scholarly journals Screening of local wild-type Xanthomonas spp. for xanthan biosynthesis using media with different carbon sources

2021 ◽  
Vol 26 (4) ◽  
pp. 2800-2807
Author(s):  
IDA ZAHOVIĆ ◽  
JELENA DODIĆ ◽  
SINIŠA MARKOV ◽  
JOVANA GRAHOVAC ◽  
MILA GRAHOVAC ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Carbon Source ◽  
Carbon Sources ◽  
Wild Type ◽  
Biotechnological Production ◽  
Aerobic Conditions ◽  
Pepper Leaves ◽  
Synthetic Media ◽  
Selection Of

In this study the screening of different Xanthomonas strains, isolated from infected crucifers and pepper leaves, for xanthan biosynthesis on semi-synthetic media containing different carbon sources was performed. The success of xanthan biosynthesis was estimated based on xanthan concentration in media and its molecular weight. Glucose and glycerol were investigated as carbon sources in a quantity of 20.0 g/L. Xanthan biosynthesis by different Xanthomonas isolates on two different cultivation media was carried out in Erlenmeyer flasks under aerobic conditions for 168 h. According to the obtained results selection of the carbon source, producing strain and their combination have a statistically significant effect on xanthan quantity and quality. The results obtained in this study indicate that local wild-type Xanthomonas strains isolated from pepper leaves have a great potential for application in biotechnological production of good-quality xanthan on glycerol-based media.

Development of mutants of Gliocladium virens tolerant to benomyl

1990 ◽  
Vol 36 (7) ◽  
pp. 484-489 ◽  
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.

A comparison between ethanol and methanol as carbon sources for denitrification

1994 ◽  
Vol 30 (6) ◽  
pp. 83-90 ◽  
Author(s):  
Magnus Christensson ◽  
Ewa Lie ◽  
Thomas Welander
Keyword(s):  
Growth Rate ◽  
Carbon Source ◽  
Pure Culture ◽  
Carbon Sources ◽  
Culture Studies ◽  
Adaptation Time ◽  
Synthetic Media ◽  
Short Time

Ethanol and methanol were compared for their performance as carbon sources for denitrification. The study was carried out in two chemostats, operated in parallel on synthetic media containing ethanol and methanol respectively as carbon sources. In addition, pure culture studies were performed on one ethanol- and one methanol-utilizing denitrifier. Ethanol was found to be considerably more readily available as a carbon source for denitrification than was methanol. An efficient denitrification with ethanol was established in a short time, while denitrification with methanol required a substantial adaptation time and never showed the same stability as denitrification with ethanol. The growth rate of denitrifiers with ethanol as carbon source was 2–3 times higher than with methanol. The amount of COD required to denitrify a certain amount of nitrate was somewhat lower for ethanol (3.85 g/gN) than for methanol (4.45 g/gN) in the continuous experiments, while it was considerably higher for ethanol (6.1 g/gN) than for methanol (4.1 g/gN) in pure culture batch cultivations.

Phosphatidylinositol phospholipase C mediates carbon sensing and vegetative nuclear duplication rates in Aspergillus nidulans

2011 ◽  
Vol 57 (7) ◽  
pp. 611-616 ◽  
Author(s):  
Ana Paula de Figueiredo Conte Vanzela ◽  
Suraia Said ◽  
Rolf Alexander Prade
Keyword(s):  
Molecular Weight ◽  
Carbon Source ◽  
Phospholipase C ◽  
Aspergillus Nidulans ◽  
Nuclear Division ◽  
Deficient Mutant ◽  
Wild Type ◽  
Pectinolytic Enzymes ◽  
In The Wild ◽  
Phosphatidylinositol Phospholipase C

In this work, we disrupted one of three putative phosphatidylinositol phospholipase C genes of Aspergillus nidulans and studied its effect on carbon source sensing linked to vegetative mitotic nuclear division. We showed that glucose does not affect nuclear division rates during early vegetative conidial germination (6–7 h) in either the wild type or the plcA-deficient mutant. Only after 8 h of cultivation on glucose did the mutant strain present some decrease in nuclear duplication. However, decreased nuclear division rates were observed in the wild type when cultivated in media amended with polypectate, whereas our plcA-deficient mutant did not show slow nuclear duplication rates when grown on this carbon source, even though it requires induction and secretion of multiple pectinolytic enzymes to be metabolized. Thus, plcA appears to be directly linked to high-molecular-weight carbon source sensing.

