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1.
Brahmi ( Bacopa monnieri) is an important medicinal plant mainly used for the treatment of neurological disorders and depression. Recent investigations
revealed that bacoside A is major chemical component shown to be responsible for memory facilitating action of brahmi. The
current investigation was carried out to assess the potential for increasing biomass and the concentration of bacoside A in
the in vitro regenerated shoots by varying sucrose and pH levels of shoot regeneration medium. The leaf explants were cultured
on the Murashige and Skoog (MS) medium supplemented with 2 mg l −1 kinetin (KN) and with varying concentrations of sucrose (0, 1, 2, 3, 4, 5 and 6% at pH 5.8) and pH (4.5, 5.0, 5.5, 6.0 and
6.5 with 2% sucrose) with the objective of verifying the effects of sucrose and pH level on shoot regeneration and to verify
the accumulation of bacoside A in the regenerated shoots. The shoot biomass increased (150.50 ± 2.84 shoots per explant, fresh
wt 6.31 ± 0.12 g and dry wt 250 ± 5.00 mg) on the medium supplemented with 2% sucrose and pH which was set at 4.5. The results
of HPLC analysis indicate that increase in sucrose concentration (0, 1, 2, 3, 4, 5 and 6% at pH 5.8) lead to decrease in the
bacoside A content (39.51, 22.43, 13.05, 12.17, 10.73, 9.56 and 8.93 mg g −1 dry wt, respectively) in regenerated shoots. These findings provide evidence that stressful condition of inadequate supply
of carbon elevated synthesis of bacoside A in brahmi shoots. However, 2% sucrose is found suitable for biomass accumulation.
Therefore, medium supplemented with 2% sucrose and pH set at 4.5 was found suitable for both biomass (6.31 ± 0.12 g fresh
wt and 250 ± 5.00 mg dry wt) and bacoside A accumulation (13.09 mg g −1 dry wt). 相似文献
2.
This study investigated the potential functions of Pleurotus florida (an edible mushroom) in the biodegradation of gas oil at concentrations of 0 (control), 2.5, 5, and 10% (V: V) for 30 days. The gas oil increased dry weight and protein concentration in all treatments (by an average of 19.5 and 108%, respectively). Moreover, the pH, surface tension (ST), and interfacial tension (IFT) were reduced by the mushroom supplementation. The lowest surface tension (31.9 mN m −1) and the highest biosurfactant production belonged to the 10% gas oil treatment (0.845 ± 0.03 mg mL −1). The results demonstrated that the adsorption isotherm agreed well with the Langmuir isotherm. The maximum Langmuir adsorption capacity was calculated at 0.743 mg g −1 wet biomass of P. florida. The fungal supplementation efficiently remedied the total petroleum hydrocarbons (TPHs) by an average of 55% after 30 days. Gas chromatography (GC) analysis revealed that P. florida effectively detoxified C 13–C 28 hydrocarbons, Pristane, and Phytane, implying its high mycoremediation function. The toxicity test showed that mycoremediation increased the germination by an average of 35.82% ± 8.89 after 30 days. Laccase activity increased significantly with increasing gas oil concentration in the treatments. The maximum laccase activity was obtained in the 10% gas oil treatment (142.25 ± 0.72 U L −1). The presence of pollutants was also associated with induction in the tyrosinase activity when compared to the control. These results underline the high mycoremediation capacity of P. florida through the involvement of biosurfactants, laccase, and tyrosinase. 相似文献
3.
