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1.
Peter von Feiten Hans Zürrer Reinhard Bachofen 《Applied microbiology and biotechnology》1985,23(1):15-20
Summary Cells ofRhodospirillum rubrum have been immobilized in various gels and tested for photobiological hydrogen production. Agar proved to be the best immobilizing
agent with respect to production rates as well as stability. Agar immobilized cells were also superior compared to liquid
suspension cultures. Growth conditions of the cells prior to immobilization, e.g. cell age, light intensity or nutrient composition,
were of primary importance for the activity in the later immobilized state. A reactor with agar immobilized cells has been
operated successfully over 3000 h with a loss of the activity of about 60%. Mean rates for hydrogen production for immobilized
cells in this work during the first 60 to 70 hours after immobilization were in the range of 18 to 34 μl H2 mg−1 d.w. h−1 and thus by a factor of up to 2 higher than liquid cultures under the same conditions. Maximal rates of hydrogen production
(57 μl H2 ml−1 immobilized cell suspension) were reached in agar gel beads with cells immobilized after 70 h growth in liquid culture in
the light and a cell density of 1.0 mg ml−1, 70 h after immobilization. 相似文献
2.
《Journal of Fermentation and Bioengineering》1992,73(1):46-50
A newly isolated autotrophic bacterium, Thiobacillus thioparus DW44, which is capable of degrading sulfur-containing gases, was inoculated into a pilot-scale peat biofilter to treat the exhaust gas from a night soil treatment plant. Hydrogen sulfide (H2S), methanethiol (MT), dimethyl sulfide (DMS) and dimethyl disulfide (DMDS) in the exhaust gas were efficiently removed for six months. Average removal ratios were 99.8% for H2S, 99.0% for MT, 89.5% for DMS and 98.1% for DMDS at a space velocity of 46 h−1 during the period of operation. No acclimation period was needed to reach such a high efficiency in the removal of the gases, indicating that the ability of this bacterium to remove these gases was occurred immediately after its inoculation to the peat. Ammonia (NH3) in the exhaust gas was neutralized with SO42−, which is the final product of the oxidation of H2S, MT, DMS and DMDS by the bacterium. No remarkable decline of pH, which often causes a deterioration in bacterial activity, was observed, mainly because of the reaction of SO42− with NH3. This study is the first report on the application of an isolated microorganism to a practical deodorizing system. The inoculation of T. thioparus DW44 into the pilot-scale peat biofilter could overcome such disadvantages of the conventional peat biofilter as a long acclimation period to reach a constant gas removability and the low removability of DMS, and resulted in enhanced removal efficiency of malodorous gases. 相似文献
3.
A methanogen, strain AK-1, was isolated from permanently cold marine sediments, 38- to 45-cm below the sediment surface at
Skan Bay, Alaska. The cells were highly irregular, nonmotile coccoids (diameter, 1 to 1.2 μm), occurring singly. Cells grew
by reducing CO2 with H2 or formate as electron donor. Growth on formate was much slower than that on H2. Acetate, methanol, ethanol, 1- or 2-propanol, 1- or 2-butanol and trimethylamine were not catabolized. The cells required
acetate, thiamine, riboflavin, a high concentration of vitamin B12, and peptones for growth; yeast extract stimulated growth but was not required. The cells grew fastest at 25 °C (range 5
°C to 25 °C), at a pH of 6.0 – 6.6 (growth range, pH 5.5 – 7.5), and at a salinity of 0.25 – 1.25 M Na+. Cells of this and other H2-using methanogens from saline environments metabolized H2 to a very low threshold pressure (less than 1 Pa) that was dependent on the methane partial pressure. We propose that the
threshold pressure may be limited by the energetics of catabolism. The sequence of the 16S rDNA gene of strain AK-1 was most
similar (98%) to the sequences of Methanogenium cariaci JR-1 and Methanogenium frigidum Ace-2. DNA–DNA hybridization between strain AK-1 and these two strains showed only 34.9% similarity to strain JR-1 and 56.5%
similarity to strain Ace-2. These analyses indicated strain AK-1 should be classified as a new species within the genus Methanogenium. Phenotypic differences between strain AK-1 and these strains (including growth temperature, salinity range, pH range, and
nutrient requirements) support this. Therefore, a new species, Methanogenium marinum, is proposed with strain AK-1 as type strain.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
4.
