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1.
Lefebvre O Quentin S Torrijos M Godon JJ Delgenès JP Moletta R 《Applied microbiology and biotechnology》2007,75(1):61-69
The anaerobic treatment of saline effluents using halophilic and halotolerant microbial consortia is of major interest. Inhibition
of anaerobic digestion is known to occur at high salt content. However, it seems that the suitable adaptation of an anaerobic
sludge makes possible the treatment of saline wastewater. In this study, a non-saline anaerobic sludge was inoculated in two
anaerobic batch reactors operating with a different substrate (distillery vinasse and ethanol) and subjected to increasing
NaCl concentrations. The performance of the digesters appeared to be highly dependent on the nature of the substrate, and
a similar level of inhibition (i.e. around 90% of the specific loading rate and specific methanogenic activity) was stated
at 10 g l−1 of NaCl with distillery vinasse and 60 g l−1 of NaCl with ethanol. The characterization of the microflora and its adaptation to increasing NaCl conditions were also investigated
using molecular tools based on the analysis of genomic 16S rDNA. The microbial communities revealed a high diversity that
could be maintained in both reactors despite the increase in NaCl concentrations. 相似文献
2.
Sasaki K Morita M Hirano S Ohmura N Igarashi Y 《Applied microbiology and biotechnology》2011,90(4):1555-1561
Ammonia accumulation is one of the main causes of the loss of methane production observed during fermentation. We investigated
the effect of addition of carbon fiber textiles (CFT) to thermophilic methanogenic bioreactors with respect to ammonia tolerance
during the process of degradation of artificial garbage slurry, by comparing the performance of the reactors containing CFT
with the performance of reactors without CFT. Under total ammonia-N concentrations of 3,000 mg L−1, the reactors containing CFT were found to mediate stable removal of organic compounds and methane production. Under these
conditions, high levels of methanogenic archaea were retained at the CFT, as determined by 16S rRNA gene analysis for methanogenic
archaea. In addition, Methanobacterium sp. was found to be dominant in the suspended fraction, and Methanosarcina sp. was dominant in the retained fraction of the reactors with CFT. However, the reactors without CFT had lower rates of
removal of organic compounds and production of methane under total ammonia-N concentrations of 1,500 mg L−1. Under this ammonia concentration, a significant accumulation of acetate was observed in the reactors without CFT (130.0 mM),
relative to the reactors with CFT (4.2 mM). Only Methanobacterium sp. was identified in the reactors without CFT. These results suggest that CFT enables stable proliferation of aceticlastic
methanogens by preventing ammonia inhibition. This improves the process of stable garbage degradation and production of methane
in thermophilic bioreactors that include high levels of ammonia. 相似文献
3.
Andreazza R Okeke BC Pieniz S Brandelli A Lambais MR Camargo FA 《Biological trace element research》2011,143(2):1182-1192
Environmental copper contamination is a serious human health problem. Copper reductase is produced by microorganisms to facilitate
copper uptake by ATPases into the cells increasing copper biosorption. This study assessed the reduction of Cu(II) by cell-free
extracts of a highly copper-resistant bacterium, Pseudomonas sp. strain NA, isolated from vineyard soil contaminated with copper. Both intact cells and cell-free extract of Pseudomonas sp. strain NA displayed substantial reduction of Cu(II). Intact cells reduced more then 80 mg L−1 of Cu(II) from medium amended with 200 mg L−1 of copper after 24 h of incubation. Cell-free extract of the isolate reduced more than 65% of the Cu(II) at initial copper
concentration of 200 mg L−1 after 24 h. Soluble protein production was high at 72 h of incubation at 100 mg L−1 of copper, with more then 60 μg L−1 of total soluble protein in cell-free extract recorded. Cu(II) reduction by isolate NA was increased when copper concentration
increased for both intact cells and cell-free extract. Results indicate that Pseudomonas sp. strain NA produces copper reductase enzyme as the key mechanism of copper biotransformation. 相似文献
4.
