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1.
Matti S. A. Leisola Duane C. Ulmer Roland Waldner Armin Fiechter 《Journal of biotechnology》1984,1(5-6)
Several aromatic compounds increased initial lignin degradation rates in cultures of Phanerochaete chrysosporium. This activation was connected to increased H2O2 production and glucose oxidation rates. Veratryl alcohol, a natural secondary metabolite of P. chrysosporium, also activated the lignin-degrading system. In the presence of added veratryl alcohol the ligninolytic system appeared 6–8 h earlier than in reference cultures. This effect was only seen when lignin was added after the primary growth was completed because lignin itself also caused earlier appearance of the degradative system. In cultures which received no added lignin or veratryl alcohol the ligninolytic activity only appeared once the alcohol started to accumulate. The degradation patterns of veratryl alcohol and lignin were similar. The activity levels of lignin degradation and glucose oxidation could be regulated by veratryl alcohol concentration. It is suggested that either veratryl alcohol itself or a metabolite derived from it is actually responsible for the low levels of ligninolytic activity in glucose grown cultures. 相似文献
2.
In order to determine the effect of substrate nitrogen (N) on ligninolytic activity, Pleurotus ostreatus was grown in solid media containing either growth-limiting (1mM) or excess (10mM) NH4Cl. After 25 days, 14C–CO2 production from 14C-cornstover lignin in low-N medium was 3 times that in nitrogen (N)-rich medium. Supplementation of low-N medium with glucose (0.3%) further enhanced ligninolytic activity. Decolorization of an aromatic, polymeric dye, Poly R-481, in solid media was also greatest under N-limiting conditions. 相似文献
3.
Ligninolytic activity in the white-rot fungus Phanerochaete chrysosporium was previously found not to be induced by lignin, but to develop in cultures in response to nitrogen starvation. Added NH
4
+
suppressed existing activity. The present study examined amino acid profiles and protein concentrations during onset of ligninolytic activity (synthetic 14C-lignin14CO2) in nitrogen-limited cultures, and defined some characteristics of subsequent suppression by added nutrient nitrogen. During the transition between depletion of medium nitrogen and the onset of ligninolytic activity, total free intracellular amino acids increased, then rapidly decreased; changes in glutamate concentration played a major role. Intracellular protein concentration fluctuated in a manner roughly converse to that of the concentration of free amino acids. Protein turnover was rapid (5–7%/h) during the transition period. Glutamate, glutamine, and histidine were the most effective of 14 nitrogenous compounds in suppressing ligninolytic activity after its onset. The suppressive effect was not mediated through carbon (glucose)-catabolite repression or by alterations in culture pH. Activities responsible for oxidation of lignin and the ligninrelated phenol, 4-hydroxy-3-methoxyacetophenone, responded similarly to added nitrogen. Synthesis of a secondary metabolite, veratryl alcohol, like lignin oxidation, was suppressed quite sharply by glutamate and significantly by NH
4
+
. Results indicate that nitrogen metabolism affects ligninolytic activity as a part of secondary metabolism, and suggest a role for glutamate metabolism in regulating this phase of culture development.Non-Standard Abbreviations DMS
2,2-dimethylsuccinate
- GLC
gas-liquid chromatography
- TCA
trichloroacetic acid 相似文献
4.
T. K. Kirk E. Schultz W. J. Connors L. F. Lorenz J. G. Zeikus 《Archives of microbiology》1978,117(3):277-285
Culture parameters influencing metabolism of synthetic14C-lignins to14CO2 in defined media have been studied in shallow batch cultures of the ligninolytic wood-destroying HymenomycetePhanerochaete chrysosporium Burds. Study of the effect of O2 concentration in the gas phase above non-agitated cultures indicated essentially complete absence of attack on the lignin polymer at 5% O2 in N2, and a 2- to 3-fold enhancement by 100% O2 as compared to air (21% O2). Agitation of the cultures resulting in the formation of mycelial pellets greatly suppressed lignin decomposition. The optimum culture pH for lignin decomposition was 4 to 4.5, with marked suppression above 5.5 and below 3.5. The source of nutrient nitrogen (NO
3
–
, NH
4
+
, amino acids) had little influence on lignin decomposition, but the concentration of nitrogen was critical; decomposition at 24 mM was only 25–35% of that at 2.4 mM N. Thiamine was the only vitamin required for growth and lignin decomposition. Under the optimum conditions developed, decomposition of 5 mg of synthetic lignin was accompanied by utilization of approximately 100 mg of glucose. The influence of the various culture parameters was analogous for metabolism of synthetic lignin labeled in the ring-,side chain-, and methoxyl carbon atoms. 相似文献
5.
