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1.
H. De Wever S. De Cort I. Noots H. Verachtert 《Applied microbiology and biotechnology》1997,47(4):458-461
2-Hydroxybenzothiazole (OBT) is present in wastewaters from the industrial production of the rubber vulcanization accelerator
2-mercaptobenzothiazole (MBT). We have achieved the first isolation of axenic bacterial cultures capable of the degradation
of OBT and growth on this substrate as the sole source of carbon, nitrogen and energy. All isolates had similar characteristics
corresponding to one particular isolate, which was studied in more detail and identified as Rhodococcus rhodochrous. The strains were also capable of degrading benzothiazole (BT) but not MBT or benzothiazole-2-sulphonate (BTSO3). OBT was degraded at a concentration of up to 600 mg · l−1. BT was toxic above 300 mg · l−1. MBT inhibited OBT degradation. Growth on OBT was not significantly different at pH values of between 6.3 and 7.9 or salt
concentrations between 1 % and 3 %. In shake flasks the cells clumped together, which resulted in a lower rate of oxygen transfer
and slower degradation as compared to cells grown on OBT in a stirred reactor.
Received: 22 August 1996 / Received revision: 29 November 1996 / Accepted: 29 November 1996 相似文献
2.
M. J. Zmijewski J. Vicenzi B. E. Landen W. Muth P. Marler B. Anderson 《Applied microbiology and biotechnology》1997,47(2):162-166
In an effort to prepare 3,4-methylene-dioxyphenyl-(S)-isopropanol from 3,4-methylene-dioxyphenylacetone, an initial screen of microbes indicated that Candida famata could catalyze this reaction efficiently at low substrate concentration. A dilute, large-scale process was developed to provide
experimental material for the chemical synthesis to be explored. However, the productivity number of this process [0.134 g
product (g␣wet␣weight cells)−1 day−1 was too low to be practical. C.␣famata was also extremely sensitive to concentrations of both the ketone and the alcohol greater than 2 g/l. A more extensive screen
of yeast and fungi revealed that Zygosaccharomyces rouxii was more tolerant to higher substrate concentrations and had a higher productivity number [0.8 g (g wet weight cells)−1 day−1]. These characteristics suggested that Z. rouxii could be used in a large-scale process at high substrate concentrations.
Received: 8 July 1996 / Received revision: 9 September 1996 / Accepted: 18 September 1996 相似文献
3.
With the goal of developing a defined medium for the production of desiccation-tolerant blastospores of the bioinsecticidal
fungus Paecilomyces fumosoroseus, we evaluated the impact of various media components such as amino acids, carbohydrates, trace metals and vitamins on hyphal
growth and sporulation of P. fumosoroseus cultures and on the freeze-drying tolerance of blastospores produced under these conditions. A comparison of 13 amino acids
as sole nitrogen sources showed that glutamate, aspartate, glycine and arginine supported biomass accumulations (12–16 mg ml−1) and blastospore yields (6–11 × 108 blastospores ml−1) comparable to our standard production medium which contains casamino acids as the nitrogen source. Using glutamate as the
sole nitrogen source, tests with various carbohydrates showed that P. fumosoroseus grew best on glucose (18.8 mg biomass ml−1) but produced similar blastospore concentrations (7.3–11.0 × 108) when grown with glucose, glycerol, fructose or sucrose. P. fumosoroseus cultures grown in media with sodium citrate or galactose as the sole carbohydrate produced lower blastospore concentrations
but more-desiccation-tolerant spores. Zinc was the only trace metal tested that was required for optimal growth and sporulation.
In a defined medium with glutamate as the nitrogen source, vitamins were unnecessary for P. fumosoroseus growth or sporulation. When blastospores were freeze-dried in the absence of a suspension medium, residual glucose (>2.5%
w/v) was required for enhanced spore survival. Thus, a defined medium containing basal salts, glucose, glutamate and zinc
can be used to produce optimal concentrations of desiccation-tolerant blastospores of P. fumosoroseus.
Received 27 October 1998/ Accepted in revised form 06 May 1999 相似文献
4.
