Regulation of valine catabolism by ammonium in Streptomyces ambofaciens, producer of spiramycin

1995 ◽  
Vol 41 (9) ◽  
pp. 800-808 ◽  
Author(s):  
Anissa Lounès ◽  
Ahmed Lebrihi ◽  
Chouki Benslimane ◽  
Gérard Lefebvre ◽  
Pierre Germain
Keyword(s):  
Growth Rate ◽  
Growth Phase ◽  
Uptake Rate ◽  
Specific Growth ◽  
Ammonium Excretion ◽  
Ammonium Ions ◽  
Significant Drop ◽  
Streptomyces Ambofaciens ◽  
Negative Effect ◽  
Kinetics Of

In Streptomyces ambofaciens, valine favored spiramycin biosynthesis by supplying aglycone precursors. The kinetics of valine consumption and isobutyrate production showed that isobutyrate accumulated in the cell during the growth phase, was excreted in the stationary phase, and then was reassimilated during spiramycin production. When valine was in excess, its deamination led to high ammonium excretion and to a significant drop in spiramycin production. We demonstrated that ammonium ions were the cause of the negative effect. Addition of a chelator agent, Ca3(PO4)2, improved spiramycin production by sixfold. In contrast, addition of ammonium, between 0 and 48 h, severely reduced spiramycin production. The negative effect of ammonium was reversed by addition of a catabolic intermediate of valine, isobutyrate. In addition to stimulating the specific growth rate, ammonium ions slowed down valine catabolism: the specific valine uptake rate, excretion, and reassimilation of isobutyrate were lowered by the pulse of ammonium. Our study showed that in addition to valine dehydrogenase, which provided the nitrogen necessary to the cell, ammonium ions repressed ketoisovalerate dehydrogenase, which introduced valine as carbon, energy, and aglycone precursor sources. However, valine dehydrogenase and ketoisovalerate dehydrogenase did not constitute the principal enzymatic targets of the negative effect of ammonium in spiramycin production.Key words: spiramycin, Streptomyces ambofaciens, valine catabolism, ammonium.

scholarly journals AKTIVITAS INULINASE OLEH Pichia manshurica DAN FUSAN F4 PADA FERMENTASI BATCH DENGAN UMBI DAHLIA (Dahlia sp) SEBAGAI SUBSTRAT

REAKTOR ◽  
2015 ◽  
Vol 14 (3) ◽  
pp. 187 ◽  
Author(s):  
Wijanarka Wijanarka ◽  
Endang Sutariningsih Soetarto ◽  
Kumala Dewi ◽  
Ari Indrianto
Keyword(s):  
Growth Rate ◽  
Specific Growth Rate ◽  
Specific Growth ◽  
Lag Phase ◽  
Growth Media ◽  
A Value ◽  
Inulinase Activity ◽  
Pichia Manshurica ◽  
Microbial Strains ◽  
Kinetics Of

