共查询到20条相似文献,搜索用时 15 毫秒
1.
J. S. Potekhina N. G. Sherisheva L. P. Povetkina A. P. Pospelov T. A. Rakitina F. Warnecke G. Gottschalk 《Applied microbiology and biotechnology》1999,51(5):639-646
In acetate-limited chemostat cultures of Acinetobacter johnsonii 210A at a dilution rate of 0.1 h−1 the polyphosphate content of the cells increased from 13% to 24% of the biomass dry weight by glucose (100 mM), which was
only oxidized to gluconic acid. At this dilution rate, only about 17% of the energy from glucose oxidation was calculated
to be used for polyphosphate synthesis, the remaining 83% being used for biomass formation. Suspensions of non-growing, phosphate-deficient
cells had a six- to tenfold increased uptake rate of phosphate and accumulated polyphosphate aerobically up to 53% of the
biomass dry weight when supplied with only orthophosphate and Mg2+. The initial polyphosphate synthesis rate was 98 ± 17 nmol phosphate min−1 mg protein−1. Intracellular poly-β-hydroxybutyrate and lipids served as energy sources for the active uptake of phosphate and its subsequent
sequestration to polyphosphate. The H+-ATPase inhibitor N,N′-dicyclohexylcarbodiimide caused low ATP levels and a severe inhibition of polyphosphate formation, suggesting the involvement
of polyphosphate kinase in polyphosphate synthesis. It is concluded that, in A. johnsonii 210A, (i) polyphosphate is accumulated as the energy supply is in excess of that required for biosynthesis, (ii) not only
intracellular poly-β-hydroxybutyrate but also neutral lipids can serve as an energy source for polyphosphate-kinase-mediated
polyphosphate formation, (iii) phosphate-deficient cells may accumulate as much polyphosphate as activated sludges and recombinants
of Escherichia coli designed for polyphosphate accumulation.
Received: 23 October 1998 / Received revision: 18 January 1999 / Accepted: 22 January 1999 相似文献
2.
Lipid storage compounds in marine bacteria 总被引:15,自引:0,他引:15
Forty psychrophile or psychrotrophic crude-oil-utilizing marine bacteria were investigated for their ability to accumulate
lipid storage compounds in the cytoplasm during cultivation under nitrogen-limiting conditions. Most of them (73%) were able
to accumulate specialized lipids like polyhydroxyalkanoic acids (PHA) while other lipids such as wax esters occurred in two
isolates. Accumulation of PHA occurred predominantly at low temperatures (4–20 °C) as demonstrated for three isolates. Electron
microscopy revealed polyphosphate inclusions occurring in two isolates in addition to PHA. Cells of the isolate Acinetobacter sp. 211 were able to synthesize and accumulate lipid inclusions during growth on acetate, ethanol, olive oil, hexadecanol
and heptadecane. The composition of the lipid inclusions depended on the compounds provided as carbon source. Wax esters and
acylglycerols occurred mainly during the cultivation on olive oil; in contrast, wax esters and free alcohols occurred during
cultivation on hexadecanol. Total fatty acids in cells of the Acinetobacter sp. 211 amounted to 25% of the cellular dry weight in olive-oil-grown cells. Palmitic acid was the main fatty acid in the
lipids when the cells were cultivated on acetate or ethanol (44% and 32% of total fatty acids respectively). In contrast,
fatty acids occurring in the lipids during cultivation on hexadecanol, heptadecane or olive oil were related to the carbon
source. The fatty acids present in the accumulated lipids consisted predominantly of saturated and unsaturated straight-chain
fatty acids with a chain length ranging from 12 to 18 carbon atoms. Analysis of the lipid-granule-associated proteins in cells
of Acinetobacter sp. 211 revealed a protein of 39 kDa as the predominant protein species.
Received: 2 July 1996 / Received revision: 3 September 1996 / Accepted: 28 September 1996 相似文献
3.
