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1.
Very good solvent formation rates were observed when Clostridium beijerinckii NRRL B592 was cultivated on different whole potato media. The increase in whole potato concentration contributed to the increased
final solvent concentrations, while the addition of yeast extract or mineral salts gave negative effects. To obtain good solvent
productivities and high final solvent concentrations during batch fermentation, no enzymatic hydrolysis of the potato starch
was necessary, indicating high activity of the clostridial amylases produced by the strain applied.
Received: 17 April 1998 / Received revision: 22 June 1998 / Accepted: 27 June 1998 相似文献
2.
T. Potrawfke T.-H. Löhnert K. N. Timmis R.-M. Wittich 《Applied microbiology and biotechnology》1998,50(4):440-446
The biphenyl-mineralizing bacterium Burkholderia sp. strain LB400 also utilized 3-chloro-, 4-chloro-, 2,3′-dichloro- and 2,4′-dichlorobiphenyl for growth. By the attack of the initial enzyme a chlorine was eliminated dioxygenolytically
from position 2 of one of the aromatic rings when hydrogens of both were substituted by chlorine. The strain mineralized 3-chloro-
and 2,3′-dichlorobiphenyl via the central intermediate 3-chlorobenzoate through its chlorocatechol pathway enzymes, but excreted
stoichiometric amounts of 4-chlorobenzoate from 4-chloro- and 2,4′-dichlorobiphenyl. These two compounds were mineralized by a co-culture of strain LB400 and a derivative of the (methyl-)
benzoate-degrading strain Pseudomonas putida mt-2 (TOL). The complete degradation was achieved upon transfer of a cluster of at least five genes, encoding the regulated
chlorocatechol pathway operon, from strain LB400 to strain mt-2. This transfer was demonstrated by the polymerase chain reaction.
Received: 15 April 1998 / Received revision: 12 June 1998 / Accepted: 19 June 1998 相似文献
3.
A transketolase mutant was first isolated from Corynebacterium glutamicum, an organism of industrial importance. The mutant strain exhibited an absolute requirement for shikimic acid or the aromatic
amino acids and vitamins for growth, and also failed to grow on ribose or gluconic acid as sole carbon source, even with the
aromatic supplement. All of these defective properties were fully restored in spontaneous revertants, indicating the existence
of a single transketolase in C. glutamicum that was indispensable both for aromatic biosynthesis and for utilization of these carbohydrates in vivo. The transketolase
mutant accumulated ribulose extracellularly when cultivated in glucose medium with shikimic acid, but no ribose was detected.
Received: 10 April 1998 / Received revision: 26 May 1998 / Accepted: 14 June 1998 相似文献
4.
The gene dak1 encoding a dihydroxyacetone kinase (DHAK) isoenzyme I, one of two isoenzymes in the Schizosaccharomyces pombe IFO 0354 strain, was cloned and sequenced. The dak1 gene comprises 1743 bp and encodes a protein of 62 245 Da. The deduced amino acid sequence showed a similarity to a putative
DHAK of Saccharomyces cerevisiae and DHAK of Citrobacter freundii. The dak1 gene was expressed at a high level in Escherichia coli, and the recombinant enzyme was purified to homogeneity and characterized. The acetone powder of recombinant E. coli cells was used to produce dihydroxyacetone phosphate.
Received: 25 August 1998 / Received revision: 22 September 1998 / Accepted: 11 October 1998 相似文献
5.
Repeated application of carvone-induced bacteria to enhance biodegradation of polychlorinated biphenyls in soil 总被引:4,自引:0,他引:4
Carvone, the principal component of spearmint oil, induces biodegradation of polychlorinated biphenyls (PCB) by Arthrobacter sp. strain B1B. This study investigated the effectiveness of the repeated application of carvone-induced bacteria for bioremediation
of Aroclor-1242-contaminated soil. Control treatments compared a single inoculation of carvone-induced cells, repeated applications
of noninduced cells, and repeated applications of cell-free carvone/fructose medium. The results showed that repeated application
of carvone-induced bacteria was the most effective treatment for mineralizing PCB, resulting in 27 ± 6% degradation of Aroclor
1242 after 9 weeks; whereas a single application of cells resulted in no significant degradation. Addition of cell-free, carvone/fructose
medium resulted in 10% degradation of PCB, which suggests that this treatment stimulated biodegradation of PCB by the indigenous
microflora. The di- and trichlorobiphenyls were the most readily degraded congeners. More highly chlorinated congeners, which
had been previously shown to be degraded in liquid culture, were not substantially degraded in soil, indicating that low bioavailability
may have limited their degradation. With the development of new technology, which permits automated in situ fermentation and
delivery of degrader microorganisms, the repeated application of carvone-induced bacteria may facilitate bioremediation of
PCB-contaminated soils.
