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1.
No increases in exopolysaccharide (EPS) yields in Aureobasidium pullulans were observed when grown with reduced-shear impellers instead of standard Rushton turbines in the same vessel. However, yields
were dramatically reduced when the organism was grown in an airlift reactor. This fall in production could be counteracted
by improving fluid circulation through the placement of impellers within the draught tube, a strategy that resulted in the
highest EPS concentration (approx. 13 g l−1) of all the fermenter configurations tested.
Received: 24 June 1997 / Revised revision: 25 September 1997 / Accepted: 29 September 1997 相似文献
2.
M. Prado Acosta E. Valdman S. G. F. Leite F. Battaglini S. M. Ruzal 《World journal of microbiology & biotechnology》2005,21(6-7):1157-1163
Summary Biosorption of heavy metals by gram-positive, non-pathogenic and non-toxicogenic Paenibacillus polymyxa P13 was evaluated. Copper was chosen as a model element because it is a pollutant originated from several industries. An
EPS (exopolysaccharide)-producing phenotype exhibited significant Cu(II) biosorption capacity. Under optimal assay conditions
(pH 6 and 25 °C), the adsorption isotherm for Cu(II) in aqueous solutions obeyed the Langmuir model. A high q value (biosorption capacity) was observed with whole cells (qmax=112 mgCu g−1). EPS production was associated with hyperosmotic stress by high salt (1 M NaCl), which led to a significant increase in
the biosorption capacity of whole cells (qmax=150 mgCu g−1). Biosorption capacity for Cu(II) of the purified EPS was investigated. The maximum biosorption value (q) of 1602 mg g−1 observed with purified EPS at 0.1 mg ml−1 was particularly promising for use in field applications. 相似文献
3.
Lakkana Laopaiboon Pornthap Thanonkeo Prasit Jaisil Pattana Laopaiboon 《World journal of microbiology & biotechnology》2007,23(10):1497-1501
Sweet sorghum juice supplemented with 0.5% ammonium sulphate was used as a substrate for ethanol production by Saccharomyces cerevisiae TISTR 5048. In batch fermentation, kinetic parameters for ethanol production depended on initial cell and sugar concentrations.
The optimum initial cell and sugar concentrations in the batch fermentation were 1 × 108 cells ml−1 and 24 °Bx respectively. At these conditions, ethanol concentration produced (P), yield (Y
ps) and productivity (Q
p
) were 100 g l−1, 0.42 g g−1 and 1.67 g l−1 h−1 respectively. In fed-batch fermentation, the optimum substrate feeding strategy for ethanol production at the initial sugar
concentration of 24 °Bx was one-time substrate feeding, where P, Y
ps and Q
p
were 120 g l−1, 0.48 g g−1 and 1.11 g l−1 h−1 respectively. These findings suggest that fed-batch fermentation improves the efficiency of ethanol production in terms of
ethanol concentration and product yield. 相似文献
4.
An efficient succinic acid production process in a metabolically engineered <Emphasis Type="Italic">Corynebacterium glutamicum</Emphasis> strain 总被引:1,自引:0,他引:1
Okino S Noburyu R Suda M Jojima T Inui M Yukawa H 《Applied microbiology and biotechnology》2008,81(3):459-464
A Corynebacterium glutamicum strain (ΔldhA-pCRA717) that overexpresses the pyc gene encoding pyruvate carboxylase while simultaneously exhibiting a disrupted ldhA gene encoding l-lactate dehydrogenase was investigated in detail for succinic acid production. Succinic acid was shown to be efficiently
produced at high-cell density under oxygen deprivation with intermittent addition of sodium bicarbonate and glucose. Succinic
acid concentration reached 1.24 M (146 g l−1) within 46 h. The yields of succinic acid and acetic acid from glucose were 1.40 mol mol−1 (0.92 g g−1) and 0.29 mol mol−1 (0.10 g g−1), respectively. The succinic acid production rate and yield depended on medium bicarbonate concentration rather than glucose
concentration. Consumption of bicarbonate accompanied with succinic acid production implied that added bicarbonate was used
for succinic acid synthesis. 相似文献
5.
