共查询到20条相似文献,搜索用时 15 毫秒
1.
Anaerobic sequencing batch reactors for wastewater treatment: a developing technology 总被引:4,自引:0,他引:4
Zaiat M Rodrigues JA Ratusznei SM de Camargo EF Borzani W 《Applied microbiology and biotechnology》2001,55(1):29-35
This paper describes and discusses the main problems related to anaerobic batch and fed-batch processes for wastewater treatment.
A critical analysis of the literature evaluated the industrial application viability and proposed alternatives to improve
operation and control of this system. Two approaches were presented in order to make this anaerobic discontinuous process
feasible for industrial application: (1) optimization of the operating procedures in reactors containing self-immobilized
sludge as granules, and (2) design of bioreactors with inert support media for biomass immobilization.
Received: 22 May 2000 / Received revision: 20 July 2000 / Accepted: 21 July 2000 相似文献
2.
Biological phosphate removal processes 总被引:9,自引:0,他引:9
M. C. M. van Loosdrecht C. M. Hooijmans D. Brdjanovic J. J. Heijnen 《Applied microbiology and biotechnology》1997,48(3):289-296
Biological phosphate removal has become a reliable and well-understood process for wastewater treatment. This review describes
the historical development of the process and the most important microbiological and process-engineering aspects. From a microbiological
point of view, the role of␣poly(hydroxyalkanoates) as storage material in a dynamic process and the use of polyphosphate as
an energy reserve are the most important findings. From a process-engineering point of view, the study of biological phosphate
removal has shown that highly complex biological processes can be designed and controlled, provided that the importance of
the prevailing microbiological ecological processes is recognised.
Received: 3 April 1997 / Received revision: 9 June 1997 / Accepted: 14 June 1997 相似文献
3.
M. Rutgers A. M. Breure J. G. van Andel W. A. Duetz 《Applied microbiology and biotechnology》1997,48(5):656-661
A polychlorophenol-degrading bacterium, Sphingomonas sp. strain P5, was grown in 2,6-dichlo-rophenol(26-DCP)-limited, 2,3,6-trichlorophenol(236-TCP)-limited, 2,4,6-trichlorophenol(246-TCP)-limited,
2,3,4,6-tetrachlorophenol(2346-TeCP)-limited, and pentachlorophenol(PCP)-limited chemostat cultures at a dilution rate of
0.02 ± 0.002 h−1. The cultures were analyzed for the yield coefficient for growth on chlorophenol during steady-state conditions. The average
growth yields coefficients (as carbon conversion efficiencies) were 0.252, 0.230, 0.219, 0.157, and 0.121 mol C mol C−1 for 26-DCP, 236-TCP, 246-TCP, 2346-TeCP, and PCP respectively. The differences in growth yield can be interpreted in terms
of the energetics of chlorinated carbon metabolism; i.e. substitution of the phenol moiety reduces the available metabolic
energy by one electron per chlorine. The growth yield coefficients on chlorinated phenols were lower than the yield coefficients
of heterotrophic growth reported in the literature on non-chlorinated and aliphatic compounds. Metabolic origins for low growth
yield coefficients on (chlorinated) aromatic compounds are postulated.
Received: 7 April 1997 / Received revision: 7 July 1997 / Accepted: 12 July 1997 相似文献
4.
I. Schneegaß M. Hofrichter K. Scheibner W. Fritsche 《Applied microbiology and biotechnology》1997,48(5):602-605
The main manganese peroxidase isoenzyme MnP2 of the South American white-rot fungus Nematoloma frowardii b19 was purified to homogeneity using anion-exchange chromatography (Mono Q) and preparative isoelectric focusing. The purified
enzyme has a molecular mass of 44 kDa and a pI of 3.2.
Received: 23 May 1997 / Received revision: 1 July 1997 / Accepted: 4 July 1997 相似文献
5.
