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1.
Smita Srivastava Ashok Kumar Srivastava 《In vitro cellular & developmental biology. Plant》2012,48(1):73-84
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
2.
Mashitha Pise Jaishree Rudra Sunita Bundale Deovrat Begde Nandita Nashikkar Avinash Upadhyay 《In vitro cellular & developmental biology. Plant》2012,48(1):85-91
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
3.
Takashi Nemoto Taisuke Watanabe Yutaka Mizogami Jun-ichi Maruyama Katsuhiko Kitamoto 《Applied microbiology and biotechnology》2009,82(6):1105-1114
The recombinant Pichia pastoris harboring an improved methionine adenosyltransferase (MAT) shuffled gene was employed to biosynthesize S-adenosyl-l-methionine (SAM). Two l-methionine (l-Met) addition strategies were used to supply the precursor: the batch addition strategy (l-Met was added separately at three time points) and the continuous feeding strategies (l-Met was fed continuously at the rate of 0.1, 0.2, and 0.5 g l−1 h−1, respectively). SAM accumulation, l-Met conversion rate, and SAM productivity with the continuous feeding strategies were all improved over the batch addition
strategy, which reached 8.46 ± 0.31 g l−1, 41.7 ± 1.4%, and 0.18 ± 0.01 g l−1 h−1 with the best continuous feeding strategy (0.2 g l−1 h−1), respectively. The bottleneck for SAM production with the low l-Met feeding rate (0.1 g L−1 h−1) was the insufficient l-Met supply. The analysis of the key enzyme activities indicated that the tricarboxylic acid cycle and glycolytic pathway
were reduced with the increasing l-Met feeding rate, which decreased the adenosine triphosphate (ATP) synthesis. The MAT activity also decreased as the l-Met feeding rate rose. The reduced ATP synthesis and MAT activity were probably the reason for the low SAM accumulation when
the l-Met feeding rate reached 0.5 g l−1 h−1. 相似文献
4.
Butanol, a four-carbon primary alcohol (C4H10O), is an important industrial chemical and has a good potential to be used as a superior biofuel. Bio-based production of
butanol from renewable feedstock is a promising and sustainable alternative to substitute petroleum-based fuels. Here, we
report the development of a process for butanol production from glycerol, which is abundantly available as a byproduct of
biodiesel production. First, a hyper butanol producing strain of Clostridium pasteurianum was isolated by chemical mutagenesis. The best mutant strain, C. pasteurianum MBEL_GLY2, was able to produce 10.8 g l−1 butanol from 80 g l−1 glycerol as compared to 7.6 g l−1 butanol produced by the parent strain. Next, the process parameters were optimized to maximize butanol production from glycerol.
Under the optimized batch condition, the butanol concentration, yield, and productivity of 17.8 g l−1, 0.30 g g−1, and 0.43 g l−1 h−1 could be achieved. Finally, continuous fermentation of C. pasteurianum MBEL_GLY2 with cell recycling was carried out using glycerol as a major carbon source at several different dilution rates.
The continuous fermentation was run for 710 h without strain degeneration. The acetone–butanol–ethanol productivity and the
butanol productivity of 8.3 and 7.8 g l−1 h−1, respectively, could be achieved at the dilution rate of 0.9 h−1. This study reports continuous production of butanol with reduced byproducts formation from glycerol using C. pasteurianum, and thus could help design a bioprocess for the improved production of butanol. 相似文献
5.
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
6.
