Showing papers on "Growth medium published in 2015"
TL;DR: Growth in aerated microtiter plates coupled with a 96-well Nile red flow-cytometric assay creates an integrated microbioreactor system for high-throughput growth and analysis of P3HB-producing methanotrophic cultures, eliminating the need for individual manipulation of experimental replicates.
Abstract: Production of poly(3-hydroxybutyrate) (P3HB) from methane has economic and environmental advantages over production by agricultural feedstock. Identification of high-productivity strains and optimal growth conditions is critical to efficient conversion of methane to polymer. Current culture conditions, including serum bottles, shake flasks, and agar plates, are labor-intensive and therefore insufficient for systematic screening and isolation. Gas chromatography, the standard method for analysis of P3HB content in bacterial biomass, is also incompatible with high-throughput screening. Growth in aerated microtiter plates coupled with a 96-well Nile red flow-cytometric assay creates an integrated microbioreactor system for high-throughput growth and analysis of P3HB-producing methanotrophic cultures, eliminating the need for individual manipulation of experimental replicates. This system was tested in practice to conduct medium optimization for P3HB production in pure cultures of Methylocystis parvus OBBP. Optimization gave insight into unexpected interactions: for example, low calcium concentrations significantly enhanced P3HB production under nitrogen-limited conditions. Optimization of calcium and copper concentrations in the growth medium increased final P3HB content from 18.1% to 49.4% and P3HB concentration from 0.69 g/liter to 3.43 g/liter while reducing doubling time from 10.6 h to 8.6 h. The ability to culture and analyze thousands of replicates with high mass transfer in completely mixed culture promises to streamline medium optimization and allow the detection and isolation of highly productive strains. Applications for this system are numerous, encompassing analysis of biofuels and other lipid inclusions, as well as analysis of heterotrophic and photosynthetic systems.
45 citations
TL;DR: The initial pH of the culture medium influences the production of organic acids by the strains UFLA03-08, UFLa03-09, UFP03-10 and UFL a03-106 but it does not affect calcium phosphate solubilization.
38 citations
TL;DR: It is demonstrated that E. coli has potential to produce itaconate and glutamate under anaerobic conditions, closing the redox balance by co-production of succinate or ethanol with H2 and CO2.
Abstract: Itaconic acid, an unsaturated C5-dicarboxylic acid, is a biobased building block for the polymer industry. The purpose of this study was to establish proof of principle for an anaerobic fermentation process for the production of itaconic acid by modification of the mixed acid fermentation pathway of E. coli. E. coli BW25113 (DE3) and the phosphate acetyltransferase (pta) and lactate dehydrogenase (ldhA) deficient strain E. coli BW25113 (DE3) Δpta-ΔldhA were used to study anaerobic itaconate production in E. coli. Heterologous expression of the gene encoding cis-aconitate decarboxylase (cadA) from A. terreus in E. coli BW25113 (DE3) did not result in itaconate production under anaerobic conditions, but 0.08 mM of itaconate was formed when the genes encoding citrate synthase (gltA) and aconitase (acnA) from Corynebacterium glutamicum were also expressed. The same amount was produced when cadA was expressed in E. coli BW25113 (DE3) Δpta-ΔldhA. The titre increased 8 times to 0.66 mM (1.2 % Cmol) when E. coli BW25113 (DE3) Δpta-ΔldhA also expressed gltA and acnA. In addition, this strain produced 8.5 mM (13 % Cmol) of glutamate. The use of a nitrogen-limited growth medium reduced the accumulation of glutamate by nearly 50 % compared to the normal medium, and also resulted in a more than 3-fold increase of the itaconate titre to 2.9 mM. These results demonstrated that E. coli has potential to produce itaconate and glutamate under anaerobic conditions, closing the redox balance by co-production of succinate or ethanol with H2 and CO2.
29 citations
TL;DR: By modifying the growth medium made from treated livestock waste water with additional nitrogen source, this work was able to increase dry cell weight of C. vulgaris by 65.7% and chlorophyll a contents by 78.8% and is an example of an indirect method to increase algal biomass by changing the population of symbiotic bacteria.