Somatic embryogenesis and plant regeneration in two wild cotton species belong to G genome 总被引:1,自引:0,他引:1
Shu-Feng Yan Qiao Zhang Jing-Er Wang Yu-Qiang Sun M. K. Daud Shui-Jin Zhu 《In vitro cellular & developmental biology. Plant》2010,46(3):298-305
The present work describes the plant regeneration via somatic embryogenesis in two wild cotton species belonging to G genome:
Gossypium nelsonii Fryx and Gossypium australe F Muell. The role of plant hormones and carbohydrates was also evaluated for somatic embryogenesis and somatic embryo development.
Normal plants were obtained from G. nelsonii Fryx; abnormal plants and somatic embryos were obtained from G. australe F Muell. The best medium for callus induction for these G genome wild cotton species was MSB5 supplemented with 0.1 mg L−1 KT and 0.1 mg L−1 2,4-D. For embryogenic callus proliferation, the best medium used was MSB5 supplemented with 0.2 mg L−1 KT and 0.5 mg L−1 IBA. The medium MSB5 supplemented with 0.15 mg L−1 KT and 0.5 mg L−1 NAA was used successfully for root initiation and plant growth. In addition, adding CuSO4 and AgNO3 in the callus-inducing and proliferation medium resulted in a number of somatic embryos. Glucose and maltose, the carbon
sources in somatic culture, were used for callus induction, but maltose worked even better than glucose for proliferation
of embryogenic callus and development of somatic embryos. 相似文献
5.
Alkaliphilic and halophilic Bacillus sp. BG-CS10 was isolated from Zabuye Salt Lake, Tibet. The gene celB, encoding a halophilic cellulase was identified from the genomic library of BG-CS10. CelB belongs to the cellulase superfamily
and DUF291 superfamily, with an unknown function domain and less than 58% identity to other cellulases in GenBank. The purified
recombinant protein (molecular weight: 62 kDa) can hydrolyze soluble cellulose substrates containing beta-1,4-linkages, such
as carboxylmethyl cellulose and konjac glucomannan, but has no exoglucanase and β-glucosidase activities. Thus, CelB is a
cellulase with an endo mode of action and glucomannanase activity. Interestingly, the enzyme activity was increased approximately
tenfold with 2.5 M NaCl or 3 M KCl. Furthermore, the optimal temperatures were 55°C with 2.5 M NaCl and 35°C without NaCl,
respectively. This indicates that NaCl can improve enzyme thermostability. The K
m
and k
cat values of CelB for CMC with 2.5 M NaCl were 3.18 mg mL−1 and 26 s−1, while the K
m
and k
cat values of CelB without NaCl were 6.6 mg mL−1 and 2.1 s−1. Thus, this thermo-stable, salt and pH-tolerant cellulase is a promising candidate for industrial applications, and provides
a new model to study salt effects on the structure of protein. 相似文献
6.
The degradation potential of trichloroethene by the aerobic methane- and ammonia-oxidizing microorganisms naturally associated
with wetland plant (Carex comosa) roots was examined in this study. In bench-scale microcosm experiments with washed (soil free) Carex comosa roots, the activity of root-associated methane- and ammonia-oxidizing microorganisms, which were naturally present on the
root surface and/or embedded within the roots, was investigated. Significant methane and ammonia oxidation were observed reproducibly
in batch reactors with washed roots incubated in growth media, where methane oxidation developed faster (2 weeks) compared
to ammonia oxidation (4 weeks) in live microcosms. After enrichment, the methane oxidizers demonstrated their ability to degrade
150 μg l−1 TCE effectively at 1.9 mg l−1 of aqueous CH4. In contrast, ammonia oxidizers showed a rapid and complete inhibition of ammonia oxidation with 150 μg l−1 TCE at 20 mg l−1 of NH4
+-N, which may be attributed to greater sensitivity of ammonia oxidizers to TCE or its degradation product. No such inhibitory
effect of TCE degradation was detected on methane oxidation at the above experimental conditions. The results presented here
suggest that microorganisms associated with wetland plant roots can assist in the natural attenuation of TCE in contaminated
aquatic environments. 相似文献
7.