Towards a reduction in excess sludge production in activated sludge processes: biomass physicochemical treatment and biodegradation 总被引:15,自引:0,他引:15
M. Rocher G. Goma A. Pilas Begue L. Louvel J. L. Rols 《Applied microbiology and biotechnology》1999,51(6):883-890
To decrease activated sludge production, microbial cell lysis can be amplified to enhance cryptic growth (biomass growth
on lysates). Cell breakage techniques (thermal, alkaline, acid) were studied to generate Alcaligenes eutrophus and sludge lysates and to evaluate their biodegradability. Gentle treatment conditions produced the best results. Complete
cell deactivation was obtained for temperatures higher than 55 °C. The release kinetics were similar for temperatures varying
from 60 °C to 100 °C. A 20-min incubation was suitable for reaching 80% of the maximum releasable carbon. In thermal-chemical
hydrolysis, NaOH was the most efficient for inducing cell lysis. Carbon release was a two-step process. First an immediate
release occurred, which was of the same order of magnitude for A. eutrophus and sludge [100–200 mg dissolved organic C (DOC) g total suspended solids (TSS)−1], followed by a post-treatment release. The second step was virtually equivalent to the first for sludge, and weaker for
A. eutrophus (<50 mg DOC g TSS−1). The biodegradability of the soluble fraction, both the immediate and the post-treatment carbon release, was investigated.
The optimal degradation yield, obtained with sludge cells, reached 55% after 48 h of incubation and 80% after 350 h. The most
consistent lysis and biodegradation results occurred at pH 10 and 60 °C after a 20-min incubation.
Received: 30 October 1998 / Received revision: 16 February 1999 / Accepted: 20 February 1999 相似文献
4.
A M Maszenan R J Seviour B M McDougall J A Soddell 《Journal of industrial microbiology & biotechnology》1997,18(4):267-271
Whole cell protein extracts from strains of the currently recognized genomic species of Acinetobacter, together with those from a range of isolates of several genomic species identified using the Biolog system and obtained
from a biological nutrient-removal activated sludge plant were analysed by SDS-PAGE. The dendrograms obtained after numerical
analysis for the known genomic species generally supported the taxonomic relationships suggested from earlier DNA–DNA hybridisation
data. In some cases the activated sludge isolates identified to genomic species level clustered closely with the corresponding
genomic species reference strains, although isolates 5 and 8/9 were scattered throughout the dendrogram. Considerable variations
were seen in the protein patterns of the 27 different environmental isolates of genomic species 7 that were analysed. Three
unidentified Acinetobacter isolates examined formed their own subcluster.
Received 06 September 1996/ Accepted in revised form 10 December 1996 相似文献
5.
M. H. A. van Eekert A. J. M. Stams J. A. Field G. Schraa 《Applied microbiology and biotechnology》1999,51(1):46-52
The dechlorinating activity of a methanogenic granular sludge from a methanol-fed upflow anaerobic sludge blanket reactor
was investigated with chlorinated ethanes. This unadapted methanogenic consortium degraded all chloroethanes tested. The product
formation rates decreased with the number of chlorine substituents. The more highly chlorinated ethanes were also converted,
although at a lower rate, in the presence of autoclaved (dead) sludge, indicating the involvement of reduced heat-stable cofactors
like vitamin B12 and F430. Direct chemical dechlorination of hexa-, penta- and tetrachloroethanes was also observed in medium without sludge, although
at a much lower rate. The results show the importance of cometabolic and abiotic (chemical) conversions for the transformation
of chlorinated ethanes by the methanogenic consortium. The types of reaction and the products formed were correlated with
the Gibbs free-energy change (ΔG
0′). Reductive hydrogenolysis and dichloroelimination were important dechlorinating mechanisms. Generally, these reactions have
a higher ΔG
0′ value than dehydrochlorination reactions, which occurred less frequently during the transformation of chloroethanes by the
methanogenic granular sludge.
Received: 8 June 1998 / Received revision: 7 September 1998 / Accepted: 13 September 1998 相似文献
6.