The objective of this study was to evaluate the effect of extracellular H2 on organic acid utilization by two lactate-utilizing strains of Selenomonas ruminantium (HD4, H18). Both strains were able to grow (optical density at 600 nm ≥ after 9 h) on either aspartate, fumarate, or malate
in the presence of 1 atmosphere (atm) of H2. Succinate was the major end product produced in these fermentations. When cells were incubated with lactate plus 1 atm H2, growth was minimal and little lactate was fermented. The electron transport inhibitor, acriflavine, was a strong inhibitor
of growth when either strain was incubated in the presence of organic acid plus H2. Compared with glucose- or lactate-grown cells, cellular carbohydrate levels were lower for both strains in cells grown on
either organic acid plus H2. These results suggest that electron transport plays a role in organic acid utilization by S. ruminantium. 相似文献
5.
Mutants exhibiting high catalase activity were derived from Candida boidinii S2 strain AOU-1, from among mutants resistant to H2O2, NaN3 or 3-amino-1,2,4-triazole (ATA). The catalase activity of an ATA-resistant strain was improved by means of a methanol-limited chemostat culture with H2O2 supplementation. The catalase activity increased with increasing H2O2 concentration in the feed medium in the range where methanol did not remain. Alcohol oxidase activity increased after adaptation of the cells to H2O2. Cells of mutant strain SA051 grown under the optimal culture conditions produced 1200 mm formaldehyde in the reaction mixture. 相似文献
6.
In vitro assessment of the growth and plasma membrane H+‐ATPase inhibitory activity of ebselen and structurally related selenium‐ and sulfur‐containing compounds in Candida albicans
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Natalie N. Orie Andrew R. Warren Jovana Basaric Cesar Lau‐Cam Magdalena Piętka‐Ottlik Jacek Młochowski Blase Billack 《Journal of biochemical and molecular toxicology》2017,31(6)
Ebselen (EB, compound 1) is an investigational organoselenium compound that reduces fungal growth, in part, through inhibition of the fungal plasma membrane H+‐ATPase (Pma1p). In the present study, the growth inhibitory activity of EB and of five structural analogs was assessed in a fluconazole (FLU)‐resistant strain of Candida albicans (S2). While none of the compounds were more effective than EB at inhibiting fungal growth (IC50 ~ 18 μM), two compounds, compounds 5 and 6, were similar in potency. Medium acidification assays performed with S2 yeast cells revealed that compounds 4 and 6, but not compounds 2, 3, or 5, exerted an inhibitory activity comparable to EB (IC50 ~ 14 μM). Using a partially purified Pma1p preparation obtained from S2 yeast cells, EB and all the analogs demonstrated a similar inhibitory activity. Taken together, these results indicate that EB analogs are worth exploring further for use as growth inhibitors of FLU‐resistant fungi. 相似文献
7.
Summary Growth and alkaloid production of surface-immobilized C. roseus cells were studied in a 2-1 bioreactor. Media designed to maximize cell growth or alkaloid production were employed. Nitrate and carbohydrate consumption rates as well as growth rates and biomass yields of immobilized cultures were equal or somewhat lower than for cell suspension cultures. Respiration rate (O2 consumption and CO2 production rates) of immobilized C. roseus cell cultures was obtained by on-line analysis of inlet and outlet gas composition using a mass spectrometer. Respiration rate increased during the growth phase and decreased once the nitrogen or the carbon source was depleted from the medium. The respiration rate of immobilized C. roseus cells resembled rates reported in the literature for suspension cultures.
