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1.
Degradation of styrene by white-rot fungi 总被引:2,自引:0,他引:2
A. Braun-Lüllemann A. Majcherczyk A. Hüttermann 《Applied microbiology and biotechnology》1997,47(2):150-155
Degradation of styrene in the gaseous phase was investigated for white-rot fungi Pleurotus ostreatus (two strains), Trametes versicolor, Bjerkandera adusta and Phanerochaete chrysosporium. Fungi were grown in liquid culture and the gas/mycelium contact surface was enhanced with the help of perlite. The influence
of various inducers on styrene degradation was studied. The best inducers for styrene degradation were lignosulphonate for
P. ostreatus and T. versicolor and wood meal for B. adusta and P. chrysosoporium. Under these conditions all fungi were able to degrade styrene almost completely in 48 h at a concentration of 44 μmol/250 ml
total culture volume; one strain of P. ostreatus was able to remove 88 μmol styrene under these conditions. Three transformation products of [14C]styrene in cultures of P. ostreatus were identified: phenyl-1,2-ethanediol, 2-phenylethanol and benzoic acid; 4% of the styrene was metabolised to CO2 in 24 h and no other volatile products were found.
Received: 16 July 1996 / Received revision: 23 September 1996 / Accepted: 29 September 1996 相似文献
2.
The white-rot basidiomycete Phanerochaete chrysosporium BKM-F-1767 was tested for its capacity to degrade dehydroabietic acid (DHA). In anaerobic treatment, this molecule is the
most recalcitrant member of the resin acid group, which is known to cause operational problems to anaerobic reactors treating
pulp and paper industry wastewaters. In this study the effect of DHA on different parameters, such as growth, ligninolytic
enzyme activity, extracellular protein production as well as both glycerol and ammonium consumption by the fungus, was determined.
Although the above parameters were affected by the addition of DHA, the results show that the fungus could still produce significant
titres of ligninolytic enzymes. The fungus removed 47% of the DHA initially present in the static culture, after 10 days of
incubation. Anaerobic toxicity assays showed that the treatment of DHA with P. chrysosporium reduced the methanogenesis and acetogenesis inhibition caused by DHA and allowed improved methane production by the anaerobic
bacteria.
Received: 10 June 1997 / Received revision: 6 January 1998 / Accepted: 24 January 1998 相似文献
3.
The white-rot fungus Phanerochaete chrysosporium can degrade macromolecules in low-rank coal, offering the potential for converting coal to specific products. We investigated
the influence of temperature, veratryl alcohol and oxygen on transformation of a solubilised fraction of Morwell brown coal
(SWC6 coal) and on the activity of lignin peroxidase and manganese (Mn) peroxidase in N-limited cultures of P. chrysosporium. After 20 days, the mass and A
400 of SWC6 coal recovered from cultures containing 0.03% SWC6 coal, incubated at 28 °C under hyperbaric oxygen, were reduced
by over 95%. The modal apparent molecular mass of the residuum was reduced by 50%. Addition of 2 mM veratryl alcohol had little
effect on the transformation of SWC6 coal. The extent of transformation was reduced in cultures incubated at 37 °C or under
air. In cultures under air, coal molecules were transiently polymerised. Decolourisation of SWC6 coal reflects conversion
to products that cannot be recovered from the medium, not the destruction of chromophores within recoverable material. The
activity of lignin peroxidase, measured in cultures free of SWC6 coal to avoid interference with the assay, correlates directly
with the degradation of SWC6 coal as measured by the decline in A
400. The data suggest that lignin peroxidase is more important than Mn peroxidase in converting SWC6 coal to products that are
assimilated by cells.
Received: 16 July 1997 / Received revision: 14 November 1997 / Accepted: 18 November 1997 相似文献
4.
Saayman M van Vuuren HJ van Zyl WH Viljoen-Bloom M 《Applied microbiology and biotechnology》2000,54(6):792-798
The dicarboxylic acid fumarate is an important intermediate in cellular processes and also serves as a precursor for the
commercial production of fine chemicals such as l-malate. Yeast species differ remarkably in their ability to degrade extracellular dicarboxylic acids and to utilise them
as their only source of carbon. In this study we have shown that the yeast Candida utilis effectively degraded extracellular fumarate and l-malate, but glucose or other assimilable carbon sources repressed the transport and degradation of these dicarboxylic acids.