Received: 7 January 1998 / Received revision: 18 June 1998 / Accepted: 27 June 1998 相似文献
6.
W. Malek M. Inaba H. Ono Y. Kaneko Y. Murooka 《Applied microbiology and biotechnology》1998,50(2):261-265
Rhizobium huakuii bv. renge B3, a native symbiont of Astragalus sinicus, outcompeted Rhizobium sp. strain ACMP18, which was isolated from Astragalus cicer nodules, in the formation of root nodules on A.␣sinicus when plants were co-inoculated with these strains. The strains occupying the nodules were identified by antibiotic resistance
and phage sensitivity markers and also by polymerase chain reaction (PCR) genomic fingerprintings, which were performed by
using enterobacterial repetitive intergenic consensus sequences. In PCR genomic fingerprintings, the total genomic DNA isolated
from pure bacterial culture and from squashed root nodules showed identical profiles, indicating that this technique can be
a useful tool for identification of rhizobia in ecological studies. When Rhizobium sp. strain ACMP18 outnumbered R. huakuii bv. renge strain B3 by a factor of ten, and even when strain ACMP18 was added to plants 1 week before bacterization with
strain B3, the strain B3 occupied most nodules. Dually infected nodules were not observed, although Rhizobium sp. ACMP18 formed active nodules on A. sinicus when the bacterial strain was inoculated alone.
Received: 5 February 1998 / Received revision: 23 March 1998 / Accepted: 27 April 1998 相似文献
7.
When grown on vegetable oils and their derivatives, the smut fungus Ustilago maydis (DSM 4500 and ATCC 14826) produces several glycolipids under nitrogen-limiting conditions. With 45 g l−1 sunflower oil fatty acids (technical grade) a yield of 30 g l−1 glycolipid was achieved. The resulting mixture contained predominantly mannosylerythritol lipids together with smaller amounts
of cellobiose lipids. The production of the more polar cellobiose lipids was enhanced when glucose was used as carbon source.
The molecular structure of the main components of the glycolipid mixture were elucidated by a combination of NMR spectroscopic
and mass-spectrometric techniques.
Received: 22 June 1998 / Received revision: 11 September 1998 / Accepted: 13 September 1998 相似文献
8.
Extraction of medium after incubation of the fungus, Cunninghamella elegans, with 0.03% (w/v) 1-methylnaphthalene produced mainly 1-hydroxymethylnaphthalene together with some 1-naphthoic acid and
hydroxynaphthoic acid. Higher concentrations of substrate were inhibitory to biotransformation. Similar incubations with 1-naphtoic
acid as substrate resulted in reduction of the carboxyl group to give 1-hydroxymethylnaphthalene. When 6-methylquinoline was
used, the main product was 6-hydroxymethylquinoline but also some quinoline-6-carboxylic acid and some 6-methylquinoline-N-oxide were identified. In a 2-l fermenter 2.5 g substrate was transformed in 324 h. The 6-hydroxymethylquinoline was also
produced by reduction of quinoline-6-carboxylic acid by the organism.
Received: 9 March 1998 / Received revision: 15 June 1998 / Accepted: 19 June 1998 相似文献
9.
N. T. Mlobeli N. A. Gutierrez I. S. Maddox 《Applied microbiology and biotechnology》1998,50(1):125-128
A strain of Bifidobacterium bifidum was grown on different sugars under pH-controlled conditions to estimate some kinetic parameters for growth and product formation.
Glucose was the preferred sugar in terms of growth rate and yield, sugar utilisation rate and acetate formation rate, while
lactose gave considerably lower values for these parameters. When present in a mixture with glucose, the rate of lactose utilisation
was lower than when present on its own.
Received: 24 February 1998 / Received revision: 15 April 1998 / Accepted: 19 April 1998 相似文献
10.