ACTIVITY OF INULINASE OF Pichia Manshuria AND FUSAN F4 ON BATCH FERMENTATION UDING DAHLIA TUBER (Dahlia sp) AS A SUBSTRATE. A dahlia tuber is one of the common inulin rich crops. Inulin is formed by units of fructans, which are polymers of D-fructose. Inulinases (EC 3.2.1.7) catalyze the hydrolysis of inulin, producing fructooligosaccharides (FOS), inulooligosaccharides (IOS), pulullan, acetone, butanol and sorbitol, therefore dahlia tubers are used as growth media. The inulin hydrolyzing activity has been reported from various microbial strains Pichia manshurica and Fusan F4 which is the result of fusion protoplast. The objective of this study was to determine the activity of inulinase Pichia manshurica and Fusan F4 on the substrate dahlia tubers. Fusan F4 to increase inulinase activity compared with Pichia manshurica and to investigate the kinetics of specific growth rate (μ) and time double (g) from of Pichia manshurica and Fusan F4. The results showed that the exponential phase occurs at 0-12 hour without a lag phase. P. manshurica has a specific growth rate (μ) of 0.18/hour with time double (g) 3.90 hours and the inulinase enzyme activity of 0.56 IU, while for Fusan F4 consecutive has a value μ of 0.20/hour, g of 3.49 hours and the activity of 0.69 IU. The conclusion of this research is to improve Fusan F4 inulinase activity and the ability has to be better than the Pichia manshurica.Umbi dahlia merupakan salah satu umbi yang mengandung inulin. Inulin merupakan polimer fruktan yang dapat dipecah oleh enzim inulinase (E.C. 3.2.1.7) menjadi fruktosa. Fruktosa merupakan bahan baku dasar untuk pembuatan FOS, IOS, pulullan, aseton dan sorbitol, oleh karena itu umbi dahlia digunakan sebagai media pertumbuhan. Enzim inulinase ini secara indigenous dimiliki oleh Pichia manshurica dan Fusan F4 yang merupakan hasil fusi protoplas.Tujuan  penelitian ini adalah  untuk mengetahui aktivitas inulinase Pichia manshurica dan Fusan F4 pada substrat umbi dahlia, Fusan F4 mampu meningkatkan aktivitas inulinase dibandingkan dengan Pichia manshurica serta untuk mengetahui kinetika kecepatan pertumbuhan specifik (µ) dan waktu generasi (g) Pichia manshurica dan Fusan F4. Hasil penelitian menunjukkan bahwa fase  eksponensial terjadi pada jam ke-0 sampai jam ke-12 tanpa diikuti fase lag, Pichia manshurica mempunyai kecepatan pertumbuhan specific (µ)  sebesar 0,18/jam dengan waktu generasi (g) 3,90 jam dan aktivitas enzim inulinase yang dihasilkan sebesar 0,56 IU, sedangkan untuk fusan F4 secara berturut-turut mempunyai nilai µ sebesar 0,20/jam, g sebesar 3,49 jam dan aktivitas sebesar 0,69 IU. Kesimpulan dari penelitian ini adalah Fusan F4 mampu meningkatkan aktivitas inulinase dan mempunyai kemampuan lebih baik dibanding dengan Pichia manshurica.

Selenium as a nutrient for freshwater bacterioplankton and its interactions with phosphorus

1990 ◽  
Vol 36 (7) ◽  
pp. 475-483 ◽  
Author(s):  
Cecilia Eriksson ◽  
Carlos Pedrós-Alió
Keyword(s):  
Growth Rate ◽  
Specific Growth Rate ◽  
Bacterial Growth ◽  
Specific Growth ◽  
Organic Phosphorus ◽  
Eutrophic Lake ◽  
Inorganic Phosphorus ◽  
Cell Yield ◽  
Lag Phase ◽  
Negative Effect