P. Barghini F. Montebove M. Ruzzi A. Schiesser 《Applied microbiology and biotechnology》1998,49(3):309-314
Pseudomonas fluorescens BF13 is especially capable of promoting the formation of vanillic acid during ferulic acid degradation. We studied the possibility
of enhancing the formation of this intermediary metabolite by using suspensions of cells at high density. The bioconversion
of ferulic into vanillic acid was affected by several parameters, such as the concentration of the biomass, the amount of
ferulic acid that was treated, the carbon source on which the biomass was grown. The optimal yield of vanillic acid was obtained
with 6 mg/ml cells pre-grown on p-coumaric acid and 2 mg/ml ferulic acid. Under these conditions the bioconversion rate was 95% in 5 h. Therefore BF13 strain
represents a valid biocatalyst for the preparative synthesis of vanillic acid.
Received: 1 July 1997 / Received revision: 28 October 1997 / Accepted: 16 November 1997 相似文献
6.
D. Segura C. Santana R. Gosh L. Escalante S. Sanchez 《Applied microbiology and biotechnology》1997,48(5):615-620
In Streptomyces peucetius var. caesius, the production of anthracyclines was suppressed either by 330 mM d-glucose or 25 mM phosphate. In addition, the anthracycline doxorubicin and the glucose analogue 2-deoxyglucose inhibited
the growth of this microorganism at concentrations of 0.025 mM and 10 mM respectively. Spontaneous and induced mutants, resistant
to the action of these compounds, were isolated, tested and chosen by their ability to overproduce anthracyclines. Genetic
recombination between representative mutants was carried out by the protoplast fusion technique. Some recombinants carrying
resistance to doxorubicin, phosphate and 2-deoxyglucose produced more than 40-fold greater levels of anthracyclines than those
obtained with the parental strain. This improvement resulted in total antibiotic titres of more than 2 g/l culture medium
at 6 days of fermentation.
Received: 14 April 1997 / Received revision: 19 June 1997 / Accepted: 4 July 1997 相似文献
7.
Changes in intrinsic fluorescence during the production of viable but nonculturable Escherichia coli
D C Roselle M Seaver J D Eversole 《Journal of industrial microbiology & biotechnology》1998,20(5):265-267
The potential of intrinsic fluorescence spectroscopy to detect and differentiate viable but nonculturable bacteria in the
presence of culturable bacteria was explored. Escherichia coli cells, starved for 210 days in nutrient-free normal saline, show new fluorescence emissions near 400 and 440 nm, and reduced
emission near 340 nm.
Received 7 July 1997/ Accepted in revised form 26 November 1997 相似文献
8.
M. J. Kujau C. Hoischen D. Riesenberg J. Gumpert 《Applied microbiology and biotechnology》1998,49(1):51-58
The paper describes the synthesis of the phosphorylcholine-binding miniantibody McPC603scFvDhl x in cell-wall-less L-form
strains of Escherichia coli and Proteus mirabilis. Cells of these strains were transformed with the plasmid pACK02scKan, carrying the miniantibody (miniAb) coding sequence
under the control of the lac promoter. L-form transformants of both species were able to synthesize the functional miniAb as an extracellular soluble
product. The highest quantities were obtained by P. mirabilis L-form strains after induction with 5 mM isopropyl β-d-thiogalactopyranoside (IPTG). Yields of 45–75 mg/l total antibody protein and of 10–18 mg/l functional miniAb were estimated
in the growth medium of shaking cultures 40–80 h after induction with IPTG. About 10% of the active miniAb remained cell-bound.
The yields of functional miniAb could be optimized by lowering the growth temperature from 37 °C to 26–32 °C and by supplementation
of the medium with 80 mM sodium fumarate. A comparison of the specific activities revealed that the P. mirabilis L-form strains have a similar synthesis capacity (2–4 mg functional miniAb/g cell dry weight) to that of the producer strain
E. coli RV308. The results show that the processes of correct folding and assembling of the miniAb molecules are possible without
the periplasmic compartment.
Received: 14 April 1997 / Received revision: 17 July 1997 / Accepted: 25 August 1997 相似文献
9.