The transport of both dicarboxylic acids was shown to be strongly inducible by either fumarate or l-malate while kinetic studies suggest that the two dicarboxylic acids are transported by the same transporter protein. In
contrast, Schizosaccharomyces pombe effectively degraded extracellular l-malate, but not fumarate, in the presence of glucose or other assimilable carbon sources. The Sch. pombe malate transporter was unable to transport fumarate, although fumarate inhibited the uptake of l-malate.
Received: 15 March 2000 / Received revision: 4 July 2000 / Accepted: 9 July 2000 相似文献
5.
The white-rot fungi Trametes versicolor PRL 572, Trametes versicolor MUCL 28407, Pleurotus ostreatus MUCL 29527, Pleurotus sajor-caju MUCL 29757 and Phanerochaete chrysosporium DSM 1556 were investigated for their ability to degrade the polycyclic aromatic hydrocarbons (PAH) anthracene, benz[a]anthracene and dibenz[a,h]anthracene in soil. The fungi were grown on wheat straw and mixed with artificially contaminated soil. The results of this
study show that, in a heterogeneous soil environment, the fungi have different abilities to degrade PAH, with Trametes showing little or no accumulation of dead-end metabolites and Phanerochaete and Pleurotus showing almost complete conversion of anthracene to 9,10-anthracenedione. In contrast to earlier studies, Phanerochaete showed the ability to degrade the accumulated 9,10-anthracenedione while Pleurotus did not. This proves that, in a heterogeneous soil system, the PAH degradation pattern for white-rot fungi can be quite different
from that in a controlled liquid system.
Received: 20 March 1996 / Received revision: 2 July 1996 / Accepted: 8 July 1996 相似文献
6.
Indirect evidence has suggested that lignin peroxidase (LiP) of the white-rot fungus Phanerochaete chrysosporium catalyses oxidative decolourisation and depolymerisation of macromolecules from brown coal in vivo. In this study we show
that LiP catalyses these transformations in vitro. Unmethylated (USC45 coal) and methylated (MWSC6 coal) fractions of solubilised
macromolecules (M
r > 30 000) from a brown coal were treated with a semi-purified preparation of LiP isozymes from P. chrysosporium. Both coal fractions were decolourised, losing between 26% and 39% of their absorbance at both 280 nm and 400 nm, in reactions
that had an absolute requirement for H2O2 and veratryl alcohol. Neither coal fraction was transformed when the enzyme was heat-inactivated or in the presence of the
LiP inhibitor metavanadate. Gel-permeation chromatography showed that MWSC6 coal but not USC45 was depolymerised and yielded
low-molecular-mass (M
r < 30 000) fragments. Nine monomeric products were identified by GC-MS.
Received: 20 March 1998 / Received revision: 3 September 1998 / Accepted: 3 September 1998 相似文献
7.
Eighteen fungal strains, known for their ability to degrade lignocellulosic material or lignin derivatives, were screened
for their potential to decolorize commercially used reactive textile dyes. Three azo dyes, Reactive Orange 96, Reactive Violet
5 and Reactive Black 5, and two phthalocyanine dyes, Reactive Blue 15 and Reactive Blue 38, were chosen as representatives
of commercially used reactive dyes. From the 18 tested fungal strains only Bjerkandera adusta, Trametes versicolor and Phanerochaete chrysosporium were able to decolorize all the dyes tested. During degradation of the nickel-phthalocyanine complex, Reactive Blue 38, by B. adusta and T. versicolor respectively, the toxicity of this dye to Vibrio fischeri was significantly reduced. In the case of Reactive Violet 5, a far-reaching detoxification was achieved by treatment with
B. adusta. Reactive Blue 38 and Reactive Violet 5 were decolorized by crude exoenzyme preparations from T. versicolor and B. adusta in a H2O2-dependent reaction. Specific activities of the exoenzyme preparations with the dyes were determined and compared to oxidation
rates by commercial horseradish peroxidase.
Received: 3 February 1997 / Received revision: 9 April 1997 / Accepted: 13 April 1997 相似文献
8.
The isopenicillin N synthases isolated thus far are related to oxidases from other microorganisms and plants. These enzymes
maintain a non-heme monoferrous-dependent catalytic centre comprising a HisXAsp(53–57)XHis motif and a crucial substrate-binding pocket with an ArgXSer motif for their functionality. The elucidation of these motifs was dependent on information collated from studies on structural
chemistry, structural biology, site-directed engineered mutations and biochemical experiments. It is envisaged that these
enzymes can potentially be improved through molecular breeding and protein engineering.