Saikat Gantait Nirmal Mandal Somnath Bhattacharyya Prakash Kanti Das 《In vitro cellular & developmental biology. Plant》2010,46(6):537-548
A novel, efficient, and simple protocol was developed on in vitro mass propagation and acclimatization of Gerbera jamesonii Bolus cv. Sciella, an ornamental plant with attractive flowers. Shoot tip was used as the primary explant for in vitro establishment in which Murashige and Skoog (MS) medium supplemented with a low level of NAA (0.5 mg l−1) and BAP (1.5 mg l−1) promoted earliest axillary bud initiation within 5 d in 91.6% of the inoculants. Five axillary buds were initiated from
a single explant within 13 d after inoculation. A very high rate of shoot multiplication (14 shoots per inoculated axillary
bud) and proliferation was achieved when MS medium was fortified with a relatively higher level of BAP (2 mg l−1) and 60 mg l−1 ADS within 27 d of multiple shoot culture. A maximum number of well-developed roots per plant was observed in MS medium with
0.5 mg l−1 IAA in the next 26 d. In the easy low-cost acclimatization process of 20 d, a combination of sand, soil, cow urine, and tea
leaves extract (1:1:1:1; v/v) ensured 95% survival rate. Sixty-one well-acclimatized plants were obtained from a single shoot tip within 86 d. The sustained
multiple shoot culture for 15 mo paved the way toward the conservation of genetic resources as well as beneficial economics.
The clonal fidelity study of micropropagated and sustained cultured clones using ISSR primers ensured the continuous supply
of quality propagules retaining genetic uniformity. The in vitro-generated plants performed better over conventionally propagated plants in the field condition. 相似文献
7.
8.
Abhinav Grover Jayashankar S. Yadav Ranjita Biswas Choppakatla S. S. Pavan Punita Mishra Virendra S. Bisaria Durai Sundar 《Plant Cell, Tissue and Organ Culture》2012,108(2):323-331
Cell suspension cultures of Camellia sinensis were established in 250 ml shake flasks. Flasks contained 50 ml liquid medium of either Murashige and Skoog (MS), N/5 MS
or Heller medium containing different levels of 6-benzyladenine (BA) (0.05–2 mg l−1), 2,4-dichlorophenoxyacetic acid (2,4-D) (1–10 mg l−1), and sucrose (10–50 g l−1). Moreover, the pH of the medium was varied from 5.2–6.2. In addition, cultures were subjected to light irradiation as well
as to complete darkness. Following optimization of aroma and terpenoid extraction methods, cell cultures were analyzed for
the volatile compounds using GC/MS. A total of 43 compounds were identified using the micro SDE apparatus. Among the major
monoterpenoids obtained were α-terpineol and nerol. Moreover, other high aroma-value compounds, including 2-ethyl hexanol,
benzyl alcohol, benzene acetaldehyde, nonanal and phenylethylalcohol were also detected. The highest levels of these compounds
were obtained from cell suspension cultures grown in MS medium containing 5 mg l−1 2,4-D, 1 mg l−1 BA and 30 g l−1 sucrose at pH of 5.8 with incubation in complete darkness. 相似文献
9.
Kim YS Lee JH Kim NH Yeom SJ Kim SW Oh DK 《Applied microbiology and biotechnology》2011,90(2):489-497
In the fed-batch culture of glycerol using a metabolically engineered strain of Escherichia coli, supplementation with glucose as an auxiliary carbon source increased lycopene production due to a significant increase in
cell mass, despite a reduction in specific lycopene content. l-Arabinose supplementation increased lycopene production due to increases in cell mass and specific lycopene content. Supplementation
with both glucose and l-arabinose increased lycopene production significantly due to the synergistic effect of the two sugars. Cell growth by the
consumption of carbon sources was related to endogenous metabolism in the host E. coli. Supplementation with l-arabinose stimulated only the mevalonate pathway for lycopene biosynthesis and supplementation with both glucose and l-arabinose stimulated synergistically only the mevalonate pathway. In the fed-batch culture of glycerol with 10 g l−1 glucose and 7.5 g l−1
l-arabinose, the cell mass, lycopene concentration, specific lycopene content, and lycopene productivity after 34 h were 42 g l−1, 1,350 mg l−1, 32 mg g cells−1, and 40 mg l−1 h−1, respectively. These values were 3.9-, 7.1-, 1.9-, and 11.7-fold higher than those without the auxiliary carbon sources,
respectively. This is the highest reported concentration and productivity of lycopene. 相似文献
10.
