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1.
Jang K. Kim George P. Kraemer Christopher D. Neefus Ik Kyo Chung Charles Yarish 《Journal of applied phycology》2007,19(5):431-440
Porphyra is one of the world’s most valued maricultured seaweeds and has been cultivated for several hundred years in Asia. The objective
of this study was to produce critical information as a guide for the selection of an appropriate Porphyra species from coastal New England for the development of a land-based aquaculture system. Four Northwest Atlantic Porphyra species: P. leucosticta,
P. amplissima, P. linearis and P. umbilicalis, were cultivated for 1 and 2 weeks at saturated light intensities (100–150 μmol photons m−2s−1) and six combinations of ammonium (25 and 250 μmoles L−1) and temperature (10, 15 and 20°C). Specific growth rate (SGR) increased with decreasing temperature in P. leucosticta, P. linearis and P. umbilicalis and increased with increasing temperature in P. amplissima. The SGR of all species was greater at the higher ammonium concentration. Porphyra linearis had the highest SGR, increasing in biomass by approximately 16% day−1. Phycoerythrin (PE) content was higher at 10°C and 250 μmoles L−1 in all species except P. amplissima. The PE content, measured as fresh weight (FW), of P. linearis (29 mg g−1 FW−1) and P. umbilicalis (26 mg g−1 FW−1) was significantly higher than the other two species. Tissue nitrogen content of all species measured in dry weight was on
average 1.45% higher at 250 μmoles L−1 than at 25 μmoles L−1 ammonium concentration. Porphyra umbilicalis had the highest tissue nitrogen contents (6.76%) at 10°C and 250 μmoles L−1 ammonium. Based on these results, P. linearis and P. umbilicalis should be considered as potential candidates for bioremediation with finfish and shellfish mariculture. 相似文献
2.
Hidenobu Kunii 《Ecological Research》1988,3(3):305-318
In order to determine the seasonal growth and biomass ofTrapa japonica Flerov, field observations were carried out at Ojaga-ike Pond, Chiba, Japan, during 1979 and 1980. In spring, the plant showed
exponential growth (c. 0.080 g g−1 day−1) and shoot elongation was as rapid as 10 cm day−1. The plant attained its maximum biomass (380.5±35.1 g m−2) in late August, and about 50% of this was concentrated in the topmost 30-cm stratum (645.7±33.1 g m−3); maximum total stem length exceeded 6m. The plant produced large (500–800 mg per fruit), but small numbers of nut-like fruit
(maximum, 5 fruits per rosette). Defoliation occurred almost linearly with time at a rate of 30.6 leaves m−2 day−1; annual net leaf production was estimated to be about twice as large as the seasonal maximum leaf biomass. While the number
of leaves per rosette showed moderate seasonal change, rosette density, rosette area and leaf dry weight changed considerably
during the year. From the negative log-log correlation between mean total leaf dry weight per rosette and rosette density,
density-dependent rosette growth was assumed. The cause of the wide spread of this species in aquatic habitats is briefly
discussed in terms of its seed size and morphology. 相似文献
3.
The distribution patterns of flavonoids hyperoside, isoquercitrin, quercitrin, quercetin, I3,II8-biapigenin and naphtodianthrones
hypericin and pseudohypericin were studied in reproductive structures during ontogenetic phase of flowering in Hypericum maculatum
Crantz. Considerable differences in the content of these secondary metabolites, in the particular flower parts were found. The content
of all the metabolites studied is stable during the whole period of flowering in green flower parts (sepals). In petals, stamens
and pistils their content undergoes considerable change associated with the biological functions of particular metabolites.
The most conspicuous changes during ontogenetic phase of flowering were the decrease of hyperoside and isoquercitrin content
in petals (average content in buds 1.589 mg g−1 dry weight, average content in overblown flowers 0.891 mg g−1 dry weight), the decrease of the I3,II8-biapigenin content in stamens (in buds 1.189 mg g−1 dry weight, in overblown flowers 0.319 mg g−1 dry weight), and the increase of hypericin and pseudohypericin content in both petals (total average content of hypericins
in the buds 0.547 mg g−1 dry weight; in overblown flowers 0.792 mg g−1 dry weight) and stamens (in buds 0.189 mg g−1 dry weight; in overblown flowers 0.431 mg g−1 dry weight). Hypericins are absent in the pistil. The flavonoids hyperoside and isoquercitrin, the content of which decreased
during ontogenetic phase of flowering, reach the highest contents in the pistil. 相似文献
4.
