Carbon Source Influence on Extracellular pH Changes along Bacterial Cell-Growth

The effect of initial pH on bacterial cell-growth and its change over time was studied under aerobic heterotrophic conditions by using three bacterial strains: Escherichia coli ATCC 25922, Pseudomonas putida KT2440, and Pseudomonas pseudoalcaligenes CECT 5344. In Luria-Bertani (LB) media, pH evolved by converging to a certain value that is specific for each bacterium. By contrast, in the buffered Minimal Medium (MM), pH was generally more stable along the growth curve. In MM with glucose as carbon source, a slight acidification of the medium was observed for all strains. In the case of E. coli, a sudden drop in pH was observed during exponential cell growth that was later recovered at initial pH 7 or 8, but was irreversible below pH 6, thus arresting further cell-growth. When using other carbon sources in MM at a fixed initial pH, pH changes depended mainly on the carbon source itself. While glucose, glycerol, or octanoate slightly decreased extracellular pH, more oxidized carbon sources, such as citrate, 2-furoate, 2-oxoglutarate, and fumarate, ended up with the alkalinization of the medium. These observations are in accordance with pH change predictions using genome-scale metabolic models for the three strains, thus revealing the metabolic reasons behind pH change. Therefore, we conclude that the composition of the medium, specifically the carbon source, determines pH change during bacterial growth to a great extent and unravel the main molecular mechanism behind this phenotype. These findings pave the way for predicting pH changes in a given bacterial culture and may anticipate the interspecies interactions and fitness of bacteria in their environment.

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Study of pH Changes in Media during Bacterial Growth of Several Environmental Strains

Proceedings ◽

10.3390/proceedings2201297 ◽

2018 ◽

Vol 2 (20) ◽

pp. 1297 ◽

Cited By ~ 10

Author(s):

Rubén Sánchez-Clemente ◽

María Isabel Igeño ◽

Ana G. Población ◽

María Isabel Guijo ◽

Faustino Merchán ◽

...

Keyword(s):

Carbon Source ◽

Pseudomonas Putida ◽

Bacterial Growth ◽

Extracellular Ph ◽

Cellular Growth ◽

Exponential Growth Phase ◽

Extracellular Medium ◽

Pseudomonas Putida Kt2440 ◽

E Coli ◽

Initial Ph

The effect of pH on bacterial cell-growth and the evolution of extracellular pH triggered by bacterial growth has been monitored for three bacterial strains, Escherichia coli ATCC 25922 and Pseudomonas putida KT2440 as reference strains, and Pseudomonas pseudoalcaligenes CECT 5344 because of its capacity to assimilate cyanide as the sole nitrogen source under alkaline conditions. In a first instance, the influence of the initial pH in the growth curve has been texted in LB-medium adjusted to pH 6, 7 and 8, for E. coli and P. putida, and 7.5, 8.25 and 9 for P. pseudoalcaligenes. Although the initial pH were different, the pH of the extracellular medium at the end of the stationary phase converged to a certain pH that is specific for each bacterium. Similar experiments were carried out in minimal medium with glucose as the carbon source. In this case, the pHs of the culture of both Pseudomonadaceae strains were almost constant, whereas it suddenly dropped during the exponential growth phase of E. coli. When the initial pH was 6 the extracellular pH fell sharply to 4.5, which irreversibly prevented further cellular growth. Nevertheless, at higher initial pH values subsequent cellular growth of E. coli restored the medium to the initial pHs values. Finally, in all cases the evolution of the pH has been shown to depend on the carbon source used. Among the sources used, cellular growth with glucose or glycerol did not affect the extracellular pH, whereas citrate caused the alkalinization of the media. This phenotype is in concordance with computational predictions, at least in the case of the genome-scale metabolic model of Pseudomonas putida KT2440.

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Technical note: Interpreting pH changes

Biogeosciences ◽

10.5194/bg-18-1407-2021 ◽

2021 ◽

Vol 18 (4) ◽

pp. 1407-1415

Author(s):

Andrea J. Fassbender ◽

James C. Orr ◽

Andrew G. Dickson

Keyword(s):

Technical Note ◽

Ion Concentration ◽

Ph Change ◽

Ph Measurements ◽

Hydrogen Ion Concentration ◽

Ph Changes ◽

The Past ◽

Initial Ph ◽

Relative Change

Abstract. The number and quality of ocean pH measurements have increased substantially over the past few decades such that trends, variability, and spatial patterns of change are now being evaluated. However, comparing pH changes across domains with different initial pH values can be misleading because a pH change reflects a relative change in the hydrogen ion concentration ([H+], expressed in mol kg−1) rather than an absolute change in [H+]. We recommend that [H+] be used in addition to pH when describing such changes and provide three examples illustrating why.