Weimei Jiang Luxi Chen Qi Pan Yingxiong Qiu Yingying Shen Chengxin Fu 《Acta Physiologiae Plantarum》2012,34(2):631-639
Dysosma versipellis (Hance) M. Cheng is an endangered plant due to overharvesting for the extraction of podophyllotoxin. Thus, the in vitro technique
is valuable for the propagation of this species. When the explants of rhizome buds were cultured on Murashige and Skoog’s
(MS) medium with 6-benzyladenine (BA) (1.0 mg l−1), gibberellic acid (GA3) (0.5 mg l−1) and zeatin (Zea) (0.5 mg l−1), multiple buds were regenerated directly on the explants without callusing within 6 weeks. Callus was induced from the leaf
segment cultures on MS basal medium supplemented with 2,4-dichlorophenoxyacetic acid (2,4-D) (0.5 mg l−1) and BA (0.2 mg l−1) within 4 weeks. The adventitious buds were differentiated when the calli were subcultured on MS medium supplemented with
BA (1.0 mg l−1) and thidiazuron (TDZ) (0.2 mg l−1) within 6 weeks. The adventitious buds obtained from callus and the rhizome-buds rooted with a frequency of 100% on half
strength MS medium fortified with indole-3-butyric acid (IBA) 0.5 mg l−1 and activated charcoal (AC) 0.5 g l−1 for 4 weeks. The rooted shoots were successfully transplanted from a mixture of vermiculite:soil (1:1 v/v) to the field with
a survival rate of 85%. Podophyllotoxin production in calli, cultured rhizomes, rhizomes of transplanting plants from the
garden and rhizomes in the wild field was confirmed by high-performance liquid chromatography (HPLC) analysis. Our results
suggest that calli, cultured rhizomes and rhizomes of transplanting plants would be the potential sources of podophyllotoxin. 相似文献
11.
Li-Hua Zhu Xiao-Qin Wu Hong-Ye Qu Jing Ji Jian-ren Ye 《Plant Cell, Tissue and Organ Culture》2010,102(1):121-128
A protocol was developed for the micropropagation of Pinus massoniana and mycorrhiza formation on rooted microshoots. Seedling explants were first cultured on Gresshoff and Doy (GD) medium supplemented
with 6-benzyladenine (BA) alone or in combination with α-napthaleneacetic acid (NAA) to stimulate the formation of intercotyledonary
axillary buds. The frequency of axillary bud induction was up to 97% on medium supplemented with 4.0 mg l−1 BA and 0. 2 mg l−1 NAA, and the average number of buds per explant reached up to 5.5 on medium with 4.0 mg l−1 BA and 0.1 mg l−1 NAA. Axillary buds elongated rapidly after being transferred to half-strength GD medium containing activated charcoal (0.1%
w/v). Shoot proliferation was achieved by cutting elongated shoots into stem segments and subculturing on GD medium containing
2 mg l−1 BA and 0.2 mg l−1 NAA. Root primordia were induced in 82% of shoots when transferred to half-strength GD medium containing 0.2 mg l−1 NAA. Root elongation was achieved in a hormone-free GD agar medium or a perlite substrate. Rooted plantlets were inoculated
with the mycelium of ectomycorrhizal fungus Pisolithus tinctorius and the formation of ectomycorrhiza-like structures was achieved in vitro. 相似文献
12.
