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1.
Development of a cost-effective glucose-corn steep medium for production of butanol by Clostridium beijerinckii 总被引:1,自引:0,他引:1
M Parekh J Formanek H P Blaschek 《Journal of industrial microbiology & biotechnology》1998,21(4-5):187-191
Corn steep water (CSW) medium (1.6% solids plus 6% glucose) was evaluated for growth and butanol production by Clostridium beijerinckii NCIMB 8052 wild-type and hyper-amylolytic, hyper-butanol-producing mutant strain BA101. CSW alone was not a suitable substrate,
whereas addition of glucose supported growth and butanol production by both strains. In a batch-scale fermentation using an
optimized 6% glucose-1.6% solids CSW medium, C. beijerinckii NCIMB 8052 and strain BA101 produced 10.7 g L−1 and 14.5 g L−1 of butanol, respectively. The total solvents (acetone, butanol, and ethanol) produced by C. beijerinckii NCIMB 8052 and strain BA101 were 14 g L−1 and 20 g L−1, respectively. Initial fermentation in small-scale flasks containing 6% maltodextrin-1.6% solids concentration CSW medium
resulted in 6 g L−1 and 12.6 g L−1 of butanol production by C. beijerinckii NCIMB 8052 and strain BA101, respectively. CSW can serve as an economic source of nitrogen, vitamins, amino acids, minerals,
and other nutrients. Thus, it is feasible to use 6% glucose-1.6% solids CSW medium in place of semi-defined P2 medium.
Received 9 February 1998/ Accepted in revised form 1 September 1998 相似文献
2.
Toluene vapour removal in a laboratory-scale biofilter 总被引:4,自引:0,他引:4
A bench-scale biofilter with a 0.5-m high filter bed, inoculated with a toluene-degrading strain of Acinetobacter sp. NCIMB 9689, was used to study toluene removal from a synthetic waste air stream. Different sets of continuous tests were
conducted at influent toluene concentrations ranging over 0.1–4.0 g m−3 and at superficial gas velocities ranging over 17.8–255 m h−1. The maximum volumetric toluene removal rate for the biofilter (242 g m−3 h−1) was obtained at a superficial gas velocity of 127.5 m h−1 (corresponding to a residence time of 28 s) and a toluene inlet concentration of 4.0 g m−3. Under these operating conditions, toluene removal efficiency was only 0.238, which suggested that effective operation required
higher residence times. Removal efficiencies higher than 0.9 were achieved at organic loads less than 113.7 g m−3 h−1. A macro-kinetic study, performed using concentration profiles along the bioreactor, revealed this process was limited by
diffusion at organic loads less than 100 g m−3 h−1 and by biological reaction beyond this threshold.
Received: 10 October 1999 / Received revision: 15 February 2000 / Accepted: 18 February 2000 相似文献
3.
The use of silica gel prepared by sol-gel method and polyurethane foam as microbial carriers in the continuous degradation of phenol 总被引:5,自引:0,他引:5
A mixed microbial culture was immobilized by entrapment into silica gel (SG) and entrapment/ adsorption on polyurethane foam
(PU) and ceramic foam. The phenol degradation performance of the SG biocatalyst was studied in a packed-bed reactor (PBR),
packed-bed reactor with ceramic foam (PBRC) and fluidized-bed reactor (FBR). In continuous experiments the maximum degradation
rate of phenol (q
s
max) decreased in the order: PBRC (598 mg l−1 h−1) > PBR (PU, 471 mg l−1 h−1) > PBR (SG, 394 mg l−1 h−1) > FBR (PU, 161 mg l−1 h−1) > FBR (SG, 91 mg l−1 h−1). The long-term use of the SG biocatalyst in continuous phenol degradation resulted in the formation of a 100–200 μm thick
layer with a high cell density on the surface of the gel particles. The abrasion of the surface layer in the FBR contributed
to the poor degradation performance of this reactor configuration. Coating the ceramic foam with a layer of cells immobilized
in colloidal SiO2 enhanced the phenol degradation efficiency during the first 3 days of the PBRC operation, in comparison with untreated ceramic
packing.
Received: 2 December 1999 / Revision received: 2 February 2000 / Accepted: 4 February 2000 相似文献
4.