The influence of selenite on the growth of bacterioplankton present in samples of three lakes was analyzed; these samples were collected in sulfate-rich, oligotrophic Lake Banyoles, moderately eutrophic Lake Erken, and hypereutrophic Lake Vallentunasjön. Experiments were set up in a completely randomized factorial design to analyze the effect of selenite alone and, in the same experiment, the effect of selenite in the presence of phosphate. Cultures of bacterioplankton, free of algae and zooplankton, diluted with filtered natural water, were used in the bioassays. The addition of 100 μg P∙L−1 to samples from Lake Banyoles, collected during the winter, enhanced cell yield 2.7 times; the addition of 10 μg P∙L−1 to samples from Lake Erken, collected during the spring, doubled the yield. Strong effects of phosphate on growth rates were found in samples from lakes Banyoles and Vallentunasjön. When bacteria from Lake Banyoles were exposed to 100 μg P∙L−1, the specific growth rate was 0.08 h−1 (log units), compared with 0.03 h−1 in the control. In spring, Lake Vallentunasjôn contained water with a considerable amount of dissolved organic phosphorus (18 μg P∙L−1); the addition of 100 μg P∙L−1, in the form of phosphate, resulted in a shorter lag phase of at least 48 h and reduced the specific growth rate to about half that in the control. Selenite had a significant positive effect on cell yield in samples from lakes Banyoles (p = 0.0001) and Vallentunasjön (p = 0.020), whereas the effect on cell yield in samples from Lake Erken was slightly negative (p = 0.110). The addition of selenite alone (550 ng Se∙L−1) to samples from Lake Banyoles, collected during the summer, doubled the biovolume of bacterioplankton within 37 h. Among winter bacteria from Lake Banyoles, selenite, at concentrations of 55 and 550 ng Se∙L−1, increased the number of bacteria twofold and threefold, respectively, but only when the phosphate level was high (100 μg P∙L−1). A high inorganic phosphorus level of 100 μg P∙L−1 was also necessary to stimulate the effect of selenite on bacterial growth in samples from Lake Vallentunasjön; 550 ng Se∙L−1 enhanced cell yield 24%. The negative effect of selenite on samples from Lake Erken was most obvious when phosphate (10 or 100 μg P∙L−1) had been added simultaneously (p = 0.030 for selenium and phosphorus interaction). Cell yields were always greater at the highest temperature. With samples from Lake Vallentunasjön, selenite stimulated bacterial growth at 25 °C but had no effect at 10 °C. With samples from Lake Banyoles, the simultaneous addition of phosphate and selenite increased cell yield threefold at 15 °C and only twofold at 30 °C. Key words: phosphorus, sulfate, Lake Erken, Lake Vallentunasjön, Lake Banyoles.

The kinetics of growth control in a colonial hydroid

1981 ◽  
Vol 61 (1) ◽  
pp. 35-63 ◽  
Author(s):  
A. R. D. Stebbing
Keyword(s):  
Growth Rate ◽  
Growth Process ◽  
Control Mechanism ◽  
Specific Growth ◽  
Growth Control ◽  
Temporal Variations ◽  
Controlled Experiments ◽  
Rates Of Growth ◽  
Kinetics Of ◽  
Colonial Hydroid

It is suggested that the cumulative view of growth in which some index of biomass is plotted against time tends to obscure temporal variations in the growth process that might provide evidence of how it is controlled. Experiments with the colonial hydroid Campanularia flexuosa show that the action of a growth control mechanism can be demonstrated by considering changes in specific rates of growth determined at frequent intervals in time. However, it is also necessary to disturb the growth process slightly in order to initiate the action of the control mechanism, and having done so, to isolate the effect of the disturbance on growth and thus the action of the control mechanism. This is done by expressing the specific growth rate of organisms whose growth is disturbed as a percentage of that of control organisms of the same age.

Vitamin B12 and Marine Ecology. IV. The Kinetics of Uptake, Growth and Inhibition in Monochrysis Lutheri

1968 ◽  
Vol 48 (3) ◽  
pp. 689-733 ◽  
Author(s):  
M. R. Droop
Keyword(s):  
Growth Rate ◽  
Substrate Concentration ◽  
Specific Growth ◽  
Marine Ecology ◽  
Vitamin B ◽  
Batch Cultures ◽  
Washed Cell ◽  
Cell Quota ◽  
Kinetics Of Uptake ◽  
Kinetics Of

57Co-labelled vitamin B12 was used to study the kinetics of vitamin B12 limitation in Monochrysis lutheri in continuous and exponentially growing batch cultures and in washed cell suspensions.Specific growth rate in the chemostats was found not to depend directly on medium substrate concentration but on the concentration within the cells (cell quota), obeying a hyperbolic equation of the form

scholarly journals NUTRIENT MEDIUM SELECTION AND OPTIMIZATION OF AVIBACTERIUM PARAGALLINARUM DEEP CULTURE METHOD

2019 ◽  
pp. 12-16
Author(s):  
M. S. Firsova ◽  
V. A. Yevgrafova ◽  
A. V. Potekhin
Keyword(s):  
Growth Rate ◽  
Specific Growth Rate ◽  
Growth Phase ◽  
Nutrient Medium ◽  
Specific Growth ◽  
Exponential Phase ◽  
Exponential Growth Phase ◽  
Lag Phase ◽  
Optimal Method ◽  
Avibacterium Paragallinarum