Abstract: To increase algal growth in treated livestock waste water, we designed a culture system targeting symbiotic bacteria. Microbacterium sp. HJ1 is a symbiotic bacteria associated with Chlorella vulgaris , which was found to increase the growth rate when controlled by nitrogen addition. The validated analysis model for nitrogen source mixture was used to analyze the growth and final pH of Microbacterium sp. HJ1, in different compositions of nitrogen sources, by elucidating the functions of each nitrogen ions such as NO 3 − , NO 2 − , and NH 4 + . By modifying the growth medium made from treated livestock waste water with additional nitrogen source, we were able to increase dry cell weight (DCW) of C. vulgaris by 65.7% and chlorophyll a contents by 78.8%. This is an example of an indirect method to increase algal biomass by changing the population of symbiotic bacteria, and it is the practical application of positive effects from symbiotic bacteria to the host.
22 citations
TL;DR: It is demonstrated that 15°C-grown baker’s yeast cells display higher fermentative capacity than those cultivated at 30°C and that decreased capacity of glycerol production impairs growth at 15 °C, and that increased NADPH- and NADH-dependent Gdh1 and Gdh2 activity were tested for growth at low temperature.
Abstract: Background: Cold stress reduces microbial growth and metabolism being relevant in industrial processes like wine making and brewing. Knowledge on the cold transcriptional response of Saccharomyces cerevisiae suggests the need of a proper redox balance. Nevertheless, there are no direct evidence of the links between NAD(P) levels and cold growth and how engineering of enzymatic reactions requiring NAD(P) may be used to modify the performance of industrial strains at low temperature. Results: Recombinant strains of S. cerevisiae modified for increased NADPH ‑ and NADH‑dependent Gdh1 and Gdh2 activity were tested for growth at low temperature. A high‑copy number of the GDH2‑encoded glutamate dehydro‑ genase gene stimulated growth at 15°C, while overexpression of GDH1 had detrimental effects, a difference likely caused by cofactor preferences. Indeed, neither the Trp − character of the tested strains, which could affect the syn‑ thesis of NAD(P), nor changes in oxidative stress susceptibility by overexpression of GDH1 and GDH2 account for the observed phenotypes. However, increased or reduced NADPH availability by knock‑out or overexpression of GRE3, the NADPH‑dependent aldose reductase gene, eliminated or exacerbated the cold‑growth defect observed in YEpGDH1 cells. We also demonstrated that decreased capacity of glycerol production impairs growth at 15 but not at 30°C and that 15°C‑grown baker’s yeast cells display higher fermentative capacity than those cultivated at 30°C. Thus, increasing NADH oxidation by overexpression of GDH2 would help to avoid perturbations in the redox metabolism induced by a higher fermentative/oxidative balance at low temperature. Finally, it is shown that overexpression of GDH2 increases notably the cold growth in the wine yeast strain QA23 in both standard growth medium and synthetic grape must. Conclusions: Redox constraints limit the growth of S. cerevisiae at temperatures below the optimal. An adequate supply of NAD(P) precursors as well as a proper level of reducing equivalents in the form of NADPH are required for cold growth. However, a major limitation is the increased need of oxidation of NADH to NAD + at low temperature. In this scenario, our results identify the ammonium assimilation pathway as a target for the genetic improvement of cold growth in industrial strains.
22 citations
TL;DR: The growth characteristics, lipid accumulation and composition during the life cycle of a newly isolated strain of Debaryomyces etchellsii were studied under nitrogen limiting conditions and a shift from sexual to asexual reproduction was observed.
Abstract: The growth characteristics, lipid accumulation and composition during the life cycle of a newly isolated strain of Debaryomyces etchellsii were studied under nitrogen limiting conditions. This yeast, grown in batch flask or bioreactor cultures, reproduced asexually by buds when nitrogen was available in the growth medium, or sexually by ascospores after nitrogen exhaustion, producing more than 7 g L−1 biomass. During ascosporogenesis, an important increase in the cellular lipid content in dry cell mass occurred, i.e. from a mass fraction of 11.9% in the vegetative phase to 22.4%, in the ascosporogenic phase. During transition of D. etchellsii from batch to continuous cultures using dilution rates 0.026 and 0.019 h−1, a shift from sexual to asexual reproduction was observed. At 0.019 h−1, few pseudomycelia were also formed. The yeast synthesized lipids containing long chain fatty acids (mainly C16 and C18). Budded cells at steady-states contained only 8.6–9.3 % of lipids mass fraction per dry cell mass that were composed of oleic and linoleic acids and, to a lesser extent, of palmitic and palmitoleic acids. Neutral lipids were the major fraction represented 61.8–66.1%, of total lipids followed by phospholipids, which was the only fraction in which linoleic acid predominated over oleic acid.
