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PubMed2000

Effect of initial carbon sources on the performance of microbial fuel cells containing Proteus vulgaris.

Mediator-coupled microbial fuel cells containing Proteus vulgaris were constructed and the cell performance was tested. Fuel cell efficiency depended on the carbon source in the initial medium of the microorganism. Maltose and trehalose were not utilized substantially by P. vulgaris; however, their presence in the initial medium resulted in enhanced cell performance. In particular, galactose showed 63% coulombic efficiency in a biofuel cell after P. vulgaris was cultured in a trehalose-containing medium. This work demonstrates that optimum utilization of carbon sources by microorganisms, which leads to the maximization of fuel cell performance, is possible simply by adjusting initial carbon sources.

Bioelectric Energy Sources↗
PubMed2006

Anaerobic and aerobic metabolism of glycogen-accumulating organisms selected with propionate as the sole carbon source.

In the microbial competition observed in enhanced biological phosphorus removal (EBPR) systems, an undesirable group of micro-organisms known as glycogen-accumulating organisms (GAOs) compete for carbon in the anaerobic period with the desired polyphosphate-accumulating organisms (PAOs). Some studies have suggested that a propionate carbon source provides PAOs with a competitive advantage over GAOs in EBPR systems; however, the metabolism of GAOs with this carbon source has not been previously investigated. In this study, GAOs were enriched in a laboratory-scale bioreactor with propionate as the sole carbon source, in an effort to better understand their biochemical processes. Based on comprehensive solid-, liquid- and gas-phase chemical analytical data from the bioreactor, a metabolic model was proposed for the metabolism of propionate by GAOs. The model adequately described the anaerobic stoichiometry observed through chemical analysis, and can be a valuable tool for further investigation of the competition between PAOs and GAOs, and for the optimization of the EBPR process. A group of Alphaproteobacteria dominated the biomass (96 % of Bacteria) from this bioreactor, while post-fluorescence in situ hybridization (FISH) chemical staining confirmed that these Alphaproteobacteria produced poly-beta-hydroxyalkanoates (PHAs) anaerobically and utilized them aerobically, demonstrating that they were putative GAOs. Some of the Alphaproteobacteria were related to Defluvicoccus vanus (16 % of Bacteria), but the specific identity of many could not be determined by FISH. Further investigation into the identity of other GAOs is necessary.

Aerobiosis↗
PubMed1963

EFFECT OF CARBON SOURCES ON FORMATION OF ALPHA-AMYLASE BY BACILLUS STEAROTHERMOPHILUS.

Welker, N. E. (Western Reserve University, Cleveland, Ohio) and L. Leon Campbell. Effect of carbon sources on formation of alpha-amylase by Bacillus stearothermophilus. J. Bacteriol. 86:681-686. 1963.-A chemically defined medium was devised for use in alpha-amylase induction studies. The addition of 0.1% casein hydrolysate to the chemically defined medium permitted growth on fructose, and with glucose, sucrose, maltose, starch, and glycerol it shortened the lag period and increased both the growth rate and the total enzyme produced. Growth did not occur when gluconate, acetate, or succinate were used as carbon sources. alpha-Amylase was produced during the logarithmic phase of growth; the amount produced was inversely proportional to the rate of growth. The poorer the carbon source for growth (glycerol, k = 0.24; glucose, k = 0.26; sucrose, k = 0.42), the higher was the amount of enzyme produced (glycerol, 109 units/ml; glucose, 103 units/ml; sucrose, 45 units/ml). Cells grown on technical-grade maltose (k = 0.26) or starch (k = 0.42) did not conform to this relationship in that unusually large amounts of alpha-amylase were produced (362 and 225 units/ml, respectively). Cells grown on fructose or sucrose had the same growth rate (k = 0.42), but smaller amounts of alpha-amylase were produced on fructose (fructose, 0 to 4 units/ml; sucrose, 45 units/ml). An intracellular alpha-amylase was not detected in Bacillus stearothermophilus.

Amylases↗
PubMed2006

Growth of E. coli BL21 in minimal media with different gluconeogenic carbon sources and salt contents.