Offprint requests to: Denis Rho 相似文献
8.
Tanaka K Miyawaki K Yamaguchi A Khosravi-Darani K Matsusaki H 《Applied microbiology and biotechnology》2011,92(6):1161-1169
Cell growth and accumulation of polyhydroxybutyric acid, P(3HB), from CO2 in autotrophic condition of a newly isolated hydrogen-oxidizing bacterium, the strain O-1, was investigated. The bacterium,
which was deposited in the Japan Collection of Microorganisms as JCM17105, autotrophically grows by assimilating H2, O2, and CO2 as substrate. 16S rRNA gene sequence of the bacterium was the closest to Ideonella dechloratans (99%). Specific growth rate of the strain O-1 was faster than a hydrogen-oxidizing bacterium, Ralstonia eutropha, which is well-known P(3HB)-producing microorganism. The strain O-1 is tolerant to high O2 concentration and it can grow above 30% (v/v) O2, while the growth of R. eutropha and Alcaligenes latus was seriously inhibited. In culture medium containing 1 g/L (NH4)2SO4, cell concentration of the strain O-1 and P(3HB) increased to 6.75 and 5.26 g/L, respectively. The content of P(3HB) in the
cells was 77.9% (w/w). The strain O-1 was very tolerant to carbon monoxide (CO) and it grew even at 70% (v/v) CO, while the growth of R. eutropha and A. latus were seriously inhibited at 5% (v/v) CO. From these results, it is expected that the strain O-1 will be useful in the manufacture of P(3HB) because the industrial
exhaust gas containing CO2, H2, and CO can be directly used as the substrate in the fermentation process. 相似文献
9.
Methanosarcina barkeri (strain MS) grew and converted acetate to CO2 and methane after an adaption period of 20 days. Growth and metabolism were rapid with gas production being comparable to that of cells grown on H2 and CO2. After an intermediary growth cycle under a H2 and CO2 atmosphere acetateadapted cells were capable of growth on acetate with formation of methane and CO2. When acetate-adapted Methanosarcina barkeri was co-cultered with Acetobacterium woodii on fructose or glucose as substrate, a complete conversion of the carbohydrate to gases (CO2 and CH4) was observed.Abbreviation CMC
carboxymethyl cellulose 相似文献
10.
The marine purple nonsulfur bacterium, Rhodopseudomonas sulfidophila, strain W4, was capable of photosynthetic growth on dinitrogen and malate. Higher growth rates were observed when either glutamate or ammonia replaced dinitrogen as nitrogen source and when bicarbonate was omitted from the culture medium. Although ammonia was released from cells growing on malate and N2, no nitrogenase activity could be detected unless -ketoglutarate was added to the culture medium. No nitrogenase activity was found in cultures grown in the presence of NH
4
+
. In cultures grown on glutamate as nitrogen source, nitrogenase and hydrogenase activities were found to be 5.4 nmol C2H2 reduced · min-1 · mg-1 dry weight and 50 nmol methylene blue reduced · min-1 · mg-1 dry weight respectively. Such activities are significantly lower than those observed for other members of the Rhodospirillaceae e.g. Rhodopseudomonas capsulata. However, the hydrogenase activity would be sufficient to recycle all H2 produced by nitrogenase. It was indeed observed that growing cells did not evolve molecular hydrogen during photoheterotrophic growth and that H2 stimulated nitrogenase activity in resting cells of R. sulfidophila. The nitrogenase from this bacterium proved to be extremely sensitive to low concentrations of oxygen, half-inhibition occurring at between 1–1.5% O2 in the gas phase, depending on the bacterial concentration. Light was essential for nitrogenase activity. No activity was found during growth in the dark under extremely low oxygen concentrations (1–2% O2), which are still sufficient to support good growth. Resting cell suspensions prepared from such cultures were unable to reduce acetylene upon illumination. Optimum nitrogenase activities were broadly defined over the temperature range, 30–38°C, and between pH 6.9 and 8.0. The results are discussed in comparison with the non-marine purple nonsulfur bacterium, R. capsulata, which somewhat resembles R. sulfidophila. 相似文献
11.