21 citations
TL;DR: Transformation of palmitoleic acid to cis-vaccenic acid is thus a rescue mechanism enabling S. cerevisiae cells to survive in the absence of triacylglycerol synthesis as the major mechanism for unsaturated fatty acid detoxification.
Abstract: The role of cis-vaccenic acid (18:1n-7) in the reduction of unsaturated fatty acids toxicity was investigated in baker's yeast Saccharomyces cerevisiae. The quadruple mutant (QM, dga1Δ lro1Δ are1Δ are2Δ) deficient in enzymes responsible for triacylglycerol and steryl ester synthesis has been previously shown to be highly sensitive to exogenous unsaturated fatty acids. We have found that cis-vaccenic acid accumulated during cultivation in the QM cells but not in the corresponding wild type strain. This accumulation was accompanied by a reduction in palmitoleic acid (16:1n-7) content in the QM cells that is consistent with the proposed formation of cis-vaccenic acid by elongation of palmitoleic acid. Fatty acid analysis of individual lipid classes from the QM strain revealed that cis-vaccenic acid was highly enriched in the free fatty acid pool. Furthermore, production of cis-vaccenic acid was arrested if the mechanism of fatty acids release to the medium was activated. We also showed that exogenous cis-vaccenic acid did not affect viability of the QM strain at concentrations toxic for palmitoleic or oleic acids. Moreover, addition of cis-vaccenic acid to the growth medium provided partial protection against the lipotoxic effects of exogenous oleic acid. Transformation of palmitoleic acid to cis-vaccenic acid is thus a rescue mechanism enabling S. cerevisiae cells to survive in the absence of triacylglycerol synthesis as the major mechanism for unsaturated fatty acid detoxification.
18 citations
TL;DR: The generation of P. pastoris strains that will secrete rLlALP2 to the extracellular medium and efforts to increase expression levels by employing a constitutive promoter from the glyceraldehyde-3-phosphate dehydrogenase gene (PGAP) in place of the strong, tightly controlled promoter of alcohol oxidase 1 gene (PAOX1) are described.
16 citations
TL;DR: The objective of this study was to optimise the culture medium, determine the pollen germination capacity, and quantify the number of pollen grains per flower of certain olive tree cultivars.
Abstract: Pollen grain germination in vitro indicates viability and consequently provides information related to fruit set. It also assists in the development of hybrids. Along with a suitable species, a standard culture medium is essential for evaluating pollen viability. It should contain a gelling agent consisting of carbohydrates and enhancer elements as well as have the correct pH, temperature, and incubation time. The objective of this study was to optimise the culture medium, determine the pollen germination capacity, and quantify the number of pollen grains per flower of certain olive tree cultivars. A basic sequential culture medium for pollen grain germination was determined, always utilizing the best result from the previous experiment to continue the sequence.The factorial treatment arrangement was: 1) agar versus boric acid; 2) pH versus sucrose; 3) calcium nitrate versus magnesium sulfate. After determining the culture medium components, two experiments were conducted evaluating temperature and incubation time. Another experiment evaluated both the germination percentage and the number of flower pollen grains of 28 cultivars. The culture medium should be composed of 4 g∙L-1 of agar, 90 g∙L-1 of sucrose, and 400 mg∙L-1 of boric acid with a pH adjusted to 5.79 and an incubation time of 60 h at 28 °C. The Manzanilla 215 cultivar had the highest germination rate while Ascolano 315 presented the highest number of pollen grains per flower.
16 citations
TL;DR: In this paper, the authors optimized the production of lipase from Pseudomonas putida 922 by modifying various physical parameters such as carbon source, nitrogen source, pH, salt concentration and biochemical parameters of the production medium such as temperature and incubation time of the growth medium.
Abstract: The production of lipase from Pseudomonas putida 922 was optimized by modifying various physical parameters such as carbon source, nitrogen source, pH, salt concentration and biochemical parameters of the production medium such as temperature and incubation time of the growth medium. Oil cakes were also used as carbon source to check for an increased production of the enzyme. The bacterium was found to have a maximal growth at pH 10 with the enzyme production being highest (24 U/ml) after 48 hours at 30°C and pH 10. The optimum composition of the medium was mustard oil cake as carbon source, yeast extract or peptone as nitrogen source and 1% sodium chloride concentration. Partial characterization of the enzyme was carried out where the optimum working pH and temperature was found to be 10 and 40oC, respectively. Enzyme stability was found to lie in the pH and temperature ranges of 5-11 and 30-40oC, respectively. Partial purification of the enzyme was carried out at 80% ammonium sulphate saturation. Molecular mass of lipase was determined by SDS PAGE and found to be 45 kDa.