N. Uematsu C. Matsuoka Y. Agemizu E. Nagoshi K. Yamamoto 《Molecular & general genetics : MGG》1999,261(3):523-529
The chromosomal tonB gene of Escherichia coli was used as a target for the detection of spontaneous deletion mutations. The deletions were isolated in both recA
+ and recA
− cells, and mutants carrying large deletions were identified because they also lacked part or all of the trp operon. The frequencies of tonB-trp deletion were 1.79 × 10−9 and 1.09 × 10−9 for recA
+ and recA
− cells, respectively. We analyzed 12 deletions from recA
+ and 10 from recA
− cells by cloning and direct sequencing. The deletions ranged in size from 5612 bp to 15142 bp for recA
+ and from 5428 bp to 13289 for recA
− cells. Three deletions from recA
+ cells and five deletions from recA
− cells were found to have occurred between short sequence repeats at the termini of the deletion, leaving one copy of the
repeat in the mutant sequence. Seven deletions from recA
+ cells and three deletions from recA
− cells did not have repeats at their termini; in these cases, the DNA sequences that are adjacent to the deletion termini
in the wild-type are characterized by short (2–4 bp) repeats. From these results, a model is presented for the generation
of deletion mutations which involves formation of an asymmetric crossover mediated by repeated sequences of 2- to 4-bp.
Received: 14 September 1998 / Accepted: 22 December 1998 相似文献
11.
Gnotobiotic systems were used to assess the competitive abilities of bioluminescent Sinorhizobium meliloti strains L1 (RecA−) and L33 (RecA+) for growth and host plant nodulation in the presence of a reconstructed S. meliloti population. Three wild-type strains belonging to infective subgroups of a natural S. meliloti population were chosen as competitors in microcosm studies. Whereas the RecA+ strain L33 dominated the reconstructed population with respect to growth and alfalfa nodulation, the competitiveness of the
RecA− strain L1 was reduced compared to that of one of the field strains, but comparable to that of the other field isolates. This
result indicates that strain L1, despite its recA mutation, has the potential to compete successfully with a resident S. meliloti population after environmental release.
Received: 4 November 1996 / Received revision: 9 January 1997 / Accepted: 17 January 1997 相似文献
12.
L. G. van Waasbergen S. P. Kidambi R. V. Miller 《Applied microbiology and biotechnology》1998,49(1):59-65
A recA mutant was constructed of a soil isolate of Burkholderia cepacia, strain ATCC 17616. Prior to mutagenesis, the recA gene was cloned from this strain by its ability to complement the methyl methanesulfonate sensitivity of an Escherichia coli recA mutant. Sequence analysis of the strain showed high sequence similarity (94% nucleic acid and 99% amino acid identity) with
the recA gene previously cloned from a clinical isolate of B. cepacia, strain JN25. The subcloned recA gene from B. cepacia ATCC 17616 restored UV resistance and recombination proficiency to recA mutants of E. coli and Pseudomonas aeruginosa, as well as restoring the ability of D3 prophages to be induced to lytic growth from a RecA− strain of P. aeruginosa. The recA mutant of B. cepacia ATCC 17616 was constructed by λ-mediated Tn5 mutagenesis of the cloned recA gene in E. coli, followed by replacement of the Tn5-interrupted gene for the wild-type allele in the chromosome of B. cepacia by marker exchange. The RecA− phenotype of the mutant was demonstrated by the loss of UV resistance as compared to the parental strain. Southern hybridization
analysis of chromosomal DNA from the mutant indicated the presence of Tn5 in the recA gene, and the location of the Tn5 insertion in the recA allele was identified by nucleotide sequence analysis. A test using the recA mutant to see if acquired resistance to d-serine toxicity in B. cepacia might be a result of RecA-mediated activities proved negative; nevertheless, RecA activity potentially contributes to the
overall genomic plasticity of B. cepacia and a recA mutant will be useful in bioengineering of this species.
Received: 24 January / Received revision: 11 July 1997 / Accepted: 25 August 1997 相似文献
13.
The effect on nisin production of increasing nisin immunity/resistance genes in Lactococcus lactis subsp. lactis MG1363 was investigated. The 60-kb nisin immunity/resistance plasmid pND300, which was isolated from a non-nisin-producing
strain, encodes five genes involved in nisin immunity/resistance, which are very similar to those of the immunity/resistance
system encoded by the nisin-production transposon. The introduction of pND300 into MG1363(TnNip) resulted in the construct being able to produce significantly more nisin than the parent MG1363(TnNip). The introduction of pND314, which contains the nisin immunity/resistance genes subcloned into pSA3, into MG1363(TnNip) allowed the strain to grow more rapidly than the parent MG1363(TnNip) with a concomitant increase in the rate of nisin production. This work illustrates that introduction of pND300 and a derivative
containing the nisin immunity/resistance system of pND300 into MG1363 (TnNip) can result in significant alterations to the kinetics of nisin production. These observations indicate approaches that may
be used successfully to improve the economics of nisin production.