Behzad Ahmadi Khoshnood Alizadeh Jaime A. Teixeira da Silva 《Plant Cell, Tissue and Organ Culture》2012,109(3):525-533
The effects of three periods of incubation (10, 20 and 30 min) at different levels of bleomycin (0, 0.1, 0.2, 0.3, 0.4 and
0.5 μg ml−1), as well as three periods of exposure (12, 24 and 48 h) to different levels of the anti-auxin p-chlorophenoxyisobutyric acid (PCIB), including 1, 2, 3, 4 and 5 mg l−1, on microspore embryogenesis of rapeseed cv. ‘Amica’ were investigated. Microspore embryogenesis was significantly enhanced
following 20 min treatment with 0.2 μg ml−1 bleomycin compared with untreated cultures. Highest embryo yield (163 embryos Petri dish−1) was observed with 24 h treatment of 4 mg l−1 PCIB. The highest percentage of secondary embryogenesis was observed on B5 medium containing 0.15 mg l−1 of gibberellic acid (GA3) and 0.2 mg l−1 6-benzyladenine (BA) in 4–6 mm microspore-derived embryos (MDEs). Most callus formed on B5 medium containing 0.15 mg l−1 GA3, 0.1 mg l−1 BA and 0.1 mg l−1 indole-3-acetic acid (IAA) when 4–6 mm embryos were used. Regeneration was highest on B5 medium containing 0.05 mg l−1 GA3 or 0.1 mg l−1 BA and 0.2 mg l−1 IAA with 2–4 mm embryos. Microspore embryogenesis and plant regeneration could be improved by both bleomycin and PCIB when
the appropriate MDE length and phytohormone level were selected. 相似文献
13.
Meiru Li Hongqing Li Xiaoying Hu Xiaoping Pan Guojiang Wu 《Plant Cell, Tissue and Organ Culture》2010,102(3):321-327
Zoysia tenuifolia Willd. ex Trin. is one of the most popularly cultivated turfgrass. This is the first report of successful plant regeneration
and genetic transformation protocols for Z. tenuifolia using Agrobacterium tumefaciens. Initial calli was induced from stem nodes incubated on a Murashige and Skoog (1962) (MS) medium supplemented with 2 mg l−1 2,4-dichlorophenoxyacetic acid (2,4-D) and 1 mg l−1 6-benzyladenine (BA), with a frequency of 53%. Compact calli were selected and subcultured monthly on the fresh medium. Sixty-nine
percent of the calli could be induced to regenerate plantlets when the calli incubated on a MS medium supplemented with 0.2 mg l−1 BA under darkness. For genetic transformation, calli were incubated with A. tumefaciens strain EHA105 harboring the binary vector pCAMBIA 1301 which contains the hpt gene as a selectable marker for hygromycin resistance and an intron-containing β-glucuronidase gene (gus-int) as a reporter gene. Following co-cultivation, about 12% of the callus explants produced hygromycin resistant calli on
MS medium supplemented with 2 mg l−1 2,4-D, 1 mg l−1 BA, 50 mg l−1 hygromycin, 500 mg l−1 cefotaxime after 8 weeks. Shoots were regenerated following transfer of the resistant calli to shoot induction medium containing
0.2 mg l−1 BA, 50 mg l−1 hygromycin, and 250 mg l−1 cefotaxime, and about 46% of the resistant calli differentiated into shoots. Finally, all the resistant shoots were rooted
on 1/2 MS media supplemented with 50 mg l−1 hygromycin, 250 mg l−1 cefotaxime. The transgenic nature of the transformants was demonstrated by the detection of β-glucuronidase activity in the primary transformants and by PCR and Southern hybridization analysis. About 5% of the total
inoculated callus explants produced transgenic plants after approximately 5 months. The procedure described will be useful
for both, the introduction of desired genes into Z. tenuifolia and the molecular analysis of gene function. 相似文献
14.
Jatropha curcas L. (Physic nut) is a commercially important non-edible oil seed crop known for its use as an alternate source of biodiesel.