Establishment of in vitro plants, cell and tissue cultures from Oldenlandia affinis for the production of cyclic peptides 总被引:1,自引:1,他引:0
In vitro cultured plants from Oldenlandia affinis were established from seeds and grown on a hormone-free medium. In vitro plants produced the cyclic peptide kalata B1 in concentrations of 0.67 mg g−1 dry weight after growth of 30 days. This was approximately 50% of the concentration analysed in green house plants (shoot tips), where different concentrations have been determined in leaves (1.82 mg g−1), shoot tips (1.36 mg g−1), stems (0.36 mg g−1), and in flowers (0.16 mg g−1). Callus and cell suspension cultures could be initiated from aseptic root, stem and leaf explants of O. affinis seedlings and plants. Different light intensities were shown to affect culture growth as well as chlorophyll synthesis. The friable callus was then used for the establishment of a cell suspension culture. Fresh and dry weight measurements showed that growth was optimal on MS medium supplemented with 0.4 mg l−1 2,4-dichlorophenoxyacetic acid (2,4-d). Leaf suspensions cultured on this medium showed a 4-fold increase of biomass by the first week of incubation. No quantifiable amounts of kalata B1 were produced under these conditions. Morphological differentiation seems to be essential for cyclic peptide production. Therefore, several undifferentiated as well as organised cell lines of O. affinis have been developed. These cell lines will constitute a worthwhile starting point for the optimisation of kalata B1 synthesis in liquid media to the objective of producing cyclic peptides under controlled and defined conditions in bioreactors. 相似文献
5.
Leader dieback associated with B deficiency in P. radiata D. Don plantations was treated with borax applied at rates of 50, 100 and 150 kg ha−1. This initially increased B in foliage from 5 to 40, 80 and 110 μg g−1 respectively, and was followed by a rapid decline and stabilisation at around 25 μg g−1 for the duration of the study. Annual fluctuations in foliage B levels were strongly correlated with rainfall during the
preceding spring and summer. Uptake of N, P and K increased as a result of applied B and comparison of the distribution of
these nutrients in crowns of fertilized and unfertilised trees six years after application indicated continued uptake of these
nutrients probably as a result of improved root growth due to B. Foliage concentrations of B like N, P and K, increased in
young needles towards the upper crown and this, together with a decline in needle concentrations of B as foliage aged, indicated
some redistribution of B from older to new foliage. A limit of 5 μg g−1 was found below which little redistribution seems to occur.
Application of B prevented further leader dieback, improved apical dominance and height growth and increased volume production
by 25 m3 ha−1 at age 8 years. Differences between application rates of B were not significant in terms of growth. 相似文献
6.
The adaptation ofCamellia rusticana, an evergreen broad-leaved shrub found in areas of heavy snowfall in Japan, to heavy snowfall environments, and the mechanisms
by which it is damaged in winter above the snow, were investigated. The stomatal response and photosynthetic characteristics
ofC. rusticana were compared to those ofCamellia japonica found in areas of light snowfall. In field conditions, the mean net photosynthesis ofC. rusticana at photon flux density (PFD) over 200 μmol m−2s−1 (Pn(>200). was 50% larger than that ofC. japonica, but in both light saturated and CO2 saturated conditions, the O2 evolution rate (Pc) ofC. rusticana was not different from that ofC. japonica. Mean leaf conductance at PFD over 200 μmol m−2s−1 (gl(>200)) was about 100% larger than that ofC. japonica in the field. The Pn(>200)) was 50% ratio ofC. rusticana was 37% higher than that ofC. japonica which suggests thatC. rusticana's larger Pn(>200) can be explained by its larger gl(>200). WhenC. rusticana trees wintering underneath the snow were projected above it, the leaves of these plants showed serious drought within five
days in non-freezing conditions. Their Pc and the maximum stomatal conductance decreased by half and did not recover. The
leaves ofC. rusticana showed larger gl(>200) and a less sensitive stomatal response to the decrease of leaf water potential than that ofC. japonica. The stomata characteristics ofC. rusticana caused larger net photosynthesis than that ofC. japonica during the no snow period, and caused the need for snow cover in winter as protector from winter drought. 相似文献
7.