14 citations
TL;DR: Study of multifactorial interactions between the growth factors in shrimp cell culture medium and to identify the most important ones for growth of lymphoid cell culture from Penaeus monodon suggested that IGF-I and IGF-II had critical roles in metabolic activity and DNA synthesis of shrimp lymphoid cells.
Abstract: Development of continuous cell lines from shrimp is essential to investigate viral pathogens. Unfortunately, there is no valid cell line developed from crustaceans in general and shrimps in particular to address this issue. Lack of information on the requirements of cells in vitro limits the success of developing a cell line, where the microenvironment of a cell culture, provided by the growth medium, is of prime importance. Screening and optimization of growth medium components based on statistical experimental designs have been widely used for improving the efficacy of cell culture media. Accordingly, we applied Plackett-Burman design and response surface methodology to study multifactorial interactions between the growth factors in shrimp cell culture medium and to identify the most important ones for growth of lymphoid cell culture from Penaeus monodon. The statistical screening and optimization indicated that insulin like growth factor-I (IGF-I) and insulin like growth factor-II (IGF-II) at concentrations of 100 and 150 ng ml(-1), respectively, could significantly influence the metabolic activity and DNA synthesis of the lymphoid cells. An increase of 53 % metabolic activity and 24.8 % DNA synthesis could be obtained, which suggested that IGF-I and IGF-II had critical roles in metabolic activity and DNA synthesis of shrimp lymphoid cells.
TL;DR: H2 generation using the mixture of acetate and glycerol at different pHs was investigated and the highest H2 yield of 5.16 mmol L−1 was detected at the log growth phase at pH 7.5.
TL;DR: It is shown that T. vaginalis grows equally well in growth media supplemented with simple sugars or with glycogen, and that added glucosidase activity to a growth medium containing glycogen generates sufficient simple sugar to support the growth of lactobacilli which, themselves, are unable to degrade glycogen.
TL;DR: The adsorption of yeast cells on Nypa fruticans leaf sheath pieces of the growth medium increased the saturated fatty acid (C16:0 and C18:0) mass fraction in the cellular membrane and that improved alcoholic fermentation performance of the immobilized yeast.
Abstract: The yeast cells of Saccharomyces cerevisiae immobilized on Nypa fruticans leaf sheath pieces were tested for ethanol tolerance (0, 23.7, 47.4, 71.0 and 94.7 g/L). Increase in the initial ethanol concentration from 23.7 to 94.7 g/L decreased the average growth rate and concentration of ethanol produced by the immobilized yeast by 5.2 and 4.1 times, respectively. However, in the medium with initial ethanol concentration of 94.7 g/L, the average growth rate, glucose uptake rate and ethanol formation rate of the immobilized yeast were 3.7, 2.5 and 3.5 times, respectively, higher than those of the free yeast. The ethanol stress inhibited ethanol formation by Saccharomyces cerevisiae cells and the yeast responded to the stress by changing the fatty acid composition of cellular membrane. The adsorption of yeast cells on Nypa fruticans leaf sheath pieces of the growth medium increased the saturated fatty acid (C16:0 and C18:0) mass fraction in the cellular membrane and that improved alcoholic fermentation performance of the immobilized yeast.
TL;DR: In this paper, the authors present a detailed description of the steps involved in the development of a optimized culture medium containing extruded bean as nitrogen source for growth of Saccharomyces cerevisiae and Pichia pastoris.
TL;DR: Examination of the role of the alternative general stress sigma factors σ(B) and rpoS on the ability of Staphylococcus aureus and Escherichia coli to grow in liquid and solid media of different osmolarity demonstrates that the increased osmotolerance of stationary growth phase E. coli cells, as compared to exponential growth phase ones, would be due to the activation of both rpo S-independent and rPOS-dependent mechanisms.
TL;DR: A mutant with a transposon insertion just upstream of the lysophosphatidic acid acyltansferase gene plsC was isolated in a screen for mutants affected in growth at low temperature of the psychrotroph Serratia plymuthica RVH1, indicating that a balanced ratio of the two main unsaturated fatty acids is required for psychrotrophy.
