scholarly journals Cellulose Catabolism by Clostridium cellulolyticum Growing in Batch Culture on Defined Medium

2000 ◽  
Vol 66 (6) ◽  
pp. 2461-2470 ◽  
Author(s):  
Mickaël Desvaux ◽  
Emmanuel Guedon ◽  
Henri Petitdemange
Keyword(s):  
Batch Culture ◽  
Cellulose Degradation ◽  
Growth Arrest ◽  
Dry Weight ◽  
Defined Medium ◽  
Carbon Flow ◽  
Natural Ecosystem ◽  
Clostridium Cellulolyticum ◽  
End Products ◽  
Cellulose Concentration

ABSTRACT A reinvestigation of cellulose degradation by Clostridium cellulolyticum in a bioreactor with pH control of the batch culture and using a defined medium was performed. Depending on cellulose concentration, the carbon flow distribution was affected, showing the high flexibility of the metabolism. With less than 6.7 g of cellulose liter−1, acetate, ethanol, H2, and CO2 were the main end products of the fermentation and cellulose degradation reached more than 85% in 5 days. The electron flow from the glycolysis was balanced by the production of H2 and ethanol, the latter increasing with increasing initial cellulose concentration. From 6.7 to 29.1 g of cellulose liter−1, the percentage of cellulose degradation declined; most of the cellulase activity remained on the cellulose fibers, the maximum cell density leveled off, and the carbon flow was reoriented from ethanol to acetate. In addition to that of previously indicated end products, lactate production rose, and, surprisingly enough, pyruvate overflow occurred. Concomitantly the molar growth yield and the energetic yield of the biomass decreased. Growth arrest may be linked to sufficiently high carbon flow, leading to the accumulation of an intracellular inhibitory compound(s), as observed on cellobiose (E. Guedon, M. Desvaux, S. Payot, and H. Petitdemange, Microbiology 145:1831–1838, 1999). These results indicated that bacterial metabolism exhibited on cellobiose was distorted compared to that exhibited on a substrate more closely related to the natural ecosystem of C. cellulolyticum. To overcome growth arrest and to improve degradation at high cellulose concentrations (29.1 g liter−1), a reinoculation mode was evaluated. This procedure resulted in an increase in the maximum dry weight of cells (2,175 mg liter−1), cellulose solubilization (95%), and end product concentrations compared to a classical batch fermentation with a final dry weight of cells of 580 mg liter−1 and 45% cellulose degradation within 18 days.

The Glucose, Insulin and Glutamine Requirements of Suspension Cultures of HeLa Cells in a Difined Culture Medium

1971 ◽  
Vol 9 (2) ◽  
pp. 529-537
Author(s):  
G. J. BLAKER ◽  
J. R. BIRCH ◽  
S. J. PIRT
Keyword(s):  
Amino Acid ◽  
Hela Cells ◽  
Growth Yield ◽  
Dry Weight ◽  
Defined Medium ◽  
Cell Populations ◽  
Serum Supplement ◽  
Protamine Sulphate ◽  
Protamine Zinc Insulin ◽  
Maximum Cell

The serum supplement in a defined medium for the growth of HeLa cells could be replaced by protamine-zinc-insulin (0.2 u./ml). Insulin (0.4 u./ml) replaced the growth-stimulatory properties of protamine-zinc-insulin, whilst protamine sulphate (5 µg/ml) was found to be toxic to the cells. The addition of insulin to cultures depleted of insulin increased both cell growth rates and maximum cell populations. In the defined medium, HeLa cells could only utilize glutamate when a small amount of glutamine was included. Glucose, at a level of 2 mg/ml, was shown to limit maximum cell populations. The growth yield from glucose was 295 µg cell dry weight/mg glucose. When the medium glucose concentration was increased to 4 mg/ml, HeLa cell populations in excess of 16 x 105 cells (i.e. 640 µg dry weight)/ml were routinely achieved in the defined medium supplemented with insulin. Growth is then limited by the amino acid supply. Increasing the amino acid concentration of the medium by 50% raised the maximum cell population to 23.5x105 cells (i.e. 940 µg dry weight)/ml.

Cellulase production by Acetivibrio cellulolyticus

1980 ◽  
Vol 26 (7) ◽  
pp. 760-765 ◽  
Author(s):  
J. N. Saddler ◽  
A. W. Khan
Keyword(s):  
Sewage Sludge ◽  
Cellulose Degradation ◽  
Cellulase Production ◽  
Cellulolytic Enzymes ◽  
Exponential Growth Phase ◽  
Cellulose Powder ◽  
Temperature Optimum ◽  
Ph Optimum ◽  
Culture Supernate ◽  
Cellulose Concentration

