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1.
P. Arvidsson K. Nilsson H. Håkanson B. Mattiasson 《Applied microbiology and biotechnology》1998,49(6):677-681
A chemiluminescence detector was used to measure the production of nitric oxide, NO, from the denitrifying bacteria Pseudomonas stutzeri. NO is an intermediate when P. stutzeri converts nitrate into nitrogen gas. The reaction between NO and ozone is selective and sensitive in generating chemiluminescence.
Calibrations were made down to 1 nM, with a signal-to-noise ratio of 3. Bacteria were immobilised in alginate beads. Denitrification
experiments were made in an anaerobic non-growth medium by adding nitrate to a certain concentration in the reactor. The bacteria
were exposed to nitrate in the concentration range 1 pM–5 mM. The lowest concentration to give a measurable NO response was
100 nM.
Received: 16 October 1997 / Received revision: 20 January 1998 / Accepted: 24 January 1998 相似文献
2.
Novotný C Erbanová P Cajthaml T Rothschild N Dosoretz C Sasek V 《Applied microbiology and biotechnology》2000,54(6):850-853
Growth parameters, ligninolytic enzyme activities and ability to degrade polycyclic aromatic hydrocarbons by the fungus Irpex lacteus were characterized and compared with those of other white rot fungi capable of rapid decolorization of poly R-478 and Remazol
Brilliant Blue R dyes. I. lacteus was able to grow on mineral and complex media and efficiently colonized sterile and non-sterile soil by exploratory mycelium
growing from a wheat straw inoculum. In shallow stationary cultures growing on high nitrogen mineral medium containing 45 mM
ammonium as nitrogen source, the fungus produced lignin peroxidase (LIP), Mn-dependent peroxidase (MnP) and laccase simultaneously,
the respective maximal activities of 70, 970 and 36 U/l being attained around day 18. Growing in nitrogen-limited medium (2.4 mM
ammonium), no LIP was formed and levels of MnP and laccase decreased significantly. During growth in sterile soil, the fungus
synthesized LIP and laccase but not MnP. I. lacteus efficiently removed three- and four-ringed PAHs from liquid media and artificially spiked soil. The variety of ligninolytic
enzymes, robust growth, capability of soil colonization and resistance to inhibitory action of soil bacteria make I. lacteus a suitable fungal organism for use in bioremediation.
Received: 30 March 2000 / Accepted: 19 May 2000 相似文献
3.
Lignite (brown coal) can be liquefied/solubilized with several fungi by different mechanisms. When applied industrially,
only catalytic mechanisms can compete with chemical methods. The well-known fungal ligninolytic peroxidases are at a disadvantage,
in that the relatively expensive hydrogen peroxide must be used as a cofactor. Comparing several fungal strains, we observed
that the fungus Trametes versicolor is able to decolorize coal-derived humic acids, producing a considerable amount of laccase in the process. During this reaction
the amount of humic acids decreases whilst that of fulvic acids increases; this was verified by optical density measurement
and GPC after the two substance classes had been separated.
Received: 27 August 1998 / Received revision: 4 November 1998 / Accepted: 7 November 1998 相似文献
4.
The majority of lignin-degrading basidiomycetes are able to depolymerize humic acids. In this presentation the relationship
and possible similarities between enzymes involved in lignin degradation and humic acid depolymerization were examined on
the genetic level. We have cloned fragments of the gene encoding the extracellular ligninolytic enzyme laccase from Clitocybula dusenii, Nematoloma frowardii and a fungal strain designated i63-2, and compared the three sequences with those of several other published laccase genes.
The sequenced fragments displayed a high homology both on the DNA (97%–77%) and amino acid (100%–85%) level. Furthermore,
the expression of this gene in the above-mentioned fungi was demonstrated by a nested polymerase chain reaction with cDNA
as template.
Received: 3 February 1998 / Received revision: 31 August 1998 / Accepted: 3 September 1998 相似文献
5.