Rembrandt Dijkerman Jeroen Ledeboer Huub J.M. Op den Camp Rudolf A. Prins Chris van der Drift 《Current microbiology》1997,34(2):91-96
The anaerobic fungus Neocallimastix sp. strain L2,
isolated from the feces of a llama, was tested for growth on a range of
soluble and insoluble carbohydrate substrates. The fungus was able to ferment
glucose, cellobiose, fructose, lactose, maltose, sucrose, soluble starch,
inulin, filter paper cellulose, and Avicel. No growth was observed on
arabinose, galactose, mannose, ribose, xylose, sorbitol, pectin, xylan,
glycerol, citrate, soya, and wheat bran. The fermentation products after
growth were hydrogen, formate, acetate, ethanol, and lactate. The
fermentation pattern was dependent on the carbon source. In general, higher
hydrogen production resulted in decreased formation of lactate and ethanol.
Recovery of the fermented carbon in products at the end of growth ranged from
50% to 80%. (Hemi)cellulolytic enzyme activities were affected
by the carbon source. Highest activities were found in filtrates from
cultures grown on cellulose. Growing the fungus on inulin and lactose yielded
the lowest cellulolytic activities. Highest specific activities for
avicelase, endoglucanase, β-glucosidase, and xylanase were obtained with
Avicel as the substrate for growth (0.29, 5.9, 0.57, and 13
IU · mg−1 protein, respectively). Endoglucanase activity
banding patterns after SDS-PAGE were very similar for all substrates. Minor
differences indicated that enzyme activities may in part be the result of
secretion of different sets of isoenzymes.
Received: 10 July 1996 / Accepted: 22 July 1996 相似文献
5.
Bioremediation of two diesel-oil-contaminated alpine subsoils, differing in soil type and bedrock, was investigated in laboratory
experiments at 10 °C after supplementation with an inorganic fertilizer. Initial diesel oil contamination of 4000 mg kg−1 soil dry matter (dm) was reduced to 380–400 mg kg−1 dm after 155 days of incubation. In both soils, about 30 % of the diesel oil contamination (1200 mg kg−1 dm) was eliminated by abiotic processes. The residual decontamination (60 %–65 %) could be attributed to microbial degradation
activities. In both soils, the addition of a cold-adapted diesel-oil-degrading inoculum enhanced biodegradation rates only
slightly and temporarily. From C/N and N/P ratios (determined by measuring the contents of total hydrocarbons, NH4
+ N, NO3
− N and PO4
3− P) of soils␣it could be deduced that there was no nutrient deficiency during the whole incubation period. Soil biological
activities (basal respiration and dehydrogenase activity) corresponded to the course of biodegradation activities in the soils.
Received: 9 September 1996 / Accepted: 7 December 1996 相似文献
6.
The culture-medium composition was optimised, on a shake-flask scale, for simultaneous production of high activities of endoglucanase
and β-glucosidase by Thermoascus aurantiacus using statistical factorial designs. The optimised medium containing 40.2 g l−1 Solka Floc as the carbon source and 9 g l−1 soymeal as the organic nitrogen source yielded 1130 nkat ml−1 endoglucanase and 116 nkat ml−1β-glucosidase activities after 264 h as shake cultures. In addition, good levels of β-xylanase (3479 nkat ml−1) and low levels of filter-paper cellulase, β-xylosidase, α-l-arabinofuranosidase, β-mannanase, β-mannosidase, α-galactosidase and β-galactosidase were detected. Batch fermentation in
a 5-l laboratory fermentor using the optimised medium allowed the production of 940 nkat ml−1 endoglucanase and 102 nkat ml−1β-glucosidase in 192 h. Endoglucanase and β-glucosidase showed optimum activity at pH 4.5 and pH 5, respectively, and they
displayed optimum activity at 75 °C. Endoglucanase and β-glucosidase showed good stability at pH values 4–8 and 4–7, respectively,
after a prolonged incubation (48 h at 50 °C). Endoglucanase had half-lives of 98 h at 70 °C and 4.1 h at 75 °C, while β-glucosidase
had half-lives of 23.5 h at 70 °C and 1.7 h at 75 °C. Alkali-treated bagasse, steam-treated wheat straw, Solka floc and Sigmacell
50 were 66, 48.5, 33.5 and 14.4% hydrolysed by a crude enzyme complex of T. aurantiacus in 50 h.