Acetivibrio cellulolyticus, an isolate from an established sewage sludge culture, degraded cellulose powder, Avicel cellulose, and cellobiose. The organism showed maximum cellulose degradation in a medium containing 10 g/L of cellulose and it could also degrade cellulose in media containing up to 75 g/L of cellulose. During the exponential growth phase, large quantities of cellulolytic enzymes were found extracellularly whereas cellobiase activity was cell associated. The crude culture supernate contained endo- and exo-glucanase activities with a pH optimum at 5.0 and a temperature optimum at 50 °C. Maximum cellulase activities were detected in 2- to 3-day-old cultures grown on 1 g/L of cellulose. Cellulose concentration above 10 g/L caused the adsorption of these enzymes to the substrate and consequently lowered their detection in the supernate. The activities at 50 °C for endoglucanase, exoglucanase, and filter paper degrading ability, expressed as micrograms of glucose equivalents released per minute per milligram of protein culture supernate, were 510, 135, and 40 respectively.

scholarly journals The Enrichment And Characterization Of Compost And Wastewater-Derived Microbial Cellulolytic Consortia For Biofuel Production

2021 ◽  
Author(s):  
Augustyna Dobosz
Keyword(s):  
Energy Demand ◽  
Defined Medium ◽  
Biofuel Production ◽  
Microbial Consortia ◽  
Extraction And Purification ◽  
End Products ◽  
Fermentative Activity ◽  
Incubation Temperatures ◽  
Current Energy

Over the last decade, a rise in energy demand and diminishing fuel resources have created a challenge for finding an alternative solution that could supplement our current energy sources. This study demonstrated that ethanol and other useful end-products can be produced from the fermentative activity of microbial consortia derived from cellulose-rich waste environments. Compost and wastewater were used as inoculum sources to enrich cellulolytic cultures at incubation temperatures 50 ºC and 60ºC. A chemically defined medium was used without complex nutrients such as yeast extract. Four cellulolytic cultures were obtained and their end-products were monitored over an active cellulose degrading period. The compost culture incubated at 50ºC produced the highest concentration of butyrate while the wastewater-derived culture incubated at 60ºC produced the highest ethanol concentration. Optimization of DNA extraction and purification from complex environmental samples such as the compost and wastewater cultures used in this study was also discussed.

scholarly journals Adjustment of Mineral Elements in the Culture Medium for the Micropropagation of Three Vriesea Bromeliads from the Brazilian Atlantic Forest: The Importance of Calcium

HortScience ◽  
2009 ◽  
Vol 44 (1) ◽  
pp. 106-112 ◽  
Author(s):  
Alice Noemí Aranda-Peres ◽  
Lázaro Eustáquio Pereira Peres ◽  
Edson Namita Higashi ◽  
Adriana Pinheiro Martinelli
Keyword(s):  
New Media ◽  
Mineral Composition ◽  
Culture Media ◽  
Dry Weight ◽  
Defined Medium ◽  
Ms Medium ◽  
Media Formulation ◽  
Half Strength

Many different species of Bromeliaceae are endangered and their conservation requires specific knowledge of their growth habits and propagation. In vitro culture of bromeliads is an important method for efficient clonal propagation and in vitro seed germination can be used to maintain genetic variability. The present work aims to evaluate the in vitro growth and nutrient concentration in leaves of the epiphyte bromeliads Vriesea friburguensis Mez, Vriesea hieroglyphica (Carrière) E. Morren, and Vriesea unilateralis Mez, which exhibit slow rates of growth in vivo and in vitro. Initially, we compared the endogenous mineral composition of bromeliad plantlets grown in half-strength Murashige and Skoog (MS) medium and the mineral composition considered adequate in the literature. This approach suggested that calcium (Ca) is a critical nutrient and this was considered for new media formulation. Three new culture media were defined in which the main changes to half-strength MS medium were an increase in Ca, magnesium, sulfur, copper, and chloride and a decrease in iron, maintaining the nitrate:ammonium rate at ≈2:1. The main difference among the three new media formulated was Ca concentration, which varied from 1.5 mm in half-strength MS to 3.0, 6.0, and 12 mm in M2, M3, and M4 media, respectively. Consistently, all three species exhibited significantly higher fresh and dry weight on M4, the newly defined medium with the highest level of Ca (12 mm). Leaf nitrogen, potassium, zinc, magnesium, and boron concentrations increased as Ca concentration in the medium increased from 1.5 to 12 mm.

Glycerol incorporation in certain oral streptococci

1980 ◽  
Vol 30 (3) ◽  
pp. 759-765
Author(s):  
T A Kral ◽  
L Daneo-Moore
Keyword(s):  
Dry Weight ◽  
Defined Medium ◽  
Oral Streptococci ◽  
Chemically Defined Medium ◽  
Low Concentrations ◽  
Saturation Kinetics ◽  
Wild Rats ◽  
Different Strains ◽  
Streptococcus Rattus ◽  
Type Strains