Enhanced biological phosphorus removal (EBPR) from wastewater can be more-or-less practically achieved but the microbiological
and biochemical components are not completely understood. EBPR involves cycling microbial biomass and influent wastewater
through anaerobic and aerobic zones to achieve a selection of microorganisms with high capacity to accumulate polyphosphate
intracellularly in the aerobic period. Biochemical or metabolic modelling of the process has been used to explain the types
of carbon and phosphorus transformations in sludge biomass. There are essentially two broad-groupings of microorganisms involved
in EBPR. They are polyphosphate accumulating organisms (PAOs) and their supposed carbon-competitors called glycogen accumulating
organisms (GAOs). The morphological appearance of microorganisms in EBPR sludges has attracted attention. For example, GAOs
as tetrad-arranged cocci and clusters of coccobacillus-shaped PAOs have been much commented upon and the use of simple cellular
staining methods has contributed to EBPR knowledge. Acinetobacter and other bacteria were regularly isolated in pure culture from EBPR sludges and were initially thought to be PAOs. However,
when contemporary molecular microbial ecology methods in concert with detailed process performance data and simple intracellular
polymer staining methods were used, a betaproteobacteria called ‘Candidatus Accumulibacter phosphatis’ was confirmed as a PAO and organisms from a novel gammaproteobacteria lineage were GAOs. To preclude making the mistakes of previous researchers, it is recommended that the sludge ‘biography’
be well understood – i.e. details of phenotype (process performance and biochemistry) and microbial community structure should
be linked.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
7.
Bioremoval of organic and inorganic sulphur from coal samples 总被引:1,自引:0,他引:1
The microbial ecology of different Spanish coal samples has been studied. Several bacteria have been isolated from enrichment
cultures and characterised and their biodesulphurization abilities evaluated. Using morphological and physiological properties,
different isolates have been related to species of the Xanthomonas, Pseudomonas, Chryseomonas and Moraxella genera. Some of the isolates, B(30)15 and T(30)10, gave important levels of organic desulphurization, close to 70%. Other
isolates, B(30)7 and B(30)8, were able to remove inorganic sulphur with high efficiencies, over 67%. One of the isolates,
B(30)10, metabolically related to Xanthomonas maltophila, was able to remove both organic and inorganic sulphur at neutral pH, with efficiencies of 69% and 68% respectively. The
results obtained underline the potential use of some of these strains for industrial coal desulphurization processes.
Received: 26 June 1998 / Received revised: 1 October 1998 / Accepted: 2 October 1998 相似文献
8.
Three Acinetobacter isolates (identified by API 20 NE as A. baumannii, A. junii, A. lwoffii) from activated sludge treating forest-industry wastewaters were used as model organisms for polyphosphate-accumulating bacteria to optimize growth conditions for acinetobacters. The optimal concentrations of carbon, nitrogen, phosphorus, magnesium and potassium for the growth of these isolates were determined by using four sets of factorially designed experiments. Maximum growth was obtained with an average C:N:P ratio of 100:14:1.5 (on a weight basis) in the medium. The average N:P ratio of about 10 is twice the ratio that is usually considered optimal for bacterial growth in activated sludge. Magnesium and potassium are crucial for polyphosphate metabolism. A. baumannii did not respond to either magnesium or potassium additions, and A. junii had a linear response to potassium. Comparison of the optimal molar Mg:P (0.93–1.8) and K:P (0.56) ratios obtained for A. lwoffii and A. junii in the experiments to the corresponding ratios in the influent wastewaters indicates that magnesium and potassium would not limit growth and concomitant polyphosphate formation in acinetobacters. The results based on the optimal concentrations of elements in the medium may provide a better basis for optimizing the growth conditions than data on the chemical composition of bacterial cells. 相似文献
9.
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
10.