Received: 12 November 1999 / Accepted: 14 November 1999 相似文献
7.
Delta-endotoxin production by a strain of Bacillus thuringiensis subsp kurstakion complex media based on crude gruel and fish meal was investigated. High proteolytic activities were concomitantly produced
with the bioinsecticide. In such complex media, the repressive regulation due to readily consumed carbon sources was partially
overcome. In order to improve substrate assimilation, 0.5 g L−1 sodium chloride and 0.1% Tween-80 were supplemented to the production medium, increasing delta-endotoxin yields when using
gruel concentrations below 59 g L−1. At and beyond 75 g L−1 gruel, delta-endotoxin yields were not affected in the presence of 0.5 g L−1 NaCl and 0.1% Tween-80, but proteolytic activity yields were remarkably reduced. Thus, the use of sodium chloride and Tween-80
allowed reduction of the initial gruel concentration to 42 g L−1 for the production of 3350 mg L−1 delta-endotoxin, while it was only 3800 mg L−1 with 92 g L−1 gruel. Moreover, similar to 0.5 g L−1 NaCl and 0.1% Tween-80, the use of 10 g L−1 sodium acetate significantly improved delta-endotoxin production and also reduced the proteolytic activity to 250 U ml−1.
Received 05 November 1998/ Accepted in revised form 19 August 1999 相似文献
8.
Effect of feed composition and upflow velocity on aggregate characteristics in anaerobic upflow reactors 总被引:4,自引:0,他引:4
V. O'Flaherty P. N. L. Lens D. de Beer E. Colleran 《Applied microbiology and biotechnology》1997,47(2):102-107
Two upflow anaerobic hybrid reactors treated lactose and a mixture of ethanol, propionate and butyrate, respectively, at
a volumetric loading rate of 3.7 kg chemical oxygen demand (COD) m−3day−1, a hydraulic retention time of 5 days and a liquid upflow velocity of 0.01 m/h. Under steady-state conditions, the lactose-fed
sludge had much higher (20%–100%) specific methanogenic conversion rates than the volatile-fatty acid␣(VFA)/ethanol-fed sludge
for all substrates tested, including VFA. In both reactors, a flocculant sludge developed, although a much higher content
of extracellular polysaccharide was measured in the lactose-fed sludge [1900 μg compared to 305 μg uronic acid/g volatile
suspended solids (VSS)]. When the liquid upflow velocity of a third, VFA/ethanol-fed reactor was increased to 0.5 m/h, granulation
of the sludge occurred, accompanied by a large increase (200%–500%) in the specific methanogenic conversion rates for the
syntrophic and methanogenic substrates studied. Granulation reduced the susceptibility of the sludge to flotation. Glucose
was degraded at a high rate (100 mg glucose gVSS−1h−1) by the sludge from the third reactor, despite not having been exposed to a sugar-containing influent for 563␣days.
Received: 7 June 1996 / Received revision: 23 September 1996 / Accepted: 29 September 1996 相似文献
9.
L. Lesage-Meessen M. Haon M. Delattre J.-F. Thibault B. Colonna Ceccaldi M. Asther 《Applied microbiology and biotechnology》1997,47(4):393-397
The effects of adding cellobiose on the transformation of vanillic acid to vanillin by two strains of Pycnoporus cinnabarinus MUCL39532 and MUCL38467 were studied. When maltose was used as the carbon source in the culture medium, very high levels
of methoxyhydroquinone were formed from vanillic acid. When cellobiose was used as the carbon source and/or added to the culture
medium of P. cinnabarinus strains on day 3 just before vanillic acid was added, it channelled the vanillic acid metabolism via the reductive route
leading to vanillin. Adding 3.5 g l−1 cellobiose to 3-day-old maltose cultures of P. cinnabarinus MUCL39532 and 2.5 g l−1 cellobiose to 3-day-old cellobiose cultures of P. cinnabarinus MUCL38467, yielded 510 mg l−1 and 560 mg l−1 vanillin with a molar yield of 50.2 % and 51.7 % respectively. Cellobiose may either have acted as an easily metabolizable
carbon source, required for the reductive pathway to occur, or as an inducer of cellobiose:quinone oxidoreductase, which is
known to inhibit vanillic acid decarboxylation.