Acetobacter aceti have been grown on ethanol under inhibitory conditions created by high concentrations of phenol. A defined medium with no
vitamin or amino acid supplements has been used such that ethanol was the sole carbon substrate. The culture temperature was
maintained at 30 °C while the pH was manually controlled to fall within the range 4.5–6.0 during ethanol consumption. Growth
on ethanol at a few thousand milligrams per litre (below the known inhibitory level) resulted in a maximum specific growth
rate of 0.16 h−1 with a 95% yield of acetic acid, followed immediately by acetic acid consumption at a growth rate of 0.037 h−1. Phenol was found to inhibit growth by decreasing both the specific growth rate and the biomass yield during ethanol consumption.
On the other hand, the yield of acetic acid during ethanol consumption and the yield of biomass during acetic acid consumption
remained constant, independent of phenol inhibition. A model is presented and is shown to represent the phenol-inhibited growth
behaviour of A. aceti during both ethanol and acetic acid consumption.
Received: 6 November 1998 / Received revision: 8 February 1999 / Accepted: 12 February 1999 相似文献
5.
Shaw-Reid CA McCormick MM Sinskey AJ Stephanopoulos G 《Applied microbiology and biotechnology》1999,51(3):325-333
The N-succinyl-ll-diaminopimelate desuccinylase gene (dapE) in the four-step succinylase branch of the l-lysine biosynthetic pathway of Corynebacterium glutamicum was disrupted via marker-exchange mutagenesis to create a mutant strain that uses only the one-step meso-diaminopimelate dehydrogenase branch to overproduce lysine. This mutant strain grew and utilized glucose from minimal medium
at the same rate as the parental strain. In addition, the dapE
−
strain produced lysine at the same rate as its parent strain. Transformation of the parental and dapE
−
strains with the amplified meso-diaminopimelate dehydrogenase gene (ddh) on a plasmid did not affect lysine production in either strain, despite an eightfold amplification of the activity of the
enzyme. These results indicate that the four-step succinylase pathway is dispensable for lysine overproduction in shake-flask
culture. In addition, the one-step meso-diaminopimelate dehydrogenase pathway does not limit lysine flux in Corynebacterium under these conditions.
Received: 20 May 1998 / Received revision: 12 August 1998 / Accepted: 3 September 1998 相似文献
6.
Thermophilic acidification of dairy wastewater 总被引:2,自引:0,他引:2
Acidification of simulated dairy wastewater was conducted in an upflow reactor at 55 °C. Results showed that the degree of
acidification decreased with the increase in chemical oxygen demand (COD) loading rate, from 60.8% at 4 g l−1 day−1 to 27.1% at 24 g l−1 day−1. Carbohydrate was readily degraded at all loading rates, but degradation of protein and lipid decreased with the increase
in loading rate. Most carbohydrate degradation occurred at the reactor bottom, whereas protein was degraded mainly after the
carbohydrate became depleted. The predominant acidification products were acetate, propionate, butyrate and ethanol, whereas
formate, i-butyrate, valerate, i-valerate, caproate, lactate, methanol, propanol and butanol were present in lesser quantities. The increase in loading rate
resulted in the increase of propionate and the decrease of acetate, but had little effect on ethanol and butyrate productions.
Only 2.5–8.8% of influent COD was converted to hydrogen and methane. The biomass yield was 0.30–0.43 mg VSS mg−1 COD.
Received: 8 December 1999 / Received revision: 14 February 2000 / Accepted: 25 February 2000 相似文献
7.
J. M. Obón J. R. Maiquez M. Cánovas H.-P. Kleber J. L. Iborra 《Applied microbiology and biotechnology》1999,51(6):760-764
The use of a biological procedure for l-carnitine production as an alternative to chemical methods must be accompanied by an efficient and highly productive reaction
system. Continuous l-carnitine production from crotonobetaine was studied in a cell-recycle reactor with Escherichia coli O44 K74 as biocatalyst. This bioreactor, running under the optimum medium composition (25 mM fumarate, 5 g/l peptone), was
able to reach a high cell density (26 g dry weight/l) and therefore to obtain high productivity values (6.2 g l-carnitine l−1 h−1). This process showed its feasibility for industrial l-carnitine production. In addition, resting cells maintained in continuous operation, with crotonobetaine as the only medium
component, kept their biocatalytic capacity for 4 days, but the biotransformation capacity decreased progressively when this
particular method of cultivation was used.