Anaerobic co-digestion of dairy manure with mulched switchgrass for improvement of the methane yield
The owners of farm-scale anaerobic digesters are relying on off-farm wastes or energy crops as a co-digestion feedstock with
animal manure in order to increase their production of methane and thus revenues. Switchgrass represents an interesting feedstock
for Canadian digesters owners as it is a high-yielding low-maintenance perennial crop, well adapted to northern climate. Methane
potential assays in batch tests showed methane production of 19.4 ± 3.6, 28.3 ± 1.7, 37.3 ± 7.1 and 45.7 ± 0.8 L kg−1, for raw manure, blended manure, manure and mulched switchgrass, manure and pretreated switchgrass, respectively. Two 6-L
lab-scale anaerobic digesters were operated for 130 days in order to assess the benefit of co-digesting switchgrass with bovine
manure (digester #2), at a 20% wet mass fraction, compared with a manure-only operation (digester #1) The digesters were operated
at an hydraulic retention time of 37 ± 6 days and at loads of 2.4 ± 0.6 and 2.6 ± 0.6 kg total volatile solids (TVS) L−1 day−1 for digesters #1 (D1) and #2 (D2), respectively. The TVS degradation reached 25 and 39%, which resulted in a methane production
of 1.18 ± 0.18 and 2.19 ± 0.31 L day−1 for D1 and D2, respectively. The addition of 20% on a wet mass ratio of switchgrass to a manure digester increased its methane
production by 86%. The co-digestion of switchgrass in a 500 m3 manure digester could yield up to 10.2 GJ day−1 of purified methane or 1.1 MWh day−1 of electricity. 相似文献
8.
Yinghao Yu Juliana A. Ramsay Bruce A. Ramsay 《Applied microbiology and biotechnology》2009,82(2):333-339
Methanotrophs expressing soluble methane monooxygenase (sMMO) may find use in a variety of industrial applications. However,
sMMO expression is strongly inhibited by copper, and the growth rate may be limited by the aqueous solubility of methane.
In this study, addition of allylthiourea decreased intracellular copper in Methylosinus trichosporium OB3b, allowing sMMO production at Cu/biomass ratios normally not permitting sMMO synthesis. The presence of about 1.5 μmoles
intracellular Cu g−1 dry biomass resulted in sMMO activity of about 250 μmoles 1-napthol formed per hour gram dry biomass whether this intracellular
Cu concentration was achieved by Cu limitation or by allylthiourea addition. No loss of sMMO activity occurred when the growth
substrate was switched from methane to methanol when allylthiourea had been added to growth medium containing copper. Addition
of copper to medium that was almost copper-free increased the yield of dry biomass from methanol from 0.20 to 0.36 g g−1, demonstrating that some copper was necessary for good growth. This study demonstrated a method by which sMMO can be produced
by M. trichosporium OB3b while growing on methanol in copper-containing medium. 相似文献
9.
10.
Samia Oueslati Najoua Karray-Bouraoui Houneïda Attia Mokded Rabhi Riadh Ksouri Mokhtar Lachaal 《Acta Physiologiae Plantarum》2010,32(2):289-296
Mentha pulegium L. is a medicinal and aromatic plant belonging to the Labiatae family present in the humid to the arid bioclimatic regions
of Tunisia. We studied the effect of different salt concentrations on plant growth, mineral composition and antioxidant responses.
Physiological and biochemical parameters were assessed in the plant organs after 2 weeks of salt treatment with 25, 50, 75
and 100 mM NaCl. Results showed that, growth was reduced even by 25 mM, and salt effect was more pronounced in shoots (leaves
and stems) than in roots. This growth decrease was accompanied by a restriction in tissue hydration and K+ uptake, as well as an increase in Na+ levels in all organs. Considering the response of antioxidant enzymes to salt, leaves and roots reacted differently to saline
conditions. Leaf and root guaiacol peroxidase activity showed an increase by different concentration of NaCl, but superoxide
dismutase activity in the same organs showed a slight modification in NaCl-treated leaves and roots. Moreover, polyphenol
contents and antioxidant activity were analysed in M. pulegium leaves and roots under salt constraint. The analysis showed an increase of total polyphenol content (2.41–8.17 mg gallic
acid equivalent g−1 dry weight) in leaves. However, methanol extract of leaves at 100 mM NaCl displayed the highest DPPH· scavenging ability
with the lowest IC50 value (0.27 μg ml−1) in comparison with control which exhibited IC50 equal to 0.79 μg ml−1. 相似文献
11.