G.O. Osuji W.C. Madu C. Braithwaite A. Beyene P.S. Roberts A. Bulgin V. Wright 《Biologia Plantarum》2003,47(2):195-202
The physiological function of glutamate dehydrogenase (GDH) was investigated by treating germinating peanut (Arachis hypogaea L.) seeds with nucleoside triphosphate (NTP) solutions in order to alter the isoenzyme distribution patterns. The free nucleosides
and nucleotides of the GTP-treated peanut were the highest [8.7 μmol g−1(f.m.)], and they decreased through the ATP-treated peanut [5.8 μmol g−1(f.m.)], and CTP-treated peanut [5.5 μmol g−1(f.m.)], to the UTP-treated peanut [4.1 μmol g−1(f.m.)]. The combination of 4 NTPs induced 20 % higher content of Pi [173 nmol g−1(f.m.)] than in the control, but the combined ATP+UTP treatment induced the lowest (93.0 nmol g−1(f.m.)] Pi. The 4 NTP treatment also induced the highest number of GDH isoenzymes (28) followed by the purine NTP treatments
(15 to 20), but the pyrimidine NTP treatments and the combined purine + pyrimidine NTP treatments induced the lowest numbers
(<15) of isoenzymes. The deamination/amination ratios were generally higher in the UTP (0.11), and CTP (0.06) treated peanuts
than in the GTP (0.04), and ATP (0.07) treated peanuts. There were mutual relationships between higher numbers of GDH isoenzymes
present in the GTP-, and ATP-treated peanuts and higher RNA (236.5 and 239.4 μg g−1, respectively) contents on one hand, and between the lower numbers of isoenzymes in the CTP-, and UTP-treated peanuts and
lower RNA (162.0 and 152.5 μg g−1, respectively) contents. The recurrent relationships of the effects of the NTP treatments of peanut were UTP > ATP > CTP
> GTP.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
8.
Tissue culture and plant regeneration of blue grama grass, Bouteloua gracilis (H.B.K.) Lag. Ex Steud
Gerardo Armando Aguado-Santacruz José Luis Cabrera-Ponce Víctor Olalde-Portugal M. A. Rosario Sánchez-González Judith Márouez-Guzmán Luis Herrera-Estrella 《In vitro cellular & developmental biology. Plant》2001,37(2):182-189
Summary As a first step towards applying biotechnology to blue grama, Bouteloua gracilis (H. B. K.) Lag. ex Steud., we have developed a regenerable tissue culture system for this grass. Shoot apices were isolated
from 3-d-old seedlings and cultured in 15 different growth regulator formulations combining 2,4-dichlorophenoxyacetic acid
(2,4-D), Picloram (4-amino-3, 5,6-trichloropicolinic acid), N6-benzyladenine (BA) or adenine (6-aminopurine). The highest induction of organogenic callus was obtained with formulations
containing 1 mg l−1 (4.52 μM) 2,4-D plus 0.5 mg l−1 (2.22 μM) BA. and 2 mg l−1 (8.88 μM) BA plus 1 mg l−1 (4.14 μM) Picloram with or without 40 mg l−1 (296.08 μM) adenine. Lower frequencies of induction were obtained for embryogenic as compared to organogenic callus. The most efficient
treatments for induction of embryogenic callus contained 2 mg l−1 (9.05 μM) 2,4-D combined with 0.25 (1.11 μM) or 0.50 mg l−1 (2.22 μM) BA, or 1 mg l−1 (4.52 μM) 2,4-D with 0.50 mg l−1 (2.22 μM) BA. Regeneration was achieved in hormonefree Murashige anmd Skoog (MS) medium, half-strength MS medium or MS medium plus
1 mg l−1 (1.44 μM) gibberellic acid. The number of plantlets regenerated per 500 mg callus fresh weight on MS medium ranged from 9 for 2 mg
l−1 (9.05 μM) 2,4-D to 62.2 for induction medium containing 2 mg l−1 (8,28 μM) Picloram, 1 mg l−1 (4.44 μM) BA and 40 mg l−1 (296.08 μM) adenine. Regnerated plants grown in soil under greenhouse conditions reached maturity and produced seeds. 相似文献
9.