Transformation of industrial food wastes into polyhydroxyalkanoates

1999 ◽  
Vol 40 (1) ◽  
pp. 365-370 ◽  
Author(s):  
P. H. F. Yu ◽  
H. Chua ◽  
A. L. Huang ◽  
W. H. Lo ◽  
K. P. Ho
Keyword(s):  
Carbon Source ◽  
Waste Management ◽  
Physical Properties ◽  
Carbon Sources ◽  
Biodegradable Plastics ◽  
Solid Wastes ◽  
Food Wastes ◽  
Proper Selection ◽  
Environmental Friendly ◽  
Selection Of

Due to the synthetic and biologically inert nature of petroleum-derived plastics, the disposal of these solid wastes has been a focus of concern for waste management. Thus, the demand for biodegradable plastics has become a highly visible issue. Broader usage of biodegradable plastics in packaging and disposable products as a solution to environmental problems would heavily depend on further reduction in costs and the discovery of novel biodegradable plastics with improved properties. As the first step in pursuit of eventual usage of industrial food wastewater as nutrients for microorganisms to synthesize environmental-friendly bioplastics, the usage of soya wastes and malt wastes from a beer brewery plant were investigated as the carbon sources for the production of bioplastics. Bench experiments showed that microorganisms from the municipal activated sludges used the nutrients from malt and soya wastes to biosynthesise PHAs. The results of experiments indicated that with the proper selection of the type of food wastes as the carbon source, bioplastics with specific PHAs copolymers could be produced with distinct polymer physical properties.

scholarly journals Study on the Influence of Different Carbon Sources on Nitrogen and Phosphorus Removal with Micro-pressure swirl Reactor

2021 ◽  
Vol 261 ◽  
pp. 02046
Author(s):  
Xi Tian ◽  
Xuejiao Li ◽  
Yanhong Lv ◽  
Penghui Dong ◽  
Longfei Yang ◽  
...  
Keyword(s):  
Carbon Source ◽  
Structural Characteristics ◽  
Carbon Sources ◽  
Operating Conditions ◽  
Test Results ◽  
Nitrogen And Phosphorus ◽  
Nitrogen And Phosphorus Removal ◽  
Operation Cycle ◽  
Pressure Swirl ◽  
Selection Of

To explore the suitable external carbon sources for Micro-pressure swirl Reactor (MPR), the experiment was run in parallel through two MPRs, using starch and glucose as carbon sources respectively. Research indicated that under the experimental operating conditions, using starch as the carbon source could more effectively promote the biological denitrification of the MPR system. Due to the structural characteristics of MPR and the slow degradation of starch, the demand for carbon source for denitrification was ensured during the operation cycle, so that the system obtained a better denitrification effect. The test results provided reference for the selection of the external carbon source of the MPR process.

Selection of a Mutant Strain Streptococcus equi SH-109 and Optimization of Culture Conditions for the Production of High Molecular Weight Hyaluronic Acid

2014 ◽  
Vol 915-916 ◽  
pp. 909-912 ◽  
Author(s):  
Jian Cheng Feng ◽  
Rong Hu Zhang
Keyword(s):  
Molecular Weight ◽  
Hyaluronic Acid ◽  
High Molecular Weight ◽  
Culture Conditions ◽  
Culture Broth ◽  
Agitation Speed ◽  
Wild Type ◽  
Streptococcus Equi ◽  
Optimal Ph ◽  
Selection Of

A high molecular weight hyaluronic acid-producing mutant, designated asStreptococcus equiSH-109 that did not produce streptolysin or hyaluronidase was selected from wild-typeStreptococcus equiSH-0 by NTG treatment. The selected mutant could produce high molecular weight HA and had perfect genetic stability after reproduction. Several culture conditions were optimized in a 5-l fermentor for the production of hyaluronic acid. It was found that the optimal pH and agitation speed were 7.6 and 550rpm, respectively. Under the optimized culture condition, hyaluronic acid with a molecular weight of 4.0 x 106was accumulated in the culture broth.