Juan Wang Wen-Yuan Gao Jian Zhang Tao Huang Tian-Tian Wen Lu-Qi Huang 《Acta Physiologiae Plantarum》2011,33(3):861-866
Lactoalbumin hydrolysate (LH) at 100 mg L−1 with methyl jasmonate (MJ) at 2 mg L−1 synergistically stimulated ginsenoside accumulation in Panax quinquefolium cells compared with 100 mg L−1 LH. Combination elicitors led to higher ginsenoside productivity (45.93 mg L−1) than single treatment of 100 mg L−1 LH (31.37 mg L−1). This present result will be helpful in providing a tool for enhancing the productivity of ginsenoside by Panax quinquefolium cell cultures on a commercial scale. 相似文献
12.
Response of methanotrophs and methane oxidation on ammonium application in landfill soils 总被引:3,自引:0,他引:3
To test the dose effect of ammonium (NH4
+) fertilization on soil methane (CH4) oxidation by methanotrophic communities, batch incubations were conducted at a wide scale of NH4
+ amendments: 0, 100, 250, 500, and 1,000 mg N kgdry soil
−1. Denaturing gradient gel electrophoresis and real-time quantitative PCR analysis were conducted to investigate the correlation
between the CH4 oxidation capacity and methanotrophic communities. Immediately after the addition of NH4
+, temporal inhibition of CH4 oxidation occurred, and this might have been due to the non-specific salt effect (osmotic stress). After a lag phase, the
CH4 oxidation rates of the soils with NH4
+ fertilization were promoted to levels higher than those of the controls. More than 100 mg N kgdry soil
−1 of NH4
+ addition resulted in the reduction of type II/type I MOB ratios and an obvious evolution of type II MOB communities, while
less than 100 mg N kgdry soil
−1 of NH4
+ addition induced nearly no change of methanotrophic community compositions. The NH4
+-derived stimulation after the lag phase was attributed to the improvement of N availability for type I MOB. Compared with
the controls, 100 mg N kgdry soil
−1 of NH4
+ addition doubled the CH4 oxidation peak value to more than 20 mg CH4 kgdry soil
−1 h−1. Therefore, an appropriate amount of leachate irrigation on the landfill cover layer might efficiently mitigate the CH4 emissions. 相似文献
13.
P. Olguín-Lora S. Le Borgne G. Castorena-Cortés T. Roldán-Carrillo I. Zapata-Peñasco J. Reyes-Avila S. Alcántara-Pérez 《Biodegradation》2011,22(1):83-93
Haloalkaliphilic sulfur-oxidizing mixed cultures for the treatment of alkaline–saline effluents containing sulfide were characterized
and evaluated. The mixed cultures (IMP-PB, IMP-XO and IMP-TL) were obtained from Mexican alkaline soils collected in Puebla
(PB), Xochimilco (XO) and Tlahuac (TL), respectively. The Ribosomal Intergenic Spacer Analysis (RISA) revealed bacteria related
to Thioalkalibacterium and Thioalkalivibrio in IMP-XO and IMP-PB mixed cultures. Halomonas strains were detected in IMP-XO and IMP-TL. In addition, an uncultured Bacteroides bacterium was present in IMP-TL. Mixed cultures were evaluated at different pH and NaCl concentrations at 30°C. IMP-PB and
IMP-TL expressed thiosulfate-oxidizing activity in the 7.5–10.5 pH range, whereas IMP-XO presented its maximal activity with
19.0 mg O2 gprotein−1 min−1, at pH 10.6; it was not affected by NaCl concentrations up to 1.7 M. In continuous culture, IMP-XO showed a growth rate of
15 day−1, productivity of 433.4 mgprotein l−1 day−1 and haloalkaliphilic sulfur-oxidizing activity was also detected up to 170 mM by means of N-methyl-diethanolamine (MDEA). Saline–alkaline soil samples are potential sources of haloalkaliphilic sulfur-oxidizing bacteria
and the mixed cultures could be applied in the treatment of inorganic sulfur compounds in petroleum industry effluents under
alkaline–saline conditions. 相似文献
14.