TL;DR: It is found that even brief rinsing of cell culture plasticware with culture medium elutes artefactual chemicals, the 1H NMR signals of which could confound assays of acetate, succinate, and glycolate.
Abstract: Metabolomic studies on cultured cells involve assays of cell extracts and culture medium, both of which are often performed by 1H NMR. Cell culture is nowadays performed in plastic dishes or flasks, and the extraction of metabolites from the cells is typically performed with perchloric acid, methanol–chloroform, or acetonitrile, ideally while the cells are still adherent to the culture dish. We conducted this investigation to identify contaminants from cell culture plasticware in metabolomic studies. Human diploid fibroblasts (IMR90) (n = 6), HeLa cells (n = 6), and transformed astrocytes with HIF-1 knockout (Astro-KO) (n = 6) were cultured. Cells were seeded in 100 mm Petri dishes with 10 ml complete growth medium (Dulbecco’s minimum essential medium) containing 10 % foetal bovine serum (FBS). Cell cultures were incubated at 37 °C in 5 % CO2 for approximately 3 days. Metabolites were extracted by use of a perchloric acid procedure. 1H NMR spectroscopy was used for metabolite analysis. “Null sample” (i.e. cell-free) experiments were performed by either rinsing dishes with medium or incubating the medium in Petri dishes from five different manufacturers for 72 h and then by performing a dummy “extraction” of each Petri dish by the perchloric acid, methanol–chloroform, or acetonitrile procedures. Principal components analysis was used for classification of samples and to determine the contaminants arising from plasticware. We found that even brief rinsing of cell culture plasticware with culture medium elutes artefactual chemicals, the 1H NMR signals of which could confound assays of acetate, succinate, and glycolate. Incubation of culture medium in cell-culture dishes for 72 h (as in a typical cell-culture experiment) followed by perchloric extraction in the dishes enhanced elution of the artefacts. These artefacts were present, but somewhat less pronounced, in the 1H NMR spectra of null samples extracted with methanol and acetonitrile. Ethanol, lactate, alanine, fructose, and fumarate signals that appear in the 1H NMR spectrum of the unused (pure) medium originate from FBS. Plastic Petri dishes from five different manufacturers gave rise to essentially identical artefactual peaks. Use of a pH indicator to assist neutralisation introduced still more artefactual signals in the aromatic region, as well as methanol and ethanol signals. Methanol and acetonitrile extracts also contained artefacts arising from the plasticware, although the amounts were less than in the perchloric acid extracts. Finally, we provide suggestions for minimizing these artefacts. The best practice would be to run a “null” extraction with every batch of cellular metabolomics experiments to test for contamination and to provide a “background” spectrum.
TL;DR: In this paper, the ability of 30 strains of soil bacteria to grow in the presence of glyphosate which was the sole source of phosphorus was examined using a modified Dworkin-Foster growth medium.
Abstract: Glyphosate is an active substance in the Roundup herbicide. The key process affecting its decomposition in the soil is microbial biodegradation. Bacteria that are able to break the C-P bond use this substance as a source of phosphorus. The aim of the study was to investigate the ability of thirty strains of soil bacteria to grow in the presence of glyphosate which was the sole source of phosphorus. Morphologically and physiologically varied soil bacteria strains were the subject of the study. Their ability to grow in the presence of glyphosate being the only phosphorus source was examined using a modified Dworkin-Foster growth medium. The modification itself consisted in introducing to the medium 0.5 mM dm of glyphosate which was to serve as an alternative source of phosphorus. The control sample in the study was the bacterial growth in two Dworkin-Foster growth media: a complete one (unmodified) and a phosphorus-free one. The growth intensity of the analyzed strains was assessed by means of spectrophotometry ( = 490 nm). Substantial differences in the growth intensity of the analyzed bacterial strains were observed in the presence of glyphosate, which was the sole source of phosphorus. Only eight out of the analyzed strains showed growth similar to what was observed in the case of the unmodified Dworkin-Foster medium, whereas all the remaining ones grew at a much slower rate.
20 Aug 2015
TL;DR: For the first time, kinetic parameters and yields are reported for D. geothermalis DSM-11302 grown on a mineral medium in well-controlled batch culture and showed that the physiological descriptors were not affected by the inoculum preparation steps.