Different liquid nutrient media supplemented with growth factors intended for Avibacterium paragallinarum strain No. 5111 cultivation were com­pared. The highest specific growth rate (μ = 0.787 ± 0.041 h-1) and the maximal accumulation of the agent’s biomass (Х = 9.52 ± 0.04 lg CFU/ cm3) were reported when cultured in casein soybean broth. Herewith, the mean time of the live microbial cell concentration doubling was minimal (td = 0.88 h), and the exponential growth phase lasted for 6 hours. The optimal method for Avibacterium paragallinarum cultivation in casein soy­bean broth in laboratory bioreactor Biotron LiFlus GX was determined through the measurements and adjustment of basic physical and chemical parameters. The time period until the culture reached the stationary growth phase was maximal with aeration at 1.0 l/min; herewith, the O2 partial pressure in the nutrient medium did not exceed 25%. The period of the intense decrease of medium’s pH was accompanied with the exponential phase of the bacterial growth. The nutrient medium’s pH ranging from 7.30 ± 0.02 to 7.90 ± 0.06 had no significant impact on the specific growth rate of the strain and the lag phase duration was minimal – 0.36–0.45 h. The strain cultivation in the nutrient medium with pH 7.90 ± 0.06 demonstrated maximal aggregation of the bacteria (9.76 ± 0.04 lg CFU/cm3). 40% glucose solution added at 0.6-0.8 g/l during cultivation facilitated the decrease of the suspension’s pH. Minimal redox value (–75 mV) was indicative of the completion of the exponential phase of the strain growth.  

scholarly journals Modeling and Use of Inter-Criteria Decision Analysis for Selecting Growth Rate Models for Batch Cultivation of Yeast Kluyveromyces marxianus var. lactis MC 5

Fermentation ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 163
Author(s):  
Mitko Petrov
Keyword(s):  
Growth Rate ◽  
Decision Analysis ◽  
Specific Growth ◽  
Batch Cultivation ◽  
Process Models ◽  
Monod Model ◽  
First Time ◽  
Kinetics Of ◽  
Additive Form ◽  
Selection Of

Ten unstructured models of Monod, Mink, Tessier, Moser, Aiba, Andrews, Haldane, Luong, Edward, and Han-Levenspiel are considered in this paper to explain the kinetics of cell growth for batch cultivation of the yeast Kluyweromyces marxianus var. lactis MC 5. For the first time, two independent kinetic models are used to model the process for the two basic substrates—lactose and oxygen. The selection of the most appropriate growth rate models has been made through a new multi-criteria decision-making approach called the Inter-Criteria Decision Analysis (ICDA) method. The application of ICDA to the growth rate of lactose and oxygen alone has shown that there have been many correlations between the studied models. Thus, the models for the growth rate, depending only on lactose, are reduced to one—Monod model and there are two models—Monod and Mink—depending on oxygen only. Separate kinetic process models have been developed for the combination of Monod–Monod and Monod–Mink models. For the first time, in addition to the multiplicative form, the additive form of a specific growth rate has been studied. The comparison of the obtained results has shown that the additive form has shown better results than the multiplicative one. For this reason, the additive form of the Monod–Monod model will be used to model the process.

scholarly journals Specific growth rate governs AOX1 gene expression, affecting the production kinetics of Pichia pastoris (Komagataella phaffii) PAOX1-driven recombinant producer strains with different target gene dosage

2019 ◽  
Vol 18 (1) ◽  
Author(s):  
Javier Garrigós-Martínez ◽  
Miguel Angel Nieto-Taype ◽  
Arnau Gasset-Franch ◽  
José Luis Montesinos-Seguí ◽  
Xavier Garcia-Ortega ◽  
...  
Keyword(s):  
Gene Expression ◽  
Growth Rate ◽  
Pichia Pastoris ◽  
Specific Growth Rate ◽  
Specific Growth ◽  
Gene Dosage ◽  
Fed Batch ◽  
Komagataella Phaffii ◽  
Production Kinetics ◽  
Kinetics Of