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Rhodotorula toruloides Single Cell Oil Production Using Eucalyptus urograndis Hemicellulose Hydrolysate as a Carbon Source

Energies ◽

10.3390/en13040795 ◽

2020 ◽

Vol 13 (4) ◽

pp. 795 ◽

Cited By ~ 4

Author(s):

Helberth Júnnior Santos Lopes ◽

Nemailla Bonturi ◽

Everson Alves Miranda

Keyword(s):

Carbon Source ◽

Lipid Production ◽

Carbon Sources ◽

Oil Production ◽

Research Area ◽

Microbial Oil ◽

Hemicellulose Hydrolysate ◽

Initial Ph ◽

Different Temperatures ◽

Active Research

Microbial oil is a potential substitute for vegetable oils in the biodiesel industry. Efforts to obtain cheap carbon sources for the cultivation of lipid-producing microorganisms comprise an active research area. This work aimed to extract the hemicellulose fraction from Eucalyptus uograndis and to use its hydrolysate as a carbon source for Rhodotorula toruloides (an oleaginous yeast) cultivation for microbial oil production. Hemicellulose hydrothermal extractions were performed at different temperatures, times, and ratios of solid to liquid (S/L). Temperature and time showed a stronger effect on the solubilization of hemicellulose. Hemicellulose extraction at 155 °C, 195 min, and an S/L ratio of 1/2 resulted in a hydrolysate with a xylose content of 37.0 g/l. R. toruloides cultivation in this hydrolysate showed that initial pH had a strong influence on cell growth. At an initial pH of 6.2, cells grew to 6.0 g/l of biomass with a lipid content of 50%. Therefore, we believe that E. urograndis hemicellulose hydrolysate could be a potential substrate for R. toruloides for lipid production based on the biorefinery concept.

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Technical note: Interpreting pH changes

10.5194/bg-2020-348 ◽

2020 ◽

Author(s):

Andrea J. Fassbender ◽

James C. Orr ◽

Andrew G. Dickson

Keyword(s):

Technical Note ◽

Ion Concentration ◽

Ph Change ◽

Ph Measurements ◽

Hydrogen Ion Concentration ◽

Ph Changes ◽

The Past ◽

Initial Ph ◽

Relative Change

Abstract. The number and quality of ocean pH measurements has increased substantially over the past few decades such that trends, variability, and spatial patterns of change are now being evaluated. However, comparing pH changes across domains with different initial pH values can be misleading because a pH change reflects a relative change in the hydrogen ion concentration ([H+]–expressed in mol kg−1) rather than an absolute change in [H+]. We recommend that [H+] be used in addition to pH when describing such changes and provide three examples illustrating why.

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Analysis of the fermentative profile of yeasts isolated from natural sources

Research Society and Development ◽

10.33448/rsd-v10i10.19127 ◽

2021 ◽

Vol 10 (10) ◽

pp. e445101019127

Author(s):

Elane Galvão dos Santos ◽

Rebeca Fasioli Silva ◽

Maria do Socorro Mascarenhas Santos ◽

Margareth Batistote

Keyword(s):

Cell Growth ◽

Carbon Source ◽

Natural Environment ◽

Solid Medium ◽

Carbon Sources ◽

Natural Sources ◽

Fermentation Profile ◽

Growing Conditions

The natural environment aggregates an immense amount of microorganisms, some unknown and others still unexplored and that may have the potential for the production of compounds. Thus, this study aims to evaluate the fermentative profile of isolates from natural sources under different growing conditions. For this purpose, the plating performing on a 2% YPD solid medium incubating in an oven at 30 °C. The isolated colonies use for the carbon source assimilation test, which carried out through cell growth. Carrying out in test tubes containing the YP fermentative added with carbon sources (glucose, lactose, sucrose, fructose, mannose, maltose, starch) with a concentration of 17 ºBrix, at pH 4 and 6, incubated at 28 and 35 ºC and at different times of cultivation, aliquots removed for analysis. For the control, the yeast Catanduva-1 was used. The isolates grew in the range of pH 4 and pH 6 at 28 ºC and isolate A4 showed greater growth at a temperature of 35 °C. Isolates A4, A5, and A6 used most sugars except for lactose. Isolate A2 assimilated glucose and fructose and A6 showed a fermentation profile similar to standard yeast.