scholarly journals Genetically Modified Strains of Ralstonia eutropha H16 with β-Ketothiolase Gene Deletions for Production of Copolyesters with Defined 3-Hydroxyvaleric Acid Contents

2012 ◽  
Vol 78 (15) ◽  
pp. 5375-5383 ◽  
Author(s):  
Nicole Lindenkamp ◽  
Elena Volodina ◽  
Alexander Steinbüchel
Keyword(s):  
Fatty Acids ◽  
Carbon Source ◽  
Sole Carbon Source ◽  
Ralstonia Eutropha ◽  
Carbon Sources ◽  
Production Capacity ◽  
Wild Type ◽  
Content Type ◽  
Storage Behavior ◽  
Copolymer Poly

ABSTRACTβ-Ketothiolases catalyze the first step of poly(3-hydroxybutyrate) [poly(3HB)] biosynthesis in bacteria by condensation of two acetyl coenzyme A (acetyl-CoA) molecules to acetoacetyl-CoA and also take part in the degradation of fatty acids. During growth on propionate or valerate,Ralstonia eutrophaH16 produces the copolymer poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [poly(3HB-co-3HV)]. InR. eutropha, 15 β-ketothiolase homologues exist. The synthesis of 3-hydroxybutyryl-CoA (3HB-CoA) could be significantly reduced in an 8-fold mutant (Lindenkamp et al., Appl. Environ. Microbiol. 76:5373–5382, 2010). In this study, a 9-fold mutant deficient in nine β-ketothiolase gene homologues (phaA,bktB, H16_A1713, H16_B1771, H16_A1528, H16_B0381, H16_B1369, H16_A0170, andpcaF) was generated. In order to examine the polyhydroxyalkanoate production capacity when short- or long-chain and even- or odd-chain-length fatty acids were provided as carbon sources, the growth and storage behavior of several mutants from the previous study and the newly generated 9-fold mutant were analyzed. Propionate, valerate, octanoate, undecanoic acid, or oleate was chosen as the sole carbon source. On octanoate, no significant differences in growth or storage behavior were observed between wild-typeR. eutrophaand the mutants. In contrast, during the growth on oleate of a multiple mutant lackingphaA,bktB, and H16_A0170, diminished poly(3HB) accumulation occurred. Surprisingly, the amount of accumulated poly(3HB) in the multiple mutants grown on gluconate differed; it was much lower than that on oleate. The β-ketothiolase activity toward acetoacetyl-CoA in H16ΔphaAand all the multiple mutants remained 10-fold lower than the activity of the wild type, regardless of which carbon source, oleate or gluconate, was employed. During growth on valerate as a sole carbon source, the 9-fold mutant accumulated almost a poly(3-hydroxyvalerate) [poly(3HV)] homopolyester with 99 mol% 3HV constituents.

scholarly journals Transcriptional Cross-Regulation of the Catechol and Protocatechuate Branches of the β-Ketoadipate Pathway Contributes to Carbon Source-Dependent Expression of the Acinetobacter sp. Strain ADP1 pobA Gene

2003 ◽  
Vol 69 (3) ◽  
pp. 1598-1606 ◽  
Author(s):  
Patricia C. Brzostowicz ◽  
Andrew B. Reams ◽  
Todd J. Clark ◽  
Ellen L. Neidle
Keyword(s):  
Carbon Source ◽  
Transcriptional Control ◽  
Direct Evidence ◽  
Carbon Sources ◽  
Exponential Growth Phase ◽  
Wild Type ◽  
Aromatic Substrates ◽  
Phase Complex ◽  
Source Preferences