Asparagus racemosus is an important monocot medicinal plant that is in great demand for its steroidal saponins called shatavarins. This study
was initiated to optimize the conditions for production of shatavarins in cell cultures of A. racemosus in a modified Murashige and Skoog (MS) medium supplemented with six different combinations of growth regulators. Biomass
accumulation was correlated with saponin production over a 30-d culture cycle. Biomass and saponin accumulation patterns were
dependent on combinations of growth regulators and the pH of the medium. Maximum levels of saponin and biomass accumulation
were recorded on day 25 of the culture cycle within a pH range of 3.4 to 5.6. Total saponin produced by the in vitro cultures was 20-fold higher than amounts produced by cultivated plants. Saponin accumulation was not a biomass-associated
phenomenon; cultures which showed the highest biomass accumulation were not the highest saponin accumulators. Maximum biomass
(28.30 ± 0.29 g l −1) and maximum levels of shatavarin IV(11.48 ± 0.61 mg g −1) accumulation was found using a medium containing 2.0 mg l −1 2,4-D, 2 g l −1 casein hydrolysate and 0.005% pectinase. The highest levels of sarsapogenin, secreted and intracellular (4.02 ± 0.09 mg g −1), accumulated using a medium containing 1.0 mg l −1 NAA, 1.0 mg l −1 2,4-D, 0.5 mg l −1 BAP, 2 g l −1 casein hydrolysate and 0.005% pectinase, after 25 d. Shatavarins were secreted into the medium and can be isolated easily
for further purification. 相似文献
4.
The objective of this study was to set up a plant micropropagation facility to mass propagate sugarcane, energy cane, and related clonally propagated species. An efficient methodology for micropropagation of energy cane and perennial grasses using temporary immersion bioreactors was developed. Several different methods of tissue culture initiation, multiplication, and rooting were evaluated for several varieties of sugarcane (Saccharum officinarum L.) and sugarcane-related species such as Erianthus spp., Miscanthus spp., and Sorghum spp. × sugarcane hybrids, all from a germplasm collection. Apical meristem cultures were initiated for all genotypes that were micropropagated, when liquid or semisolid Murashige and Skoog (MS) medium was used, which was supplemented with 0.1–0.2 mg L−1 BAP, 0.1 mg L−1 kinetin, 0–0.1 mg L−1 NAA, and 0–0.2 μg L−1 giberellic acid. These cultures produced shoots between 4 and 8 wk after initiation. Shoot regeneration from leaf rolls or immature inflorescences was observed as early as 4 wk after initiation. Shoot multiplication was successful for all genotypes cultured in MS medium with 0.2 mg L−1 BAP and 0.1 mg L−1 kinetin. Energy cane had a significantly higher combined multiplication rate when grown under four or five LED lamps than when grown under three LED lamps, or under fluorescent lights in a growth chamber. The addition of 2 mg L−1 NAA produced faster and better rooting in all of the genotypes tested. Shoots produced well-developed roots after one cycle of 15–21 d in the bioreactors. The maximum number of plantlets produced per bioreactor was 1080. Plantlets developed a vigorous root system and were ready to be transplanted into the field after 2 mo. A protocol was standardized for different energy cane clones that were recommended for their biomass production and cell wall composition. Different tissues were used to speed up or facilitate tissue culture initiation. Visual assessment of micropropagated plants in the field did not show any off-types, based on gross morphological changes of plant morphology or disease reaction, compared to plants of the same genotype derived from a traditional propagation method (stem cuttings). This is the first report of energy cane and Miscanthus spp. micropropagation using the SETIS bioreactor. 相似文献
5.
Miroestrol and deoxymiroestrol are highly active phytoestrogens derived from the tuberous roots of Pueraria candollei var. mirifica. To date, there have been no reports regarding the production of miroestrol and deoxymiroestrol in in vitro cell culture.
In this study, callus and cell suspension cultures were established for the purpose of investigating miroestrol and deoxymiroestrol
content in P. candollei var. mirifica cells. Stem-derived callus cultured on Murashige and Skoog (MS) medium supplemented with 0.1 mg l −1 thidiazuron (TDZ), 0.5 mg l −1 naphthaleneacetic acid (NAA), and 1.0 mg l −1 benzyladenine (BA) provided optimal conditions for the accumulation of deoxymiroestrol and total isoflavonoids. The calli
produced 184.83 ± 20.09 μg g −1 dry weight of total chromene and 20.72 ± 2.38 mg g −1 dry weight of total isoflavonoid. This is the first report to suggest that callus culture is a suitable alternative method
for producing miroestrol and deoxymiroestrol. Carbon sources were evaluated for the cell suspension cultures of P. candollei var. mirifica. Sucrose provided optimal conditions for biomass production, whereas fructose was the most suitable carbon source for deoxymiroestrol
and isoflavonoid production. The information from our study can be employed for enhancing the production of miroestrol, deoxymiroestrol,
and total isoflavonoids using in vitro cell culture of P. candollei var. mirifica. 相似文献
6.