Abstract Background The PAOX1-based expression system is the most widely used for producing recombinant proteins in the methylotrophic yeast Pichia pastoris (Komagataella phaffii). Despite relevant recent advances in regulation of the methanol utilization (MUT) pathway have been made, the role of specific growth rate (µ) in AOX1 regulation remains unknown, and therefore, its impact on protein production kinetics is still unclear. Results The influence of heterologous gene dosage, and both, operational mode and strategy, on culture physiological state was studied by cultivating the two PAOX1-driven Candida rugosa lipase 1 (Crl1) producer clones. Specifically, a clone integrating a single expression cassette of CRL1 was compared with one containing three cassettes over broad dilution rate and µ ranges in both chemostat and fed-batch cultivations. Chemostat cultivations allowed to establish the impact of µ on the MUT-related MIT1 pool which leads to a bell-shaped relationship between µ and PAOX1-driven gene expression, influencing directly Crl1 production kinetics. Also, chemostat and fed-batch cultivations exposed the favorable effects of increasing the CRL1 gene dosage (up to 2.4 fold in qp) on Crl1 production with no significant detrimental effects on physiological capabilities. Conclusions PAOX1-driven gene expression and Crl1 production kinetics in P. pastoris were successfully correlated with µ. In fact, µ governs MUT-related MIT1 amount that triggers PAOX1-driven gene expression—heterologous genes included—, thus directly influencing the production kinetics of recombinant protein.

scholarly journals Kinetika detoksifikasi umbi gadung (dioscorea hispida dennst.) secara fermentasi dengan kapang mucor racemosus

REAKTOR ◽  
2017 ◽  
Vol 17 (2) ◽  
pp. 81 ◽  
Author(s):  
Marissa Widiyanti ◽  
Andri Cahyo Kumoro
Keyword(s):  
Growth Rate ◽  
Specific Growth Rate ◽  
Specific Growth ◽  
Cyanogenic Glucosides ◽  
Mucor Racemosus ◽  
Dry Land ◽  
Physical Chemical ◽  
Fungal Fermentation ◽  
Biological Methods ◽  
Kinetics Of

Abstract THE KINETICS OF GADUNG (Dioscorea hispida dennst.) TUBER DETOXIFICATION VIA FUNGAL FERMENTATION USING Mucor racemosus. Bitter yam (Dioscorea hispida Dennst.) is one of carbohydrate sources used as staple food commonly found in Indonesian dry-land. However, this tuber has been underutilized due to the presence of an antinutrition compound, namely cyanogenic glucosides. Removal of cyanides from foodstuffs can be done either by physical, chemical or biological methods. In this study, the effect of time on the detoxification of gadung tuber chips from cyanides via fermentation using Mucor racemosus and its kinetics were investigated. Gadung chip samples were withdrawn from the fermentation system at every 24 hours interval for biomass and cyanides contents analysis. It was clear that the cyanides content decreased as the fermentation went by. Safely consumed gadung tuber chips were obtained from fermentation of the chips for 120 hours from which cyanides content as low as 49.41 mg/kg was achieved. The logistic equation successfully described the growth rate of Mucor racemosus under studied condition. The specific growth rate of Mucor racemosus in gadung chips was found to be 0.0297/hr or about a half of specific growth rate of that mold when grown in the readily consumed yeast-pepton-glucose (YPG) media. Keywords: fermentation; yam; monod; Mucor racemosus; cyanogen  Abstrak Umbi gadung (Dioscorea hispida Dennst.) merupakan salah satu sumber karbohidrat yang digunakan sebagai makanan pokok yang biasa ditemukan di lahan kering di wilayah Indonesia. Namun, umbi ini kurang dimanfaatkan karena adanya senyawa antinutrisi, yaitu cyanogenic glucosides. Penghilangan senyawa sianida dari bahan makanan dapat dilakukan baik dengan metode fisik, kimia atau biologi. Penelitian ini bertujuan untuk mengkaji pengaruh waktu pada detoksifikasi irisan umbi gadung dari senyawa sianida melalui fermentasi dengan menggunakan kapang Mucor racemosus dan kinetikanya. Cuplikan irisan umbi gadung diambil dari sistem fermentasi pada setiap jeda waktu 24 jam untuk dianalisis kadar biomassa dan sianidanya. Hasil penelitian menunjukkan bahwa kandungan sianida menurun seiring dengan bertambahnya waktu fermentasi. Irisan umbi gadung yang aman dikonsumsi dapat diperoleh dari fermentasi irisan ubi gadung selama 120 jam dengan kandungan sianida serendah 49,41 mg/kg. Persamaan logistik berhasil menggambarkan tingkat pertumbuhan kapang Mucor racemosus dengan baik. Tingkat pertumbuhan spesifik dari Mucor racemosus pada irisan umbi gadung adalah 0,0297/jam atau sekitar setengah dari laju pertumbuhan spesifik jamur tersebut saat dibudidayakan pada media yang siap dikonsumsi, seperti ragi-pepton-glukosa (YPG). Kata kunci: fermentasi; gadung; monod; Mucor racemosus; sianogen 