Received: 24 July 1996 / Received revision: 29 November 1996 / Accepted: 29 November 1996 相似文献
10.
A Pseudomonas sp. strain NGK 1 (NCIM 5120) was immobilized in various matrices, namely, alginate, agar (1.8 × 1011 cfu g−1 beads) and polyacrylamide (1.6 × 1011 cfu g−1 beads). The degradation of naphthalene was studied, by freely suspended cells (4 × 1010 cfu ml−1) and immobilized cells in batches, with shaken culture and continuous degradation in a packed-bed reactor. Free cells brought
about the complete degradation of 25 mmol naphthalene after 3 days of incubation, whereas, a maximum of 30 mmol naphthalene
was degraded by the bacteria after 3–4 days of incubation with 50 mmol and 75 mmol naphthalene, and no further degradation
was observed even after 15 days of incubation. Alginate-entrapped cells had degraded 25 mmol naphthalene after 3.5 days of
incubation, whereas agar- and polyacrylamide-entrapped cells took 2.5 days; 50 mmol naphthalene was completely degraded by
the immobilized cells after 6–7 days of incubation. Maximum amounts of 55 mmol, 70 mmol and 67 mmol naphthalene were degraded,
from an initial 75 mmol naphthalene, by the alginate-, agar- and polyacrylamide-entrapped cells after 15 days of incubation.
When the cell concentrations were doubled, 25 mmol and 50 mmol naphthalene were degraded after 2 and 5.5 days of incubation
by the immobilized cells. Complete degradation of 75 mmol naphthalene occurred after 10 days incubation with agar- and polyacrylamide-entrapped␣cells,
whereas only 60 mmol naphthalene was degraded by alginate-entrapped cells after 15 days of␣incubation. Further, with 25 mmol
naphthalene, alginate-, agar- and polyacrylamide-entrapped cells (1.8 × 1011 cfu g−1 beads) could be reused 18, 12 and 23 times respectively. During continuous degradation in a packed-bed reactor, 80 mmol naphthalene
100 ml−1 h−1 was degraded by alginate- and polyacrylamide-entrapped cells whereas 80 mmol naphthalene 125 ml−1␣h−1 was degraded by agar-entrapped cells.
Received: 21 October 1997 / Received revision: 15 January 1998 / Accepted: 18 January 1998 相似文献
11.
The Aspergillus niger strain BO-1 was grown in batch, continuous (chemostat) and fed-batch cultivations in order to study the production of the
extracellular enzyme glucoamylase under different growth conditions. In the pH range 2.5–6.0, the specific glucoamylase productivity
and the specific growth rate of the fungus were independent of pH when grown in batch cultivations. The specific glucoamylase
producivity increased linearly with the specific growth rate in the range 0–0.1 h−1 and was constant in the range 0.1–0.2 h−1. Maltose and maltodextrin were non-inducing carbon sources compared to glucose, and the maximum specific growth rate was
0.19 ± 0.02 h−1 irrespective of whether glucose or maltose was the carbon source. In fed-batch cultivations, glucoamylase titres of up to
6.5 g l−1 were obtained even though the strain contained only one copy of the glaA gene.
Received: 5 May 1999 / Received revision: 7 September 1999 / Accepted: 17 September 1999 相似文献
12.
Halogenating activities detected in Antarctic macroalgae 总被引:1,自引:0,他引:1
Halogenating activities were determined in samples of 18 cultivated species of brown, red and green macroalgae from the Antarctic.
Activities for the halogenating organic compounds with bromide, iodide and chloride were found. Investigated red algae (rhodophytes)
showed higher brominating and iodinating activities compared to brown (phaeophytes) and green (chlorophytes) algae. The highest
brominating and iodinating activities were measured in the red algae Plocamium cartilagineum (1.11±0.01 U g-1 wet algal weight and 0.18 U g-1 wet algal weight, respectively) and Myriogramme mangini (3.62±0.17 U g-1 wet algal weight and 4.5 U g-1 wet algal weight, respectively). Chlorinating activities were detected in the red alga Plocamium cartilagineum only (0.086 U g-1 wet algal weight).