Hwang HS Lee SH Baek YM Kim SW Jeong YK Yun JW 《Applied microbiology and biotechnology》2008,78(3):419-429
In the present study, optimum culture conditions for the production of extracellular polysaccharides (EPS) in submerged culture
of an edible mushroom, Laetiporus sulphureus var. miniatus and their stimulatory effects on insulinoma cell (RINm5F) proliferation and insulin secretion were investigated. The maximum
mycelial growth (4.1 g l−1) and EPS production (0.6 g l−1) in submerged flask culture were achieved in a medium containing 30 g l−1 maltose, 2 g l−1 soy peptone, and 2 mM MnSO4·5H2O at an initial pH 2.0 and temperature 25°C. In the stirred-tank fermenter under optimized medium, the concentrations of mycelial
biomass and EPS reached a maximum level of 8.1 and 3.9 g l−1, respectively. Interestingly, supplementation of deep sea water (DSW) into the culture medium significantly increased both
mycelial biomass and EPS production by 4- and 6.7-fold at 70% (v/v) DSW medium, respectively. The EPS were proved to be glucose-rich polysaccharides and were able to increase proliferation
and insulin secretary function of rat insulinoma RINm5F cells, in a dose-dependent manner. In addition, EPS also strikingly
reduced the streptozotocin-induced apoptosis in RINm5F cells indicating the mode of the cytoprotective role of EPS on RINm5F
cells. 相似文献
6.
Kiviharju K Moilanen U Leisola M Eerikäinen T 《Applied microbiology and biotechnology》2007,73(6):1267-1274
The behavior of Streptomyces peucetius var. caesius N47 was studied in a glucose limited chemostat with a complex cultivation medium. The steady-state study yielded the characteristic
constants μ
max over 0.10 h−1, Y
XS 0.536 g g−1, and mS 0.54 mg g−1 h−1. The product of secondary metabolism, ɛ-rhodomycinone, was produced with characteristics Y
PX 12.99 mg g−1 and m
P 1.20 mg g−1 h−1. Significant correlations were found for phosphate and glucose consumption with biomass and ɛ-rhodomycinone production. Metabolic
flux analysis was conducted to estimate intracellular fluxes at different dilution rates. TCA, PPP, and shikimate pathway
fluxes exhibited bigger values with production than with growth. Environmental perturbation experiments with temperature,
airflow, and pH changes on a steady-state chemostat implied that an elevation of pH could be the most effective way to shift
the cells from growing to producing, as the pH change induced the biggest transient increase to the calculated ɛ-rhodomycinone
flux. 相似文献
7.
Ulrich Metzger Ulrich Lankes Kai Fischpera Fritz H. Frimmel 《Applied microbiology and biotechnology》2009,85(1):197-206
Extracellular polymeric substances were extracted from the bacterial strain Pseudomonas putida and the fungal species Aureobasidium pullulans using three different methods (formaldehyde–NaOH, ethylenediaminetetraacetic acid (EDTA) and cation-exchange-resin). The
composition of the extracellular polymeric substances (EPS) was analysed by biochemical and high-resolution solid state 13C nuclear magnetic resonance (NMR) spectroscopic methods. The EPS yield was strongly dependent on the extraction method, with
the formaldehyde–NaOH method showing the best extraction efficiency. The NMR method revealed that when using the EDTA extraction
method, about 40% of the EDTA accumulated in the EPS and that was responsible for the apparent high extraction yields. EPS
protein content determined by the NMR method was up to 30% higher than the protein content determined using the biochemical
(Lowry) method for P. putida and for A. pullulans. The average protein carbon content determined by the NMR method was approximately 70% of the total carbon content. NMR results
could be supported by elemental analysis, which showed a high nitrogen content (~10%) in the EPS. The carbohydrate carbon
content detected with both methods in the cell aggregates and the EPS was approximately 20% in each. In this study, quantitative
13C cross-polarisation magic angle spinning NMR spectroscopy was conducted on unlabeled cell strains, and EPS and could be used
to quantify protein and carbohydrate of different samples. 相似文献
8.