Escherichia coli strain BL21 is commonly used as a host strain for protein expression and purification. For structural analysis, proteins are frequently isotopically labeled with deuterium (2H), 13C, or 15N by growing E. coli cultures in a medium containing the appropriate isotope. When large quantities of fully deuterated proteins are required, E. coli is often grown in minimal media with deuterated succinate or acetate as the carbon source because these are less expensive. Despite the widespread use of BL21, we found no data on the effect of different minimal media and carbon sources on BL21 growth. In this study, we assessed the growth behavior of E. coli BL21 in minimal media with different gluconeogenic carbon sources. Though BL21 grew reasonably well on glycerol and pyruvate, it had a prolonged lag-phase on succinate (20 h), acetate (10 h), and fumarate (20 h), attributed to the physiological adaptation of E. coli cells. Wild-type strain NCM3722 (K12) grew well on all the substrates. We also examined the growth of E. coli BL21 in minimal media that differed in their salt composition but not in their source of carbon. The commonly used M9 medium did not support the optimum growth of E. coli BL21 in minimal medium. The addition of ferrous sulphate to M9 medium (otherwise lacking it) increased the growth rate of E. coli cultures and significantly increased their cell density in the stationary phase.

Adaptation, Physiological↗
PubMed1994

Carbon Source Requirements for Exopolysaccharide Production by Lactobacillus casei CG11 and Partial Structure Analysis of the Polymer.

Exopolysaccharide production by Lactobacillus casei CG11 was studied in basal minimum medium containing various carbon sources (galactose, glucose, lactose, sucrose, maltose, melibiose) at concentrations of 2, 5, 10, and 20 g/liter. L. casei CG11 produced exopolysaccharides in basal minimum medium containing each of the sugars tested; lactose and galactose were the poorest carbon sources, and glucose was by far the most efficient carbon source. Sugar concentrations had a marked effect on polymer yield. Plasmid-cured Muc derivatives grew better in the presence of glucose and attained slightly higher populations than the wild-type strain. The values obtained with lactose were considerably lower for both growth and exopolysaccharide yield. The level of specific polymer production per cell obtained with glucose was distinctively lower for Muc derivatives than for the Muc strain. The polymer produced by L. casei CG11 in the presence of glucose was different from that formed in the presence of lactose. The polysaccharide produced by L. casei CG11 in basal minimum medium containing 20 g of glucose per liter had an intrinsic viscosity of 1.13 dl/g. It was rich in glucose (76%), which was present mostly as 2- or 3-linked residues along with some 2,3 doubly substituted glucose units, and in rhamnose (21%), which was present as 2-linked or terminal rhamnose; traces of mannose and galactose were also present.

Journal Article↗
PubMed1989

Identification of psychrotrophic pseudomonads from goats' milk by computer-assisted analysis of carbon source assimilation data.

The results of carbon source assimilation tests on a group of psychrotrophic pseudomonas were compared with published data for established Pseudomonas taxa, using computer-assisted numerical taxonomic analysis and a modified diagnostic computer program. Several phenons were not grouped at the biovar level by numerical taxonomic analysis. Identification of strains by the diagnostic program revealed heterogeneity among those in the unassigned phenons, and supported a continuum concept among the fluorescent pseudomonads.

Animals↗
PubMed2000

PhaG-mediated synthesis of Poly(3-hydroxyalkanoates) consisting of medium-chain-length constituents from nonrelated carbon sources in recombinant Pseudomonas fragi.