Effects of sequential procedures required for cryopreservation of embryos excised from the recalcitrant seeds of Haemanthus montanus were assessed ultrastructurally and in conjunction with respiratory activity and the rate of protein synthesis. Fresh material
(water content, 5.05 ± 0.92 g g−1 dry mass) afforded ultrastructural evidence of considerable metabolic activity, borne out by respiratory rates. Neither exposure
to glycerol nor sucrose as penetrating and non-penetrating cryoprotectants, respectively, brought about degradative changes,
although increased vacuolation and autophagy accompanied both, while respiratory and protein synthetic activity were not adversely
affected. Glycerol-cryoprotected embryos flash dried to water contents >0.4 g g−1 showed organised ultrastructural features and considerable autophagy consistent with metabolic activity, and although respiratory
activity was lower, protein synthesis rate was enhanced relative to fresh material. However, at water contents <0.4 g g−1, embryo tissue presented a mosaic of cells of variable density and ultrastructural status, but trends in rates of respiration
and protein synthesis remained similar. Flash drying after sucrose exposure was accompanied by considerable ultrastructural
abnormality particularly at water contents <0.4 g g−1, lysis of individual and groups of cells and considerable depression of respiration, but not of protein synthesis. Success,
assessed as ≥50% axes forming seedlings after cryogen exposure, was obtained only when glycerol-cryoprotected embryos at water
contents >0.4 g g−1—in which the degree of vacuolation remained moderate—were rapidly cooled. The outcomes of this study are considered particularly
in terms of the stresses imposed by prolonged, relatively slow dehydration and ultimate water contents, on embryos showing
considerable metabolic activity. 相似文献
10.
Batch cultivation of Ralstonia eutropha NRRL B14690 attained 21 g biomass l−1 and 9.4 g poly(β-hydroxybutyrate) l−1 (0.45 g PHB g−1 dry wt−1) in 60 h. Repeated batch operation (empty-and-fill protocol) to remove 20% (v/v) of the culture broth and to supplement an
equal volume of fresh media resulted in 49 g biomass l−1 and 25 g PHB l−1 (0.51 g PHB g−1 dry wt−1) with an overall productivity of 0.42 g PHB l−1 h−1 in 67 h. In the two cycles of repeated batch fermentation there was a 3-fold increase in productivity as compared to batch. 相似文献
11.
Liu Y Sha Q Wu S Wang J Yang L Sun W 《Journal of industrial microbiology & biotechnology》2006,33(4):274-282
A microorganism with the ability to catalyze the resolution of racemic phenyloxirane was isolated and identified as Aspergillus niger SQ-6. Chiral capillary electrophoresis was successfully applied to separate both phenyloxirane and phenylethanediol. The
epoxide hydrolase (EH) involved in this resolution process was (R)-stereospecific and constitutively expressed. When whole cells were used during the biotransformation process, the optimum
temperature and pH for stereospecific vicinal diol production were 35°C and 7.0, respectively. After a 24-h conversion, the
enantiomer excess of (R)-phenylethanediol produced was found to be >99%, with a conversion rate of 56%. In fed-batch fermentations at 30°C for 44 h,
glycerol (20 g L−1) and corn steep liquor (CSL) (30 g L−1) were chosen as the best initial carbon and nitrogen sources, and EH production was markedly improved by pulsed feeding of
sucrose (2 g L−1 h−1) and continuous feeding of CSL (1 g L−1 h−1) at a fermentation time of 28 h. After optimization, the maximum dry cell weight achieved was 24.5±0.8 g L−1; maximum EH production was 351.2±13.1 U L−1 with a specific activity of 14.3±0.5 U g−1. Partially purified EH exhibited a temperature optimum at 37°C and pH optimum at 7.5 in 0.1 M phosphate buffer. This study
presents the first evidence for the existence of a predicted epoxide racemase, which might be important in the synthesis of
epoxide intermediates. 相似文献
12.