K. M. J. Van Laere G. Beldman A. G. J. Voragen 《Applied microbiology and biotechnology》1997,47(3):231-235
An arabinofuranohydrolase (AXH-d3) was purified from a cell-free extract of Bifidobacterium adolescentis DSM 20083. The enzyme had a molecular mass of approximately 100 kDa as determined by gel filtration. It displayed maximum
activity at pH 6 and 30 °C. Using an arabinoxylan-derived oligosaccharide containing double-substituted xylopyranosyl residues
established that the enzyme specifically released terminal arabinofuranosyl residues linked to C-3 of double-substituted xylopyranosyl
residues. In addition, this arabinofuranohydrolase released arabinosyl groups from wheat flour arabinoxylan polymer but showed
no activity towards p-nitrophenyl α-l-arabinofuranoside or towards sugar-beet arabinan, soy arabinogalactan, arabino-oligosaccharides and arabinogalacto-oligosaccharides.
Received: 15 July 1996 / Received revision: 18 October 1996 / Accepted: 18 October 1996 相似文献
10.
Riboflavin production is significantly determined by the type and initial concentration of the carbon and nitrogen sources
and also by other flavinogenic stimulants. Using an optimum carbon and nitrogen concentration, an industrial fermentation
medium has been designed with molasses as the carbon source and peanut seed cake as the nitrogen source. In addition the stimulatory
effect of some of the low-cost agro-industrial by-products on riboflavin yield was investigated.
Received: 10 March 1996 / Received revision: 25 June 1996 / Accepted: 14 July 1996 相似文献
11.
The effects of different phenolic compound concentrations on the fatty acid composition of Lactobacillus plantarum isolated from traditional home-made olive brines were determined. Increasing amounts of caffeic and ferulic acids induced
a gradual increase in the amounts of myristic, palmitoleic, stearic and 9,10-methylenehexadecanoic (C17Δ, where Δ represents
the cyclopropane group) acid with a concomitant decrease of lactobacillic acid (C19Δ). On the other hand, the addition of tannins induced an increase in the C19Δ level at the expense of vaccenic acid content. The presence of acidic phenols and tannins also affected bacterial growth,
inducing the most obvious effect with tannin at 1 g l−1.
Received: 1 July 1997 / Received revision: 9 September 1997 / Accepted: 15 September 1997 相似文献
12.
R. Webster M. Pacey T. Winchester P. Johnson S. Jezequel 《Applied microbiology and biotechnology》1998,49(4):371-376
The 4′-hydroxylated metabolite of diclofenac was produced by biocatalysis for probing specific human drug-metabolising enzymes
(CYP2C9). An initial screen of 11 microorganisms was carried out (50 ml scale) to identify the organism best suited to the
regioselective conversion of diclofenac to its 4′-hydroxylated metabolite. From this screen, the fungus Epicoccum nigrum IMI354292 was selected as the most suitable microorganism. Scale-up was carried out in a 30-l fermenter to which 2 g diclofenac
was added. After 48 h, 50% of the diclofenac had been converted to it 4′-hydroxylated metabolite. The broth was then extracted
with ethyl acetate and purified by chromatography and crystallisation. This yielded 0.3 g 4′-hydroxydiclofenac with a purity
of at least 99%. The 4′-hydroxydiclofenac produced by E. nigrum was characterised by HPLC, mass spectrometry and NMR.
Received: 28 July 1997 / Received revision: 8 December 1997 / Accepted: 14 December 1997 相似文献
13.
P. Dürre 《Applied microbiology and biotechnology》1998,49(6):639-648
Clostridial acetone/butanol fermentation used to rank second only to ethanol fermentation by yeast in its scale of production
and thus is one of the largest biotechnological processes known. Its decline since about 1950 has been caused by increasing
substrate costs and the availability of much cheaper feedstocks for chemical solvent synthesis by the petrochemical industry.
The so-called oil crisis in 1973 led to renewed interest in novel fermentation and product recovery technologies as well as
in the metabolism and genetics of the bacterial species involved. As a consequence, almost all of the enzymes leading to solvent
formation are known, their genes have been sequenced (in fact, Clostridium acetobutylicum has been recently included in the microbial genome sequencing project), the regulatory mechanisms controlling solventogenesis
have begun to emerge and recombinant DNA techniques have been developed for these clostridia to construct specific production
strains. In parallel, cheap agricultural-waste-based feedstocks have been exploited for their potential as novel substrates,
continuous culture methods have been successfully established and new on-line product recovery technologies are now available,
such as gas stripping, liquid/liquid extraction, and membrane-based methods. In combination with these achievements, a reintroduction
of acetone/butanol fermentation on an industrial scale seems to be economically feasible, a view that is supported by a new
pilot plant in Austria recently coming into operation.