Received: 11 February 1998 / Received revision: 25 June 1998 / Accepted: 27 June 1998 相似文献
14.
Murai T Ueda M Shibasaki Y Kamasawa N Osumi M Imanaka T Tanaka A 《Applied microbiology and biotechnology》1999,51(1):65-70
The construction of a whole-cell biocatalyst with its sequential reaction has been performed by the genetic immobilization
of two amylolytic enzymes on the yeast cell surface. A recombinant strain of Saccharomyces cerevisiae that displays glucoamylase and α-amylase on its cell surface was constructed and its starch-utilizing ability was evaluated.
The gene encoding Rhizopus oryzae glucoamylase, with its own secretion signal peptide, and a truncated fragment of the α-amylase gene from Bacillus stearothermophilus with the prepro secretion signal sequence of the yeast α factor, respectively, were fused with the gene encoding the C-terminal
half of the yeast α-agglutinin. The constructed fusion genes were introduced into the different loci of chromosomes of S. cerevisiae and expressed under the control of the glyceraldehyde-3-phosphate dehydrogenase promoter. The glucoamylase and α-amylase
activities were not detected in the culture medium, but in the cell pellet fraction. The transformant strain co-displaying
glucoamylase and α-amylase could grow faster on starch as the sole carbon source than the transformant strain displaying only
glucoamylase.
Received: 16 June 1998 / Received last revision: 21 August 1998 / Accepted: 3 September 1998 相似文献
15.
Shaw-Reid CA McCormick MM Sinskey AJ Stephanopoulos G 《Applied microbiology and biotechnology》1999,51(3):325-333
The N-succinyl-ll-diaminopimelate desuccinylase gene (dapE) in the four-step succinylase branch of the l-lysine biosynthetic pathway of Corynebacterium glutamicum was disrupted via marker-exchange mutagenesis to create a mutant strain that uses only the one-step meso-diaminopimelate dehydrogenase branch to overproduce lysine. This mutant strain grew and utilized glucose from minimal medium
at the same rate as the parental strain. In addition, the dapE
−
strain produced lysine at the same rate as its parent strain. Transformation of the parental and dapE
−
strains with the amplified meso-diaminopimelate dehydrogenase gene (ddh) on a plasmid did not affect lysine production in either strain, despite an eightfold amplification of the activity of the
enzyme. These results indicate that the four-step succinylase pathway is dispensable for lysine overproduction in shake-flask
culture. In addition, the one-step meso-diaminopimelate dehydrogenase pathway does not limit lysine flux in Corynebacterium under these conditions.
Received: 20 May 1998 / Received revision: 12 August 1998 / Accepted: 3 September 1998 相似文献
16.
F. Laborda I. F. Monistrol N. Luna M. Fernández 《Applied microbiology and biotechnology》1999,52(1):49-56
Several fundamental aspects of microbial coal liquefaction/solubilization were studied. The liquefied/solubilized products
from coal by microorganisms were analysed. The liquid products analysed by IR titration and UV/visible spectrometry showed
some alterations with regard to the original coal. Humic acids extracted from the liquefied lignite showed a reduction in
the average molecular weight and a increase in the condensation index, probably due to depolymerization caused by microorganisms.
The mechanisms implicated in coal biosolubilization by two fungal strains, M2 (Trichoderma sp.) and M4 (Penicillium sp.) were also studied. Extracellular peroxidase, esterase and phenoloxidase enzymes appear to be involved in coal solubilization.
Received: 15 June 1998 / Received revision: 23 November 1998 / Accepted: 29 November 1998 相似文献
17.