Respiratory and fermentative pathways co-exist to support growth and product formation in Pichia stipitis. This yeast grows rapidly without ethanol production under fully aerobic conditions, and it ferments glucose or xylose under
oxygen-limited conditions, but it stops growing within one generation under anaerobic conditions. Expression of Saccharomyces cerevisiaeURA1 (ScURA1) in P. stipitis enabled rapid anaerobic growth in minimal defined medium containing glucose when essential lipids were present. ScURA1 encodes a dihydroorotate dehydrogenase that uses fumarate as an alternative electron acceptor to confer anaerobic growth.
Initial P. stipitis transformants grew and produced 32 g/l ethanol from 78 g/l glucose. Cells produced even more ethanol faster following two
anaerobic serial subcultures. Control strains without ScURA1 were incapable of growing anaerobically and showed only limited fermentation. P. stipitis cells bearing ScURA1 were viable in anaerobic xylose medium for long periods, and supplemental glucose allowed cell growth, but xylose alone could
not support anaerobic growth even after serial anaerobic subculture on glucose. These data imply that P. stipitis can grow anaerobically using metabolic energy generated through fermentation but that it exhibits fundamental differences
in cofactor selection and electron transport with glucose and xylose metabolism. This is the first report of genetic engineering
to enable anaerobic growth of a eukaryote.
Received: 6 January 1998 / Received revision: 9 April 1998 / Accepted: 19 April 1998 相似文献
6.
The agaric basidiomycete Clitocybula dusenii was used for the production of the extracellular ligninolytic enzyme, manganese (Mn) peroxidase. An immobilization technique
is described using cellulose and polypropylene as carrier for the fungal mycelium. High amounts of Mn peroxidase were obtained
with agitated cultures of immobilized fungus (up to 3,000 U l−1) while the biomass was recovered and used for further production cycles. Purification of Mn peroxidase revealed the existence
of two forms: MnP1 (molecular mass 43 kDa, pI 4.5) and MnP2 (42 kDa, pI 3.8).
Received: 30 July 1999 / Received revision: 1 December 1999 / Accepted: 3 December 1999 相似文献
7.
The production of ligninolytic enzymes was studied in surface cultures of the South American white-rot fungus Nematoloma frowardii b19 and four other strains of this ecophysiological group (Clitocybula dusenii b11, Auricularia sp. m37a, wood isolates u39 and u45), which are able to depolymerize low-rank-coal-derived humic acids with the formation
of fulvic-acid-like compounds. The fungi produced the three crucial enzymes of lignin degradation – lignin peroxidase, manganese
peroxidase and laccase. In the case of N. frowardii b19, laccase and the two peroxidases could be stimulated by veratryl alcohol. Manganese (II) ions (Mn2+) caused a rapid increase of Mn peroxidase activity accompanied by the complete repression of lignin peroxidase. Under nitrogen-limited
conditions the growth as well as the production of ligninolytic enzymes was partly repressed. During the depolymerization
process of coal humic acids using solid agar media, gradients of ligninolytic enzyme activities toward 2,2′-azinobis(3-ethylbenzthiazoline-6-sulphonate)
and syringaldazine were detectable inside the agar medium.
Received: 5 August 1996 / Received revision: 13 November 1996 / Accepted: 15 November 1996 相似文献
8.
C. Suresh A. K. Dubey S. Srikanta S. Umesh Kumar N. G. Karanth 《Applied microbiology and biotechnology》1999,51(5):673-675
A UV-induced mutant strain of Aspergillus niger (CFTRI-1105-U9) overproduced a starch-hydrolysing enzyme with properties characteristically different from the known amylases
of the fungus. The purified enzyme of 4.0 pI had an apparent molecular mass of 125 kDa and it dextrinised starch and then
saccharified the dextrins. Patterns of the enzyme activity on starch, resulting in glucose at 60 °C and glucose, maltose and
maltodextrins at 70 °C as primary products, suggested significant applications for the enzyme in starch-processing industries.
Received: 29 October 1998 / Received revision: 11 January 1999 / Accepted: 19 January 1999 相似文献
9.