The inhibitory effect of antimicrobial zeolite coated concrete specimens (Z2) against Acidithiobacillus thiooxidans was studied by measuring biomass dry cell weight (DCW), biological sulphate generation, and oxygen uptake rates (OURs). Uncoated
(UC), and blank zeolite coated without antimicrobial agent (ZC) concrete specimens were used as controls. The study was undertaken
by exposing inoculated basal nutrient medium (BNM) to the various specimens. The coating material was prepared by mixing zeolite,
epoxy and cure with ratios, by weight of 2:2:1. Concrete specimens were characterized before and after exposure to inoculated
or sterile BNM by field emission-scanning electron microscopy (FE-SEM). Gypsum, which was absent in the other test concrete
specimens, was detected in uncoated specimens exposed to the bacterium. In UC and ZC, the growth of the bacteria increased
throughout the duration of the experiment. However, significant biomass inhibition was observed in experiments where Z2 was
used. The overall biomass growth rate in suspension before the specimens were placed ranged from 3.18 to 3.5 mg DCW day −1. After the bacterium was exposed to UC and ZC, growth continued with a corresponding value of 4 ± 0.4 and 5.5 ± 0.6 mg DCW day −1, respectively. No biomass growth was observed upon exposure of the bacterium to Z2. Similarly, while biological sulphur oxidation
rates in UC and ZC were 88 ± 13 and 238 ± 25 mg SO 4
2− day −1, respectively, no sulphate production was observed in experiments where Z2 concrete specimens were used. Peak OURs for UC
and ZC ranged from 2.6 to 5.2 mg l −1 h −1, and there was no oxygen uptake in those experiments where Z2 was used. The present study revealed that the antimicrobial
zeolite inhibits the growth of both planktonic as well as biofilm populations of Acidithiobacillus thiooxidans. 相似文献
7.
Life cycle assessment (LCA) of indigenous freshwater microalgae, Scenedesmus dimorphus, cultivation in open raceway pond and its conversion to biodiesel and biogas were carried out. The LCA inventory inputs for the biogas scenario was entirely based on primary data obtained from algal cultivation (in pilot scale raceway pond), harvesting, and biogas production; while only the downstream processing involved in biodiesel production namely drying, reaction and purification were based on secondary data. Overall, eight scenarios were modeled for the integrated process involving: algae-based CO2 capture and downstream processing scenarios for biodiesel and biogas along with impact assessment of nutrient addition and extent of recycling in a life cycle perspective. The LCA results indicated a huge energy deficit and net CO2 negative in terms of CO2 capture for both the biodiesel and biogas scenarios, majorly due to lower algal biomass productivity and higher energy requirements for culture mixing. The sensitivity analysis indicated that variability in the biomass productivity has predominant effect on the primary energy demand and global warming potential (GWP, kg CO2 eq.) followed by specific energy consumption for mixing algal culture. Furthermore, the LCA results indicated that biogas conversion route from microalgae was more energy efficient and sustainable than the biodiesel route. The overall findings of the study suggested that microalgae-mediated CO2 capture and conversion to biodiesel and biogas production can be energy efficient at higher biomass productivity (> 10 g m−2 day−1) and via employing energy-efficient systems for culture mixing (< 2 W m−3). 相似文献
8.