H2 production from glucose by Ruminococcus albus was almost completely inhibited by 10–5 M molybdate only when sulfide was present in the growth medium. Inhibition was accompanied by a significant increase in the production of formate. Extracts of molybdate-sulfide-grown cells did not contain hydrogenase activity. Active enzyme in extracts of uninhibited cells was not inhibited by the molybdate-sulfide-containing growth medium. The results indicate that a complex formed from molybdate and sulfide prevents the formation of active hydrogenase and electrons otherwise used to form H2 are used to reduce CO2 to formate. Growth was significantly inhibited when molybdate was increased to 10–4 M. Reversal of growth inhibition but not inhibition of H2 production occurred between 10–4 and 10–3 M molybdate. H2 production by R. bromei but not by R. flavefaciens, Butyrivibrio fibrisolvens, Veillonella alcalescens, Klebsiella pneumoniae and Escherichia coli was inhibited by molybdate and sulfide. 相似文献
6.
Yuan-Kun Lee Sun-Yeun Ding Chye-Hock Hoe Chin-Seng Low 《Journal of applied phycology》1996,8(2):163-169
Chlorella sorokiniana was cultured in heterotrophic or mixotrophic mode in outdoor enclosed tubular photobioreactor. The culture temperature was maintained at 32–35 °C. At night, theChlorella culture grew heterotrophically, and 0.1 M glucose was completely consumed. The biomass growth yield of glucose was 0.35 ± 0.001 g-biomass g-glucose–1. During the day, the algal culture grew mixotrophically and the biomass growth yield was 0.49 g-biomass g-glucose–1 in low density culture (initial biomass concentration, Xo = 2 g l–1), 0.56 g-biomass g-glucose–1 in medium density culture (Xo = 4 g l–1) and 0.46 g-biomass g-glucose–1 in high density culture (Xo = 7 g l–1). The daily area productivity of the culture, with Xo = 4 g l–1 corresponded to 127 g-biomass m–2 d–1 during the day and 79 g-biomass m–2 d–1 during the night. In all the cultures, the dissolved O2 concentration increased in the morning, reached the maximum value at noon, and then decreased in the afternoon. The dissolved CO2 concentration remained at 3 mBar in the morning and increased in the afternoon. Glycolate was not found to accumulate in culture medium. 相似文献
7.
Inorganic-carbon transport was investigated in the eukaryotic marine microalgaeStichococcus minor, Nannochloropsis oculata and aMonallantus sp. Photosynthetic O2 evolution at constant inorganic-carbon concentration but varying pH showed thatS. minor had a greater capacity for CO2 rather than HCO
3
–
utilization but forN. oculata andMonallantus HCO
3
–
was the preferred source of inorganic carbon. All three microalgae had a low affinity for CO2 as shown by the measurement of inorganic-carbon-dependent photosynthetic O2 evolution at pH 5.0. At pH 8.3, where HCO
3
–
is the predominant form of inorganic carbon, the concentration of inorganic carbon required for half-maximal rate of photosynthetic O2 evolution [K
0.5 (CO2)] was 53 M forMonallantus sp. and 125 M forN. oculata, values compatible with HCO
3
–
transport. Neither extra- nor intracellular carbonic anhydrase was detected in these three microalgal species. It is concluded that these microalgae lack a specific transport system for CO2 but that HCO
3
–
transport occurs inN. oculata andMonallantus, and in the absence of intracellular carbonic anhydrase the conversion of HCO
3
–
to CO2 may be facilitated by the internal pH of the cell. 相似文献
8.