Waldina P. Reyes-Velázquez Rosa M. Figueroa-Gómez Mauricio Barberis María Marta Reynoso Federico G. A. Rojo Sofía N. Chulze Adriana M. Torres 《Mycotoxin Research》2011,27(3):187-194
Fusarium species can produce fumonisins (FBs), fusaric acid, beauvericin (BEA), fusaproliferin (FUS) and moniliformin. Data on the
natural occurrence of FBs have been widely reported, but information on BEA and FUS in maize is limited. The aims of this
study were to establish the occurrence of Fusarium species in different maize hybrids in Mexico, to determine the ability of Fusarium spp. isolates to produce BEA, FUS and FBs and their natural occurrence in maize. Twenty-eight samples corresponding to seven
different maize hybrids were analyzed for mycobiota and natural mycotoxin contamination by LC. Fusarium verticillioides was the dominant species (44–80%) followed by F. subglutinans (13–37%) and F. proliferatum (2–16%). Beauvericin was detected in three different hybrids with levels ranging from 300 to 400 ng g−1, while only one hybrid was contaminated with FUS (200 ng g−1). All samples were positive for FB1 and FB2 contamination showing levels up to 606 and 277 ng g−1, respectively. All F. verticillioides isolates were able to produce FB1 (13.8–4,860 μg g−1) and some also produced FB2 and FUS. Beauvericin, FUS, FB1 and FB2 were produced by several isolates including F. proliferatum and F. subglutinans and co-production was observed. This is the first report on the co-occurrence of these toxins in maize samples from Mexico.
The analysis of the presence of multiple mycotoxins in this substrate is necessary to understand the significance of these
compounds in the human and animal food chains. 相似文献
9.
Ha SJ Kim SY Seo JH Moon HJ Lee KM Lee JK 《Applied microbiology and biotechnology》2007,76(1):109-116
The production yield of Coenzyme Q10 (CoQ10) from the sucrose consumed by Agrobacterium tumefaciens KCCM 10413 decreased, and high levels of exopolysaccharide (EPS) accumulated after switching from batch culture to fed-batch
culture. Therefore, we examined the effect of sucrose concentration on the fermentation profile by A. tumefaciens. In the continuous fed-batch culture with the sucrose concentration maintained constantly at 10, 20, 30, and 40 g l−1, the dry cell weight (DCW), specific CoQ10 content, CoQ10 production, and the production yield of CoQ10 from the sucrose consumed increased, whereas EPS production decreased as maintained sucrose concentration decreased. The
pH-stat fed-batch culture system was adapted for CoQ10 production to minimize the concentration of the carbon source and osmotic stress from sucrose. Using the pH-stat fed-batch
culture system, the DCW, specific CoQ10 content, CoQ10 production, and the product yield of CoQ10 from the sucrose consumed increased by 22.6, 13.7, 39.3, and 39.3%, respectively, whereas EPS production decreased by 30.7%
compared to those of fed-batch culture in the previous report (Ha SJ, Kim SY, Seo JH, Oh DK, Lee JK, Appl Microbiol Biotechnol,
74:974–980, 2007). The pH-stat fed-batch culture system was scaled up to a pilot scale (300 l), and the CoQ10 production results obtained (626.5 mg l−1 of CoQ10 and 9.25 mg g DCW−1 of specific CoQ10 content) were similar to those obtained at the laboratory scale. Thus, an efficient and highly competitive process for microbial
CoQ10 production is available. 相似文献
10.