scholarly journals Phenol Degradation Kinetics by Free and Immobilized Pseudomonas putida BCRC 14365 in Batch and Continuous-Flow Bioreactors

Processes ◽  
2020 ◽  
Vol 8 (6) ◽  
pp. 721
Author(s):  
Yen-Hui Lin ◽  
Yu-Siang Cheng
Keyword(s):  
Growth Rate ◽  
Specific Growth Rate ◽  
Pseudomonas Putida ◽  
Growth Phase ◽  
Continuous Flow ◽  
Specific Growth ◽  
Immobilized Cells ◽  
Phenol Degradation ◽  
Exponential Growth Phase ◽  
Steady State Condition

Phenol degradation by Pseudomonas putida BCRC 14365 was investigated at 30 °C and a pH of 5.0–9.0 in the batch tests. Experimental results for both free and immobilized cells demonstrated that a maximum phenol degradation rate occurred at an initial pH of 7. The peak value of phenol degradation rates by the free and immobilized cells were 2.84 and 2.64 mg/L-h, respectively. Considering the culture at 20 °C, there was a lag period of approximately 44 h prior to the start of the phenol degradation for both free and immobilized cells. At the temperatures ranging from 25 to 40 °C, the immobilized cells had a higher rate of phenol degradation compared to the free cells. Moreover, the removal efficiencies of phenol degradation at the final stage were 59.3–92% and 87.5–92%, for the free and immobilized cells, respectively. The optimal temperature was 30 °C for free and immobilized cells. In the batch experiments with various initial phenol concentrations of 68.3–563.4 mg/L, the lag phase was practically negligible, and a logarithmic growth phase of a particular duration was observed from the beginning of the culture. The specific growth rate (μ) in the exponential growth phase was 0.085–0.192 h−1 at various initial phenol concentrations between 68.3 and 563.4 mg/L. Comparing experimental data with the Haldane kinetics, the biokinetic parameters, namely, maximum specific growth rate (μmax), the phenol half-saturation constant (Ks) and the phenol inhibition constant (KI), were determined to equal 0.31 h−1, 26.2 mg/L and 255.0 mg/L, respectively. The growth yield and decay coefficient of P. putida cells were 0.592 ± 4.995 × 10−3 mg cell/mg phenol and 5.70 × 10−2 ± 1.122 × 10−3 day−1, respectively. A completely mixed and continuous-flow bioreactor with immobilized cells was set up to conduct the verification of the kinetic model system. The removal efficiency for phenol in the continuous-flow bioreactor was approximately 97.7% at a steady-state condition. The experimental and simulated methodology used in this work can be applied, in the design of an immobilized cell process, by various industries for phenol-containing wastewater treatment.

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