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Effect of carbon source on Phenobarbital metabolism by Rhizopus stolonifer

International Journal of Pharmaceutical Sciences and Nanotechnology ◽

10.37285/ijpsn.2010.3.2.17 ◽

2010 ◽

Vol 3 (2) ◽

pp. 1022-1027

Author(s):

Kavitha K ◽

Asha S ◽

Hima Bindu T.V.L ◽

Vidyavathi M

Keyword(s):

Carbon Source ◽

High Performance ◽

Carbon Sources ◽

In Vitro Models ◽

Rhizopus Stolonifer ◽

Safety And Efficacy ◽

Alternative Systems ◽

Toxicological Studies ◽

Microbial Model

The safety and efficacy of a drug is based on its metabolism or metabolite formed. The metabolism of drugs can be studied by different in vitro models, among which microbial model became popular. In the present study, eight microbes were screened for their ability to metabolize phenobarbital in a manner comparable to humans with a model to develop alternative systems to study human drug metabolism. Among the different microbes screened, a filamentous fungi Rhizopus stolonifer metabolized phenobarbital to its metabolite which is used for further pharmacological and toxicological studies. The transformation of phenobarbital was identified by high- performance liquid chromatography (HPLC). Interestingly, Rhizopus stolonifer sample showed an extra metabolite peak at 3.11min. compared to its controls. The influence of different carbon sources in media used for growth of fungus, on metabolite production was studied, to find its effect in production of metabolite as the carbon source may influence the growth of the cell.

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Denitrification Control in a Recirculating Aquaculture System—A Simulation Study

Processes ◽

10.3390/pr8101306 ◽

2020 ◽

Vol 8 (10) ◽

pp. 1306

Author(s):

Pedro Almeida ◽

Laurent Dewasme ◽

Alain Vande Wouwer

Keyword(s):

Carbon Source ◽

Carbon Sources ◽

Aquatic Organisms ◽

Operating Conditions ◽

Toxic Substances ◽

Recirculating Aquaculture System ◽

Treatment Technology ◽

Tuning Method ◽

Recirculating Aquaculture ◽

Aquaculture System

The recirculating aquaculture system (RAS) is a land-based water treatment technology, which allows for farming aquatic organisms, such as fish, by reusing the water in the production (often less than 5%). This technology is based on the use of filters, either mechanical or biological, and can, in principle, be used for any species grown in aquaculture. Due to the low recirculation rate, ammonia accumulates in the system and must be converted into nitrate using nitrification reactors. Although less toxic for fish, nitrate can also be further reduced into nitrogen gas by the use of denitrification biofilters which may create several issues, such as incomplete denitrification, resulting in toxic substances, such as nitrite and nitric oxide, or a waste of carbon source in excess. Control of the added quantity of carbon source in the denitrification biofilter is then mandatory to keep nitrate/nitrite concentrations under toxic levels for fish and in accordance with local effluent regulations, and to reduce costs related to wasted organic carbon sources. This study therefore investigates the application of different control methodologies to a denitrification reactor in a RAS. To this end, a numerical simulator is built to predict the RAS behavior and to allow for the comparison of different control approaches, in the presence of changes in the operating conditions, such as fish density and biofilter removal efficiency. First, a classical proportional-integral-derivative (PID) controller was designed, based on an SIMC tuning method depending on the amount of ammonia excreted by fish. Then, linearizing and cascade controllers were considered as possible alternatives.

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The carbon source-dependent pattern of antimicrobial activity and gene expression in Pseudomonas donghuensis P482

Scientific Reports ◽

10.1038/s41598-021-90488-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Marta Matuszewska ◽

Tomasz Maciąg ◽

Magdalena Rajewska ◽

Aldona Wierzbicka ◽

Sylwia Jafra

Keyword(s):