A chemically defined medium for mycelial growth and exopolysaccharide (EPS) production by submerged culture of Phellinus igniarius was investigated. The mainly defined medium compositions were optimized by using orthogonal matrix method. The optimal defined
medium (per liter) was 40.0 g glucose, 4.0 g. glutamic acid, 4.0 g (NH4)2SO4, and initial pH 6.0. Under the optimal medium, the maximal mycelial biomass and EPS production were 12.33 ± 0.89 and 1.21 ± 0.08 g l−1 at 192 h in shake flask, while the maximal mycelial biomass and EPS production reached 13.86 ± 0.52 and 1.92 ± 0.07 g l−1 at 168 h in 3 l fermenter, respectively. The molecular weights (g mol−1) of four fractions isolated from EPS by gel permeation were about 6.4 × 106, 3.3 × 105, 2.7 × 105 and 2.9 × 103. This study should be widely applied to other secondary metabolites production from higher fungus in a chemically defined
medium and quantitative regulation of the metabolic flux in polysaccharide biosynthesis. 相似文献
11.
T Roukas 《Journal of industrial microbiology & biotechnology》1999,22(6):617-621
Aureobasidium pullulans P56 was investigated using an adaptation technique and a mixed culture system. The adaptation of A. pullulans and the mixed cultures of A. pullulans and/or Lactobacillus brevisX20, Debaryomyces hansenii 194 and Aspergillus niger did not increase the production of polysaccharide. Enzymic hydrolysis of lactose in deproteinized whey gave a higher polysaccharide
concentration and polysaccharide yield than acidic hydrolysed lactose. Maximum polysaccharide concentration (11.0 ± 0.5 g L−1), biomass dry weight (10.5 ± 0.4 g L−1), polysaccharide yield (47.2 ± 1.8%) and sugar utilization (93.2 ± 2.8%) were achieved using enzyme-hydrolysed whey (pH 6.5)
containing 25 g L−1 lactose and supplemented with K2HPO4 0.5%, L-glutamic acid 1%, olive oil 2.5%, and Tween 80 0.5%. In this case the pullulan content of the crude polysaccharide was 40%.
Received 16 December 1997/ Accepted in revised form 12 March 1999 相似文献
12.
Mounir R Durieux A Bodo E Allard C Simon JP Achbani EH El-Jaafari S Douira A Jijakli MH 《Biotechnology letters》2007,29(4):553-559
Aureobasidium pullulans (de Bary) Arnaud (Ach 1-1) was grown in a glucose fed-batch fermentor to 106 g dry wt l−1 in 48 h. The cells were dried in a fluidized bed dryer with a final viability of 62%. After 7 months at 4°C, the viability
was 28% of the initial value (= 2.3 × 1010 c.f.u. g−1 dry matter). A protection level of 89% was achieved with the biomass preparation at 1 × 108 c.f.u. ml−1 after 28 and 7 days for apples stored respectively at 5 and 25°C against Penicillium expansum. Our process is suitable to produce large quantities of the strain Ach 1-1 as biological control agent for apple preservation. 相似文献
13.
One-hundred and five fungal strains, belonging to 46 different species, were screened for exopolysaccharide production. Phytopathogenicity
and, in particular, inability to produce conidia, were physiological characteristics positively associated and correlated
with the fungal ability to produce polysaccharides. Among the 29 positive strains, Botryosphaeria rhodina DABAC-P82 was the most interesting reaching, when grown on optimal nitrogen source and concentration (NaNO3 and 2.0 g l−1, respectively) and culture medium pH (3.7), 17.7 g l−1 of exopolysaccharide production after only 24 h of fermentation; yield and productivity were 0.69 g g−1 and 0.73 g l−1 h−1, respectively. The purified polysaccharide was characterised as a homopolysaccharide of glucose with a molecular weight of
4.875·106 Da. Studies of structural analysis indicated the presence of β-1,3 and β-1,6 linkages; the EPS structure was very similar
to that of scleroglucan.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
14.