Received: 10 December 1998 / Received revision: 19 February 1999 / Accepted: 20 February 1999 相似文献
8.
Effects of ethanol concentration and stripping temperature on continuous fermentation rate 总被引:1,自引:0,他引:1
F. Taylor M. J. Kurantz N. Goldberg J. C. Craig Jr. 《Applied microbiology and biotechnology》1997,48(3):311-316
The operation of a pilot plant consisting of a 14-l fermentor, 10-cm packed column and condenser for continuous fermentation
and stripping of ethanol was stable for more than 100 days. The feed consisted of a non-sterile solution of 560 g/l glucose
with 100 g/l corn steep water. Fouling of the packing in the column with attached growth of yeast cells was controlled by
in situ washing at intervals of 3–6 days. A computer simulation of the pilot plant was developed and used to analyze the data.
The productivity of the continuous fermentor varied from 14 g ethanol to 17 g ethanol l−1 h−1. The yield was equal to the maximum theoretically possible: 0.51 g ethanol/g glucose consumed. Results are fit to linear
models for the effects of ethanol concentration on specific growth rate and cell yield, and for the effect of stripping temperature
on specific growth rate.
Received: 16 October 1996 / Received revision: 3 January 1997 / Accepted: 24 January 1997 相似文献
9.
John Ejnik Amalia Muñoz Tong Gan C. Frank Shaw III D. H. Petering 《Journal of biological inorganic chemistry》1999,4(6):784-790
− 1 s − 1 at 25 °C and pH 7.4 in Tris.HCl buffer and 0.1 M KCl. At 25 °C, Zn7-metallothionein also exchanged metal ions with Cd-carbonic anhydrase with a rate constant of 0.33 ± 0.02 M − 1 s − 1 to reconstitute enzymatically active protein. Cd-carbonic anhydrase reacted within the time of mixing with the peptide sequence
49–61 of rabbit metallothionein 2 which contains four cysteinyl residues, leading to the exchange of most of the Cd2+ into the peptide. At pH 7.4 and 25 °C, Cd2+ has higher affinity for apometallothionein than for the apo-peptide.
Received: 25 February 1999 / Accepted: 17 September 1999 相似文献
10.
P. Schmitt C. Vasseur V. Phalip D. Q. Huang C. Diviès H. Prévost 《Applied microbiology and biotechnology》1997,47(6):715-718
The co-metabolism of citrate plus xylose by Leuconostoc mesenteroides subsp. mesenteroides results in a growth stimulation, an increase in d-lactate and acetate production and repression of ethanol production. This correlated well with the levels of key enzymes
involved. A partial repression of alcohol dehydrogenase and a marked stimulation of acetate kinase were observed. High citrate
bioconversion yields in diacetyl plus acetoin were obtained at pH 5.2 in batch (11.5%) or in chemostat (up to 17.4%) culture.
In contrast, no diacetyl or acetoin was detected in citrate plus glucose fermentation.
Received: 6 December 1996 / Received revision: 14 February 1997 / Accepted: 14 February 1997 相似文献
11.
C. J. Israilides A. Smith J. E. Harthill C. Barnett G. Bambalov B. Scanlon 《Applied microbiology and biotechnology》1998,49(5):613-617
Ethanol-precipitated substances after fermentation of various agro-industrial wastes by Aureobasidium pullulans were examined for their pullulan content. Grape skin pulp extract, starch waste, olive oil waste effluents and molasses served
as substrates for the fermentation. A glucose-based defined medium was used for comparison purposes. Samples were analysed
by an enzyme-coupled assay method and by high-performance anion-exchange chromatography with pulsed amperometric detection
after enzymic hydrolysis with pullulanase. Fermentation of grape skin pulp extract gave 22.3 g l−1 ethanol precipitate, which was relatively pure pullulan (97.4% w/w) as assessed by the coupled-enzyme assay. Hydrolysed starch
gave only 12.9 g l−1 ethanol precipitate, which increased to 30.8 g l−1 when the medium was supplemented with NH4NO3 and K2HPO4; this again was relatively pure pullulan (88.6% w/w). Molasses and olive oil wastes produced heterogeneous ethanol-precipitated
substances containing small amounts of pullulan, even when supplemented with nitrogen and phosphate. Overall, grape skin pulp
should be considered as the best substrate for pullulan production. Starch waste requires several hydrolyis steps to provide
a usable carbon source, which reduces its economic attraction as an industrial process.