Received: 15 December 1999 / Received revision: 26 January 2000 / Accepted: 27 January 2000 相似文献
9.
Microbial and cytoplasmic membrane-based potentiometric biosensors for direct determination of organophosphorus insecticides 总被引:1,自引:0,他引:1
Potentiometric biosensors for the determination of organophosphorus (OP) insecticides were developed by applying either immobilized
whole cells or cytoplasmic membrane fractions of wild-type Flavobacterium sp. on the surface of a glass pH electrode. The ability of Flavobacterium sp. to degrade OP compounds as sole carbon source was demonstrated for parathion with a degradation rate of almost 100% after
30 min and for chlorpyrifos of 33% after 48 h incubation. The products of hydrolysis of these compounds, p-nitrophenol and 3,5,6-trichloro-2-pyridinol, were accumulated in the medium and not used as substrates for growth by Flavobacterium sp. In the course of hydrolysis, which is catalyzed by organophosphorus hydrolase, two protons are released for each substrate
molecule hydrolyzed. This stoichiometry forms the electrochemical basis of the potentiometric biosensors. Direct determination
without previous extraction of OP was carried out in a stirred measuring cell with a pH electrode as transducer. Poly(carbamoyl
sulfonate) (PCS) prepolymer, a hydrogel with good adhesive properties, was used for immobilization of whole cells and membrane-associated
organophosphorus hydrolase. The sensor with cytoplasmic membrane fractions was superior to the one with whole cells and showed
a linear range for paraoxon from 0.01 to 0.47 mM and 3 weeks' working stability.
Received: 11 February 2000 / Received revision: 25 May 2000 / Accepted: 26 May 2000 相似文献
10.
Heterologous protein production in methylotrophic yeasts 总被引:15,自引:0,他引:15
Gellissen G 《Applied microbiology and biotechnology》2000,54(6):741-750
The facultative methylotrophic yeasts Candida boidinii, Pichia methanolica, Pichia pastoris and Hansenula polymorpha have been developed as systems for heterologous gene expression. They are based on strong and regulatable promoters for expression
control derived from methanol metabolism pathway genes. An increasing number of biotechnological applications attest to their
status as preferred options among the various gene expression hosts. The well-established P. pastoris and H. polymorpha systems have been utilized in especially competitive and consistent industrial-scale production processes. Pharmaceuticals
and technical enzymes produced in these methylotrophs have either already entered the market or are expected to do so in the
near future. The article describes the present status of the methylotrophic yeasts as expression systems, focusing on applied
examples of the recent past.
Received: 9 May 2000 / Received revision: 20 June 2000 / Accepted: 23 June 2000 相似文献
11.
Van Aken B Cameron MD Stahl JD Plumat A Naveau H Aust SD Agathos SN 《Applied microbiology and biotechnology》2000,54(5):659-664
Manganese-dependent peroxidase (MnP) H5 from the white-rot fungus Phanerochaete chrysosporium, in the presence of either Mn(II) (10 mM) or GSH (10 mM), was able to mineralize 14C-U-ring-labeled 2-amino-4,6-dinitrotoluene (2-A-4,6-DNT) up to 29% in 12 days. When both Mn(II) and GSH were present, the
mineralization extent reached 82%. On the other hand, no significant mineralization was observed in the absence of both Mn(II)
and GSH, suggesting the requirement of a mediator [either Mn(II) or GSH] for the degradation of 2-A-4,6-DNT by MnP. Using
electron spin resonance (ESR) techniques, it was found that the glutathionyl free radical (GS•) was produced through the oxidation of GSH by MnP in the presence as well as in the absence of Mn(II). GS• was also generated through the direct oxidation of GSH by Mn(III). Our results strongly suggest the involvement of GS• in the GSH-mediated mineralization of 2-A-4,6-DNT by MnP.
Received: 18 February 2000 / Received revision: 24 May 2000 / Accepted: 26 May 2000 相似文献
12.
This short review covers metabolic pathways, genetics and metabolic engineering of 1,2-propanediol formation in microbes.
1,2-Propanediol production by bacteria and yeasts has been known for many years and two general pathways are recognized. One
involves the metabolism of deoxyhexoses, where lactaldehyde is formed during the glycolytic reactions and is then reduced
to 1,2-propanediol. The second pathway derives from the formation of methylglyoxal from dihydroxyacetonephosphate and its
subsequent reduction to 1,2-propanediol. The enzymes involved in the reduction of methylglyoxal can generate isomers of lactaldehyde
or acetol, which can be further reduced by specific reductases, giving chiral 1,2-propanediol as the product. The stereospecificity
of the enzymes catalyzing the two reduction steps is important in deriving a complete pathway. Through genetic engineering,
appropriate combinations of enzymes have been brought together in Escherichia coli and yeast to generate 1,2-propanediol from glucose. The optimization of these strains may yield microbial processes for the
production of this widely used chemical.
