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1.
Optimization and characterization of an extracellular polysaccharide produced byGlomerella
cingulata
Summary A new strain of the fungusGlomerella
cingulata has been isolated, which produces an extracellular highly viscous polysaccharide in a simple mineral medium. Optimum conditions for its production and properties are described. The polysaccharide produced was a glucan type. The viscosity remained stable during storage over a period of seven days. Large changes in temperature and pH have no effect on viscosity. 相似文献
2.
Cadmium adsorption by bacterial capsular polysaccharide coatings 总被引:1,自引:0,他引:1
Conclusions Excretion of a polysaccharide capsular coating byP.putida provided enhanced cadmium uptake when compared to the noncapsularP.cruciviae. As this advantage is most significant for cadmium concentrations below 2.5 mg/l, levels which are commonly found in waste discharges, it does suggest a potential role for extracellular polysaccharide producers as biosorbents. These encouraging results have led to further work to determine the desorption characteristics, by pH adjustment, ofP.putida along with long term viability after successive cycles of adsorption and desorption. 相似文献
3.
Summary A yeast strainMoniliella
pollinis produces an extracellular highly viscous gum-like polysaccharide of glucan type in a simple mineral medium. Optimum conditions for its production and properties are described. The viscosity decreased after lyophilization. 相似文献
4.
Summary The swollen seeds ofOcimum
basilicum consist of a hard core with a pectious porous outer layer to which urease was bound after epoxy activation, through ethylenediamine-glutaraldehyde arm. These seeds can serve as an inexpensive ready to use natural pellicular polysaccharide support for immobilizing enzymes. 相似文献
5.
Influence of impeller speed upon the pullulan fermentation 总被引:4,自引:0,他引:4
Summary The effect of impeller speed on pullulan production and the morphology ofAureobasidium
pullulans in batch culture was studied. Pullulan production and the percentage of yeast cells in the culture rose with impeller speed, as did molecular weight of the polysaccharide. 相似文献
6.
Summary The gel-forming polysaccharide of the sugary kefir grains (11.5% of dry matter) or one taken from aLactobacillus brevis culture were identified as dextrans with some 1)-Gp-(3 links in the main chain, with a ratio (branched/total units) of 0.19 and 0.14 respectively, instead of 0.07 for the non-gelling polysaccharide. 相似文献
7.
Enhancement of pullulan elaboration by fluoroacetate 总被引:1,自引:0,他引:1
Summary The addition of fluoroacetate, the precursor of the aconitase inhibitor, fluorocitrate, to resting cell suspensions of Aureobasidium pullulans was found to increase the quantity of extracellular polysaccharide elaborated and to raise the pullulan content to 93%. 相似文献
8.
Jutta Cerning C. Bouillanne M. J. Desmazeaud Michèle Landon 《Biotechnology letters》1988,10(4):255-260
Summary
Streptococcus thermophilus strains grown on skim milk produce exocellular polysaccharide, essentially composed of galactose and glucose. Small amounts of xylose, arabinose, rhamnose and mannose are identified also. A relationship exists between viscosity of the culture medium and the amount of polymer produced. However, the thickness producing trait in the strains studied is highly unstable. 相似文献
9.
M.A. Manresa M.C. Fusté A.M. Marqués F. Congregado M. D. Simon-Pujol J. Guinea 《Biotechnology letters》1986,8(2):91-94
Summary
E. coli CF3 isolated after the infection ofE. coli K12 C600 with the bacteriophage B278 produces quantities of extracellular exopoly-saccharide characterized by gas chromatography as composed of glucose, galactose and fucose in the molar ratio 111.2 and being partly acetylated. Solutions of the polysaccharide were pseudoplastic and its viscosity is constant at extreme pH (3.5–10) and compatible with temperature (90°C). 相似文献
10.