Daniel Krekeler Pavel Sigalevich A. Teske H. Cypionka Yehuda Cohen 《Archives of microbiology》1997,167(6):369-375
In an investigation on the oxygen tolerance of sulfate-reducing bacteria, a strain was isolated from a 107-fold dilution of the upper 3-mm layer of a hypersaline cyanobacterial mat (transferred from Solar Lake, Sinai). The isolate,
designated P1B, appeared to be well-adapted to the varying concentrations of oxygen and sulfide that occur in this environment.
In the presence of oxygen strain P1B respired aerobically with the highest rates [260 nmol O2 min–1 (mg protein)–1] found so far among marine sulfate-reducing bacteria. Besides H2 and lactate, even sulfide or sulfite could be oxidized with oxygen. The sulfur compounds were completely oxidized to sulfate.
Under anoxic conditions, it grew with sulfate, sulfite, or thiosulfate as the electron acceptor using H2, lactate, pyruvate, ethanol, propanol, or butanol as the electron donor. Furthermore, in the absence of electron donors the
isolate grew by disproportionation of sulfite or thiosulfate to sulfate and sulfide. The highest respiration rates with oxygen
were obtained with H2 at low oxygen concentrations. Aerobic growth of homogeneous suspensions was not obtained. Additions of 1% oxygen to the gas
phase of a continuous culture resulted in the formation of cell clumps wherein the cells remained viable for at least 200
h. It is concluded that strain P1B is oxygen-tolerant but does not carry out sulfate reduction in the presence of oxygen under
the conditions tested. Analysis of the 16S rDNA sequence indicated that strain P1B belongs to the genus Desulfovibrio, with Desulfovibrio halophilus as its closest relative. Based on physiological properties strain P1B could not be assigned to this species. Therefore, a
new species, Desulfovibrio oxyclinae, is proposed.
Received: 7 August 1996 / Accepted: 29 January 1997 相似文献
12.
Aims: Applying competitive exclusion micro‐organisms to control hydrogen sulfide (H2S) gas produced by hydrogen sulfide–producing bacteria (SPB) in chicken meat. Methods and Results: Five SPB strains, isolated from animal by‐products, were used for screening lactic acid bacteria (LAB) that can inhibit the production of H2S by SPB in trypticase soy broth supplemented with l ‐cysteine (TSB‐l ‐cys). A sensitive and accurate test strip method was developed for H2S determination in real time. One LAB strain, isolate L86, from cheese whey, demonstrated the highest inhibitory activity against the production of H2S by SPB. The isolate L86 was confirmed as Enterococcus faecium that does not possess genes encoding for vancomycin resistance based on PCR analysis. Enterococcus faecium strain L86 reduced (P < 0·05) the yield of H2S upto 51·2% in 10 h at 35°C in TSB‐l ‐cys medium. In fresh chicken meat, the yield of H2S produced by the artificially inoculated SPB was reduced (P < 0·05) by 48·6, 49·7 and 69·8% in 10 h at 35, 30 and 25°C, respectively. Enterococcus faecium strain L86 also reduced (P < 0·05) by 53·8% on the yield of H2S produced by the indigenous SPB in partially spoiled chicken meat at 35°C for 10 h. Conclusions: Enterococcus faecium strain L86 is effective on inhibiting the production of H2S by SPB. Significance and Impact of the Study: The application of this biological agent to raw animal by‐products will provide a safer working environment in rendering processing plants and produce higher‐quality rendered products. 相似文献
13.