Two coals of different rank, mined in Russia, were treated by an anaerobic methanogenic enrichment culture. The addition
of alkaline enclosing rock to the lower-rank coal increased the pH of the incubation medium and methane production above that
of the higher-rank coal with addition of its enclosing rock. This effect was accompanied by the leaching of cations from the
incubation medium. The coal was processed without a preliminary chemical treatment in a two-stage aerobic/anaerobic bioreactor
containing an anaerobic methanogenic granulated enrichment culture.
Received: 15 January 1998 / Received revision: 2 October 1998 / Accepted: 2 October 1998 相似文献
10.
G Feijoo M T Moreira E Roca J M Lema 《Journal of industrial microbiology & biotechnology》1999,23(2):86-90
Manganese peroxidase, MnP, is one of the major ligninolytic enzymes produced by a number of white-rot fungi. The ability of
this enzyme to degrade lignin by the fungus Bjerkanderasp BOS55 has opened its application to related bioprocesses such as recalcitrant-compound degradation and effluent decolorization.
The medium reported to induce MnP production is composed of chemical grade reagents, all with relatively high costs for application
to detoxification purposes. The use of inexpensive sources for MnP production can bring its implementation closer. For this
purpose, dairy residues from cheese processing were considered. MnP production obtained using crude whey as the sole substrate
reached appreciable levels, around 190 U L−1, values comparable to those found with synthetic media (between 175–250 U L−1). Thus, this cheese-processing byproduct can be used as an inexpensive alternative for the large-scale production of MnP.
Received 14 December 1998/ Accepted in revised form 29 April 1999 相似文献
11.
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
12.
Towards a high-yield bioconversion of ferulic acid to vanillin 总被引:13,自引:2,他引:11
Natural vanillin is of high interest in the flavor market. Microbial routes to vanillin have so far not been economical as
the medium concentrations achieved have been well below 1 g l−1. We have now screened microbial isolates from nature and known strains for their ability to convert eugenol or ferulic acid
into vanillin. Ferulic acid, in contrast to the rather toxic eugenol, was found to be an excellent precursor for the conversion
to vanillin, as doses of several g l−1 could be fed. One of the isolated microbes, later identified as Pseudomonas putida, very efficiently converted ferulic acid to vanillic acid. As vanillin was oxidized faster than ferulic acid, accumulation
of vanillin as an intermediate was not observed. A completely different metabolic flux was observed with Streptomyces setonii. During the metabolism of ferulic acid, this strain accumulated vanillic acid only to a level of around 200 mg l−1 and then started to accumulate vanillin as the principal metabolic overflow product. In shake-flask experiments, vanillin
concentrations of up to 6.4 g l−1 were achieved with a molar yield of 68%. This high level now forms the basis for an economical microbial production of vanillin
that can be used for flavoring purposes.
Received: 15 October 1998 / Received revision: 13 January 1999 / Accepted: 18 January 1999 相似文献
13.
Antimould activity of sourdough lactic acid bacteria: identification of a mixture of organic acids produced by Lactobacillus sanfrancisco CB1 总被引:1,自引:0,他引:1
A. Corsetti M. Gobbetti J. Rossi P. Damiani 《Applied microbiology and biotechnology》1998,50(2):253-256
Sourdough lactic acid bacteria, cultivated in wheat flour hydrolysate, produced antimould compounds. The antimould activity
varied greatly among the strains and was mainly detected within obligately heterofermentative Lactobacillus spp. Among these, Lb. sanfrancisco CB1 had the largest spectrum. It inhibited moulds related to bread spoilage such as Fusarium, Penicillium, Aspergillus and Monilia. A mixture of acetic, caproic, formic, propionic, butyric and n-valeric acids, acting in a synergistic way, was responsible for the antimould activity. Caproic acid played a key role in
inhibiting mould growth.
Received: 20 January 1998 / Received revision: 17 April 1998 / Accepted: 27 April 1998 相似文献
14.