Cells of 30 different strains of oral streptococci were grown in a chemically defined medium supplemented with [14C]glycerol to determine their ability to incorporate the labeled glycerol. Of the five species tested, only two, the rat-type strains (Streptococcus rattus) and strains isolated from wild rats (Streptococcus ferus), were able to incorporate the nonfermentable substrate, glycerol. For those strains capable of incorporating glycerol, the amount incorporated ranged from 0.15 to 0.43% of the cellular dry weight and followed simple saturation kinetics. The amount of glycerol incorporated depended solely on the concentration of glycerol in the growth medium. As a result, cultures exposed to low concentrations of glycerol ceased incorporation of the labeled glycerol before cessation of exponential growth.

scholarly journals New Insights into Methyl Bromide Cooxidation byNitrosomonas europaea Obtained by Experimenting with Moderately Low Density Cell Suspensions

2000 ◽  
Vol 66 (7) ◽  
pp. 2726-2731 ◽  
Author(s):  
Khrystyne N. Duddleston ◽  
Peter J. Bottomley ◽  
Angela J. Porter ◽  
Daniel J. Arp
Keyword(s):  
Cell Division ◽  
Methyl Bromide ◽  
Cell Activity ◽  
Dry Weight ◽  
Cell Suspensions ◽  
Low Density ◽  
Level Of Activity ◽  
End Products ◽  
Uptake Activity ◽  
Fresh Growth Medium

ABSTRACT We examined the rates and sustainability of methyl bromide (MeBr) oxidation in moderately low density cell suspensions (∼6 � 107 cells ml−1) of the NH3-oxidizing bacterium Nitrosomonas europaea. In the presence of 10 mM NH4 + and 0.44, 0.22, and 0.11 mM MeBr, the initial rates of MeBr oxidation were sustained for 12, 12, and 24 h, respectively, despite the fact that only 10% of the NH4 +, 18% of the NH4 +, and 35% of the NH4 +, respectively, were consumed. Although the duration of active MeBr oxidation generally decreased as the MeBr concentration increased, similar amounts of MeBr were oxidized with a large number of the NH4 +-MeBr combinations examined (10 to 20 μmol mg [dry weight] of cells−1). Approximately 90% of the NH3-dependent O2uptake activity and the NO2 −-producing activity were lost after N. europaea was exposed to 0.44 mM MeBr for 24 h. After MeBr was removed and the cells were resuspended in fresh growth medium, NO2 −production increased exponentially, and 48 to 60 h was required to reach the level of activity observed initially in control cells that were not exposed to MeBr. It is not clear what percentage of the cells were capable of cell division after MeBr oxidation because NO2 − accumulated more slowly in the exposed cells than in the unexposed cells despite the fact that the latter were diluted 10-fold to create inocula which exhibited equal initial activities. The decreases in NO2 −-producing and MeBr-oxidizing activities could not be attributed directly to NH4 + or NH3 limitation, to a decrease in the pH, to the composition of the incubation medium, or to toxic effects caused by accumulation of the end products of oxidation (NO2 − and formaldehyde) in the medium. Additional cooxidation-related studies of N. europaea are needed to identify the mechanism(s) responsible for the MeBr-induced loss of cell activity and/or viability, to determine what percentages of cells damaged by cooxidative activities are culturable, and to determine if cooxidative activity interferes with the regulation of NH3-oxidizing activity.

A chemically defined medium for Treponema strain PR-7 isolated from the intestine of a pig with swine dysentery

1972 ◽  
Vol 18 (7) ◽  
pp. 1073-1078 ◽  
Author(s):  
Robert M. Smibert ◽  
Raymond L. Claterbaugh Jr
Keyword(s):  
Carbon Dioxide ◽  
Energy Source ◽  
Intestinal Tract ◽  
Defined Medium ◽  
Vitamin B ◽  
Chemically Defined Medium ◽  
Aminobenzoic Acid ◽  
Phenotypic Characteristics ◽  
Swine Dysentery ◽  
End Products

The nutrition of treponeme strain PR-7 isolated from the intestinal tract of a pig with swine dysentery was studied. The organism fermented arabinose, xylose, maltose, cellobiose, glucose, galactose, mannose, lactose, pectin, and starch. The end products of fermentation of glucose were major amounts of succinic acid, moderate amounts of acetic and formic acid, and a trace of lactic acid and ethanol.Strain PR-7 required glutamate, aspartate, proline, leucine, methionine, arginine, valine, alanine, serine, lysine, glycine, threonine, isoleucine, phenylalanine, tyrosine, histidine, tryptophan, glutamine, asparagine, and spermine. The organism also required nicotinamide, folic acid, pyridoxal, thiamine, riboflavin, pantothenate, choline, α-lipoic acid, and biotin. The fatty acids isobutyrate, n-valerate, acetate, and pyruvate were needed as well as ammonium sulfate. A fermentable energy source such as glucose was necessary for growth, as well as carbon dioxide. Heme was also required and the organism was stimulated by vitamin B12, ascorbic acid, ornithine, and para-aminobenzoic acid. Heme could be replaced by catalase, myoglobin, and peroxidase.Ten other treponemes that were isolated from the intestines of normal pigs as well as from pigs with swine dysentery and had phenotypic characteristics similar to strain PR-7 grew in the defined medium.

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