Abstract: Due to their remarkable resistance to extreme conditions, Deinococcaceae strains are of great interest to biotechnological prospects. However, the physiology of the extremophile strain Deinococcus geothermalis has scarcely been studied and is not well understood. The physiological behaviour was then studied in well-controlled conditions in flask and bioreactor cultures. The growth of D. geothermalis type strains was compared. Among the strains tested, the strain from the German Collection of Microorganisms (Deutsche Sammlung von Mikroorganismen DSM) DSM-11302 was found to give the highest biomass concentration and growth rate: in a complex medium with glucose, the growth rate reached 0.75 h−1 at 45 °C. Yeast extract concentration in the medium had significant constitutive and catalytic effects. Furthermore, the results showed that the physiological descriptors were not affected by the inoculum preparation steps. A batch culture of D. geothermalis DSM-11302 on defined medium was carried out: cells grew exponentially with a maximal growth rate of 0.28 h−1 and D. geothermalis DSM-11302 biomass reached 1.4 g·L−1 in 20 h. Then, 1.4 gDryCellWeight of biomass (X) was obtained from 5.6 g glucose (Glc) consumed as carbon source, corresponding to a yield of 0.3 CmolX·CmolGlc−1; cell specific oxygen uptake and carbon dioxide production rates reached 216 and 226 mmol.CmolX−1·h−1, respectively, and the respiratory quotient (QR) value varied from 1.1 to 1.7. This is the first time that kinetic parameters and yields are reported for D. geothermalis DSM-11302 grown on a mineral medium in well-controlled batch culture.
Journal Article•
TL;DR: Results showed that radial growth of S. rolfsii on solid medium and its biomass on liquid medium were s ignificantly decreased with the increase in concentrations of Cr(III) up to 100 ppm, while fungus was unable to grow at concentrations above 100 ppm.
Abstract: Tolerance of plant pathogens to heavy metal stress is an important area of research that has been rarely explored in Pakistan. The current research work was carried out to investigate the impact of Cr(III) on growth of Sclerotium rolfsii Sacc., the cause of collar rot of chilli ( Capsicum annuum L.). Laboratory bioassays were conducted in using solid as well as liquid malt extract growth medium amended with 14 different concentrations (0, 5, 10, 20, 30, …,100, 150, 200, 300, 400, 500 ppm) of Cr(III). Growth medium flasks with different concentrations of Cr(III) were inoculated with the pathogen and incubated for 7 days at 25±2 o C. Results showed that radial growth of S. rolfsii on solid medium and its biomass on liquid medium were s ignificantly decreased with the increase in concentrations of Cr(III) up to 100 ppm, while fungus was unable to grow at concentrations above 100 ppm. There was a linear relationship (R 2 = 0.9242) between Cr(III) concentrations and fungal biomass on liquid medium, and a non-linear relationship (R 2 = 0.9264) between Cr(III) concentrations and fungal radial growth on solid growth medium.
TL;DR: It is found that two Bacillus isolates, I-009 and FRIN-001-1 strains, produced cellulase and siderophore, but not chitinase, while the Pseudomonas YPIN-022 strain was found to release only siderophile, implying that three antagonistic bacteria commonly interrupt Fe uptake by the large patch pathogen.
Abstract: Our previous report demonstrated successful isolation of soil-borne bacteria that suppressed the potential of Rhizoctonia solani AG2-2 (IV) causing turfgrass large patch disease when applied to Korean lawngrass ( Zoysia japonica). The current study aimed to uncover the mechanisms of this antagonism of Rhizoctonia solani and to define culture conditions for the isolated microbes. We found that two Bacillus isolates, I-009 and FRIN-001-1 strains, produced cellulase and siderophore, but not chitinase, while the Pseudomonas YPIN-022 strain was found to release only siderophore, implying that three antagonistic bacteria commonly interrupt Fe uptake by the large patch pathogen. The I-009 and FRIN-001-1 isolates grew best at 35 and 30°C in growth medium of pH 5 to 8 for 32 and 28 h, respectively, while optimum growth for the YPIN-022 strain was found at 35°C at pH 5 to 9 for 24 h. Good growth of I-009 and YPIN-022 over 24 h was obtained in M9 minimal medium supplemented with 1% sucrose, 0.5% yeast extract and 0.1% potassium chloride. FRIN-001-1 grew well in M9 medium with 1% mannitol, 0.5% yeast extract and 0.1% potassium phosphate dibasic.Additional key words:
TL;DR: The aim of this study was to establish a scientific and rational method to optimize the fermentation medium used for plasmid production, and investigate the effect of growth medium composition on the production ofplasmid pSVK-HBVA harboured in E. coli XL10-Gold.