Biotechnology of succinic acid production and markets for derived industrial products 总被引:29,自引:4,他引:25
Succinic acid, derived from fermentation of agricultural carbohydrates, has a specialty chemical market in industries producing
food and pharmaceutical products, surfactants and detergents, green solvents and biodegradable plastics, and ingredients to
stimulate animal and plant growth. As a carbon-intermediate chemical, fermentation-derived succinate has the potential to
supply over 2.7 × 108 kg industrial products/year including: 1,4-butanediol, tetrahydrofuran, γ-butyrolactone, adipic acid, n-methylpyrrolidone and linear aliphatic esters. Succinate yields as high as 110 g/l have been achieved from glucose by the
newly discovered rumen organism Actinobacillus succinogenes. Succinate fermentation is a novel process because the greenhouse gas CO2 is fixed into succinate during glucose fermentation. New developments in end-product recovery technology, including water-splitting
electrodialysis and liquid/liquid extraction have lowered the cost of succinic acid production to U.S. $ 0.55/kg at the 75 000
tonne/year level and to $ 2.20/kg at the 5000 tonne/year level. Research directions aimed at further improving the succinate
fermentation economics are discussed.
Received: 27 October 1998 / Received revision: 22 January 1999 / Accepted: 22 January 1999 相似文献
15.
T. Yokochi D. Honda T. Higashihara T. Nakahara 《Applied microbiology and biotechnology》1998,49(1):72-76
Culture conditions of Schizochytrium limacinum SR21 for the purpose of microbial docosahexaenoic acid (DHA) production were investigated. The strain SR21 showed a wide
tolerance to salinity; that is, the optimum salinity was between 50% and 200% that of sea water. Monosaccharides (glucose
and fructose) and glycerol supported good cell growth and DHA yield. Di- and polysaccharides, oleic acid, and linseed oil
gave low DHA yields. A high content of DHA (more than 30% of total fatty acids) was obtained from culture on glucose, fructose,
and glycerol, and also the strain had simple polyunsaturated fatty acid profiles. The major polyunsaturated fatty acids other
than DHA were n-6 docosapentaenoic acid only, and the contents of icosapentaenoic acid and arachidonic acid were less than 1%. Using corn
steep liquor as a nitrogen source, a high total fatty acid content was obtained. The total fatty acid content in the dry cell
weight increased as the concentration of the nitrogen source decreased, reached more than 50%. An increase in carbon source
concentration led to a high DHA yield. A maximum DHA yield of more than 4 g/l was obtained in both glucose and glycerol media
at 9% and 12% respectively. S. limacinum SR21 was thought to be a promising resource for microbial DHA production yielding a good level of productivity as well as
a simple polyunsaturated fatty acid profile.
Received: 26 June 1997 / Received revision: 29 August 1997 / Accepted: 19 September 1997 相似文献
16.
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
17.
Mineralisation of 14C-labelled synthetic lignin and ligninolytic enzyme activities of litter-decomposing basidiomycetous fungi 总被引:4,自引:0,他引:4
Within a screening program, 27 soil litter-decomposing basidiomycetes were tested for ligninolytic enzyme activities using
agar-media containing 2,2′-azinobis(3-ethylbenzthiazoline-6-sulphonate), a humic acid or Mn2+ ions as indicator substrates. Most active species were found within the family Strophariaceae (Agrocybe praecox, Stropharia coronilla, S. rugosoannulata) and used for mineralisation experiments with a 14C-ring-labelled synthetic lignin (14C-DHP). The fungi mineralised around 25% of the lignin to 14CO2 within 12 weeks of incubation in a straw environment; about 20% of the lignin was converted to water-soluble fragments. Mn-peroxidase
was found to be the predominant ligninolytic enzyme of all three fungi in liquid culture and its production was strongly enhanced
in the presence of Mn2+ ions. The results of this study demonstrate that certain ubiquitous litter-decomposing basidiomycetes possess ligninolytic
activities similar to the wood-decaying white-rot fungi, the most efficient lignin degraders in nature.
Received: 20 April 2000 / Received revision: 12 July 2000 / Accepted: 16 July 2000 相似文献
18.