Cometabolic biodegradation of methyl t-butyl ether by Pseudomonas aeruginosa grown on pentane 总被引:1,自引:0,他引:1
A bacterial strain identified as Pseudomonas aeruginosa was isolated from a soil consortium able to mineralize pentane. P. aeruginosa could metabolize methyl t-butyl ether (MTBE) in the presence of pentane as the sole carbon and energy source. The carbon balance for this strain, grown
on pentane, was established in order to determine the fate of pentane and the growth yield (0.9 g biomass/g pentane). An inhibition
model for P. aeruginosa grown on pentane was proposed. Pentane had an inhibitory effect on growth of P. aeruginosa, even at a concentration as low as 85 μg/l. This resulted in the calculation of the following kinetic parameters (μmax = 0.19 h−1, K
s = 2.9 μg/l, K
i = 3.5 mg/l). Finally a simple model of MTBE degradation was derived in order to predict the quantity of MTBE able to be degraded
in batch culture in the presence of pentane. This model depends only on two parameters: the concentrations of pentane and
MTBE.
Received: 16 July 1998 / Received revision: 11 November 1998 / Accepted 31 November 1998 相似文献
18.
Isolation and characterization of a 2-methylphenanthrene utilizing bacterium: identification of ring cleavage metabolites 总被引:1,自引:0,他引:1
J. Sabaté M. Grifoll M. Viñas A. M. Solanas 《Applied microbiology and biotechnology》1999,52(5):704-712
A bacterial strain capable of utilizing 2-methylphenanthrene (2-MP) as its sole source of carbon and energy for growth was
isolated from creosote contaminated soil. The isolate was identified as a strain of Sphingomonas sp. and was designated strain JS5. Utilization of 2-MP by strain JS5 was demonstrated by an increase in bacterial biomass
concomitant with a decrease of 2-MP in liquid mineral medium with this compound as sole source of carbon and energy. Growth
yield indicated a 23% assimilation of 2-MP carbon. Washed-cell suspensions of strain JS5 incubated with 2-MP accumulated a
major metabolite identified as 1-hydroxy-6-methyl-2-naphtoic acid, according to its UV, mass and NMR spectra, and a minor
compound with HPLC R
t
and UV spectrum indistinguishable from 5-methylsalicylate. The identification of those metabolites, and the demonstration
of 2,3-catechol dioxygenase activity in 2-MP induced cells show that the biodegradation of 2-MP by strain JS5 is initiated
via dioxygenation and meta-cleavage of the non-methylated aromatic ring, and then proceeds by reactions similar to those reported for phenanthrene.
Incubation of the strain with a MP-containing mixture from a pyrolytic fuel oil demonstrates that strain JS5 also acts on
other methylated phenanthrenes.
Received: 28 December 1998 / Received revision: 21 June 1999 / Accepted: 27 June 1999 相似文献
19.
Manipulation of the DNA coding for the desulphurizing activity in a new isolate of Arthrobacter sp. 总被引:3,自引:0,他引:3
A new bacterial strain able to cleave CS bonds from organosulphur heterocyclic compounds through the 4-S pathway and tentatively
classified as Arthrobacter sp. was recently isolated. In the present short article we describe the cloning and the characterization of the DNA encoding
the enzymes responsible for desulphurization in this microorganism, referred to as Arthrobacter sp. DS7. The desulphurization operon was found to be located in a large plasmid that also bears the genes conferring cadmium
and arsenic resistance. By shortening this plasmid, a new cloning vector was prepared and used to obtain a recombinant derivative
strain that desulphurizes dibenzothiophene despite of the presence of inorganic sulphur in the growth medium.
Received: 25 May 1998 / Received revision: 4 September 1998 / Accepted: 13 September 1998 相似文献
20.
Poly-(3-hydroxybutyrate) production from whey by high-density cultivation of recombinant Escherichia coli 总被引:2,自引:0,他引:2
Recombinant Escherichia coli strain GCSC 6576, harboring a high-copy-number plasmid containing the Ralstonia eutropha genes for polyhydroxyalkanoate (PHA) synthesis and the E. coli ftsZ gene, was employed to produce poly-(3-hydroxybutyrate) (PHB) from whey. pH-stat fed-batch fermentation, using whey powder
as the nutrient feed, produced cellular dry weight and PHB concentrations of 109 g l−1 and 50 g l−1 respectively in 47 h. When concentrated whey solution containing 210 g l−1 lactose was used as the nutrient feed, cellular dry weight and PHB concentrations of 87 g l−1 and 69 g l−1 respectively could be obtained in 49 h by pH-stat fed-batch culture. The PHB content was as high as 80% of the cellular dry
weight. These results suggest that cost-effective production of PHB is possible by fed-batch culture of recombinant E. coli using concentrated whey solution as a substrate.
Received: 19 December 1997 / Received revision: 17 March 1998 / Accepted: 20 March 1998 相似文献