Pseudomonas putida and Pseudomonas fluorescens present as a coculture were studied for their abilities to degrade benzene, toluene, ethylbenzene, and xylenes (collectively known as BTEX) under various growth conditions. The coculture effectively degraded various concentrations of BTEX as sole carbon sources. However, all BTEX compounds showed substrate inhibition to the bacteria, in terms of specific growth, degradation rate, and cell net yield. Cell growth was completely inhibited at 500mgl–1 of benzene, 600mgl–1 of o-xylene, and 1000mgl–1 of toluene. Without aeration, aerobic biodegradation of BTEX required additional oxygen provided as hydrogen peroxide in the medium. Under hypoxic conditions, however, nitrate could be used as an alternative electron acceptor for BTEX biodegradation when oxygen was limited and denitrification took place in the culture. The carbon mass balance study confirmed that benzene and toluene were completely mineralized to CO2 and H2O without producing any identifiable intermediate metabolites. 相似文献
9.
M Vitolo M A Duranti M B Pellegrim 《Journal of industrial microbiology & biotechnology》1995,15(2):75-79
S. cerevisiae was grown in a blackstrap molasses containing medium in batch and fed-batch cultures. The following parameters were varied: pH (from 4.0 to 6.5), dissolved oxygen (DO) (from 0 to 5.0 mg O2L–1) and sucrose feeding rate. When glucose concentration (S) was higher than 0.5 g L–1 a reduction in the specific invertase activity of intact cells (v) and an oscillatory behavior of v values during fermentation were observed. Both the invertase reduction and the oscillatory behavior of v values could be related to the glucose inhibitory effect on invertase biosynthesis. The best culture conditions for attainingS. cerevisiae cells suitable for invertase production were: temperature=30°C; pH=5.0; DO=3.3 mg O2L–1; (S)=0.5 g L–1 and sucrose added into the fermenter according to the equations: (V–Vo)=t2/16 or (V–Vo)=(Vf–Vo)·(e0.6t–1)/10.This work was supported by FAPESP 相似文献
10.
Mutational and kinetic analysis of basic amino acid transport in the cyanobacterium Synechocystis sp. PCC 6803 总被引:4,自引:0,他引:4
Two nitrogen-deregulated mutants of Phanerochaete chrysosporium, der8-2 and der8-5, were isolated by subjecting wild type conidia to gamma irradiation, plating on Poly-R medium containing high levels of nitrogen, and identifying colonies that are able to decolorize Poly-R. The mutants showed high levels of ligninolytic activity (14C-synthetic lignin 14CO2), and lignin peroxidase, manganese peroxidase and glucose oxidase activities in both low nitrogen (2.4 mM) and high nitrogen (24 mM) media. The wild type on the otherhand displayed these activities in low nitrogen medium but showed little or no activities in high nitrogen medium. Fast protein liquid chromatographic analyses showed that the wild type as well as the der mutants produce three major lignin peroxidase peaks (designated L1, L2 and L3) with lignin peroxidase activity in low nitrogen medium. Furthermore, in low nitrogen medium, mutant der8-5 produced up to fourfold greater lignin peroxidase activity than that produced by the wild type. In high nitrogen medium, the wild type produced no detectable lignin peroxidase peaks whereas the mutants produced peaks L1 and L2, but not L3, and a new lignin peroxidase protein peak designated LN. Mutants der8-2 and der8-5 also produced high levels of glucose oxidase, an enzyme known to be associated with secondary metabolism and an important source of H2O2 in ligninolytic cultures, both in low and high nitrogen media. In contrast, the wild type produced high levels of glucose oxidase in low nitrogen medium and only trace amounts of this enzyme in high nitrogen medium. The results of this study indicate that the der mutants are nitrogen-deregulated for the production of a set of secondary metabolic activities associated with lignin degradation such as lignin peroxidases, manganese peroxidases and glucose oxidase. 相似文献
11.