In order to investigate the morphogenic potential of immature embryo, explants from four developmental stages were cultured
on medium supplemented with combinations of auxins and cytokinins. It was found that the size of embryo is critical for the
establishment of callus. Immature embryos (1.1–1.5 cm) obtained from the fruits 6 weeks after pollination showed a good response
of morphogenic callus induction (85.7%) and subsequent plant regeneration (70%) with the maximum number of plantlets (4.7/explant)
on Murashige and Skoog’s (MS) medium supplemented with IBA (0.5 mg l−1) and BA (1.0 mg l−1). The above medium when supplemented with growth adjuvants such as 100 mg l−1 casein hydrolysate + 200 mg l−1
l-glutamine + 8.0 mg l−1 CuSO4 resulted in an even higher frequency of callus induction (100%). Plant regeneration (90%) with the maximum number of plantlets
(10/explant) was achieved on MS medium supplemented with 500 mg l−1 polyvinyl pyrrolidone + 30 mg l−1 citric acid + 1 mg l−1 BA + 0.5 mg l−1 Kn + 0.25 mg l−1 IBA. It was observed that plantlet regeneration could occur either through organogenesis of morphogenic callus or via multiplication
of pre-existing meristem in immature embryos. The age of immature embryos and addition of a combination of growth adjuvants
to the culture medium appear to be critical for obtaining high regeneration rates. Well-developed shoots rooted on half-strength
MS medium supplemented with 0.5 mg l−1 IBA and 342 mg l−1 trehalose. The rooted plants after acclimatization were successfully transferred to the field in different agro-climatic
zones in India. This protocol has been successfully evaluated on five elite lines of J. curcas. 相似文献
15.
Su-Juan Zhao Zhong-Chun Zhang Xiang Gao Gulsum Tohsun Bao-Sheng Qiu 《Plant Cell, Tissue and Organ Culture》2009,99(1):9-16
An efficient micropropagation system for mining ecotype Sedum alfredii Hance, a newly identified Zn/Cd hyperaccumulator, was developed. Frequency of callus induction reached up to 70% from leaves
incubated on Murashige and Skoog (MS) medium supplemented with 1.0 mg l−1 2,4-dichlorophenoxy acetic acid (2,4-D) and 0.5 mg l−1 6-benzyladenine (BA), and 83% from internodal stem segments grown on MS medium with 0.1 mg l−1 2,4-D and 0.1 mg l−1 BA. Callus proliferated rapidly on MS medium containing 0.2 mg l−1 2,4-D and 0.05 mg l−1 thidiazuron. The highest number of adventitious buds per callus (17.3) and frequency of shoot regeneration (93%) were obtained
when calli were grown on MS medium supplemented with 2.0 mg l−1 BA and 0.3 mg l−1 α-naphthalene acetic acid (NAA). Elongation of shoots was achieved when these were incubated on MS medium containing 3.0 mg l−1 gibberellic acid. Induction of roots was highest (21.4 roots per shoot) when shoots were transferred to MS medium containing
2.0 mg l−1 indole 3-butyric acid rather than either indole 3-acetic acid or NAA. When these in vitro plants were acclimatized and transferred
to the greenhouse, and grown in hydroponic solutions containing 200 μM cadmium (Cd), they exhibited high efficiency of Cd
transport, from roots to shoots, and hyperaccumulation of Cd. 相似文献
16.
Compared with steady state, oscillation in continuous very-high-gravity ethanol fermentation with Saccharomyces cerevisiae improved process productivity, which was thus introduced for the fermentation system composed of a tank fermentor followed
by four-stage packed tubular bioreactors. When the very-high-gravity medium containing 280 g l−1 glucose was fed at the dilution rate of 0.04 h−1, the average ethanol of 15.8% (v/v) and residual glucose of 1.5 g l−1 were achieved under the oscillatory state, with an average ethanol productivity of 2.14 g h−1 l−1. By contrast, only 14.8% (v/v) ethanol was achieved under the steady state at the same dilution rate, and the residual glucose was as high as 17.1 g l−1, with an ethanol productivity of 2.00 g h−1 l−1, indicating a 7% improvement under the oscillatory state. When the fermentation system was operated under the steady state
at the dilution rate of 0.027 h−1 to extend the average fermentation time to 88 h from 59 h, the ethanol concentration increased slightly to 15.4% (v/v) and residual glucose decreased to 7.3 g l−1, correspondingly, but the ethanol productivity was decreased drastically to 1.43 g h−1 l−1, indicating a 48% improvement under the oscillatory state at the dilution rate of 0.04 h−1. 相似文献
17.