Received: 18 December 1997 / Received revision: 27 January 1998 / Accepted: 27 January 1998 相似文献
14.
Triglycerides, a major class of wood extractives, contribute to the colloidal pitch that initiates pitch deposits. Because
industrial or pilot-scale treatments with lipolytic enzymes to reduce triglyceride concentrations in pulp have not been successful
in North America, we investigated such treatments at a laboratory scale. Different batches of industrial softwood chemithermomechanical
pulps (CTMP) were treated with a range of concentrations of two commercial lipases: Resinase A 2X (Novo Nordisk AG) and Lipidase
10 000 (American Laboratories Inc.). A pilot-scale thermomechanical pulp (TMP) made from the same wood as the CTMP, but without
the sodium hydrosulfite used in the CTMP, was also treated with the lipases. While triglycerides decreased in all the pulp
treatments, the extent of their hydrolysis varied according to the ratio of triglyceride to the fatty/resin acid fraction.
As this ratio can vary significantly in softwood TMP and CTMP, the success of industrial treatments of softwood mechanical
pulps by commercial lipases may be related to variations in this ratio. Supporting this, adding linoleic acid to an extractives-free
pulp that was spiked with olive oil reduced lipase activity by up to 55%.
Received: 7 August 1997 / Received last revision: 8 December 1997 / Accepted: 14 December 1997 相似文献
15.
Effect of various inhibitors on the (NH4
+ + Na+)-activated ATPase of an anaerobic alkaliphile, Ep01(a strain of Amphibacillus xylanus), was examined. Among the chemicals tested, the enzyme was drastically inactivated by p-chloromercuribenzoic acid and diethyl pyrocarbonate. The ATPase activity of the enzyme, which was inactivated by p-chloromercuribenzoic acid and diethyl pyrocarbonate, was remarkably restored by β-mercaptoethanol and hydroxylamine, respectively,
suggesting the involvement of cysteine and histidine residues in the enzyme activity. Analysis of the inhibition kinetics
by diethyl pyrocarbonate indicated that modification of a single histidine residue per ATPase molecule was sufficient to inactivate
the enzyme.
Received: 2 June 1997 / Accepted: 7 July 1997 相似文献
16.
D Di Simine C Finoli A Vecchio V Andreoni 《Journal of industrial microbiology & biotechnology》1998,20(2):116-120
This paper explores the use of an experimental system based on polyacrylamide-entrapped cells of Brevibacterium sp strain PBZ for the removal of metal ions from solutions. Experiments were performed in columns filled with the immobilised
cells and challenged with influents containing 20 mg L−1 of lead and 10 mg L−1 of cadmium. The cells were able to accumulate lead (about 40 mg g−1 dry biomass) and, to a lesser extent, cadmium (about 13 mg g−1 dry biomass) from solutions. In the presence of 0.4 g L−1 of glucose, the cells removed up to 53% of lead. Lead competed with cadmium for attachment to the binding sites when a solution
containing both the metals was applied. Lead removal occurred by a combination of fast physico-chemical adsorption and prolonged
low rate accumulation mediated by cell metabolism. The biosorptive capacity of the cells was sensitive to pH. Desorption of
the metal with EDTA restored the binding capability of the cells.
Received 07 July 1997/ Accepted in revised form 26 November 1997 相似文献
17.
S. Halldórsdóttir E. T. Thórólfsdóttir R. Spilliaert M. Johansson S. H. Thorbjarnardóttir A. Palsdottir G. Ó. Hreggvidsson J. K. Kristjánsson O. Holst G. Eggertsson 《Applied microbiology and biotechnology》1998,49(3):277-284
A gene library from the thermophilic eubacterium Rhodothermus marinus, strain ITI 378, was constructed in pUC18 and transformed into Escherichia coli. Of 5400 transformants, 3 were active on carboxymethylcellulose. Three plasmids conferring cellulase activity were purified
and were all found to contain the same cellulase gene, celA. The open reading frame for the celA gene is 780 base pairs and encodes a protein of 260 amino acids with a calculated molecular mass of 28.8 kDa. The amino acid
sequence shows homology with cellulases in glycosyl hydrolase family 12. The celA gene was overexpressed in E. coli when the pET23, T7 phage RNA polymerase system was used. The enzyme showed activity on carboxymethylcellulose and lichenan,
but not on birch xylan or laminarin. The expressed enzyme had six terminal histidine residues and was purified by using a
nickel nitrilotriacetate column. The enzyme had a pH optimum of 6–7 and its highest measured initial activity at 100 °C. The
heat stability of the enzyme was increased by removal of the histidine residues. It then retained 75% of its activity after
8 h at 90 °C.