Recently, a new metabolic link between fatty acid de novo biosynthesis and biosynthesis of poly(3-hydroxy-alkanoate) consisting of medium-chain-length constituents (C(6) to C(14)) (PHA(MCL)), catalyzed by the 3-hydroxydecanoyl-[acyl-carrier-protein]:CoA transacylase (PhaG), has been identified in Pseudomonas putida (B. H. A. Rehm, N. Krüger, and A. Steinbüchel, J. Biol. Chem. 273:24044-24051, 1998). To establish this PHA-biosynthetic pathway in a non-PHA-accumulating bacterium, we functionally coexpressed phaC1 (encoding PHA synthase 1) from Pseudomonas aeruginosa and phaG (encoding the transacylase) from P. putida in Pseudomonas fragi. The recombinant strains of P. fragi were cultivated on gluconate as the sole carbon source, and PHA accumulation to about 14% of the total cellular dry weight was achieved. The respective polyester was isolated, and GPC analysis revealed a weight average molar mass of about 130,000 g mol(-1) and a polydispersity of 2.2. The PHA was composed mainly (60 mol%) of 3-hydroxydecanoate. These data strongly suggested that functional expression of phaC1 and phaG established a new pathway for PHA(MCL) biosynthesis from nonrelated carbon sources in P. fragi. When fatty acids were used as the carbon source, no PHA accumulation was observed in PHA synthase-expressing P. fragi, whereas application of the beta-oxidation inhibitor acrylic acid mediated PHA(MCL) accumulation. The substrate for the PHA synthase PhaC1 is therefore presumably directly provided through the enzymatic activity of the transacylase PhaG by the conversion of (R)-3-hydroxydecanoyl-ACP to (R)-3-hydroxydecanoyl-CoA when the organism is cultivated on gluconate. Here we demonstrate for the first time the establishment of PHA(MCL) synthesis from nonrelated carbon sources in a non-PHA-accumulating bacterium, employing fatty acid de novo biosynthesis and the enzymes PhaG (a transacylase) and PhaC1 (a PHA synthase).

Acyltransferases↗
PubMed2002

Antibacterial activity of surfactants against Escherichia coli cells is influenced by carbon source and anaerobiosis.

AIMS: In order to clarify the involvement of an energy-yielding system in the antibacterial action of surfactants, the effects of carbon source and anaerobiosis during the growth period on the surfactant sensitivity of Escherichia coli cells were investigated. METHODS AND RESULTS: Cetyltrimethylammonium bromide (CTAB) and N-dodecyl-N,N-dimethylglycine, at relatively low concentrations, caused a delay in growth of E. coli cells. Cells grown in M9 medium supplemented with glycerol, succinate or acetate as a carbon source were more sensitive to surfactants and had a higher respiratory activity than those grown with glucose. Cultivation under anaerobiosis made cells resistant to CTAB. CONCLUSIONS: Bacterial sensitivity to surfactants was affected by carbon source and anaerobiosis. SIGNIFICANCE AND IMPACT OF THE STUDY: The results obtained should be helpful in determining suitable conditions of treatment in the practical use of surfactants for bacterial decontamination.

Anaerobiosis↗
PubMed2002

Evaluation of N-acetylchitooligosaccharides as the main carbon sources for the growth of intestinal bacteria.

N-Acetylchitooligosaccharides ((GlcNAc)(n)) with different degrees of polymerization (n=1-6) were prepared as the main carbon sources in media for evaluating the growth of nine intestinal bacteria. A chitohydrolysate was prepared by hydrolyzing shrimp-shell chitin using HCl. After purification, the purity of each (GlcNAc)(1-6) was >86%. The growth of intestinal bacteria was carried out in a basal medium (BM) containing 0.2% (w/v) of each sugar or glucose as the main carbon source and was evaluated using maximum cell densities and specific growth rates. Bacteroides fragilis and Clostridium perfringens could respectively utilize GlcNAc and (GlcNAc)(2) more efficiently for growth than glucose. Bifidobacterium adolescentis and Eubacterium limosum could use (GlcNAc)(1-6) slightly as their main carbon source. Escherichia coli, Lactococcus lactis and Proteus vulgaris could utilize glucose more efficiently than (GlcNac)(1-6). GlcNAc was used more readily than (GlcNAc)(2-6) by Staphylococcus aureus, exhibiting almost the same specific growth rates. In BM, Streptococcus faecalis grew well even without adding each of the sugars tested.

Acetylglucosamine↗
PubMed2001

Carbon source regulation of beta-galactosidase biosynthesis in Penicillium chrysogenum.

Growth and beta-galactosidase activity of the penicillin producer industrial Penicillium chrysogenum NCAIM 00237 strain were examined using different carbon sources. Good growth was observed using glucose, sucrose, glycerol and galactose, while growth on lactose was substantially slower. beta-Galactosidase activity was high on lactose and very low on all the other carbon sources tested. In glucose grown cultures after exhaustion of glucose as repressing carbon source a derepressed low level of the enzyme was observed. cAMP concentration in lactose grown cultures was relatively high, in glucose grown cultures was low. Caffeine substantially decreased glucose consumption and growth but did not increase beta-galactosidase activity and did not prevent glucose repression which rules out the involvement of cAMP in the regulation of beta-galactosidase biosynthesis in Penicillium chrysogenum.