The effect of osmotic stress on cell growth and phenylethanoid glycosides (PeGs) biosynthesis was investigated in cell suspension
cultures of Cistanche deserticola Y. C. Ma, a desert medicinal plant grown in west region of China. Various initial sucrose concentrations significantly affected
cell growth and PeGs biosynthesis in the suspension cultures, and the highest dry weight and PeGs accumulation reached 15.9 g l−1-DW and 20.7 mg g−1-DW respectively at the initial osmotic stress of 300 mOsm kg−1 where the sucrose concentration was 175.3 mM. Stoichiometric analysis with different combinations of sucrose and non-metabolic
sugar (mannitol) or non-sugar osmotic agents (PEG and NaCl) revealed that osmotic stress itself was an important factor for
enhancing PeGs biosynthesis in cell suspension cultures of C. deserticola. The maximum PeGs contents of 26.9 and 23.8 mg g−1-DW were obtained after 21 days at the combinations of 87.6 mM sucrose with 164.7 mM mannitol (303 mOsm kg−1) or 20 mM PEG respectively, which was higher than that of C. deserticola cell cultures grown under an initial sucrose concentration of 175.3 mM after 30 days. The stimulated PeGs accumulation in
the cell suspension cultures was correlated to the increase of phenylalanine ammonium lyase (PAL) activity induced by osmotic
stress. 相似文献
13.
On sedimentary tidal flats in the Wadden Sea near the Island of Sylt, the periwinkleLittorina littorea occurred preferentially on clusters and beds of mussels and on shell beds (100 to 350 m−2), achieved moderate densities on green algal patches or mats (20 to 50 m−2), and remained rare on bare sediments (<5 m−2). Green algae covering>10% of sediment surface appeared in summer on approximately one third of the tidal zone, mainly in
the upper and sheltered parts and almost never on mussel and shell beds. In feeding experiments,L. littorea ingested more of the dominant alge,Enteromorpha, than ofUlva, irrespective of whether or not algae were fresh or decaying. The tough thalli ofChaetomorpha were hardly consumed. Snails feeding onEnteromorpha produced fecal pellets from which new growth ofEnteromorpha started. In the absence of periwinkles,Enteromorpha developed on mussels and the attached fucoids. Experimentally increased snail densities on sediments prevented green algal
development, but the snails were unable to graze down established algal mats. It is concluded that natural densities ofL. littorea hardly affect the ephemeral mass development of green algae on sediments. However, where the snails occur at high densities,
i.e. on mussel beds, green algal development may be prevented. 相似文献
14.
In vitro cultures of Berberis buxifolia were established using thidiazuron (4.5, 23 and 45 mM) or picloram (4 and 40 mM) as plant growth regulators for sustaining
growth. For producing berberine, a two-stage culture was performed. In the first step, thidiazuron or picloram were used for
biomass production followed by the production stage where benzylaminopurine (4.4 mM) was added as a plant growth regulator.
Berberine yields (102 mg g−1 DW) and in vitro shoot cultures (200 mg g−1 DW) were significantly lower than those of whole plants in the field (416 mg g−1 DW). The highest productivity (0.18 mg 1−1 day−1) was attained using picloram (either 4 on 40 mM) in the first stage for producing biomass. 相似文献
15.