M. Ramirez J. M. Gómez D. Cantero J. Páca M. Halecký E. I. Kozliak M. Sobotka 《Folia microbiologica》2009,54(5):409-414
A strain of Acidithiobacillus thiooxidans immobilized in polyurethane foam was utilized for H2S removal in a bench-scale trickle-bed reactor, testing the limits of acidity and SO4
2− accumulation. The use of this acidophilic strain resulted in remarkable stability in the performance of the system. The reactor
maintained a >98–99 % H2S removal efficiency for c of up to 66 ppmv and empty bed residence time ≤12–15 s. Removal of >98 % H2S was achieved under steady-state conditions, over the pH range of 0.44–7.30. Despite the accumulation of acidity and SO4
2− (up to 97 g/L), the system operated without inhibition. 相似文献
14.
Photoautotrophic growth of a marine non-heterocystous filamentous cyanobacterium, Symploca sp. strain S84, was examined under nitrate-assimilating and N2-fixing conditions. Under continuous light, photon flux density of 55 μmol photons·m−2 ·s−1 was at a saturating level for growth, and light did not inhibit the growth rate under N2-fixing conditions even when the photon flux density was doubled (110 μmol photons·m−2 ·s−1). Doubling times of the N2-fixing cultures under 55 and 110 μmol photons·m−2 ·s−1 were about 30 and 31 h, respectively. Under 110 μmol photons·m−2 ·s−1 during the light phase of an alternating 12:12-h light:dark (L:D) cycle, the doubling time of the N2-fixing culture was also about 30 h. When grown diazotrophically under a 12:12-h L:D regime, C2H2 reduction activity was observed mainly during darkness. In continuous light, relatively large cyclic fluctuations in C2H2 reduction were observed during growth. The short-term (<4 h) effect of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU; 5 μM) indicated that C2H2 reduction activity was not influenced by photosynthetic O2 evolution. Long-term (24 h) effects of DCMU indicated that photosynthesis and C2H2 reduction activity occur simultaneously. These results indicate that strain S84 grows well under diazotrophic conditions when saturating light is supplied either continuously or under a 12:12-h L:D diel light regime. 相似文献
15.
The unicellular green alga Chlamydomonas reinhardtii possesses a [FeFe]-hydrogenase HydA1 (EC 1.12.7.2), which is coupled to the photosynthetic electron transport chain. Large
amounts of H2 are produced in a light-dependent reaction for several days when C. reinhardtii cells are deprived of sulfur. Under these conditions, the cells drastically change their physiology from aerobic photosynthetic
growth to an anaerobic resting state. The understanding of the underlying physiological processes is not only important for
getting further insights into the adaptability of photosynthesis, but will help to optimize the biotechnological application
of algae as H2 producers. Two of the still most disputed questions regarding H2 generation by C. reinhardtii concern the electron source for H2 evolution and the competition of the hydrogenase with alternative electron sinks. We analyzed the H2 metabolism of S-depleted C. reinhardtii cultures utilizing a special mass spectrometer setup and investigated the influence of photosystem II (PSII)- or ribulosebisphosphate-carboxylase/oxygenase
(Rubisco)-deficiency. We show that electrons for H2-production are provided both by PSII activity and by a non-photochemical plastoquinone reduction pathway, which is dependent
on previous PSII activity. In a Rubisco-deficient strain, which produces H2 also in the presence of sulfur, H2 generation seems to be the only significant electron sink for PSII activity and rescues this strain at least partially from
a light-sensitive phenotype. The latter indicates that the down-regulation of assimilatory pathways in S-deprived C. reinhardtii cells is one of the important prerequisites for a sustained H2 evolution. 相似文献
16.