ABSTRACT Transcriptional control of carbon source preferences by Acinetobacter sp. strain ADP1 was assessed with a pobA::lacZ fusion during growth on alternative substrates. The pobA-encoded enzyme catalyzes the first step in the degradation of 4-hydroxybenzoate, a compound consumed rapidly as a sole carbon source. If additional aromatic carbon sources are available, 4-hydroxybenzoate consumption is inhibited by unknown mechanisms. As reported here, during growth on aromatic substrates, pobA was not expressed despite the presence of 4-hydroxybenzoate, an inducer that normally causes the PobR regulator to activate pobA transcription. Growth on organic acids such as succinate, fumarate, and acetate allowed higher levels of pobA expression. In each case, pobA expression increased at the end of the exponential growth phase. Complex transcriptional regulation controlled 4-hydroxybenzoate catabolism in multisubstrate environments. Additional studies focused on the wild-type preference for benzoate consumption prior to 4-hydroxybenzoate consumption. These compounds are degraded via the catechol and protocatechuate branches of the β-ketoadipate pathway, respectively. Here, mutants were characterized that degraded benzoate and 4-hydroxybenzoate concurrently. These mutants lacked the BenM and CatM transcriptional regulators that normally activate genes for benzoate catabolism. A model is presented in which BenM and CatM prevent pobA expression indirectly during growth on benzoate. These regulators may affect pobA expression by lowering the PcaK-mediated uptake of 4-hydroxybenzoate. Consistent with this model, BenM and CatM bound in vitro to an operator-promoter fragment controlling the expression of several pca genes, including pcaK. These studies provide the first direct evidence of transcriptional cross-regulation between the distinct but analogous branches of the β-ketoadipate pathway.

scholarly journals The regulation of NADL-glutamate dehydrogenase inAspergillus nidulans

1974 ◽  
Vol 23 (1) ◽  
pp. 119-124 ◽  
Author(s):  
J. R. Kinghorn ◽  
J. A. Pateman
Keyword(s):  
Amino Acids ◽  
Linkage Group ◽  
Carbon Source ◽  
Glutamate Dehydrogenase ◽  
Aspergillus Nidulans ◽  
Dehydrogenase Activity ◽  
Carbon Sources ◽  
Wild Type ◽  
Group Iii ◽  
Glutamate Dehydrogenase Activity

SummaryWild-type cells ofAspergillus nidulanshave undetectable NADL-glutamate dehydrogenase activity when utilizing glucose and high levels of NADL-glutamate dehydrogenase when utilizing certain amino acids as sole carbon sources.A mutant, designatedgdhCl, has appreciable NAD-GDH activity when utilizing glucose as a carbon source. ThegdhC1mutation is semi-dominant and is located in linkage group III.

scholarly journals Regulation of hly Expression inListeria monocytogenes by Carbon Sources and pH Occurs through Separate Mechanisms Mediated by PrfA

1998 ◽  
Vol 66 (8) ◽  
pp. 3635-3642 ◽  
Author(s):  
Jaideep Behari ◽  
Philip Youngman
Keyword(s):  
Listeria Monocytogenes ◽  
Carbon Source ◽  
Virulence Genes ◽  
Carbon Sources ◽  
Virulence Gene ◽  
Anomalous Behavior ◽  
Negative Regulation ◽  
Wild Type ◽  
Glucosidase Activity ◽  
Strain Nctc

ABSTRACT Expression of the PrfA-controlled virulence gene hly(encoding the pore-forming cytolysin listeriolysin) is under negative regulation by readily metabolized carbon sources in Listeria monocytogenes. However, the hyperhemolytic strain NCTC 7973 exhibits deregulated hly expression in the presence of repressing sugars, raising the possibility that a defect in carbon source regulation is responsible for its anomalous behavior. We show here that the activity of a second glucose-repressed enzyme, α-glucosidase, is 10-fold higher in NCTC 7973 than in 10403S. Usinghly-gus fusions, we show that the prfA allele from NCTC 7973 causes deregulated hly-gus expression in the presence of sugars in either the wild-type or the NCTC 7973 background, while the 10403S prfA allele restores carbon source regulation. However, the prfA genotype does not affect the regulation of α-glucosidase activity by repressing sugars. Of the two mutational differences in PrfA, only a Gly145Ser change is important for regulation of hly-gus. Therefore, NCTC 7973 and 10403S have genetic differences in at least two loci: one in prfAthat affects carbon source regulation of virulence genes and another in an unidentified gene(s) that up-regulates α-glucosidase activity. We also show that the decrease in pH associated with utilization of sugars negatively regulates hly-gus expression, although sugars can affect hly-gus expression by another mechanism that is independent of pH.

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