Gene Expression ◽

Antimicrobial Activity ◽

Carbon Source ◽

Reference Genes ◽

Plant Pathogens ◽

Plant Protection ◽

Carbon Sources ◽

Unknown Compound ◽

Fungal Plant Pathogens ◽

The Impact

AbstractPseudomonas donghuensis P482 is a tomato rhizosphere isolate with the ability to inhibit growth of bacterial and fungal plant pathogens. Herein, we analysed the impact of the carbon source on the antibacterial activity of P482 and expression of the selected genes of three genomic regions in the P482 genome. These regions are involved in the synthesis of pyoverdine, 7-hydroxytropolone (7-HT) and an unknown compound (“cluster 17”) and are responsible for the antimicrobial activity of P482. We showed that the P482 mutants, defective in these regions, show variations and contrasting patterns of growth inhibition of the target pathogen under given nutritional conditions (with glucose or glycerol as a carbon source). We also selected and validated the reference genes for gene expression studies in P. donghuensis P482. Amongst ten candidate genes, we found gyrB, rpoD and mrdA the most stably expressed. Using selected reference genes in RT-qPCR, we assessed the expression of the genes of interest under minimal medium conditions with glucose or glycerol as carbon sources. Glycerol was shown to negatively affect the expression of genes necessary for 7-HT synthesis. The significance of this finding in the light of the role of nutrient (carbon) availability in biological plant protection is discussed.

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Development of mutants of Gliocladium virens tolerant to benomyl

Canadian Journal of Microbiology ◽

10.1139/m90-084 ◽

1990 ◽

Vol 36 (7) ◽

pp. 484-489 ◽

Cited By ~ 12

Author(s):

G. C. Papavizas ◽

D. P. Roberts ◽

K. K. Kim

Keyword(s):

Carbon Source ◽

Type Strain ◽

Wild Type Strain ◽

Carbon Sources ◽

Sclerotium Rolfsii ◽

Wild Type ◽

Gliocladium Virens ◽

Rhizosphere Competence ◽

Filter Paper Cellulase ◽

Type Strains

Aqueous suspensions of conidia of Gliocladium virens strains Gl-3 and Gl-21 were exposed to both ultraviolet radiation and ethyl methanesulfonate. Two mutants of Gl-3 and three of Gl-21 were selected for tolerance to benomyl at 10 μg∙mL−1, as indicated by growth and conidial germination on benomyl-amended potato dextrose agar. The mutants differed considerably from their respective wild-type strains in appearance, growth habit, sporulation, carbon-source utilization, and enzyme activity profiles. Of 10 carbon sources tested, cellobiose, xylose, and xylan were the best for growth, galactose and glucose were intermediate, and arabinose, ribose, and rhamnose were poor sources of carbon. The wild-type strains and the mutants did not utilize cellulose as the sole carbon source for growth. Two benomyl-tolerant mutants of Gl-3 produced less cellulase (β-1,4-glucosidase, carboxymethylcellulase, filter-paper cellulase) than Gl-3. In contrast, mutants of Gl-21 produced more cellulase than the wild-type strain. Only Gl-3 provided control of blight on snapbean caused by Sclerotium rolfsii. Wild-type strain Gl-21 and all mutants from both strains were ineffective biocontrol agents. Key words: Gliocladium, benomyl tolerance, Sclerotium, rhizosphere competence.

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OBSERVATIONS ON AMYLOLYTIC BACTERIA: III. CULTURAL CONDITIONS INFLUENCING THE BREAKDOWN OF STARCH BY STENOTHERMOPHILIC BACTERIA BELONGING TO BACILLUS STEAROTHERMOPHILUS

Canadian Journal of Botany ◽

10.1139/b52-028 ◽

1952 ◽

Vol 30 (4) ◽

pp. 360-370 ◽

Cited By ~ 2

Author(s):

Egon Stark ◽

P. A. Tetrault

Keyword(s):

Yeast Extract ◽

Bacillus Stearothermophilus ◽

Soluble Starch ◽

The Other ◽

Ph Changes ◽

Proteose Peptone ◽

Cultural Conditions ◽

Initial Ph ◽

Commercial Medium ◽

Agar Media

Thirty-five cultures of Bacillus stearothermophilus hydrolyzed five starches under various cultural conditions. Hydrolysis occurred regardless of the type, brand, or batch of starch; regardless of the initial pH or of the subsequent pH changes of the medium. Starch in broth was better attacked than in agar media. Some cultures hydrolyzed 0.5%, but not 1% starch; others hydrolyzed easily 10% soluble starch. Length of incubation was important. Certain cultures never formed acid or sugar from starch. Dextrinization was a more reliable indication of starch hydrolysis than was the formation of acid or sugar. Soluble starch gave more consistent results in repeated experiments than did nonsoluble starches. The type of protein medium determines strongly the formation of amylase. Trypticase was the best commercial medium, yeast extract came second. The other 10 media yielded fewer amylolytic cultures. Yeast extract added to media enhanced amylase formation, except with trypticase. Tryptose, proteose-peptone, and neopeptone inhibited the growth of most cultures.

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