Received: 24 October 1997 / Received revision: 10 February 1998 / Accepted: 15 February 1998 相似文献
12.
Pilot-scale production of butanol by Clostridium beijerinckii BA101 using a low-cost fermentation medium based on corn steep water 总被引:3,自引:0,他引:3
To improve the economic competitiveness of the acetone/butanol/ethanol fermentation process, glucose/corn steep water (CSW)
medium was used on a pilot scale for the production of solvents. The production of butanol by the Clostridium beijerinckii NCIMB 8052 parent strain and the solvent-hyperproducing BA101 mutant was compared. In a 20-l fermentation using 5% glucose/CSW
medium, C. beijerinckii 8052 produced 8.5 g butanol/l and 5 g acetone/l, while C. beijerinckii BA101 produced 16 g butanol/l and 7.5 g acetone/l. Further studies were carried out on a larger scale using an optimized
6% glucose/CSW medium. In a 200-l pilot-scale fermentor, C. beijerinckii 8052 produced 12.7 g butanol/l and 6 g acetone/l following 96 h of fermentation. C. beijerinckii BA101 produced 17.8 g/l and 5.5 g/l butanol and acetone respectively, following 130 h of fermentation. These results represent
a 40% increase in final butanol concentration by the C. beijerinckii BA101 mutant strain when compared to the 8052 parent strain. The total solvents (acetone, butanol, and ethanol) produced
by C. beijerinckii NCIMB 8052 and BA101 in a 200-l fermentation were 19.2 g/l and 23.6 g/l respectively. This is the first report of pilot-scale
butanol production by the solvent-hyperproducing C. beijerinckii BA101 mutant employing an inexpensive glucose/CSW medium.
Received: 26 May 1998 / Received revision: 21 September 1998 / Accepted: 11 October 1998 相似文献
13.
The maximum ethanol concentration produced from glucose in defined media at 45°C by the thermotolerant yeast Kluyveromyces marxianus IMB3 was 44 g L−1. Acclimatisation of the strain through continuous culture at ethanol concentrations up to 80 g L−1, shifted the maximum ethanol concentration at which growth was observed from 40 g L−1 to 70 g L−1. Four isolates were selected from the continuous culture, only one of which produced a significant increase in final ethanol
concentration (50 ± 0.4 g L−1), however in subsequent fermentations, following storage on nutrient agar plates, the maximum ethanol concentration was comparable
with the original isolate. The maximum specific ethanol production rates (approximately 1.5 g (gh)−1) were also comparable with the original strain except for one isolate (0.7 g (gh)−1). The specific ethanol productivity decreased with ethanol concentration; this decrease correlated linearly (rval 0.92) with
cell viability. Due to the transience of induced ethanol tolerance in the strain it was concluded that this was not a valid
method for improving final ethanol concentrations or production rates.
Received 18 July 1997/ Accepted in revised form 19 February 1998 相似文献
14.
The esterification reaction between stearic acid and lactic acid using Rhizomucor miehei lipase and porcine pancreas lipase was optimized for maximum esterification using response surface methodology. The formation
of the ester was found to depend on three parameters namely enzyme/substrate ratio, lactic acid (stearic acid) concentration
and incubation period. The maximum esterification predicted by theoretical equations for both lipases matched well with the
observed experimental values. In the case of R. miehei lipase, stearoyl lactic acid ester formation was found to increase with incubation period and lactic acid (stearic acid)
concentrations with maximum esterification of 26.9% at an enzyme/substrate (E/S) ratio of 125 g mol−1. In the case of porcine pancreas lipase, esterification showed a steady increase with increase in incubation period and lactic
acid (stearic acid) concentration independent of the E/S ratios employed. In the case of PPL, a maximum esterification of
18.9% was observed at an E/S ratio of 25 g mol−1 at a lactic acid (stearic acid) concentration of 0.09 M after an incubation period of 72 h.