Osmotic adjustment and ion balance traits of an alkali resistant halophyte Kochia sieversiana during adaptation to salt and alkali conditions 总被引:1,自引:0,他引:1
Chunwu Yang Jianna Chong Changyou Li Changmin Kim Decheng Shi Deli Wang 《Plant and Soil》2007,294(1-2):263-276
Kochia sieversiana (Pall.) C. A. M., a naturally alkali-resistant halophyte, was chosen as the test organism for our research. The seedlings
of K. sieversiana were treated with varying (0–400 mM) salt stress (1:1 molar ratio of NaCl to Na2SO4) and alkali stress (1:1 molar ratio of NaHCO3 to Na2CO3). The concentrations of various solutes in fresh shoots, including Na+, K+, Ca2+, Mg2+, Cl−, SO42−, NO3−, H2PO3−, betaine, proline, soluble sugar (SS), and organic acid (OA), were determined. The water content (WC) of the shoots was calculated
and the OA components were analyzed. Finally, the osmotic adjustment and ion balance traits in the shoots of K. sieversiana were explored. The results showed that the WC of K. sieversiana remained higher than 6 [g g−1 Dry weight (DW)] even under the highest salt or alkali stress. At salinity levels >240 mM, proline concentrations increased
dramatically, with rising salinity. We proposed that this was not a simple response to osmotic stress. The concentrations
of Na+ and K+ all increased with increasing salinity, which implies that there was no competitive inhibition for absorption of either in
K. sieversiana. Based on our results, the osmotic adjustment feature of salt stress was similar to that of alkali stress in the shoots of
K. sieversiana. The shared essential features were that the shoots maintained a state of high WC, OA, Na+, K+ and other inorganic ions, accumulated largely in the vacuoles, and betaine, accumulated in cytoplasm. On the other hand,
the ionic balance mechanisms under both stresses were different. Under salt stress, K. sieversiana accumulated OA and inorganic ions to maintain the intracellular ionic equilibrium, with close to equal contributions of OA
and inorganic ions to anion. However, under alkali stress, OA was the dominant factor in maintaining ionic equilibrium. The
contribution of OA to anion was as high as 84.2%, and the contribution of inorganic anions to anion was only 15.8%. We found
that the physiological responses of K. sieversiana to salt and alkali stresses were unique, and that mechanisms existed in it that were different from other naturally alkali-resistant
gramineous plants, such as Aneurolepidium chinense, Puccinellia tenuiflora.
Responsible Editor: John McPherson Cheeseman. 相似文献
16.
Adventitious roots of Echinacea purpurea were cultured in airlift bioreactors (20 l, 500 l balloon-type, bubble bioreactors and 1,000 l drum-type bubble bioreactor)
using Murashige and Skoog (MS) medium with 2 mg indole butyric acid l−1 and 50 g sucrose l−1 for the production of chichoric acid, chlorogenic acid and caftaric acid. In the 20 l bioreactor (containing 14 l MS medium)
a maximum yield of 11 g dry biomass l−1 was achieved after 60 days. However, the amount of total phenolics (57 mg g−1 DW), flavonoids (34 mg g−1 DW) and caffeic acid derivatives (38 mg g−1 DW) were highest after 50 days. Based on these studies, pilot-scale cultures were established and 3.6 kg and 5.1 kg dry biomass
were achieved in the 500 l and 1,000 l bioreactors, respectively. The accumulation of 5 mg chlorogenic acid g−1 DW, 22 mg chichoric acid g−1 DW and 4 mg caftaric acids g−1 DW were achieved with adventitious roots grown in 1,000 l bioreactors. 相似文献
17.
Microbial and decomposition efficiencies of monoculture and polyculture vermireactors,based on epigeic and anecic earthworms 总被引:2,自引:0,他引:2
Surindra Suthar 《World journal of microbiology & biotechnology》2008,24(8):1471-1479
Efforts have been made to evaluate the microbial and decomposition efficiency of three different vermireactors: (i) polyculture
(introducing equal numbers of anecic and epigeic earthworms), (ii) monoculture (anecic) and (iii) monoculture (epigeic), designed
by using earthworms of two different ecological categories i.e. anecic (Lampito mauritii Kinberg) and epigeic (Eisenia fetida (Savigny)). The microbial load of vermireactors was measured through substrate-induced respiration rate (SIR), microbial
biomass N content and rate of dehydrogenase activity, while mineralization rate was evaluated measuring some chemical parameters
of the substrate. Earthworms caused a decrease (as compared to initial value) in pH (41.9–80.7%), organic C (10.3–14.2%) and
C:N ratio (41.9–80.7%) and an increase in total N (29.1–58.8%), NH4-N (876.1–1485.7%), NO3-N (29081.8–56792.6%), available P (16–19.4%) and exchangeable K (9.8–13.5%) contents of the substrate. The mineralization
efficiency of the reactors was in the order: polyculture (epigeic + anecic) > monoculture (anecic) > monoculture (epigeic).