Summary Methanol formation during the degradation of synthetic lignin (DHP), spruce and birch milled wood lignin (MWL) by Phanerochaete chrysosporium Burds. was studied under different culture conditions. When 100-ml flasks with 15–20 ml volumes of culture media containing high glucose and low nitrogen concentrations were used the metabolism of methanol to formaldehyde, formic acid and CO2 was repressed thereby facilitating methanol determination. In standing cultures with oxygen flushing the fungus converted up to 25% of the DHP-methoxyl groups to methanol and 0.5–1.5% to 14CO2 within 22–24 h. Methanol formation from methoxyl-labelled DHP was strongly repressed by high nitrogen in the medium, by addition of glutamic acid and by culture agitation. These results indicate that methanol is formed only under ligninolytic conditions and during secondary metabolism. Methanol is most likely released both from the lignin polymer itself and from lignin degradation products. Methanol was also formed from MWL preparations with higher percentage yields produced from birch as compared to spruce MWL.Small amounts of methanol detected in cultures without lignin probably emanated from demethoxylation of veratryl alcohol synthesized de novo from glucose by the fungus during secondary metabolism. Catalase or superoxide dismutase added to the fungal culture prior to addition of lignin, did not decrease methanol formation. Horseradish peroxidase plus H2O2 in vitro caused 5–7% demethoxylation of O14CH3-DHP in 22 h, while laccase gave smaller amounts of methanol (1.8%). Since addition of H2O2 gave similar results as peroxidase plus H2O2, it seems likely that the main effect of peroxidase demethoxylation emanates from the hydrogen peroxide. 相似文献
12.
The response of stomata in isolated epidermis to the concentration of CO2 in the gaseous phase was examined in a C3 species, the Argenteum mutant of Pisum sativum, and a crassulacean-acid-metabolism (CAM) species, Kalanchoë daigremontiana. Epidermis from leaves of both species was incubated on buffer solutions in the presence of air containing various volume fractions of CO2 (0 to 10000·10–6). In both species and in the light and in darkness, the effect of CO2 was to inhibit stomatal opening, the maximum inhibition of opening occurring in the range 0 to 360·10–6. The inhibition of opening per unit change in concentration was greatest between volume fractions of 0 and 240·10–6. There was little further closure above the volume fraction of 360·10–6, i.e. approximately ambient concentration of CO2. Thus, although leaves of CAM species may experience much higher internal concentrations of CO2 in the light than those of C3 plants, this does not affect the sensitivity of their stomata to CO2 concentration or the range over which they respond. Stomatal responses to CO2 were similar in both the light and the dark, indicating that effects of CO2 on stomata occur via mechanisms which are independent of light. The responses of stomata to CO2 in the gaseous phase took place without the treatments changing the pH of the buffered solutions. Thus it is unlikely that CO2 elicited stomatal movement by changing either the pH or the HCO
3
–
/CO
3
2-
equilibria. It is suggested that the concentration of dissolved unhydrated CO2 may be the effector of stomatal movement and that its activity is related to its reactivity with amines. 相似文献
13.
Several Nocardia and Pseudomonas spp., as well as some unidentified bacteria, isolated from lake water containing high loads of waste lignin, were tested for their capacity to release 14CO2 from specifically 14C-labelled dehydropolymer of coniferyl alcohol (DHP) or corn stalk lignins. The bacteria were selected according to their ability to degrade phenolic compounds. However, only some of them could release significant amounts of 14CO2 from the labelled lignin. The tested Nocardia spp. were more active than the Pseudomonas spp. and the unidentified bacteria. The most active strains belonged to N. autotrophica. These strains released CO2 significantly from the methoxyl group and transformed the other carbons from the phenylpropane skeleton of lignin also into CO2. Other less demethylating strains also released little CO2 from the other carbons of the lignin molecule. From corn stalk materials which were specifically labelled in the lignin part only small amounts of labelled CO2 were released.Non-Common-Abbreviation Used DHP
dehydropolymers of coniferyl alcohol 相似文献
14.
The influence of Zn2+ (6.0 × 10–3 –18.0 × 10–3
M) and Cu2+ (4 × 10–4 –1.2 × 10–4
M) in the basal medium on mycelial growth (dry weight), activities of lignin peroxidase (Lip), manganese peroxidase (Mnp), solubilization, and mineralization (14CO2 evolution) of lignin during a period of 3 weeks was studied in Phanerochaete chrysosporium strain MTCC-787. Highest mycelial growth was obtained at 0.6 M Zn2+ and 0.4 M Cu2+ levels. Enzyme activities were found to increase up to the highest levels of both the trace elements. However, Zn2+ had a relatively more stimulatory effect on Lip production and the reverse was true in case of Cu2+. [14C]Lignin solubilization was also promoted by higher levels of both trace elements. Mineralization of [14C]lignin was optimal at 6.0 M Zn2+ and 1.2 M Cu2+. The stimulatory effect of Zn2+ on Lip production was correlated with higher rates of [14C]lignin mineralization. 相似文献
15.