Detoxification of wood hydrolysates with laccase and peroxidase from the white-rot fungus Trametes versicolor 总被引:1,自引:0,他引:1
L. J. Jönsson E. Palmqvist N.-O. Nilvebrant B. Hahn-Hägerdal 《Applied microbiology and biotechnology》1998,49(6):691-697
Fermentation of wood hydrolysates to desirable products, such as fuel ethanol, is made difficult by the presence of inhibitory
compounds in the hydrolysates. Here we present a novel method to increase the fermentability of lignocellulosic hydrolysates:
enzymatic detoxification. Besides the detoxification effect, treatment with purified enzymes provides a new way to identify
inhibitors by assaying the effect of enzymatic attack on specific compounds in the hydrolysate. Laccase, a phenol oxidase,
and lignin peroxidase purified from the ligninolytic basidiomycete fungus Trametes versicolor were studied using a lignocellulosic hydrolysate from willow pretreated with steam and SO2. Saccharomyces cerevisiae was employed for ethanolic fermentation of the hydrolysates. The results show more rapid consumption of glucose and increased
ethanol productivity for samples treated with laccase. Treatment of the hydrolysate with lignin peroxidase also resulted in
improved fermentability. Analyses by GC-MS indicated that the mechanism of laccase detoxification involves removal of monoaromatic
phenolic compounds present in the hydrolysate. The results support the suggestion that phenolic compounds are important inhibitors
of the fermentation process.
Received: 3 November 1997 / Received revision: 4 February 1998 / Accepted: 6 February 1998 相似文献
19.
Production of ligninolytic enzymes and synthetic lignin mineralization by the bird's nest fungus Cyathus stercoreus 总被引:3,自引:0,他引:3
Production of ligninolytic enzymes and degradation of 14C-ring labeled synthetic lignin by the white-rot fungus Cyathus stercoreus ATCC 36910 were determined under a variety of conditions. The highest mineralization rate for 14C dehydrogenative polymerizates (DHP; 38% 14CO2 after 30 days) occurred with 1 mM ammonium tartrate as nitrogen source and 1% glucose as additional carbon source, but levels
of extracellular laccase and manganese peroxidase (MnP) were low. In contrast, 10 mM ammonium tartrate with 1% glucose gave
low mineralization rates (10% 14CO2 after 30 days) but higher levels of laccase and manganese peroxidase. Lignin peroxidase was not produced by C. stercoreus under any of the studied conditions. Mn(II) at 11 ppm gave a higher rate of 14C DHP mineralization than 0.3 or 40 ppm, but the highest manganese peroxidase level was obtained with Mn(II) at 40 ppm. Cultivation
in aerated static flasks gave rise to higher levels of both laccase and manganese peroxidase compared to the levels in shake
cultures. 3,4-Dimethoxycinnamic acid at 500 μM concentration was the most effective inducer of laccase of those tested. The
purified laccase was a monomeric glycoprotein having an apparent molecular mass of 70 kDa, as determined by calibrated gel
filtration chromatography. The pH optimum and isoelectric point of the purified laccase were 4.8 and 3.5, respectively. The
N-terminal amino acid sequence of C. stercoreus laccase showed close homology to the N-terminal sequences determined from other basidiomycete laccases. Information on C. stercoreus, whose habitat and physiological requirements for lignin degradation differ from many other white-rot fungi, expands the
possibilities for industrial application of biological systems for lignin degradation and removal in biopulping and biobleaching
processes.
Received: 29 January 1999 / Received revision: 5 July 1999 / Accepted: 9 July 1999 相似文献
20.
Y. Shiba F. Fukui K. Ichikawa N. Serizawa H. Yoshikawa 《Applied microbiology and biotechnology》1998,50(1):34-41
In order to develop a production process for carboxypeptidase Y (CPY, yeast vacuolar protease) secreted by Saccharomyces cerevisiae KS58-2D, medium composition, culture conditions, and expression systems were investigated. We found that the addition of
histidine to thiamine-free medium, in which CPY production was almost negligible, raised the intracellular thiamine level,
resulting in the increase of CPY production. On the basis of the choice of an expression system that uses an inducible GAL10 promoter, reassessment of histidine concentration in the medium, and optimization of the pH level during cultivation (pH
6.5), active CPY was secreted in a quantity of over 400 mg/l, which was more than tenfold that higher than that previously
reported. The process developed could be easily scaled-up to industrial-scale fermentation.
Received: 16 January 1998 / Received revision: 16 February 1998 / Accepted: 27 February 1998 相似文献