Received: 5 August 1997 / Received revision: 6 November 1997 / Accepted: 7 November 1997 相似文献
18.
Chemically defined media for commercial fermentations 总被引:13,自引:0,他引:13
The use of chemically defined media is gaining popularity in some commercial fermentations, particularly for the preparation
of biological products. Although these media are still not frequently developed for industrial processes, they do exhibit
favorable characteristics at large scale that are not observed with traditional complex media. This review focuses on the
application, development, and practical considerations, especially process economics, of fermentations in chemically defined
media in an industrial environment.
Received: 3 August 1998 / Received revision: 16 November 1998 / Accepted: 21 November 1998 相似文献
19.
R. H. Müller D. Simon H. J. Große W. Babel 《Applied microbiology and biotechnology》1997,48(5):648-655
Ralstonia eutropha (formerly Alcaligenes eutrophus) JMP 134 was continuously grown on phenol and 2,4-dichlorophenoxyacetate at elevated levels of stationary substrate concentration
by using the nutristat principle in order to study the physiological impact exerted by these toxic substrates. Growth at stationary
concentrations of both the substrates resulted in the reduction of growth efficiency and growth rate. The growth yield data
revealed a pronounced dependence on the substrate concentration, and the growth yield increasingly diminished with rising
substrate concentration. Inhibition was more pronounced with 2,4-dichlorophenoxyacetate, which reduced the growth yield coefficient
by 50% at a substrate concentration of 0.1–0.25 mM. The same effect was obtained with phenol at about 5 mM. The growth rate
profile had two distinct phases: after an initially strong reduction, the rate levelled-off at higher substrate concentrations.
Standardizing the inhibition profiles, by taking into account the maximum effect after extrapolating the data to zero growth
yield, revealed an almost identical pattern with both substrates, indicating some common mechanism. The growth yield data
show that an increased amount of energy is required for both growth and maintenance. Homeostatic work was increased by a factor
of 8 at 75% inhibition; growth collapsed once this amount of energy was no longer available. The effects are discussed with
respect to the properties of these substrates functioning as potential uncouplers of energy conservation.
Received: 5 June 1997 / Received revision: 7 July 1997 / Accepted: 12 July 1997 相似文献
20.
Continuous vapor-phase trichloroethylene biofiltration using hydrocarbon-enriched compost as filtration matrix 总被引:3,自引:0,他引:3
Two sources of finished compost material were examined for the capacity to support trichloroethylene(TCE)-degrading microbial
populations in a gas-phase bioreactor. Gaseous hydrocarbon was passed through the bioreactor to stimulate cometabolic oxidation
of TCE. Significant differences in TCE removal efficiencies were observed between the two compost types, and between hydrocarbon-stimulated
and non-stimulated compost. At an average column retention time of 5.6 min, deciduous leaf debris compost removed more than
95% of a 5–50 ppm (by vol.) TCE gas stream, whereas less than 15% removal was observed under similar conditions with a woodchip
and bark compost. Trichloroethylene removal efficiency varied with the hydrocarbon-stimulation regime employed, although propane
and methane stimulated TCE degradation equally well. Amendment of compost with granular activated carbon substantially increased
biological TCE removal. Differences in TCE removal efficiencies observed between the two compost types and between hydrocarbon-stimulated
and non-stimulated composts were investigated in terms of changes in the overall heterotrophic microbial populations by using
community-level physiological profile analysis.
Received: 14 April 1997 / Received revision: 21 July 1997 / Accepted: 25 August 1997 相似文献