Decolourization of Direct Red 80 (DR-80) by the white rot fungus Phanerochaete chrysosporium MTCC 787 was investigated employing sequential design of experiments. Media components for growing the white rot fungus were
first screened using Plackett-Burman design and then optimized using response surface methodology (RSM), which resulted in
enhancement in the efficiency of dye removal by the fungus. For determining the effect of media constituents on the dye removal,
both percent dye decolourization and specific dye removal due to maximum enzyme activity were chosen as the responses from
the experiments, and the media constituents glucose, veratryl alcohol, KH2PO4, CaCl2 and MgSO4 were screened to be the most effective with P values less than 0.05. Central composite design (CCD) followed by RSM in the optimization study revealed the following optimum
combinations of the screened media constituents: glucose, 11.9 g l−1; veratryl alcohol, 12.03 mM; KH2PO4, 23.08 g l−1; CaCl2, 2.4 g l−1; MgSO4, 10.47 g l−1. At the optimum settings of the media constituents, complete dye decolourization (100% removal efficiency) and a maximum
specific dye removal due to lignin peroxidase enzyme of 0.24 mg U−1 by the white rot fungus were observed. 相似文献
18.
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
19.
Rhamnolipid biosurfactant production by Pseudomonas nitroreducens isolated from petroleum-contaminated soil was investigated. The effects of carbon, nitrogen and carbon to nitrogen ratio
on biosurfactant production were examined using mineral salts medium as the growth medium. The tenso-active properties (surface
activity and critical micelle concentrations of the produced biosurfactant were also evaluated. The best carbon source, nitrogen
source were glucose and sodium nitrate giving rhamnolipid yields of 5.28 and 4.38 g l−1, respectively. The maximum rhamnolipid production of 5.46 g l−1 was at C/N (glucose/sodium nitrate) of 22. The rhamnolipid biosurfactant reduced the surface tension of water from 72 to
~37 mN/m. It also has critical micelle concentration of ~28 mg l−1. Thus, the results presented in our reports show that the produced rhamnolipid can find wide applications in various bioremediation
activities such as enhanced oil recovery and petroleum degradation. 相似文献
20.
L. Lesage-Meessen M. Haon M. Delattre J.-F. Thibault B. Colonna Ceccaldi M. Asther 《Applied microbiology and biotechnology》1997,47(4):393-397
The effects of adding cellobiose on the transformation of vanillic acid to vanillin by two strains of Pycnoporus cinnabarinus MUCL39532 and MUCL38467 were studied. When maltose was used as the carbon source in the culture medium, very high levels
of methoxyhydroquinone were formed from vanillic acid. When cellobiose was used as the carbon source and/or added to the culture
medium of P. cinnabarinus strains on day 3 just before vanillic acid was added, it channelled the vanillic acid metabolism via the reductive route
leading to vanillin. Adding 3.5 g l−1 cellobiose to 3-day-old maltose cultures of P. cinnabarinus MUCL39532 and 2.5 g l−1 cellobiose to 3-day-old cellobiose cultures of P. cinnabarinus MUCL38467, yielded 510 mg l−1 and 560 mg l−1 vanillin with a molar yield of 50.2 % and 51.7 % respectively. Cellobiose may either have acted as an easily metabolizable
carbon source, required for the reductive pathway to occur, or as an inducer of cellobiose:quinone oxidoreductase, which is
known to inhibit vanillic acid decarboxylation.
Received: 24 July 1996 / Received revision: 29 November 1996 / Accepted: 29 November 1996 相似文献