Abstract: At present, there are production processes to produce protein by Escherichia coli (E. coli) fermentation. Research on the design and optimization of the plasmid fermentation medium, however, is less advanced. The fermentation medium that is optimized for plasmid DNA production is different from the medium that is optimized for protein production. So, establishing a scientific and rational method to optimize the fermentation medium used for plasmid production is very important. Previously, our laboratory developed a novel therapeutic DNA vaccine (named pSVK-HBVA) for hepatitis B based on the alphavirus replicon, and found that E. coli XL10-Gold was the optimal host strain for the production of plasmid pSVK-HBVA. The aim of this study was to establish a scientific and rational method to optimize the fermentation medium used for plasmid production, and investigate the effect of growth medium composition on the production of plasmid pSVK-HBVA harboured in E. coli XL10-Gold, as well as to optimize the medium composition. The one-factor-at-a-time experiments demonstrated that Luria-Bertani (LB) was the optimal basic medium. The optimal carbon source and nitrogen source were glycerol and home-made proteose peptone, respectively. Based on the Plackett-Burman (PB) design, proteose peptone, glycerol and NH4Cl were identified as the significant variables, which were further optimized by the steepest ascent (descent) method and central composite design. Growth medium optimization in 500-mL shake flasks by response surface methodology resulted in a maximum volumetric yield of 13.61 mg/L, which was approximately 2.5 times higher than that obtained from the basic medium (LB).
Patent•
15 Dec 2015
TL;DR: In this paper, the authors present methods for screening clinical or biological samples to determine the presence of L-form bacteria within the sample, which includes contacting a sample to a liquid growth medium and incubating it at a temperature lower than 37 degrees C.
Abstract: Disclosed herein are methods for screening clinical or biological samples to determine the presence of L-form bacteria within the sample. Methods include contacting a sample to a liquid growth medium and incubating the liquid growth medium at a temperature lower than 37 degrees C. The liquid growth medium is monitored for L-form bacterial growth. An amount of the liquid growth medium is transferred as an inoculant to a solid growth medium, and the solid growth medium is incubated under conditions that maintain a hydrated state of the inoculant to enable the L-form bacteria to efficiently interface with the solid growth medium and continue to grow.
Patent•
07 Jul 2015
TL;DR: In this paper, a method of mass-producing tea-plants is described, through which teaplants are mass-produced by which conditions to culture in a vessel are established.
Abstract: The present invention relates to a method of mass-producing tea-plant, through which tea-plants are mass-produced by which conditions to culture in a vessel are established. The method comprises the steps of: (a) collecting seeds from tea plants, removing the outer shell of seeds collected, and sterilizing seeds whose outer shell has been removed; (b) adding sucrose and phyta gel to a MS basal medium to prepare a seeds germinating medium and germinating the sterilized seeds in the seeds germinating medium prepared; (c) adding either BAP or TDZ, or both to a MS basal medium, or adding IAA to a MS basal medium, to prepare a shoots growth medium, and growing shoots of the germinated seeds in the shoots growth medium prepared; (d) adding either BAP or TDZ to a MS basal medium to prepare a node seedlings growth medium, and growing seedlings with grown shoots in a node seedlings growth medium; and (e) adding either IBA or NAA to a MS basal medium to prepare a seedlings rooting medium, and rooting the seedlings in the seedlings rooting medium.
Journal Article•
TL;DR: Pre-culturing of green algae Chlorella vulgaris (C Vulgaris) proved that the cells responded productively in the organic mode of growth medium, which vindicated the optimum algae growth.
Abstract: Algae cells were cultivated both at micro and macro level under heterotrophic conditions in a prepared growth medium to analyze the cell response under the given conditions. Micro-cultivation of the cells was carried out separately in small-sized flasks, whereas mass cultivation of the cells was performed in a large-size tank. Pre-culturing of green algae Chlorella vulgaris (C Vulgaris) proved that the cells responded productively in the organic mode of growth medium. Saturated cycles of DO concentration in the range of 14 mg/L/d or above were observed during mass cultivation of C Vulgaris along with consequent occurrence of lowered pH values, which vindicated the optimum algae growth. The optimum C Vulgaris growth transpired that during the log phase every 1 g growth in C Vulgaris cell mass caused a COD reduction of 13%. Similarly, every 1g drop in C Vulgaris growth during stationary or death phase coincided with a COD increase of 730 mg l-1 likely caused by the release of soluble organic fraction of the decaying algae cells along with the generation of insoluble algae detritus in the cultivation medium.