The contents of fungal biomass markers were analysed in the fruit bodies of dominant basidiomycetes from an ectomycorrhiza-dominated coniferous forest, and used to estimate the fungal biomass content in the litter and soil. The content of ergosterol (3.8 ± 2.0 mg g ?1 dry fungal biomass) and the phospholipid fatty acid 18:2ω6,9 (11.6 ± 4.3 mg g ?1) showed less variation than the internal transcribed spacer (ITS) copy numbers (375 ± 294 × 10 9 copies g ?1). A high level of variation in the ITS copy numbers (per ng DNA) was also found among fungal taxa. The content of fungal biomass in the litter and soil, calculated using the mean contents, varied between 0.66 and 6.24 mg g ?1 fungal biomass in the litter, and 0.22 and 0.68 mg g ?1 in the soil. The ratio of fungal biomass in the litter to that in the soil varied greatly among the markers. The estimates of fungal biomass obtained with different biomarkers are not exactly comparable, and caution should be used when analysing taxon abundance using PCR amplification of fungal rDNA. 相似文献
9.
The present study describes the potential of in vitro grown adventitious roots of Hypericum perforatum L. commonly known as St. John’s wort at low nutrient and auxin levels in the liquid medium for micropropagation. Roots were
regenerated from shoot-derived callus on MS medium containing 4.0 mg l −1 Indole-3 acetic acid (IAA). IAA and Indole-3 butyric acid (IBA) were equally effective for the induction of roots from shoot
cultures. Half strength MS medium containing 1.0 mg l −1 IAA was most found suitable for culturing roots in liquid medium. A total biomass of 4.13 ± 0.67 g comprising 226 ± 34.4
shoots and shoot buds along with roots was obtained per culture starting with 200 mg roots inoculum. Pretreatment with kinetin
(2.0 mg l −1) enhanced the shoot multiplication. Shoots proliferated profusely from excised roots in static liquid medium supported with
glass bead matrix. Growtek ™ vessel was found suitable and cost effective system for high throughput plantlet production. In vitro grown roots regardless
of their source of origin were an excellent and easy to handle source of explant for aseptic production of plantlets without
loosing the morphogenetic potential over the generations. The plants exhibited 84–99% similarity among themselves through
RAPD. The in vitro shoots produced can either be multiplied or rooted perpetually, and alternatively they can also be explored
for the in vitro production of hypericin and hyperforin. 相似文献
10.
A soil sample collected underneath a sewage pipe of the west side of Yangpu refining factory in Haikou city, Hainan Province, China was inoculated in minimum medium supplemented with fluoranthene. After 8 enrichment cycles, a bacterial consortium (Y12) was obtained through water-silicone oil dual system in the laboratory. The consortium Y12 could degrade a mixture of polycyclic aromatic hydrocarbons (PAHs) including phenanthrene, anthracene, fluoranthene, pyrene and benzo[a]pyrene. The consortium Y12 was repeatedly cultured for more than 40 circles, from which a bacterial strain FB3 was isolated. This strain was identified as a Sphingobium sp. through the 16S rDNA sequence alignment. Strain FB3 could degrade 99 ± 0.4%, 67 ± 2%, 97 ± 3%, 72 ± 8%, and 6 ± 2% (uncorrected degradation percentages) of phenanthrene, anthracene, fluoranthene and pyrene each at level of 100 mg L −1 and benzo[a]pyrene at 10 mg L −1, respectively, in 10 days, which the five PAHs were the sole carbon source as a mixture in minimum medium. The degradation percentages of phenanthrene, anthracene, fluoranthene, pyrene (each at level of 100 mg L −1) and benzo[a]pyrene (10 mg L −1) by consortium Y12 were 99 ± 0.1%, 65 ± 3%, 99 ± 0.3%, 79 ± 1% and 7 ± 6%, respectively, in 10 days. Strain FB3 could degrade those PAHs under a range of pH 5–9, being optimum at pH 7. 相似文献
11.