Received: 12 February 1996/Accepted: 20 June 1996 相似文献
13.
In order to improve the production rate of l-lysine, a mutant of Corynebacterium glutamicum ATCC 21513 was cultivated in complex medium with gluconate and glucose as mixed carbon sources. In a batch culture, this
strain was found to consume gluconate and glucose simultaneously. In continuous culture at dilution rates ranging from 0.2
h−1 to 0.25 h−1, the specific l-lysine production rate increased to 0.12 g g−1 h−1 from 0.1 g g−1 h−1, the rate obtained with glucose as the sole carbon source [Lee et al. (1995) Appl Microbiol Biotechnol 43:1019–1027]. It
is notable that l-lysine production was observed at higher dilution rates than 0.4 h−1, which was not observed when glucose was the sole carbon source. The positive effect of gluconate was confirmed in the shift
of the carbon source from glucose to gluconate. The metabolic transition, which has been characterized by decreased l-lysine production at the higher glucose uptake rates, was not observed when gluconate was added. These results demonstrate
that the utilization of gluconate as a secondary carbon source improves the maximum l-lysine production rate in the threonine-limited continuous culture, probably by relieving the limiting factors in the lysine
synthesis rate such as NADPH supply and/or phosphoenolpyruvate availability.
Received: 16 May 1997 / Received revision: 28 August 1997 / Accepted: 29 August 1997 相似文献
14.
M Chellapandian C Larios M Sanchez-Gonzalez A Lopez-Munguia 《Journal of industrial microbiology & biotechnology》1998,21(1-2):51-56
Dextransucrase was produced from a Leuconostoc mesenteroides isolated from pulque, a traditional Aztec alcoholic beverage produced from agave juice containing sucrose as the main carbon source. Almost all
the dextransucrase activity (87%) was associated with the cells, and was unusually high (1.04 U mg−1 of cells). The culture medium composition was optimized through a Box-Behnken method resulting in a process yielding 2.2 U ml−1 of insoluble glucosyltransferase activity. The enzyme had a molecular weight of 166 kDa. Optimal temperature was 35°C with
a half-life of 137 min at the same temperature. As with dextransucrase from the industrial strain L. mesenteroides NRRL B-512F, the enzyme showed Michaelis–Menten kinetic behavior with excess substrate inhibition (K
m and K
i values of 0.026 M and 1.23 M respectively); produced soluble linear dextran with glucose molecules linked mainly in α(1–6)
with branching in α(1–3) in a proportion of 4:1 as shown by NMR studies; and produced a high yield of isomalto-oligosaccharides
in the presence of maltose.
Received 4 February 1998/ Accepted in revised form 25 July 1998 相似文献
15.
Removal of nitrobenzene vapors by a trickling air biofilter 总被引:1,自引:0,他引:1
A stable microbial consortium that grew on nitrobenzene (NB) as its sole source of carbon, nitrogen and energy and liberated
excess nitrogen as ammonia, was immobilized on a perlite-packed trickling air biofilter. On a sustained basis, the biofilter
removed 50 g NB m−3 packing h−1 and its operation at pH 8.7 resulted in ammonia stripping, making pH and salinity controls unnecessary. Low maintenance
and stable performance during 4 months of continuous operation invite the scale-up of this biofilter for control of NB emissions.
Received 12 September 1996/ Accepted in revised form 17 December 1996 相似文献
16.
H. Sudo A. Yamada K. Kokatsu N. Nakamura T. Matsunaga 《Applied microbiology and biotechnology》1997,47(1):78-82
The marine photosynthetic bacterium Chromatium sp. successfully removed orthophosphate when grown phototrophically. The phosphate-uptake rate was almost constant at more
than 5.0 mg- PO4
3−/l in synthetic medium. Addition of seawater causes flocculation of this strain. The successful use of seawater as an inexpensive
source of magnesium could prove to be effective in the removal of photosynthetic bacterial cells from a medium. A semicontinuous
culture system was used for the removal of low concentrations of phosphate and the phosphate-uptake activity of Chromatium sp. was maintained under 0.1 day−1 dilution rate. This strain was also able to remove high concentrations of phosphate from domestic sewage.