The polyculture reactor showed the maximum rate of SIR (2.91 ± 0.2 mg CO2 g−1 substrate), microbial biomass N (3108.1 ± 289.2 mg N g−1 substrate), and dehydrogenase activity (2453.3 ± 379.8 μg g−1 substrate 24 h), while in the monoculture (epigeic) the lowest values of the same parameters were observed. It is concluded
that the observed differences among reactors were due to different feeding behaviour and niche structures of epigeic and anecic
earthworms. Data suggests that burrowing earthworms in waste-decomposing-system not only enhance the microbial efficiencies,
but at the same time also accelerate the organic matter mineralization in a vermireactor. However, most of the previous studies
were based on monoculture reactors (using epigeic earthworms) which have been recommended for waste decomposition operations,
but this study revealed that polyculture vermicomposting (adding of burrowing worms with epigeic earthworms in vermicomposting
system) might be beneficial for rapid decomposition of organic wastes. 相似文献
18.
Durban MA Silbersack J Schweder T Schauer F Bornscheuer UT 《Applied microbiology and biotechnology》2007,74(3):634-639
Twenty-two Bacillus cereus strains were screened for phospholipase C (PLC, EC 3.1.4.3) activity using p-nitrophenyl phosphorylcholine as a substrate. Two strains (B. cereus SBUG 318 and SBUG 516) showed high activity at elevated temperatures (>70°C) at acidic pH (pH 3.5–6) and were selected for
cloning and functional expression using Bacillus subtilis. The genes were amplified from B. cereus DNA using primers based on a known PLC sequence and cloned into the expression vector pMSE3 followed by transformation into
B. subtilis WB800. On the amino acid level, one protein (PLC318) was identical to a PLC described from B. cereus, whereas PLC516 contained an amino acid substitution (E173D). PLC production using the recombinant strains was performed
by an acetoin-controlled expression system. For PLC516, 13.7 U g−1 wet cell weight was determined in the culture supernatant after 30 h cultivation time. Three purification steps resulted
in pure PLC516 with a specific activity of 13,190 U mg−1 protein. 相似文献
19.
Camelini CM Maraschin M de Mendonça MM Zucco C Ferreira AG Tavares LA 《Biotechnology letters》2005,27(17):1295-1299
β-Glucans of Agaricus brasiliensis fruiting bodies in different stages of maturity were isolated and characterized by FTIR and NMR. These fractions had greater
amount of (1→6)-β-glucan and the (1→3)-β-glucan increased with fruiting bodies maturation. Yields of β-glucans increased from 42 mg β-glucans g−1 fruiting bodies (dry wt) in immature stage to 43 mg g−1 in mature stage with immature spores, and decreased to 40 mg g−1 in mature stage with spore maturation. Mature fruiting bodies, which included these glucans, have potential therapeutical benefits for use in nutraceutical products. 相似文献
20.
Two new effective microbial producers of inulinases were isolated from Jerusalem artichoke tubers grown in Thailand and identified
as Aspergillus niger TISTR 3570 and Candida
guilliermondii TISTR 5844. The inulinases produced by both these microorganisms were appropriate for hydrolysing inulin to fructose as the
principal product. An initial inulin concentration of ∼100 g l−1 and the enzyme concentration of 0.2 U g−1 of substrate, yielded 37.5 g l−1 of fructose in 20 h at 40°C when A. niger TISTR 3570 inulinase was the biocatalyst. The yield of fructose on inulin was 0.39 g g−1. Under identical conditions, the yeast inulinase afforded 35.3 g l−1 of fructose in 25 h. The fructose yield was 0.35 g g−1 of substrate. The fructose productivities were 1.9 g l−1 h−1 and 1.4 g l−1 h−1 for the mold and yeast enzymes, respectively. After 20 h of reaction, the mold enzyme hydrolysate contained 53% fructose
and more than 41% of initial inulin had been hydrolysed. Using the yeast enzymes, the hydrolysate contained nearly 38% fructose
at 25 h and nearly 36% of initial inulin had been hydrolysed. The A. niger TISTR 3570 inulinases exhibited both endo-inulinase and exo-inulinase activities. In contrast, the yeast inulinases displayed
mainly exo-inulinase activity. The mold and yeast crude inulinases mixed in the activity ratio of 5:1 proved superior to individual
crude inulinases in hydrolysing inulin to fructose. The enzyme mixture provided a better combination of endo- and exo-inulinase
activities than did the crude extracts of either the mold or the yeast individually. 相似文献