Bixa orellana L. is a tree native to South America known for its reddish orange pigment ‘annatto’ produced only on the aril portion of
its seeds. It is the most preferred natural food colorant next to saffron, having wide applications in the dairy industry
and also as a cosmeceutical. Normal root cultures of B. orellana were established under in vitro conditions on Murashige and Skoog (MS) medium containing α-naphthaleneacetic acid (NAA),
indole-3-butyric acid (IBA) and indole-3-acetic acid (IAA) at 0.05–0.2 mg l −1. The annatto pigment from in vitro-raised normal roots was extracted with chloroform, and later the ethanol-dissolved extract
was analyzed both qualitatively by thin-layer chromatography (TLC) and spectrophotometrically quantified followed by High
Performance Liquid Chromatography (HPLC) confirmation. The maximum amount of annatto pigment (346 ± 3.8 mg/100 g dry wt.)
and maximum root biomass (152 ± 2.5 mg dry wt.) were recorded after 45 and 60 days of growth, respectively, on MS medium containing
0.1 mg l −1 indole-3-butyric acid (IBA). Producing annatto pigment from normal root cultures under in vitro conditions is a novel approach
when compared to the natural annatto pigment that is produced only on the aril portion of seeds. This allows the production
of fresh pigment throughout the year. 相似文献
12.
A low-cost floating photobioreactor (PBR) without the use of aeration and/or an agitation device, in which carbon was supplied in the form of bicarbonate and only wave energy was utilized for mixing, was developed in our previous study. Scaling up is a common challenge in the practical application of PBRs and has not yet been demonstrated for this new design. To fill this gap, cultivation of Spirulina platensis was conducted in this study. The results demonstrated that S. platensis had the highest productivity at 0.3 mol L−1 sodium bicarbonate, but the highest carbon utilization (104 ± 2.6%) was obtained at 0.1 mol L−1. Culture of Spirulina aerated with pure oxygen resulted in only minor inhibition of growth, indicating that its productivity will not be significantly reduced even if dissolved oxygen is accumulated to a high level due to intermittent mixing resulting from the use of wave energy. In cultivation using a floating horizontal photobioreactor at the 1.0 m2 scale, the highest biomass concentration of 2.24 ± 0.05 g L−1 was obtained with a culture depth of 5.0 cm and the highest biomass productivity of 18.9 g m−2 day−1 was obtained with a depth of 10.0 cm. This PBR was scaled up to 10 m2 (1000 L) with few challenges; biomass concentration and productivity during ocean testing were little different than those at the 1.0 m2 (100 L) scale. However, the larger PBR had an apparent carbon utilization efficiency of 45.0 ± 2.8%, significantly higher than the 39.4 ± 0.9% obtained at the 1 m2 scale. These results verified the ease of scaling up floating horizontal photobioreactors and showed their great potential in commercial applications. 相似文献
13.
The effects of type of explant (leaves and roots), donor plants, and plant growth regulators on naphthoquinone (NQ) production
of Impatiens balsamina L. root cultures were evaluated. The root cultures were initiated in liquid Gamborg’s B5 medium supplemented with 0.1 mg l −1 α-naphthaleneacetic acid (NAA), 0.1 mg l −1 kinetin (Kn) and 1.0 mg l −1 6-benzyladenine (BA). The present investigation indicated that the root cultures established from the leaf explants produced
higher total NQ content [1.01 ± 0.046 mg/g dry weight (DW)] than those established from the root explants (0.62 ± 0.023 mg/g
DW). The leaf explants of four I. balsamina strains including white flower plant (IbW), pink flower plant (IbP), violet flower plant (IbV) and red flower plant (IbR)
were used to establish the root cultures. Based on HPLC analysis, IbP strain produced the highest total NQ content (3.39 ± 0.072 mg/g
DW), while IbR strain produced the lowest one (1.45 ± 0.055 mg/g DW). The root cultures established from the IbP explant were
capable of producing higher content of total NQs (2.76 ± 0.093 mg/g DW) than those established from the other strains. The
results suggest that the tissue cultures initiated from the high-yielding donor plants should be capable of producing higher
content of secondary compounds than those initiated from low-yielding donor plants. In addition, plant growth regulator manipulation
exhibited that a combination of 0.1 mg l −1 NAA, 1.0 mg l −1 Kn and 2.0 mg l −1 BA is capable of increasing NQ production (2.97 ± 0.072 mg/g DW) in I. balsamina root cultures. 相似文献
14.