Héctor Guzmán Doan Van-Thuoc Javier Martín Rajni Hatti-Kaul Jorge Quillaguamán 《Applied microbiology and biotechnology》2009,84(6):1069-1077
The paper reports a study involving the use of Halomonas boliviensis, a moderate halophile, for co-production of compatible solute ectoine and biopolyester poly(3-hydroxybutyrate) (PHB) in a
process comprising two fed-batch cultures. Initial investigations on the growth of the organism in a medium with varying NaCl
concentrations showed the highest level of intracellular accumulation of ectoine (0.74 g L−1) at 10–15% (w/v) NaCl, while at 15% (w/v) NaCl, the presence of hydroxyectoine (50 mg L−1) was also noted. On the other hand, the maximum cell dry weight and PHB concentration of 10 and 5.8 g L−1, respectively, were obtained at 5–7.5% (w/v) NaCl. A process comprising two fed-batch cultivations was developed—the first culture aimed at obtaining high cell mass
and the second for achieving high yields of ectoine and PHB. In the first fed-batch culture, H. boliviensis was grown in a medium with 4.5% (w/v) NaCl and sufficient levels of monosodium glutamate, NH4+, and PO43−. In the second fed-batch culture, the NaCl concentration was increased to 7.5% (w/v) to trigger ectoine synthesis, while nitrogen and phosphorus sources were fed only during the first 3 h and then stopped
to favor PHB accumulation. The process resulted in PHB yield of 68.5 wt.% of cell dry weight and volumetric productivity of
about 1 g L−1 h−1 and ectoine concentration, content, and volumetric productivity of 4.3 g L−1, 7.2 wt.%, and 2.8 g L−1 day−1, respectively. At salt concentration of 12.5% (w/v) during the second cultivation, the ectoine content was increased to 17 wt.% and productivity to 3.4 g L−1 day−1. 相似文献
15.
Effects of copper on expression of methane monooxygenases,trichloroethylene degradation,and community structure in methanotrophic consortia
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Zhilin Xing Tiantao Zhao Lijie Zhang Yanhui Gao Shuai Liu Xu Yang 《Engineering in Life Science》2018,18(4):236-243
Copper plays a key role in regulating the expression of enzymes that promote biodegradation of contaminants in methanotrophic consortia (MC). Here, we utilized MC isolated from landfill cover to investigate cometabolic degradation of trichloroethylene (TCE) at nine different copper (Cu2+) concentrations. The results demonstrated that an increase in Cu2+ concentration from 0 to 15 μM altered the specific first‐order rate constant k1,TCE, the expression levels of methane monooxygenase (pmoA and mmoX) genes, and the specific activity of soluble methane monooxygenase (sMMO). High efficiency TCE degradation (95%) and the expression levels of methane monooxygenase (MMO) were detected at a Cu2+ concentration of 0.03 μM. Notably, sMMO‐specific activity ranged from 74.41 nmol/(mgcell h) in 15 μM Cu2+ to 654.99 nmol/(mgcell h) in 0.03 μM Cu2+, which contrasts with cultures of pure methanotrophs in which sMMO activity is depressed at high Cu2+ concentrations, indicating a special regulatory role for Cu2+ in MC. The results of MiSeq pyrosequencing indicated that higher Cu2+ concentrations stimulated the growth of methanotrophic microorganisms in MC. These findings have important implications for the elucidation of copper‐mediated regulatory mechanisms in MC. 相似文献
16.