Received: 12 February 1999 / Received revision: 31 May 1999 / Accepted: 4 June 1999 相似文献
15.
Gnotobiotic systems were used to assess the competitive abilities of bioluminescent Sinorhizobium meliloti strains L1 (RecA−) and L33 (RecA+) for growth and host plant nodulation in the presence of a reconstructed S. meliloti population. Three wild-type strains belonging to infective subgroups of a natural S. meliloti population were chosen as competitors in microcosm studies. Whereas the RecA+ strain L33 dominated the reconstructed population with respect to growth and alfalfa nodulation, the competitiveness of the
RecA− strain L1 was reduced compared to that of one of the field strains, but comparable to that of the other field isolates. This
result indicates that strain L1, despite its recA mutation, has the potential to compete successfully with a resident S. meliloti population after environmental release.
Received: 4 November 1996 / Received revision: 9 January 1997 / Accepted: 17 January 1997 相似文献
16.
Inhibition of Clostridium butyricum by 1,3-propanediol and diols during glycerol fermentation 总被引:3,自引:0,他引:3
1,3-Propanediol inhibition during glycerol fermentation to 1,3-propanediol by Clostridium butyricum CNCM 1211 has been studied. The initial concentration of the 1,3-propanediol affected the growth of the bacterium more than
the glycerol fermentation. μ
max was inversely proportional to the initial concentration of 1,3-propanediol (0–65 g l−1). For glycerol at 20 g l−1, the growth and fermentation were completely stopped at an initial 1,3-propanediol concentration of 65 g l−1. However, for an initial 1,3-propanediol concentration of 50 g l−1 and glycerol at 70 g l−1, the final concentration (initial and produced) of 1,3-propanediol reached 83.7 g l−1(1.1 M), with complete consumption of the glycerol. Therefore, during the fermentation, the strain tolerated a 1,3-propanediol
concentration higher than the initial inhibitory concentration (65 g l−1). The addition of 1,2-propanediol or 2,3-butanediol (50 g l−1) in the presence of glycerol (50–100 g l−1), showed that 2-diols reduced the μ
max in a similar way to 1,3-propanediol. The measurement of the osmotic pressure of glycerol solutions, diols and diol/glycerol
mixtures did not indicate any differences between these compounds. The hypothesis of diol inhibition was discussed. Taking
into account the strain tolerance of highly concentrated 1,3-propanediol during fermentation, the fermentation processes for
optimising production were considered.
Received: 15 November 1999 / Revision received: 1 February 2000 / Accepted: 4 February 2000 相似文献
17.
Poly-(3-hydroxybutyrate) production from whey by high-density cultivation of recombinant Escherichia coli 总被引:2,自引:0,他引:2
Recombinant Escherichia coli strain GCSC 6576, harboring a high-copy-number plasmid containing the Ralstonia eutropha genes for polyhydroxyalkanoate (PHA) synthesis and the E. coli ftsZ gene, was employed to produce poly-(3-hydroxybutyrate) (PHB) from whey. pH-stat fed-batch fermentation, using whey powder
as the nutrient feed, produced cellular dry weight and PHB concentrations of 109 g l−1 and 50 g l−1 respectively in 47 h. When concentrated whey solution containing 210 g l−1 lactose was used as the nutrient feed, cellular dry weight and PHB concentrations of 87 g l−1 and 69 g l−1 respectively could be obtained in 49 h by pH-stat fed-batch culture. The PHB content was as high as 80% of the cellular dry
weight. These results suggest that cost-effective production of PHB is possible by fed-batch culture of recombinant E. coli using concentrated whey solution as a substrate.
Received: 19 December 1997 / Received revision: 17 March 1998 / Accepted: 20 March 1998 相似文献
18.