In this environmental-sample based study, rapid microbial-mediated degradation of 2,4,6-trinitrotoluene (TNT) contaminated soils is demonstrated by a novel strain, Achromobacter spanius STE 11. Complete removal of 100 mg L −1 TNT is achieved within only 20 h under aerobic conditions by the isolate. In this bio-conversion process, TNT is transformed to 2,4-dinitrotoluene (7 mg L −1), 2,6-dinitrotoluene (3 mg L −1), 4-aminodinitrotoluene (49 mg L −1) and 2-aminodinitrotoluene (16 mg L −1) as the key metabolites. A. spanius STE 11 has the ability to denitrate TNT in aerobic conditions as suggested by the dinitrotoluene and NO 3 productions during the growth period. Elemental analysis results indicate that 24.77 mg L −1 nitrogen from TNT was accumulated in the cell biomass, showing that STE 11 can use TNT as its sole nitrogen source. TNT degradation was observed between pH 4.0–8.0 and 4–43 °C; however, the most efficient degradation was at pH 6.0–7.0 and 30 °C. 相似文献
15.
Withanolides are biologically active secondary metabolites present in roots and leaves of Withania somnifera. In the present study, we have induced adventitious roots from leaf explants of W. somnifera for the production of withanolide-A, which is having pharmacological activities. Adventitious roots were induced directly
from leaf segments of W. somnifera on half strength Murashige and Skoog (MS) semisolid medium (0.8% agar) with 0.5 mg l −1 indole-3-butyric acid (IBA) and 30 g l −1 sucrose. Adventitious roots cultured in flasks using half strength MS liquid medium with 0.5 mg l −1 IBA and 30 g l −1 showed higher accumulation of biomass (108.48 g l −1FW and 10.76 g l −1 DW) and withanolide-A content (8.8 ± 0.20 mg g −1 DW) within five weeks. Nearly 11-fold increment of fresh biomass was evident in suspension cultures and adventitious root
biomass produced in suspension cultures possessed 21-fold higher withanolide-A content when compared with the leaves of natural
plants. An inoculum size of 10 g l −1 FW favoured the biomass accumulation and withanolide-A production in the tested range of 2.5, 5.0, 10.0 and 20.0 g l −1 FW. Among different media tested [Murashige and Skoog (MS), Gamborg’s (B5), Nitsch and Nitsch (NN) and Chu’s (N6)], MS medium
favoured both biomass accumulation and withanolide-A production. Half strength MS medium favoured the biomass accumulation
and withanolide-A production among the different strength MS medium tested (0.25, 0.5, 0.75, 1.0, 1.5 and 2.0). The current
results showed great potentiality of adventitious roots cultures for the production of withanolide-A. 相似文献
17.
Echinodorus ‘Indian Red’ is an underwater plant, used worldwide for aquarium ornamentation. An efficient method for in vitro propagation and plantlet acclimatization of this popular aquarium plant was standardized. Surface-disinfected shoot-tips were cultured in submerged conditions in a solid–liquid bilayer medium, consisting of an upper, liquid layer (sterile distilled water) and a lower, solid layer Murashige and Skoog (MS) basal medium supplemented with 3.0% (w/v) sucrose, 0.8% (w/v) agar-agar, and plant growth regulators (PGRs) in different combinations and concentrations. The combination of 2.5 mg L−1 6-benzylaminopurine and 1.0 mg L−1 α-naphthaleneacetic acid improved the multiplication rate to a maximum of 26.8 ± 0.51 shoots per explant after 60 d of culture. The number of multiplied shoots increased with each regeneration cycle, thus from only 26.8 ± 0.51 shoots per explant (first regeneration cycle), this number increased to 33.5 ± 0.58 (second regeneration cycle), and to 38.3 ± 0.62 for the third regeneration cycle with the same medium composition. The highest number of roots (8.3 ± 0.28) per shoot was induced in the presence of 1.0 mg L−1 indole-3-butyric acid, but further growth of these roots was stunted. The best rooting was achieved on PGR-free ½-strength MS medium, where 6.1 ± 0.21 roots per shoot were induced with 5.8 ± 0.35 cm length after 30 d of culture. The regenerated plantlets were successfully acclimatized to submerged underwater conditions, with 100% survival rate. The present protocol is suitable for the commercial propagation of Echinodorus ‘Indian Red’ for aquarium-industries. 相似文献
18.
