclohexanedimethanol Polyesters. Dendronized Polymers. Dental Applications. Diacethylene and Triacethylene Polymers. Elasticity, Rubber-Like. Electronic Packaging. Electrooptical Applications. Engineering, Thermoplastics, Overview. Enzymatic Polymerization. Ethylene Polymers, Chlorosulfonated. Ethylene Polymers, HDPE. Ethylene Polymers, LDPE. Ehtylene Polymers, LLDPE. Ethylene-Acrylic Elastomers. Ethylene-Norbornene Copolymers. Extrusion. Films, Orientation. Fluorocarbon Elastomers. Fractography. Fracture. Glass Transition. Hardness. Hydrogels. Hyperbranched Polymers. VOLUME 3 Injection Molding. Inorganic Polymers. Laser Light Scattering. Light-Emiting Diodes. Lignin. Liquid Crystalline Polymers, Main-Chain. Liquid Crystalline Thermosets. Mass Spectrometry. Membrane Technology. Methacrylic Ester Polymers. Micromechanical Properties. Modeling of Polymer Processing and Properties. Nanocomposites, Polymer-Clay. Packaging, Flexible. Perfluorinated Polymers, Perfluorinated Ethylene-Propylene Copolymers. Perfluorinated Polymers Polytetrafluoroethylene. Perfluorinated Polymers Tetrafluoroethylene-Ethylene Copolymers. Perfluorinated Polymers, Tetrafluoroethylene-Perfluorinated Copolymers. Perfluorinated Polymers. Tetrafluoroethylene-Perfluorovinyl Ether Copolymers. Phosgene. Phosphorus-Containing Polymers and Oligomers. Piezoelectric Polymers. Plasticizers. Poly(3-Hydroxyalkanoates). Poly(Trimethylene Terephthalate). Polyamides, Atomatic. Polyamides, Fibers. Polyamides, Plastics. Polycyanoacrylates. Polyesters, Fibers. Polyketones. Polynucleotides. Polysulfides. VOLUME 4 Polysulfones. Polyurethanes. Pressure-Sensitive Adhesive. Reinforcement. Release Agents. Shape-Memory Polymers. Single-Site Catalysis. Stabilization. Styrene-Butadiene Rubber (SBR). Styrene Polymers. Sulfur-Containing Polymers. Surface Properties. Syndiotactic Polystyrene. Vinyl Fluoride Polymers (PVF). Vinylidene Chloride Polymers. Vinylidene Fluoride Polymers. Viscoelasticity. Weathering.
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439 citations
TL;DR: Observation on factors affecting production of dextransucrase from Leuconostoc mesenteroides, strain NRRL B-512 and the possibility that more than one enzyme may be involved in the synthesis ofdextran is recognized.
Abstract: Present knowledge on the characteristics of dextransucrase and its mode of action is based primarily on the important investigations of Hehre (1941, 1946, 1951) and Hehre and Sugg (1942). Hitherto, a serious impediment to studies of this interesting enzyme has been the difficulty of procuring dextransucrase. Development of further knowledge about it would be greatly facilitated by the availability of culture liquors rich in dextransucrase. The rapid formation of dextransucrase in high yields has been reported in a preliminary note (Koepsell and Tsuchiya, 1952). The present report deals in greater detail with our observations on factors affecting production of dextransucrase from Leuconostoc mesenteroides, strain NRRL B-512.2 However, culture liquors high in activity have been obtained from a large number of the organisms tested. The dextran produced by strain NRRL B-512 in the conventional whole culture procedure contains about 95 per cent a-1,6-glucopyranosidic linkage. Although the non-1,6 linkages have been assumed to be of the a-1,4 type, definite proof on this point is lacking (Jeanes and Wilham, 1950). L. mesenteroides, strain NRRL B-512, or its substrains, is the organism principally used in investigations of clinical dextran in the United States. Although the term \"dextransucrase\" is used in the singular for convenience, the possibility that more than one enzyme may be involved in the synthesis of dextran is recognized.
152 citations
TL;DR: Mineral sources such as CaCO3 and KH2PO4 proved to be important factors influencing polysaccharide production and quality and the use of high carbon to nitrogen ratios in the defined medium resulted in a major increase in the broth consistency index.
83 citations