Caffeine↗
PubMed2000

Synthesis of phosphatidylserine in carrot cells cultured under carbon-source starvation.

When carrot suspension cells were cultured on medium containing no carbon source (starvation), the levels of phosphatidylserine (PS) increased transiently 3-4 d after the initiation of starvation while levels of most other phospholipid (PL) species decreased. We previously reported that fatty acids of these PLs served as an alternative carbon source during starvation. The present study showed that cells possess two different biosynthetic pathways involving phosphatidylcholine (PC)/phosphatidylethanolamine (PE) exchange enzymes and PS synthase to synthesize PS. These activities peaked similarly 4 d after the initiation of starvation and coincided with the peak of PS level. The synthesis of serine was also significantly activated during starvation. The activity of phosphoserine aminotransferase (PSAT) which is involved in serine synthesis increased with a time course similar to that of the increase in the PS level. These observations suggest that the increase in PS level plays an important role in membranes which are degraded during starvation.

CDPdiacylglycerol-Serine O-Phosphatidyltransferase↗
PubMed1979

Relationship between carbon source and susceptibility of Cephalosporium acremonium to selected amino acid analogues.

The susceptibility of Cephalosporium acremonium to selected amino acid analogues was markedly influenced by the carbon source used in the test media. Lysine hydroxamate, beta-hydroxy norvaline, and hexafluorovaline were toxic when tested with ribose, ribose or fructose, and ribose or galactose, respectively. In contrast, thialysine and thiaisoleucine inhibited C. acremonium with glucose, fructose, galactose, sucrose, mannitol, sorbitol, and soluble starch. Neither of these analogues was toxic at levels tested when glycerol was used as a carbon source. The minimal inhibitory concentrations (MIC) of thialysine, homoserine, and alpha-methylserine were greater than 1000, greater than 1000, and 250 microgram/mL, respectively, with glycerol. In contrast, the MIC values for the same three analogues were 31, 62, and 125 microgram/mL, respectively, with mannitol. The matching of the carbon sources with the specific amino acid analogues expands the number of analogues useful for selecting derepressed mutants. Thialysine-resistant mutants (tlysR) of C. acremonium which excrete lysine were isolated on a medium containing mannitol.

Acremonium↗
PubMed2006

Thermal decomposition of ferrocene as a method for production of single-walled carbon nanotubes without additional carbon sources.

A new method to grow bulk quantities of single-walled carbon nanotubes (SWCNTs) by a catalytic chemical vapor deposition (CVD) process with the possibility of varying the pressure has been developed and is reported in this paper. Thermal decomposition of ferrocene provides both catalytic particles and carbon sources for SWCNT growth using Ar as a carrier gas. Upon an increase in the pressure, the mean diameter of the SWCNTs decreases. In fact, high abundances of SWCNT with diameters as small as 0.7 nm, which is the limit for stable caps with isolated pentagons, can be obtained. An additional advantage of this method is that as no external carbon sources are required, SWCNT synthesis can be achieved at temperatures as low as 650 degrees C.

Journal Article↗
PubMed2003

Effect of carbon source on pyrimidine biosynthesis in Pseudomonas alcaligenes ATCC 14909.

The effect of carbon source on the regulation of the de novo pyrimidine biosynthetic enzymes in Pseudomonas alcaligenes ATCC 14909 was investigated. The de novo pyrimidine biosynthetic enzymes were measured in extracts of P. alcaligenes ATCC 14909 cells and of cells from an auxotroph deficient for orotate phosphoribosyltransferase activity. Pyrimidine biosynthetic enzyme activities in ATCC 14909 were influenced by pyrimidine supplementation to the culture medium but not by the carbon source present. Pyrimidine limitation of the auxotroph elevated the de novo enzyme activities indicating that this pathway may be controlled at the transcriptional level by a pyrimidine-related compound. Its regulation seemed to be subject to less transcriptional control by a pyrimidine-related compound than what was observed in the closely related species Pseudomonas pseudoalcaligenes.