Received 24 May 1996 / Received revision: 5 August 1996 / Accepted: 6 September 1996 相似文献
17.
α-Amylase activities of Aspergillus oryzae grown on dextrin or indigestible dextrin were 7·8 and 27·7 U ml−1, respectively. Glucoamylase activities of the cultures grown on dextrin or indigestible dextrin were 5·4 and 301 mU ml−1, respectively. The specific glucoamylase production rate in indigestible dextrin batch culture reached 1·35 U g DW−1 h−1. In contrast, biomass concentration of A. oryzae in indigestible dextrin culture was 35% of that in dextrin culture. Thus, the culture method using indigestible dextrin has
the potential to improve amylolytic enzyme production and fungal fermentation broth rheology. 相似文献
18.
When grown on vegetable oils and their derivatives, the smut fungus Ustilago maydis (DSM 4500 and ATCC 14826) produces several glycolipids under nitrogen-limiting conditions. With 45 g l−1 sunflower oil fatty acids (technical grade) a yield of 30 g l−1 glycolipid was achieved. The resulting mixture contained predominantly mannosylerythritol lipids together with smaller amounts
of cellobiose lipids. The production of the more polar cellobiose lipids was enhanced when glucose was used as carbon source.
The molecular structure of the main components of the glycolipid mixture were elucidated by a combination of NMR spectroscopic
and mass-spectrometric techniques.
Received: 22 June 1998 / Received revision: 11 September 1998 / Accepted: 13 September 1998 相似文献
19.
A.-M. Davila R. Marchal J.-P. Vandecasteele 《Applied microbiology and biotechnology》1997,47(5):496-501
Sophorose lipid production by Candida bombicola is a two-step process where sophorose lipids are mainly produced after a first stage of growth, ending because of nitrogen
limitation. The influence of the following parameters was individually studied for both the stages of growth and of product
formation with respect to final sophorose lipid production performance: pH, temperature and carbon source. Glucose and rapeseed
ethyl esters were supplied individually or as a dual carbon source. The lipidic substrate was added by continuous feeding.
It was found that supplying both carbon sources during the production step was crucial for obtaining a high production performance
ranging from 250 g l−1 to 300 g l−1 or more. Controlling the feeding of rapeseed ethyl esters to avoid inhibition by fatty acids was essential for a successful
scale-up of the fermentation on the industrial scale. The conditions of substrate feeding markedly affected the composition
of the mixture of sophorose lipids produced, namely the extent of acetylation of the sophorose moieties and distribution of
the acidic and lactonic forms. The results suggest that the physiological role of sophorose lipid production is related to
the regulation of energy metabolism.
Received: 26 June 1996 / Received revision: 12 December 1996 / Accepted: 15 December 1996 相似文献
20.
K. Kirimura T. Sato N. Nakanishi M. Terada S. Usami 《Applied microbiology and biotechnology》1997,47(2):127-131
Interspecific protoplast fusion between␣Aspergillus terreus, an itaconic acid producer, and A.␣usamii, a glucoamylase producer, was done to breed new koji molds producing itaconic acid from starch. Protoplast fusion between auxotrophic mutant strains by poly(ethylene glycol) treatment
produced prototrophic fusants with a fusion frequency of 10−5−10−4. The stabilities of some fusants obtained were confirmed by successive subcultures. Conidial analyses of DNA contents and
the number of nuclei indicated that the fusants obtained were haploids like the parental strains. One of the stable fusants,
F-112, morphologically resembled A. terreus, and produced maximally 35.9 mg/ml itaconic acid from soluble starch (120 mg/ml) at day 6 of cultivation. This productivity
from soluble starch was five times as high as that of A. terreus and 70 % of that of A. terreus from glucose (120 mg/ml).
Received: 28 June 1996 / Received revision: 3 September 1996 / Accepted: 29 September 1996 相似文献