Periasamy Saravanan S. R. Prabagaran Y. Venkata Nancharaiah M. Krishnaveni Vayalam P. Venugopalan Seetharaman Jayachandran 《World journal of microbiology & biotechnology》2008,24(4):509-515
Biofilm formation in bacteria is closely linked with production of exopolysaccharides (EPS). This study examined the quantitative
variations in EPS production and biofilm-forming ability among bacteria isolated from the seawater intake point of a power
station located on the east coast of India. Of the 233 isolates obtained from the intake site, 71 bacterial isolates displayed
different colony morphological characteristics. Thirteen isolates that produced wide and thick mucoid colonies were further
tested for their ability to attach and form biofilms by microtitre plate assay and confocal microscopy. EPS production among
the selected bacterial isolates ranged from 826 to 1838 μg ml−1. Strain SBT033, which produced the maximum amount of EPS also displayed the maximum biofilm-forming ability among the 13
isolates. This strain was selected for further characterization using biochemical and molecular methods. The pale orange-pigmented
isolate was a Gram negative, aerobic, short rod-shaped and grew well only in the presence of 2% NaCl. On the basis of phenotypic
characteristics the isolate SBT033 is shown to belong to the genus Pseudoalteromonas. Analysis of 16S rRNA of the isolate revealed 99% homology with Pseudoalteromonas ruthenica. 相似文献
15.
From a survey of more than 50 diverse strains of Aureobasidium pullulans, 21 produced extracellular heavy oils. Most oil producers fell into phylogenetic clades 8, 9, and 11. Oil colors ranged from
bright yellow to malachite. More than half of the strains produced oil that was fluorescent. In medium containing 5% (w/v)
sucrose, oil yields ranged from 0.5 to 6 g oil/l. Strain CU 43 reached stationary growth phase at day 4 while oil yields were
maximal at day 6. CU 43 produced bright yellow, highly fluorescent oil that also was visible as intracellular droplets under
fluorescent microscopy. Oil was surface active, suggesting that it functions as a biosurfactant. Oil from two strains (CU
43 and NRRL Y-12974) differentially inhibited mammalian cancer cell lines. MALDI-TOF MS spectra suggested that A. pullulans strains produce a family of related oil structures. 相似文献
16.
Irzykowska L Bocianowski J Waśkiewicz A Weber Z Karolewski Z Goliński P Kostecki M Irzykowski W 《Journal of applied genetics》2012,53(2):237-247
Thirty single-spore isolates of a toxigenic fungus, Fusarium oxysporum, were isolated from asparagus spears and identified by species-specific polymerase chain reaction (PCR) and translation elongation
factor 1-α (TEF) sequence analysis. In the examined sets of F. oxysporum isolates, the DNA sequences of mating type genes (MAT) were identified. The distribution of MAT idiomorph may suggest that MAT1-2 is a predominant mating type in the F. oxysporum population. F. oxysporum is mainly recognised as a producer of moniliformin—the highly toxic secondary metabolite. Moniliformin content was determined
by high-performance liquid chromatography (HPLC) analysis in the range 0.05–1,007.47 μg g−1 (mean 115.93 μg g−1) but, also, fumonisin B1 was detected, in the concentration range 0.01–0.91 μg g−1 (mean 0.19 μg g−1). There was no association between mating types and the mycotoxins biosynthesis level. Additionally, a significant intra-species
genetic diversity was revealed and molecular markers associated with toxins biosynthesis were identified. 相似文献
17.
Shannon KE Saleh-Lakha S Burton DL Zebarth BJ Goyer C Trevors JT 《Antonie van Leeuwenhoek》2011,100(2):183-195
The effect of glucose addition (0 and 500 μg C g−1 soil) and nitrate (NO3) addition (0, 10, 50 and 500 μg NO3–N g−1 soil) on nitric oxide reductase (cnorB) gene abundance and mRNA levels, and cumulative denitrification were quantified over 48 h in anoxic soils inoculated with
Pseudomonas mandelii. Addition of glucose-C significantly increased cnorB
p
(P. mandelii and related species) mRNA levels and abundance compared with soil with no glucose added, averaged over time and NO3 addition treatments. Without glucose addition, cnorB
p
mRNA levels were higher when 500 μg NO3–N g−1 soil was added compared with other NO3 additions. In treatments with glucose added, addition of 50 μg NO3–N g−1 soil resulted in higher cnorB
p
mRNA levels than soil without NO3 but was not different from the 10 and 500 μg NO3–N g−1 treatments. cnorB
p
abundance in soils without glucose addition was significantly higher in soils with 500 μg NO3–N g−1 soil compared to lower N-treated soils. Conversely, addition of 500 μg NO3–N g−1 soil resulted in lower cnorB
p
abundance compared with soil without N-addition. Over 48 h, cumulative denitrification in soils with 500 μg glucose-C g−1 soil, and 50 or 500 μg NO3–N g−1 was higher than all other treatments. There was a positive correlation between cnorB
p
abundance and cumulative denitrification, but only in soils without glucose addition. Glucose-treated soils generally had
higher cnorB
p
abundance and mRNA levels than soils without glucose added, however response of cnorB
p
abundance and mRNA levels to NO3 supply depended on carbon availability. 相似文献
18.