Aspartate Carbamoyltransferase↗
PubMed1978

Effect of carbon source on enzymes involved in glycerol metabolism in Neurospora crassa.

Specific activities of eight enzymes involved in glycerol metabolism were determined in crude extracts of three strains of Neurospora crassa after growth on six different carbon sources. One of the strains was wild type, which grew poorly on glycerol as sole carbon source; the other two were mutant strains which were efficient glycerol utilizers. A possible basis for this greater efficiency of glycerol utilization was catabolite repression of glyceraldehyde kinase by glycerol in wild type, and two-fold higher glycerate kinase activity in the mutant strains after growth on glycerol, thus apparently allowing two routes for glyceraldehyde to enter the glycolytic pathway in the mutant strains but only one in wild type. The preferential entry of glyceraldehyde to the glycolytic pathway through glycerate was suggested by the lack of glyceraldehyde kinase in all three strains after growth on one or more of the carbon sources and the generally higher levels of aldehyde dehydrogenase and of glycerate kinase than of glyceraldehyde kinase.

Aldehyde Oxidoreductases↗
PubMed1982

Effect of different carbon sources on delta 5 desaturation activity of HTC cells.

The effect of different carbon sources on delta 5 desaturation activity in Minimal Deviation Hepatoma 7288 c (HTC) cells was studied. When HTC cells were incubated in the absence of carbon sources in the medium (fasted cells) the conversion of [1-14C]eicosa-8,11,14-trienoic acid to arachidonic acid increased significantly compared to those cells incubated in S-77 medium (fed cells). This activity was not modified if fasted cells were refed with glucose. However, the activity decreased significantly by the addition of lactalbumin hydrolysate to fasted cells. This effect can not be attributed to individual aminoacids since the addition of them to an aminoacid free medium produced no changes on delta 5 desaturation activity. The incubation of HTC cells with S-77 medium supplemented with glucose, pyruvate or glucose plus pyruvate, showed similar delta 5 desaturation activity to those cells incubated in S-77 medium alone.

8,11,14-Eicosatrienoic Acid↗
PubMed1989

Prostate epithelial cells utilize glucose and aspartate as the carbon sources for net citrate production.

The prostate gland (human, rat ventral prostate) has the major function of accumulating and secreting extremely high levels of citrate. This function requires unique and specialized metabolic pathways associated with prostate secretory epithelial cells by which exogenous substrates must be utilized as the six-carbon sources of citrate. Recent studies demonstrated that aspartate can serve as the four-carbon source of oxalacetate for citrate synthesis. Identification of the two-carbon source of acetyl CoA (AcCoA) had not been established. The present study investigated the probability that exogenous glucose, via pyruvate oxidation, is a physiological source of AcCoA for net citrate production by isolated epithelial cells from rat ventral prostate. Under adequate oxygenation, 5 mM glucose in the presence of aspartate plus glutamate markedly stimulated citrate production. Exogenous and endogenous pyruvate also stimulated net citrate production. We propose that glucose via aerobic glycolysis and pyruvate oxidation provides AcCoA, which condenses with oxalacetate obtained from aspartate transamination for citrate synthesis. Prostate epithelial cells do not readily oxidize citrate, which permits accumulation and secretion of the synthesized citrate.

Acetyl Coenzyme A↗
PubMed2002

An alternate carbon source for enhancing production of polysaccharides by Silene vulgaris callus.

Pectin termed silenan and acidic arabinogalactan were isolated as cell-wall polysaccharides of Silene vulgaris callus in the presence of various carbon sources as components of the media. The maximum yields, productivity per litre of medium and production per day of acidic arabinogalactan, were achieved using glucose or galactose as the carbon source. Sucrose was found to increase the production of the polysaccharides. Yields, productivity and rate of production of arabinogalactan per day were decreased in the presence of arabinose. Yields of silenan, productivity and rate of production per day were closely related irrespective of the sugar used as the carbon source in the media (sucrose, glucose or galactose) and yields of silenan from the callus growing on arabinose were comparable. A concentration of sucrose in the 20-50 g/L range enhanced the biosynthesis of silenan and at 50 g/L the silenan contained the linear backbone and the ramified regions of the macromolecule.

Carbon↗