TL;DR: There was a significantly higher antioxidant potential found in lipid extracts suggests that next to the well studied phenolic compounds, microalgal lipids should also be considered when using microalgae as a source of natural antioxidants.
Abstract: Up-scaling the production of value added products from microalgae requires reliable techniques. This study has been carried out in order to determine whether microalgae have an inherent tendency to contain similar proportions of antioxidant properties in its lipid and phenolic extracts under varying growth medium. Chlorella vulgaris and Acutodesmus obliquus (Scenedesmus obliquus) were cultivated in normal water, Bold’s medium and sewage water followed by extraction of lipids and phenolics. The extracts were subjected to in vitro antioxidant assays performed in triplicates in which higher scavenging activity of DPPH and super oxide radical was observed in phenolic extracts. However, there was a significantly higher antioxidant potential found in lipid extracts suggests that next to the well studied phenolic compounds, microalgal lipids should also be considered when using microalgae as a source of natural antioxidants. Further, antioxidant profile of lipid and phenolic extracts from same species varied with growth medium.
TL;DR: The results support the hypothesis that the inhibitory molecule secreted by Bacillus cereus GS1 is a novel, low molecular weight bacteriocin from Bacillin cereus and the proposed name is Cerein GS1, which is proposed for this molecule.
Abstract: Bacillus cereus GS1 secretes a diffusible bacteriocin-like molecule into culture medium that can be detected by a modified spot-on-lawn agar plate method. The secreted molecule exhibits a narrow inhibitory spectrum, affecting only the growth of Bacillus subtilis 6633 and certain other Gram-positive species. The molecule, in cell-free supernatant, is heat-stable and resistant to degradation by a number of proteases and to denaturation by several solvents. Clearing on agar plates is inversely related to the ionic strength of the growth medium, consistent with a membrane-directed activity. Analysis of activity gels reveals a clearing that coincides with a low molecular weight protein of about three kilodaltons. The inhibitory spectrum and protease sensitivity profile observed for this bacteriocin-like molecule distinguish it from similarly described molecules produced by other strains of Bacillus cereus. Our results support our hypothesis that the inhibitory molecule is a novel, low molecular weight...
Patent•
29 Apr 2015
TL;DR: In this paper, a fermentation medium is used for growing Pichia pastoris for expressing PLC, the protease content in a fermentation process is inhibited effectively, the enzyme production time of the interest protein PLC is prolonged effectively, and the stability of the PLC in finally obtained fermentation broth is improved greatly and can be even improved by more than four times.
Abstract: The invention provides a fermentation medium. The content of Mg in the fermentation medium is 1.5-4.6 g/l. The fermentation medium is used for cultivating Pichia pastoris for expressing PLC, the protease content in a fermentation process is inhibited effectively, the enzyme production time of the interest protein PLC is prolonged effectively, the stability is improved remarkably, and the enzyme activity of the PLC in finally obtained fermentation broth is improved greatly and can be even improved by more than four times.
TL;DR: The increase of calcium, magnesium and potassium content in plant tissues in response to different Cd treatment reflected a kind of adaptive mineral strategy that apparently failed to give resistance to M. truncatula plant against Cd treatments.
Abstract: Medicago truncatula (A17) were cultivated under strictly controlled growth conditions, in a nutrient solution in the absence or presence of Cd (10, 20 and 50 µM CdSO4). After 20 days, decrease on the plant growth was detected and chlorosis appeared on the foliar limbs. Root growth, relative root growth (Cd -treated /untreated seedlings) and tolerance index (difference of root growth between Cd-treated and untreated seedlings) were considered as the indices of tolerance to this toxic metal. The results showed that the internal quantity of cadmium increases essentially in roots level with the elevation of the cadmium concentration in the growth medium. Different cadmium treatments significantly and considerably decreased shoot growth and root growth at Cd concentration 20µM. In addition, cadmium induced the proteolytic activity endopeptidase in roots. The increase of calcium, magnesium and potassium content in plant tissues in response to different Cd treatments reflected a kind of adaptive mineral strategy that apparently failed to give resistance to M. truncatula plant against Cd treatments.