Jong Won Kang Chang Moon Jeong Nag Jong Kim Moon Il Kim Ho Nam Chang 《Biotechnology and Bioprocess Engineering》2010,15(3):505-511
H2S in biogas was removed by sludge-loaded biofiltration, rendering the biogas suitable for catalytic reforming into a mixture
of CO and H2 syngas that was then applied for the generation of electricity using a solid oxide fuel cell or for the chemical synthesis
of methanol. The biogas was anaerobically produced in a 2 m3 bioreactor at 35°C for 2 years using restaurant food waste from Korea Advanced Institute of Science and Technology (KAIST),
and the concentration of H2S in the biogas ranged from 612 to 1,500 ppmv (Avg. 1,060 ppmv). Two immobilized cell bioreactors 0.2 and 8.5 L in volume
were loaded with aerobic sludge and used to study characteristics of H2S removal from biogas. At a retention time of 400 sec, the removal efficiency of H2S was over 99% following initial stabilization for 7 days in the 8.5 L bioreactor installed at the on-site biogas facility.
The maximum rate of H2S removal in this study was 359 g-H2S/m3/h with an average mass loading rate of 14.7 g-H2S/m3/h (kinetic analysis: V
m = 842.6 g-H2S/m3/h and K
s = 2.2 mg/L). Therefore, purified biogas with a negligible concentration H2S was efficiently reformed to syngas. This study demonstrates the feasibility of biogas purification as a part of high-quality
syngas production. 相似文献
17.
Hydrogen production by Rhodopseudomonas capsulata cells entrapped in carrageenan beads 总被引:2,自引:0,他引:2
Summary The photosynthetic bacteria Rhodopseudomonas capsulata strain B10 were immobilized in agar or in carrageenan beads (Ø = 1–3 mm). Beads containing 5.8 mg cell dry weight/mL of gel produced hydrogen from lactate at a rate of 54 mL/h.g dry weight; the efficiency of H2 production by immobilized cells was comparable to that of free cells and was 60 to 65% that of the theoretical maximum from lactate. Carrageenan-entrapped cells produced H2 steadily over a 16-day period. 相似文献
18.
Cell suspensions of uptake-hydrogenase-deficient (hup
-) mutants of a wild-type (B10S) and a nifHDK deletion strain of Rhodobacter capsulatus were used comparatively to characterize the conventional, Mo-containing and the alternative, “iron-only” nitrogenase of this
organism by determining the H2 production and acetylene reduction activities under argon and dinitrogen atmospheres. A comparison with the corresponding
hup
+ strains revealed that the hup
- mutation did not affect the nitrogenase activity and specificity within the acetylene-reduction assay, but caused a significant
increase in H2 production, which was more prominent in the case of the ΔnifHDK strain. The ΔnifHDK hup
- cells, grown in Mo-depleted medium and, thus, expressing the alternative nitrogenase system, were more than ten times less
active in the acetylene-reduction assay but exhibited H2 production rates equivalent to about 60% of the rates obtained with B10S hup
- cells after growth in a medium containing 10 μM MoO-
4. When these conditions were applied, the B10S strain only expressed the Mo nitrogenase. Under an argon atmosphere containing
about 5.5% (v/v) acetylene and under a dinitrogen atmosphere, ΔnifHDK hup
- cells produced H2 at even higher rates than B10S hup
- cells. The implications of our findings on a possible biotechnological H2 production and on the mechanism of nitrogenase catalysis are considered.
Received: 24 February 1996/Received revision: 15 May 1996/Accepted: 19 May 1996 相似文献
19.
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
20.
Mercury resistance of Clostridium cochlearium T-2P was found to be controlled by a different mechanism from those reported so far since no mercury-reducing activity was
detected in this strain.
The H2S generating ability as well as the demethylating activity of this bacterium was eliminated by the treatment with acridine
dye and recovered by the conjugation of the cured strain with the parent strain. In addition, the strain which lost their
abilities to generate H2S and to decompose methylmercury, showed higher sensitivity to mercurials than the parent strain. From these results, the
genes conferring both the activities seemed to reside on the plasmid and the mechanism of mercury resistance was probably
based on a detoxification mechanism involving methylmercury decomposition and inactivation of the inorganic mercury with H2S. 相似文献