E. D. Crandall H. I. Winter J. D. Schaeffer A. Bidani 《The Journal of membrane biology》1982,65(1-2):139-145
Summary Changes in extracellular pH (pH
o
) in human red cell suspensions were monitored in a stopped-flow rapid reaction apparatus. A 20% suspension of washed human RBC in saline at pH 7 containing NaHCO3 and extracellular carbonic anhydrase was mixed with an equal volume of buffered saline solution at pH 6.7. Sodium salicylate, when present, was added to both the erythrocyte suspension and the buffer solution. The effects of salicylate in the therapeutic to toxic concentration range on HCO
3
–
/Cl– exchange were studied at 37°C. HCO
3
–
/Cl– exchange flux was estimated using the extracellular buffer capacity and the difference betweendpH
o
/dt using a control RBC suspension and that using a suspension of RBC whose anion exchange pathway was markedly inhibited. The results show that salicylate competitively decreases the rate of HCO
3
–
/Cl– exchange, with inhibition increasing as salicylate concentration increases.K
I is 2.4mm. At a salicylate concentration of 10mm, HCO
3
–
/Cl– exchange under the conditions of our experiments was inhibited by more than 70%. These findings are consistent with the possibility that CO2 transfer in capillary bedsin vivo may be diminished in the presence of salicylate due to slowing of red cell HCO
3
–
/Cl– exchange. 相似文献
16.
Cultural conditions affecting lignin degradation by Phanerochaete chrysosporium in various lignocellulosic materials were studied in comparison to an isolated lignin preparation. With shallow mycelial cultures, the degradation of lignin in wood proceeded more slowly in a 100% O2-atmosphere than in an air atmosphere, indicating that pure oxygen was toxic to the fungus. The organism was able to degrade lignin efficiently even under 30% CO2 and 10% O2 concentrations. Evolution of 14CO2 from labelled lignocellulosic materials was shown not to be representative of total lignin degradation. Addition of glucose to the culture did not affect lignin degradation measured by 14CO2 evolution, whereas lignin degradation measured by Klason lignin method stopped completely (poplar) or slowed considerably (straw). Due to partial depolymerization of lignin to soluble products, measuring only the evolution of 14CO2 results in an underestimation of the total amount of lignin bioaltered. The soluble products from all of the tested lignocellulosic materials and from the isolated lignin had an average molecular weight of about 1,000 and the products could be further fractionated by ion exchange chromatography. The relative amount of these products could be varied from 15 to 45% from the original lignin. 相似文献
17.
Dietrich Werner Arno Krotzky Regine Berggold Heidemarie Thierfelder Marianne Preiß 《Archives of microbiology》1982,132(1):51-56
Specific nitrogenase activity inAzospirillum brasilense ATCC 29145 in surface cultures under air is enhanced from about 50 nmol C2H4·mg protein-1·h-1 to 400 nmol C2H4 by the addition of 1 mM phenol. 0.5 and 2 mM phenol added increase the rate 5-fold and 4-fold. This enhancement effect is observed only between 2 and 3 days after inoculation, with only a small reduction of the growth of the cells by the phenol added. In surface cultures under 1% O2, nitrogenase activity is slightly reduced by the addition of 1–0.01 mM phenol. Utilization of succinate is enhanced during the period of maximum enhancement of nitrogenase activity by 60% by addition of 1 mM phenol. The cells did not produce14CO2 from [U-14C] phenol, neither in surface cultures nor in liquid cultures and less than 0.1% of the phenol was incorporated into the cells. A smaller but significant enhancement of nitrogenase activity by about 100% in surface cultures under air was found withKlebsiella pneumoniae K 11 after addition of 1 mM phenol. However, inRhizobium japonicum 61-A-101 all phenol concentrations above 0.01 mM reduced nitrogenase activity. With 1 mM phenol added activity was reduced to less than 10% with no effect on the growth in the same cultivation system. With thisRhizobium japonicum strain significant quantities of phenol (25 mol in 24 h by 2·1012 cells) were metabolized to14CO2, with phenol as sole carbon source. WithAzospirillum brasilense in liquid culture under 1% and 2% O2 in the gas phase, no enhancement of nitrogenase activity by phenol was noticed. 相似文献
18.