Emmanuelle Bechet Sébastien Guiral Sophie Torres Ivan Mijakovic Alain-Jean Cozzone Christophe Grangeasse 《Amino acids》2009,37(3):499-507
When considering protein phosphorylation in bacteria, phosphorylation of aspartic acid and histidine residues mediated by
the two-component systems is the first to spring to mind. And yet other phosphorylation systems have been described in bacteria
in the past 20 years including eukaryotic-like serine/threonine kinases and more recently tyrosine-kinases. Among the latter,
a peculiar type is widespread among bacteria, but not in higher organisms. These enzymes possess unique structural features
defining thus a new family of enzymes termed Bacterial tyrosine kinases (BY-kinases). BY-kinases have been shown to be mainly involved in polysaccharide production, but their ability
to phosphorylate endogenous substrates indicates that they participate in the regulation of other functions of the bacterial
cell. Recent advances in mass spectrometry based phosphoproteomics provided lists of many new phosphotyrosine-proteins, indicating
that BY-kinases may be involved in regulating a large array of other cellular functions. One may expect that in a near future,
tyrosine phosphorylation will turn out to be one of the key regulatory processes in the bacterial cell and will yield new
insights into the understanding of its physiology. 相似文献
11.
Congregado F. Estañol I. Espuny M. J. Fusté M. C. Manresa M. A. Marqués A. M. Guinea J. Simon-Pujol M. D. 《Biotechnology letters》1985,7(12):883-888
Summary Exopolysaccharide production byPseudomonas sp. strain EPS-5028 increased under conditions of high C/N ratios at the pH range 6.7–8 and 25°C. The polymer was formed from a variety of carbon substrates and contains D-glucose, D-galactose and uronic acid in the approximate molar ratio of 325. The polysaccharide produced is of high viscosity (1,600 cP; 1% polymer in D. I. water). 相似文献
12.
Summary The instability of Lac+ and Cit+ phenotypes was investigated inLeuconostoc
mesenteroides subsp.cremoris ATCC 19245 and in four strains ofLeuconostoc
mesenteroides subsp.dextranicum. The two phenotypes were linked respectively to a 14 Mdal and a 34 Mdal plasmid in Leuconostoc mesenteroides subsp.cremoris ATCC 19245. InLeuconostoc
mesenteroides subsp.dextranicum the character Lac+ was linked to a 28 Mdal plasmid, while the Cit+ phenotype was stable. 相似文献
13.
Jong-Won Oh Jin-Ho Lee Kap-Soo Noh Hyune-Hwan Lee Jae-Heung Lee Hyung-Hwan Hyun 《Biotechnology letters》1991,13(10):727-732
Summary ThedapA gene (L-2,3-dihydrodipicolinate synthetase: DHDP synthetase) ofCorynebacterium
glutamicum JS231, a lysine overproducer, cloned and subcloned inE.
coli/C.
glutamicum shuttle vector pECCG117 was used to transformE.
coli threonine producer and threonine and lysine coproducer. The plasmid pDHDP5812 carryingdapA gene ofC.
glutamicum led to increase in lysine production in theseE.
coli strains. Threonine and lysine co-producerE.
coli TF1 with pDHDP5812 produced lysine with small amount of threonine. The DHDP synthetase activity ofE.
coli TF1 carrying pDHDP5812 showed high resistance toward inhibition by lysine. 相似文献
14.
Ken-ichi Ishiwata Tadashi Suzuki Satoru Iwamori Setsuo Yoshino Nobuyoshi Makiguchi 《Biotechnology letters》1990,12(3):185-190
Summary The tryptophan synthase genes,trpA andtrpB, from a moderate thermophile,Bacillus
stearothermophilus IFO13737, were expressed efficiently inEscherichia
coli. The recombinant tryptophan synthase amounted to 22% of the soluble cellular protein, and was purified to homogeneity by three steps. The enzyme is more thermostable thanE.coli tryptophan synthase, especially the subunit. The enzyme is also more resistant to sodium dodecylsulfate and methanol thanE.coli enzyme. 相似文献
15.