Received: 25 May 2000 / Received revision: 24 July 2000 / Accepted: 25 July 2000 相似文献
13.
Naumov GI Naumova ES Aigle M Masneuf I Belarbi A 《Applied microbiology and biotechnology》2001,55(1):108-111
Using genetic hybridization analysis, pulsed-field gel electrophoresis of chromosomal DNA and PCR/RFLP analysis of the MET2 gene, we reidentified 11 Champagne yeast strains. Two of them, SCPP and SC4, were found to belong to Saccharomyces bayanus var. uvarum and the remaining strains to S. cerevisiae. Strain SCPP (CLIB 2025) of S. bayanus var. uvarum is known as a producer of three pectinolytic enzymes.
Received: 28 April 2000 / Received revision: 20 July 2000 / Accepted: 25 July 2000 相似文献
14.
Biotechnological production of flavours and fragrances 总被引:7,自引:0,他引:7
The biotechnological generation of natural aroma compounds is rapidly expanding. Aroma chemicals, such as vanillin, benzaldehyde
(bitter almond, cherry) and 4-(R)-decanolide (fruity–fatty) are marketed on a scale of several thousand tons per year. Their possible production by single-step
biotransformations, bioconversions and de novo synthesis using microorganisms, plant cells or isolated enzymes is shown. The
perspectives of bioprocesses for the oxifunctionalisation of lower terpenes by genetically modified organisms and economic
aspects are discussed.
Received: 27 May 1997 / Received revision: 25 September 1997 / Accepted: 28 September 1997 相似文献
15.
Giffhorn F 《Applied microbiology and biotechnology》2000,54(6):727-740
Pyranose oxidases are widespread among lignin-degrading white rot fungi and are localized in the hyphal periplasmic space.
They are relatively large flavoproteins which oxidize a number of common monosaccharides on carbon-2 in the presence of oxygen
to yield the corresponding 2-keto sugars and hydrogen peroxide. The preferred substrate of pyranose oxidases is d-glucose which is converted to 2-keto-d-glucose. While hydrogen peroxide is a cosubstrate in ligninolytic reactions, 2-keto-d-glucose is the key intermediate of a secondary metabolic pathway leading to the antibiotic cortalcerone. The finding that
2-keto-d-glucose can serve as an intermediate in an industrial process for the conversion of d-glucose into d-fructose has stimulated research on the use of pyranose oxidases in biotechnical applications. Unique catalytic potentials
of pyranose oxidases have been discovered which make these enzymes efficient tools in carbohydrate chemistry. Converting common
sugars and sugar derivatives with pyranose oxidases provides a pool of sugar-derived intermediates for the synthesis of a
variety of rare sugars, fine chemicals and drugs.
Received: 26 April 2000 / Received revision: 8 June 2000 / Accepted: 9 June 2000 相似文献
16.
During cassava starch production, large amounts of cyanoglycosides were released and hydrolysed by plant-borne enzymes, leading
to cyanide concentrations in the wastewater as high as 200 mg/l. For anaerobic degradation of the cyanide during pre-acidification
or single-step methane fermentation, anaerobic cultures were enriched from soil residues of cassava roots and sewage sludge.
In a pre-acidification reactor this culture was able to remove up to 4 g potassium cyanide/l of wastewater at a hydraulic
retention time (t
HR) of 4 days, equivalent to a maximal cyanide space loading of 400 mg CN− l−1 day−1. The residual cyanide concentration was 0.2–0.5 mg/l. Concentrated cell suspensions of the mixed culture formed ammonia and
formate in almost equimolar amounts from cyanide. Little formamide was generated by chemical decay. A concentration of up
to 100 mmol ammonia/l had no inhibitory effect on cyanide degradation. The optimal pH for cyanide degradation was 6–7.5, the
optimal temperature 25–37 °C. At a pH of 5 or lower, cyanide accumulated in the reactor and pre-acidification failed. The
minimal t
HR for continuous cyanide removal was 1.5 days. The enriched mixed culture was also able to degrade cyanide in purely mineralic
wastewater from metal deburring, either in a pre-acidification reactor with a two-step process or in a one-step methanogenic
reactor. It was necessary to supplement the wastewater with a carbon source (e.g. starch) to keep the population active enough
to cope with any possible inhibiting effect of cyanide.