José Antonio Morillo Victor Guerra del Águila Margarita Aguilera Alberto Ramos-Cormenzana Mercedes Monteoliva-Sánchez 《World journal of microbiology & biotechnology》2007,23(12):1705-1710
Paenibacillus jamilae, a strain isolated from compost prepared with olive-mill wastewaters, produced an extracellular polysaccharide (EPS) when
it was grown in a culture containing olive-mill waste waters (OMWW) as sole carbon and energy sources. Maximal EPS production
in 100 mL batch-culture experiments (5.1 g L−1) was reached with a concentration of 80% of OMWW as fermentation substrate (v/v). Although an inhibitory effect was observed
on growth and EPS production when OMWW concentration was increased, an appreciable amount of EPS (2.7 g L−1) was produced with undiluted OMWW. Sepharose CL-2B chromatography showed that the EPS presented two fractions, EPS I (>2000 kDa)
and EPS II (500 kDa). Both fractions were characterized by GC-MS as two different acidic heteropolysaccharides containing
glucose, galactose and mannose as the major components. The performed study made evident the possibility of using OMWW as
substrate for the production of EPS by P. jamilae with a satisfactory yield. 相似文献
19.
The objective of this study was to improve the biological water–gas shift reaction for producing hydrogen (H2) by conversion of carbon monoxide (CO) using an anaerobic thermophilic pure strain, Carboxydothermus hydrogenoformans. Specific hydrogen production rates and yields were investigated at initial biomass densities varying from 5 to 20 mg volatile
suspended solid (VSS) L−1. Results showed that the gas–liquid mass transfer limits the CO conversion rate at high biomass concentrations. At 100-rpm
agitation and at CO partial pressure of 1 atm, the optimal substrate/biomass ratio must exceed 5 mol CO g−1 biomass VSS in order to avoid gas–liquid substrate transfer limitation. An average H2 yield of 94 ± 3% and a specific hydrogen production rate of ca. 3 mol g−1 VSS day−1 were obtained at initial biomass densities between 5 and 8 mg VSS−1. In addition, CO bioconversion kinetics was assessed at CO partial pressure from 0.16 to 2 atm, corresponding to a dissolved
CO concentration at 70°C from 0.09 to 1.1 mM. Specific bioactivity was maximal at 3.5 mol CO g−1 VSS day−1 for a dissolved CO concentration of 0.55 mM in the culture. This optimal concentration is higher than with most other hydrogenogenic
carboxydotrophic species. 相似文献
20.
Microbial conversion of lignocellulose to hydrogen is a fascinating way to provide a renewable energy source. A mesophilic
bacterium strain G1 that had high cellulose degradation and hydrogen production activity (2.38 mmol H2 g−1 cellulose) was isolated from rumen fluid and identified as the Enterococcus gallinarum. Hydrogen production from cellulose by using sequential co-cultures of a cellulosic-hydrolysis bacterium G1 and Ethanoigenens harbinense B49 was investigated. With an initial Avicel concentration of 5 g l−l, the sequential co-culture with G1 and strain Ethanoigenens harbinense B49 produced H2 yield approximately 2.97 mmol H2 g−1 cellulose for the co-culture system. 相似文献