N. Selvaraj S. Kasthurirengan A. Vasudevan M. Manickavasagam C. W. Choi A. Ganapathi 《In vitro cellular & developmental biology. Plant》2010,46(4):329-337
Efficient Agrobacterium tumefaciens-mediated transformation and a higher recovery of transformed plants of cucumber cv. Poinsett76 were achieved via direct organogenesis
from cotyledon explants. Stable transformants were obtained by inoculating explants with A. tumefaciens strains EHA105 or LBA4404, both harboring the binary vector pME508, which contains the neomycin phosphotransferase II (nptII) and phosphinothricin resistance genes (bar) conferring resistance to kanamycin and PPT, respectively, as selectable markers and the sgfp-tyg gene for the green fluorescent protein (GFP) as a visual marker driven by the constitutive CaMV35S promoter in the presence
of acetosyringone (50 μM). Transformed shoots were obtained on MS Murashige and Skoog (Plant Physiol. 15: 473–497, 1962) medium supplemented with 1 mg L−1 benzyladenine (BA), 20 mg L−1
l-glutamine and 2 mg L−1 phosphinothricin (PPT) or 100 mg L−1 kanamycin. The regenerated shoots were examined in vivo using a hand-held long wave UV lamp for GFP expression. The GFP screening helped identify escapes and chimeric shoots at
regular intervals to increase the growth of transformed shoots on cotyledon explants. Elongation and rooting of putative transformants
were achieved on PPT (2 mg L−1) containing MS media with 0.5 mg L−1 gibberellic acid (GA3) and 0.6 mg L−1 indole butyric acid (IBA), respectively. PCR and Southern analyses confirmed the integration of the sgfp gene into the genome of T0 and the progenies. T1 segregation of transgenic progeny exhibited Mendelian inheritance of the transgene. The use of EHA105 resulted in 21% transformation
efficiency compared to 8.5% when LBA4404 was used. This higher rate was greatly facilitated by PPT selection coupled with
effective screening of transformants for GFP expression, thus making the protocol highly useful for the recovery of a higher
number of transgenic cucumber plants. 相似文献
17.
Y. H. Qin Jaime A. Teixeira da Silva J. H. Bi S. L. Zhang G. B. Hu 《Plant Growth Regulation》2011,65(1):183-193
By identifying antibiotics that had the least phytotoxic effects on explants during genetic transformation, we evaluated the
effect of various antibiotics on callus induction and morphogenesis from leaf explants and in vitro growth of Fragaria × ananassa Duch. cv. Toyonaka. Results showed that kanamycin (Kan) significantly inhibited callus induction, bud differentiation and
root morphogenesis while carbenicillin (Carb), cefotaxime (Cef) and an equal concentration of Cef and Carb up to 500 mg L−1 had no significant effects on callus induction and shoot growth. Kan, even at 2.5 mg L−1, significantly inhibited callus induction, shoot regeneration and root formation, while no shoots regenerated at concentrations
above 15 mg L−1. Rooting was completely inhibited in the presence of 50 mg L−1 Kan. Cef had negative effects on shoot regeneration from leaf explants and in vitro growth of strawberry. Compared to Cef,
Carb at ≤300 mg L−1 significantly promoted shoot and root organogenesis. However, an equal concentration of Carb plus Cef could alleviate the
negative effect of Cef on strawberry. Results from relative electrolyte leakage, root and antioxidant activities, O2·− production rate, H2O2, proline and MDA contents showed that Kan, Cef and Carb caused electrolyte leakage and triggered active enzymatic processes
and metabolism. This offers a possible mechanism for the inhibition or stimulation of strawberry growth caused by these antibiotics. 相似文献
18.
William J. Hunter 《Current microbiology》2009,58(6):622-627
Microbial biobarriers are an established technique for cleansing contaminants from aquifers. This study evaluated their use
under well-drained conditions within the vadose or unsaturated zone. Three sets of sand filled columns, the positive control,
field-capacity, and sub-field-capacity groups, contained biobarriers formed by mixing sand with sawdust and soybean oil. The
biobarriers were positioned 1 m from the top of the 145 cm columns. A fourth set of column, the negative control, contained
no biobarrier. The positive control group’s biobarriers were saturated while biobarriers in the other groups were allowed
to drain. At intervals water containing 20 mg l−1 NO3−–N was applied to the columns, the water was allowed to percolate through the columns, and the effluents were collected and
analyzed. The biobarriers were highly effective at removing NO3−. NO3−–N in the effluents from the field-capacity, sub-field-capacity, and positive control groups averaged 0.4 ± 0.1, 0.6 ± 0.1,
and 0.8 ± 0.1 mg l−1, respectively, during the final weeks of the study while effluents from the negative control group averaged 17.9 ± 0.4 mg l−1. The barriers removed NO3− even when the water content was in the 20–40% pore filled space range. During the 12-week study the field-capacity barriers
lost 5.6% of their organic content while those in the sub-field-capacity group lost no detectable organic matter indicating
that the barriers contained sufficient substrate to last for several years. Vadose zone biobarriers could provide a useful
means of protecting surface waters and aquifers from NO3−. 相似文献
19.