K. L. Larsen H. J. S. Christensen F. Mathiesen L. H. Pedersen W. Zimmermann 《Applied microbiology and biotechnology》1998,50(3):314-317
The conversion of soluble starch to cyclomaltohexaose (α-CD), cyclomaltoheptaose (β-CD), cyclomaltooctaose (γ-CD) and cyclomaltononaose
(δ-CD) by cyclodextrin glycosyltransferases (E.C. 2.4.1.19) from Bacillus spp. and bacterial isolates was studied. The results show that δ-CD was formed by all the enzymes investigated in the range
of 5%–11.5% of the total amount of α-, β-, γ-, and δ-CD produced.
Received: 17 February 1998 / Received revision: 18 May 1998 / Accepted: 21 May 1998 相似文献
11.
Nylon-6, a man-made polymer that finds its application in the manufacture of car tires, ropes, fabrics, automobile parts
etc., is manufactured with ε-caprolactam. Waste water generated during production of nylon-6 contains the unreacted monomer.
Owing to the polluting and toxic nature of ε-caprolactam, its removal from waste streams is necessary. Pseudomonas aeruginosa MCM B-407 was isolated from activated sludge used to treat waste from a factory producing nylon-6. This organism was able
to remove ε-caprolactam with simultaneous reduction in chemical oxygen demand (COD). The degradation of ε-caprolactam in waste
water was found to be optimal over a wide range of pH from 5.0 to 9.0, temperature of 30°C, and under shake or aerated conditions,
with an inoculum density of 105 cells/ml and with an incubation period of 24 – 48 h. Thus, Pseudomonas aeruginosa MCM B-407 isolated from the activated sludge exposed to ε-caprolactam may play an important role in the bioremediation of
ε-caprolactam from the waste waters of industries manufacturing nylon-6.
Received: 13 November 1997 / Accepted: 9 April 1998 相似文献
12.
Composition of the cell walls of several yeast species 总被引:14,自引:0,他引:14
Cell walls, representing 26%–32% of the cell dry weight, were prepared from several strains of the yeasts Kloeckera apiculata, Debaryomyces hansenii, Zygosaccharomyces bailii,Kluyveromyces marxianus and Saccharomyces cerevisiae. Extraction of the walls with potassium hydroxide at 4 °C, followed by saturation of the alkali-soluble extract with ammonium
sulphate gave fractions of mannoprotein, alkali-soluble glucan and alkali-insoluble glucan. Chitin was associated with the
alkali-insoluble glucan. The proportions of the different fractions within the walls varied with the species and strain. Mannoprotein
comprised between 25% and 34% of the walls, the content of alkali-insoluble glucan ranged from 15% to 48%, and the content
of alkali-soluble glucan ranged from 10% to 48%. There was significant variation in the physical appearance of the alkali-soluble
glucans and the relative viscosity of suspensions of these glucans. The yeasts could represent novel sources of polysaccharides
with industrial and medical applications.
Received: 30 December 1997 / Received revision: 24 March 1998 / Accepted: 27 March 1998 相似文献
13.
Candida tropicalis, a strain isolated from the sludge of a factory manufacturing xylose, produced a high xylitol concentration of 131 g/l from
150 g/l xylose at 45 h in a flask. Above 150 g/l xylose, however, volumetric xylitol production rates decreased because of
a lag period in cell growth. In fed-batch culture, the volumetric production rate and xylitol yield from xylose varied substantially
with the controlled xylose concentration and were maximum at a controlled xylose concentration of 60 g/l. To increase the
xylitol yield from xylose, feeding experiments using different ratios of xylose and glucose were carried out in a fermentor.
The maximum xylitol yield from 300 g/l xylose was 91% at a glucose/xylose feeding ratio of 15%, while the maximum volumetric
production rate of xylitol was 3.98 g l−1 h−1 at a glucose/xylose feeding ratio of 20%. Xylitol production was found to decrease markedly as its concentration rose above
250 g/l. In order to accumulate xylitol to 250 g/l, 270 g/l xylose was added in total, at a glucose/xylose feeding ratio of
15%. Under these conditions, a final xylitol production of 251 g/l, which corresponded to a yield of 93%, was obtained from
270 g/l xylose in 55 h.