Carmen Lapadatescu Gilles Feron Catherine Vergoignan Aleth Djian Alain Durand Pascal Bonnarme 《Applied microbiology and biotechnology》1997,47(6):708-714
Three white-rot basidiomycetes, Bjerkandera adusta, Ischnoderma benzoinum and Dichomitus squalens, were cultivated on a liquid medium supplemented with l-phenylalanine, a precursor for benzaldehyde (bitter almond aroma) and benzyl alcohol. Remarkable amounts of benzaldehyde
(587 mg l−1) were found in cultures of B. adusta. Immobilization of this fungus on polyurethane foam cubes allowed an 8.3-fold increase of the production of benzaldehyde
and a 15-fold increase of the productivity as compared with non-immobilized cells. Aryl-alcohol oxidase activity was only
detected in B. adusta. This activity was also significantly enhanced in immobilized cells, suggesting that it plays an important role in benzaldehyde
biosynthesis. Conversely, consistent amounts of benzyl alcohol (340 mg l−1 for B. adusta and I. benzoinum and 100 mg l−1 for D. squalens) were produced by the three fungi when immobilized. Laccase activity was found only in the strains I. benzoinum and D. squalens. This activity was markedly enhanced in free cells cultures. Immobilization of the fungi did not promote benzyl alcohol production
by comparison with free cell cultures (500 mg l−1).
Received: 10 December 1996 / Received revision: 17 February 1997 / Accepted: 22 February 1997 相似文献
19.
Chlorinated propanes are important pollutants that may show persistent behaviour in the environment. The biotransformation
of 1-chloropropane, 1,2-dichloropropane, 1,3-dichloropropane and 1,2,3-trichloropropane was studied using resting cell suspensions
of Methylosinus trichosporium OB3b expressing soluble methane monooxygenase. The transformation followed first-order kinetics. The rate constants were
in the order 1-chloropropane > 1,3-dichloropropane > 1,2-dichloropropane > 1,2,3-trichloropropane, and varied from 0.07 to
1.03 ml min−1 mg of cells−1 for 1,2,3-trichloropropane and 1-chloropropane respectively. Turnover-dependent inactivation occurred for all of the chloropropanes
tested. The inactivation constants were lower for 1-chloropropane and 1,2-dichloropropane than for 1,2,3-trichloropropane
and 1,3-dichloropropane. Not all the chloride was released during cometabolic transformation of the chlorinated propanes and
production of monochlorinated- and dichlorinated propanols was found by gas chromatography. The reaction pathway of 1,2,3-trichloropropane
conversion was studied by mass spectrometric analysis of products formed in 2H2O, which indicated that 1,2,3-trichloropropane was initially oxidized to 2,3-dichloropropionaldehyde and 1,3-dichloroacetone,
depending on whether oxygen insertion occurred on the C-3 or C-2 carbon of 1,2,3,-trichloropropane, followed by reduction
to the corresponding propanols. The results show that chloropropanes are susceptible to cometabolic oxidation by methanotrophs,
but that the transformation kinetics is worse than with cometabolic conversion of trichloroethylene.
Received: 27 November 1997 / Received revision: 27 February 1998 / Accepted: 27 February 1998 相似文献
20.
López-Contreras AM Claassen PA Mooibroek H De Vos WM 《Applied microbiology and biotechnology》2000,54(2):162-167
Domestic organic waste (DOW) collected in The Netherlands was analysed and used as substrate for acetone, butanol and ethanol
(ABE) production. Two different samples of DOW, referred to as fresh DOW and dried DOW, were treated by extrusion in order
to expand the polymer fibres present and to obtain a homogeneous mixture. The extruded material was analysed with respect
to solvent and hot water extractives, uronic acids, lignin, sugars and ash. The total sugar content in the polymeric fractions
of the materials varied from 27.7% to 39.3% (w/w), in which glucose represented the 18.4 and 25.1% of the materials, for fresh
and dried DOW, respectively. The extruded fresh DOW was used as substrate for the ABE fermentation by the solventogenic strain
Clostridium acetobutylicum ATCC 824. This strain was grown on a suspension of 10% (w/v) DOW in demineralised water without further nutrient supplement.
This strain produced 4 g ABE/100 g extruded DOW. When C. acetobutylicum ATCC 824 was grown on a suspension of 10% (w/v) DOW hydrolysed by a combination of commercial cellulases and β-glucosidases,
the yield of solvents increased to 7.5 g ABE/100 g extruded DOW. The utilisation of sugar polymers in both hydrolysed and
non-hydrolysed DOW was determined, showing that only a small proportion of the polymers had been consumed by the bacteria.
These results indicate that growth and ABE production on DOW is mainly supported by soluble saccharides in the medium.
Received: 5 November 1999 / Received revision: 21 February 2000 / Accepted: 25 February 2000 相似文献