Juan Wang Wenyuan Gao Jian Zhang Tao Huang Tiantian Wen Liming Zhang Luqi Huang 《Plant Growth Regulation》2011,63(3):217-223
In this article, ginsenosides and polysaccharide contents in suspension cells and native roots of Panax quinquefolium L. were studied. In order to enhance the contents of ginsenosides and polysaccharide in P. quinquefolium suspension cells, we tested the effects of lactoalbumin hydrolysate on the growth of P. quinquefolium suspension cell, synthesis of ginsenosides and polysaccharide in flask and bioreactor. In flask culture, cells growth ratio
was significantly enhanced by the addition of lower concentration of lactoalbumin hydrolysate. Addition of 100 mg L−1 lactoalbumin hydrolysate significantly enhanced the contents of total saponins (5.44 mg g−1 DW) and the contents were 3.89-fold over the control group. Addition of lactoalbumin hydrolysate significantly promoted the
accumulation of polysaccharide, except 200 mg L−1 lactoalbumin hydrolysate. The highest total saponins yield (36.72 mg L−1 DW) and polysaccharide yield (0.83 g L−1 DW) were obtained at 100 mg L−1 lactoalbumin hydrolysate. In a 5-L stirred tank bioreactor, the highest contents of total saponins and TRb group ginsenosides
were achieved on day 26, while the effect of lactoalbumin hydrolysate on the contents of TRg group ginsenosides were insignificant.
This result suggests that lactoalbumin hydrolysate might have triggered the enzyme activities for the synthesis of TRb group
ginsenosides. Overall, the highest total saponins yield (31.37 mg L−1 DW) and polysaccharide yield (1.618 g L−1 DW) were obtained on day 26 and day 24 respectively and the polysaccharide yield was 1.95-fold higher than the shake flask
culture (0.83 g L−1 DW). These results provided theoretical reference for two-stage culture in suspension cells of P. quinquefolium in bioreactor. 相似文献
20.
Nitrification in fixed-bed reactors treating saline wastewater 总被引:2,自引:0,他引:2
Utomo Sudarno Stephan Bathe Josef Winter Claudia Gallert 《Applied microbiology and biotechnology》2010,85(6):2017-2030
Halophilic nitrifiers belonging to the genus Nitrosomonas and Nitrospira were enriched from seawater and marine sediment samples of the North Sea. The maximal ammonia oxidation rate (AOR) in batch
enrichments with seawater was 15.1 mg N L−1 day−1. An intermediate nitrite accumulation was observed. Two fixed-bed reactors for continuous nitrification with either polyethylene/clay
sinter lamellas (FBR A) or porous ceramic rings (FBR B) were run at two different ammonia concentrations, three different
ammonia loading rates (ALRs), ± pH adjustment, and at an increased upflow velocity. A better overall nitrification without
nitrite accumulation was observed in FBR B. However, FBR A revealed a higher AOR and nitrite oxidation rate of 6 and 7 mg N L−1 h−1, compared to FBR B with 5 and 5.9 mg N L−1 h−1, respectively. AORs in the FBRs were at least ten times higher than in suspended enrichment cultures. Whereas a shift within
the ammonia-oxidizing population in the genus Nitrosomonas at the subspecies level occurred in FBR B with synthetic seawater at an increasing ALR and a decreasing pH, the nitrite oxidizing
Nitrospira population apparently did not change. 相似文献