Received: 20 April 1998 / Received revision: 29 May 1998 / Accepted: 19 June 1998 相似文献
14.
We studied in batch reactors the kinetics and characterization of 70 °C, volatile fatty acids (VFAs)-grown, upflow anaerobic
sludge blanket granular sludge with 55 and 35 °C sludge as reference. The half-saturation constant (K
s), the inhibition constant (K
i), the maximum specific methane production rate (μCH4max), and the inhibition response coefficient (n) of the 70 °C sludge were 6.15 mM, 48.2 mM, 0.132 h−1, and 2.48, respectively, while no inhibition occurred at 55 and 35 °C, where the K
s was 3.67 and 3.82 mM, respectively. At 70 °C, the highest initial specific methanogenic activity (ISMA, 0.311 gCH4-COD per gram volatile solids per day) on VFAs was about 12–15% lower than that on acetate and three to four times less than
the ISMA for the 55 and 35 °C sludge. In the acetate conversion study, residual acetate (79 mg l−1) at 70 °C was three to five times higher than that at 55 and 35 °C. Further, the methane produced as percentage of the acetate
consumed at 70 °C (89%) was lower than that at 55 (95%) and 35 °C (97%). At 70 °C, 10% of the ISMA remained after 15 days
of starvation as compared to 26% (55 °C) and 92% (35 °C) after 30 days of starvation. Thus, the kinetics of the 70 °C granular
sludge seem to differ from those at 55 and 35 °C.
Received: 1 February 1999 / Accepted: 20 March 1999 相似文献
15.
P. Ledent H. Michels G. Blackman H. Naveau S. N. Agathos 《Applied microbiology and biotechnology》1999,51(3):370-374
Anionic, cationic, amphoteric and non-ionic surfactants inhibited spore germination and subsequent growth of a mixture of
two Bacillus strains at surfactant concentrations ranging from 1 ppm to 50 ppm. Germination appeared to be more affected than cell growth
by the presence of surfactants, the inhibitory thresholds being largely increased when media were inoculated with vegetative
cells. The bacterial species forming the consortium were incapable of growing on liquid and agar-solidified media prepared
with non-diluted domestic wastewater. Addition of hydrolases (protease, cellulase, α-amylase and lipase) to the wastewater
medium allowed the germination of spores and their vegetative growth.
Received: 9 July 1998 / Received revision: 26 October 1998 / Accepted: 30 October 1998 相似文献
16.
J. Q. Liu M. Odani T. Dairi N. Itoh S. Shimizu H. Yamada 《Applied microbiology and biotechnology》1999,51(5):586-591
A new enzymatic resolution process was established for the production of l-threo-3-[4-(methylthio)phenylserine] (MTPS), an intermediate for synthesis of antibiotics, florfenicol and thiamphenicol, using
the recombinant low-specificity d-threonine aldolase from Arthrobacter sp. DK-38. Chemically synthesized dl-threo-MTPS was efficiently resolved with either the purified enzyme or the intact recombinant Escherichiacoli cells overproducing the enzyme. Under the optimized experimental conditions, 100 mM (22.8 g l−1) l-threo-MTPS was obtained from 200 mM (45.5 g l−1) dl-threo-MTPS, with a molar yield of 50% and a 99.6% enantiomeric excess.
Received: 2 September 1998 / Received revision: 27 October 1998 / Accepted: 29 November 1998 相似文献
17.