The kinetic parameters of in vivo ethylene metabolism by seedlings of Pisum sativum L. cv. Alaska have been determined. The oxidation of ethylene to CO2, (Ox) and the incorporation of ethylene into the tissue (TI) were both shown to display Michaelis-Menten kinetics (Km Ox = 0.9 × 10–6 M liquid phase, Vmax Ox = 2.4 × 10–10 moles g– dry mass h–1 Km TI = 1.6 × 10–6 M liquid phase, Vmax TI = 4.5 × 10–10 moles g–1 dry mass h–1). Propylene competitively inhibited both Ox (Ki = 7.0 × 10–6 M) and TI (Ki = 3.7 × 10–7 M). A system comparable to Ox was absent from imbibed cotyledons of Vicia faba L. cv. Aquadulce even at saturating concentrations of ethylene similar to those used in kinetic analysis on Pisum. Silver ions were shown to inhibit TI but promoted Ox, while carbon dioxide inhibited Ox but promoted TI. Kinetic data on both these effects are presented. Data on the effect of a range of concentrations of CO2 on TI and Ox are also presented.To whom editorial correspondence should be sent 相似文献
19.
Lyophilized biomass of a Pseudomonas soilisolate adsorbed thorium (IV) (430 mg g–1 dry wt) optimally at pH 4, with 91% of equilibrium loading being reached in 1 min. Equilibrium metal sorption showing conformity to Langmuir isotherm model suggested a monolayered thorium binding. Thorium binding remained unaffected or slightly affected (< 20% inhibition) in presence of equimolar (430 M) concentration of several interfering ions except Fe3+ (40% inhibition). More than 90% of loaded thorium could be recovered using 1 M CaCO3, though mineral acids and Na2CO3 were also effective. 相似文献
20.
Summary Experiments were undertaken on the fresh water algaChara corallina to determine the form of inorganic carbon (CO2 or HCO
3
–
) which enters the cell during photosynthesis at alkaline pH. Recent proposals have centered on the possibility that proton efflux in alkaline solution is able to generate, in the immediate vicinity of the cell, a sufficiently low pH to raise the partial pressure of CO2, and hence facilitate its passive permeation into the cell. Predictions have been made by modelling this situation (N.A. Walker, F.A. Smith & I.R. Cathers, 1980,J. Membrane Biol.
5751–58, J.M. Ferrier, 1980,Plant Physiol.
661198–1199), and these were tested by placing recessed-tip pH microelectrodes in the unstirred layer surrounding cells in stagnant solution (bulk pH 8.2, buffered only with 1mm HCO
3
–
). Even as close as 2 m from the cell wall, the pH was typically 7.2 to 7.6 in the acid band center — over 1 pH unitgreater than that suggested by the models for CO2 entry at the necessary rate for C-fixation. Further evidence for the entry of HCO
3
–
, rather than CO2, at high solution pH was obtained from experiments in which the radial pH gradient in the unstirred layer was reduced. Buffer solutions containing 5mm phosphate or 5mm HEPES, raised the pH at the cell surface in the acid regions from around 7.2 to 7.8 or higher. This pH increase (reduction in acid gradient) would have greatly reduced the CO2 level at the cell surface and should, therefore, have greatly reduced the CO2-related14C-influx. However,14C-fixation was reduced by only 31% (phosphate) or 15% (HEPES), compared with buffer-free controls. Reduction of the unstirred layer thickness by fast solution flow resulted in a stimulation, and not a reduction, of14C-fixation. The similarity of our radial pH profiles near the wall with that predicted by the model (Walker et al., 1980) assuming H+–HCO
3
–
cotransport, together with the effects of buffer, and the results of increased solution flow rate, lead to the conclusion that cotransport of HCO
3
–
with H+ is the likely method of entry of inorganic carbon. Longitudinal pH profiles of theChara cell were obtained at a distance of 25 m from the wall. These revealed much sharper delineation of the acid and alkaline bands than has previously been possible with miniature pH electrodes. Profiles of local electric field, obtained with a vibrating probe, were in excellent agreement with the high resolution pH profiles. This supports the hypothesis that membrane proton transport has a role (direct) in the generation of the extracellular currents. 相似文献