Norma de Magalhães Erismann Ana M. Fernandez Jaime Baeza Juanita Freer Hector Mansilla Nelson Duran 《Biotechnology letters》1990,12(4):305-308
Summary We report the delignification ofPinus
radiata D Don,Eucalyptus
globulus andEucalyptus
grandis woods (formic acid treated and untreated) by 2 h treatment with a hemin/hydrogen peroxide system. The untreated chips and sawdust ofE.
globulus were 30% and 50% delignified respectively. No significant effects were found forP.
radiata sawdust;P.
radiata treated chips (organosolv pulp) did not show any further delignification upon hemin/peroxide action, 25% delignification was achieved in untreated chips. In the case ofE.
grandis untreated wood the delignification was better in sawdust than in chips, but in smaller percentage than in the otherEucalyptus species. This relation is maintained in substrates, treated with formic acid or untreated. The delignification of chips in both species ofEucalyptus was improved when they were pre-treated with formic acid. The loss of lignin in theE.
grandis andE.
globulus sawdust (pre-treated with formic acid) was 79% and 75% respectively. 相似文献
16.
Summary Plasmids fromZ.
mobilis could be stably maintained inE.
coli HB101 in which the expression of various drug resistance markers could be monitored. A large molecular weight plasmid (5.2 kbp) ofZ.
mobilis was found to harbour the genes for mercuric chloride degradation and to confer uponE.
coli, resistance to a higher mercuric chloride concentration as compared toZ.
mobilis. The introduction of this plamsid madeE.
coli sensitive to concentrations of cadmium acetate which were originally non-inhibitory to it. 相似文献
17.
Summary A 4.1-kb cryptic plasmid, designated pCA134, has been isolated fromClostridium species. In order to develop a vector suitable for transforming saccharolytic clostridia three hybrid plasmids were constructed by inserting pCA134 into pHV32 withEcoRI, orBglII andBamHI. The newly constructed plasmids were propagated inEscherichia
coli and were used to transformBacillus
subtilis andClostridium
acetobutylicum. One of them, pCAB32 (10.1 kb), which contains chloramphenicol acetyltransferase gene and an origin of replication derived from pCA134 was introduced intoB.subtilis andC.acetobutylicum as well asE.coli. 相似文献
18.
Influence of the inoculum size ofLactobacillus
plantarum on the competition withEnterobacter
cloacae
Summary The size of the inoculum ofLactobacillus
plantarum or its natural density, appears to be of predominant importance in the exclusion ofEnterobacter
cloacae in mixed fermentations, such as ensilage. In a liquid medium, simulating adverse silage conditions, an initial density ofL.
plantarum at least twice that ofE.
cloacae was found necessary in order to obtain a succesful silage. 相似文献
19.
Summary The plasmid pRH271, harboring a xylanase gene cioned fromBacilius
subtilis, has been transferred into a mutant ofE.
coli SK2284 which allowed the release of part of the xylanase in the culture supernatant. Kinetic parameters of this recombinantE.
coll strain were determined in microscale batch culture with and without the selective pressure of antibiotics. No significant difference in µmax was observed for the nontransformedE.
coli strain when compared to the recombinant strain. However, K5 values for glucose were two times higher in the case of the recombinant strain. Preliminary study of xylanase production in a large batch farmenter was also described. 相似文献
20.
Characterization of a cytochrome oxidase-deficient yeast mutant which accumulates porphyrins 总被引:1,自引:0,他引:1
M R Arrese D Vojensky J R Mattoon 《Biochemical and biophysical research communications》1982,107(3):848-855
A cytochrome oxidase-deficient mutant (pop4) of Saccharomycescerevisiae which accumulates porphyrins has been characterized. The pop4 mutation is recessive and affects a single nuclear gene. The bulk of the accumulated porphyrins consists of uroporphyrin and its partial decar?ylation products, suggesting that the mutation causes a block at the level of uroporphyrinogen decar?ylase. However, pop4 is not allelic to hem6 or pop3, putative decar?ylase structural-gene mutants. These results suggest that there may be a uroporphyrinogen decar?ylase isoenzyme specifically involved in heme a production. 相似文献