The annual leaf growth and shoot dynamics of Thalassia testudinum were examined in a meadow located near Havana City, Cuba, using direct censuses between January 1995 and January 1996. The net rate of shoot population change, specific shoot recruitment and mortality rates were calculated as the difference between the densities of shoots (tagged or untagged) in consecutive sampling events. The leaf biomass, the daily production, the turnover rate and the rate of leaf biomass loss were also estimated. The estimated mean dry leaf biomass (124.9 ± 9.5 g m −2), daily dry leaf production (3.3 ± 0.2 g m −2 day −1) and turnover rate (2.7 ± 0.1% day −1) were comparable to values previously reported for this species in Cuba and elsewhere. The production of leaves and shoots were higher in spring, declined towards mid summer, and showed the minimum values in January. Shoot recruitment prevailed over shoot mortality from January to March and from July to August, whereas most of the annual shoot mortality occurred between May and July and between August and October. The meadow examined was in close demographic balance along the study period. The results demonstrate that direct census provides reliable estimates of rapid shoot dynamics in T. testudinum. 相似文献
19.
In the present study, the effects of four different culture media on the growth, astaxanthin production and morphology of Haematococcus pluvialis LUGU were studied under two-step cultivation. The interactions between astaxanthin synthesis and secondary messengers, reactive oxygen species (ROS) and mitogen-activated protein kinases (MAPK) were also investigated. In the first green vegetative cell stage, maximal biomass productivity (86.54 mg L−1 day−1) was obtained in BBM medium. In the induction stage, the highest astaxanthin content (21.5 mg g−1) occurred in BG-11 medium, which was higher than in any other media. The expressions of MAPK and astaxanthin biosynthetic genes in BG-11 were higher than in any other media, whereas the ROS content was lower. Biochemical and physiological analyses suggested that the ROS, MAPK and astaxanthin biosynthetic gene expression was involved in astaxanthin biosynthesis in H. pluvialis under different culture media conditions. This study proposes a two-step cultivation strategy to efficiently produce astaxanthin using microalgae. 相似文献
20.
Azadirachtin, a well-known biopesticide, is a secondary metabolite extracted from the seeds of Azadirachta indica. In the present study, azadirachtin was produced in hairy roots of A. indica, generated by Agrobacterium rhizogenes-mediated transformation of leaf explants. Liquid cultures of A. indica hairy roots were developed with a liquid-to-flask volume ratio of 0.15. The kinetics of growth and azadirachtin production
were established in a basal plant growth medium containing MS medium major and minor salts, Gamborg’s medium vitamins, and
30 g l −1 sucrose. The highest azadirachtin accumulation in the hairy roots (up to 3.3 mg g −1) and azadirachtin production (∼44 mg l −1) was obtained on Day 25 of the growth cycle, with a biomass production of 13.3 g l −1 dry weight. To enhance the production of azadirachtin, a Plackett–Burman experimental design protocol was used to identify
key medium nutrients and concentrations to support high root biomass production and azadirachtin accumulation in hairy roots.
The optimal nutrients and concentrations were as follows: 40 g l −1 sucrose, 0.19 g l −1 potassium dihydrogen phosphate, 3.1 g l −1 potassium nitrate, and 0.41 g l −1 magnesium sulfate. Concentrations were determined by a central composite design protocol and verified in shake-flask cultivation.
The optimized medium composition yielded a root biomass production of 14.2 g l −1 and azadirachtin accumulation of 5.2 mg g −1, which was equivalent to an overall azadirachtin production of 73.84 mg l −1, 68% more than that obtained under non-optimized conditions. 相似文献
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