M. Arnold A. Reittu A. von Wright P. J. Martikainen M.-L. Suihko 《Applied microbiology and biotechnology》1997,48(6):738-744
A biofiltration process was developed for styrene-containing off-gases using peat as filter material. The average styrene
reduction ratio after 190 days of operation was 70% (max. 98%) and the mean styrene elimination capacity was 12 g m−3 h−1 (max. 30 g m−3 h−1). Efficient styrene degradation required addition of nutrients to the peat, adjustment of the pH to a neutral level and efficient
control of the humidity. Maintenance of the water balance was easier in a down-flow than in an up-flow process, the former
consequently resulting in much better filtration efficiency. The optimum operation temperature was around 23 °C, but the styrene
removal was still satisfactory at 12 °C. Seven different bacterial isolates belonging to the genera Tsukamurella, Pseudomonas, Sphingomonas, Xanthomonas and an unidentified genus in the γ group of the Proteobacteria isolated from the microflora of active peat filter material were capable of styrene degradation. The isolates differed in
their capacity to decompose styrene to carbon dioxide and assimilate it to biomass. No toxic intermediate degradation products
of styrene were detected in the filter outlet gas or in growing cultures of isolated bacteria. The use of these isolates in
industrial biofilters is beneficial at low styrene concentrations and is safe from both the environmental and public health
points of view.
Received: 30 May 1997 / Received revision: 22 August 1997 / Accepted: 25 August 1997 相似文献
18.
A total of 10 non-repetitive multi-drug-resistant Acinetobacter strains were collected. With reference to A. calcoaceticus (ATCC23055), A. baumannii (ATCC19606), A. lwoffii (ATCC17986), and A. junii (NCTC5866),DNA fingerprint technique, amplified ribosomal DNA restriction analysis (ARDRA), and random amplified polymorphism
DNA (RAPD) were carried out to identify the genomic species of Acinetobacter spp. The distances between them were calculated by the unweighted pair group method with arithmetic (UPGMA). Genotypes of
Acinetobacter spp. were effectively classified and an A. junii together with nine A. baumannii isolates was genomically identified. The combination of ARDRA and RAPD DNA-fingerprint technique shows high complementarity,
and could be a useful tool in Acinetobacter genomic species identification.
__________
Translated from Microbiology, 2007, 34(2): 303–306 [译自:微生物学通报] 相似文献
19.
Daniel HJ Otto RT Binder M Reuss M Syldatk C 《Applied microbiology and biotechnology》1999,51(1):40-45
In order to produce sophorolipids from whey, thereby lowering the lactose content and biological oxygen demand, a two-step
batch cultivation process was developed including medium sterilization by filtration. In the first step, whey was sterilized
by a combination of crossflow and sterile filtration. Because the sophorolipid-producing yeast Candida bombicola ATCC 22214 was not able to use lactose as a carbon source directly, the oleaginous yeast Cryptococcus curvatus ATCC 20509 was grown on deproteinized whey concentrates (DWC). With 1: 1 diluted DWC-20, lactose was consumed as the carbon
source and biomass (24 g/l dry weight content) as well as single-cell oil (SCO, 10 g/l) were produced. The cultivation broth
was disrupted with a glass bead mill and it served as medium for growth (29 g cell dry mass/l) and sophorolipid production
(12 g/l) of the yeast C. bombicola.
Received: 29 July 1998 / Received revision: 5 October 1998 / Accepted: 11 October 1998 相似文献
20.
N. Kitamoto S. Yoshino M. Ito T. Kimura K. Ohmiya N. Tsukagoshi 《Applied microbiology and biotechnology》1998,50(5):558-563
A xylanase gene, xynF1, was cloned and characterized from a shoyu koji mould Aspergillus oryzae KBN616. The xynF1 gene was found to be comprised of 1484 bp with ten introns. The deduced amino acid sequence encodes a protein consisting
of 327 amino acids (35,402 Da) which is very similar to the fungal family F xylanases such as Aspergillus nidulans XlnC, Aspergillus kawachii XynA and Penicillium chrysogenum XylP. The intron/exon organization of xynF1 is very similar to that of the fungal family F xylanase genes. Plasmid pXPR64, which contains 64 copies of the xynF1 promoter region (PxynF1) in the same direction, was constructed and introduced into A. oryzae. This led to reduced expression of both xylanase and β-xylosidase genes in the transformants.
Received: 18 May 1998 / Received revision: 7 July 1998 / Accepted: 9 July 1998 相似文献