Received: 29 April 1998 / Received revision: 8 June 1998 / Accepted: 14 June 1998 相似文献
17.
Manganese peroxidase (Mn peroxidase) catalyses the oxidation of Mn(II) to Mn(III), a diffusible non-specific oxidant likely
to be involved in the transformation of polyphenolic macromolecules from brown coal by the white-rot fungus Phanerochaete chrysosporium. We report here that solubilised macromolecules from Morwell brown coal were depolymerised by Mn(III) ions when incubated
under hyperbaric O2. However, under N2 or air they were polymerised, suggesting that net depolymerisation by Mn(III) requires molecular oxygen to inhibit coupling
of coal radicals. Coal macromolecules were also polymerised when separated by a semipermeable membrane from a culture of P. chrysosporium or from a solution of Mn peroxidase, Mn(II) and H2O2, probably by Mn(III) crossing the membrane. In oxygenated cultures in which Mn peroxidase␣was up-regulated by Mn(II), the
extent of depolymerisation correlated with cumulative Mn peroxidase activity suggesting that Mn-peroxidase-generated Mn(III)
has a central role in initial depolymerisation of coal molecules in vivo. However, mutant ME446-B17-1, which produces Mn peroxidase
but not lignin peroxidase, polymerised coal macromolecules in oxygenated cultures. In sum, it appears Mn peroxidase can both
polymerise and depolymerise brown coal macromolecules and that, in vivo, both hyperbaric O2 and lignin peroxidase are also required to force net depolymerisation to products assimilable by cells.
Received: 4 September 1997 / Received revision: 29 January 1998 / Accepted: 30 January 1998 相似文献
18.
Wild-type Streptomyces sp. strains, able to utilise both naturally occurring and synthetic organophosphonates, were isolated. High levels of inorganic
phosphate were necessary for their growth in complete medium as well as in medium, supplemented with phosphonates as the sole
carbon or nitrogen source. Isolate StA expressed detectable enzymatic activity against 2-aminoethylphosphonate in vivo. Streptomycete
StC had a surprising ability to degrade N-phosphonomethylglycine (glyphosate) in a phosphate-independent manner via C–P bond cleavage accompanied by sarcosine formation.
Received: 5 January 1999 / Received revision: 8 March 1999 / Accepted: 14 March 1999 相似文献
19.
A. Mutzel U. M. Reinscheid G. Antranikian R. Müller 《Applied microbiology and biotechnology》1996,46(5-6):593-596
A phenol-degrading thermophilic bacterium, designated Bacillus sp. A2, was isolated from a water and mud sample from a hot spring in Iceland. The aerobic isolate grew optimally on phenol
at 65 °C. At 70 °C, 85% of the optimal growth rate was still observed. No growth was observed at 40 °C and 75 °C. Bacillus sp. A2 is a gram-positive spore-forming rod. According to 16S rDNA analysis Bacillus sp. A2 is closely related to Bacillus stearothermophilus, Bacillus kaustophilus and Bacillus thermoleovorans. Bacillus sp. A2 degraded phenol completely in concentrations up to 5 mM. In addition, all three isomers of cresol were utilized as
sole carbon and energy sources. The degradation of phenols proceeds via the meta-cleavage pathway and the enzymes involved in its degradation are constitutively expressed.
Received: 13 May 1996 / Received revision: 29 July 1996 / Accepted: 12 August 1996 相似文献
20.
Jeffke T Jende D Mätje C Ehlers RU Berthe-Corti L 《Applied microbiology and biotechnology》2000,54(3):326-330
Photorhabdus luminescens, a bacterial symbiont of entomopathogenic biocontrol nematodes, was grown in batch and glucose fed-batch culture. The cell
density, bioluminescence, production of antibiotic substances, number of cells with inclusion bodies, glucose concentration
and oxygen uptake rate were recorded. The addition of 12.4 g l−1 glucose prolonged the growth, and the yield almost doubled, from 6.85 g l−1 to 12.45 g l−1 dry mass. The production of antibiotic substances increased by 140%. Bioluminescence was higher in the batch culture. A shift
of P. luminescens to phase II variants was not detected.
Received: 21 January 2000 / Received revision: 3 April 2000 / Accepted: 7 April 2000 相似文献