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1.
Incomplete beta-ketone processing as a mechanism for polyene structural variation in the FR-008/candicidin complex 总被引:1,自引:0,他引:1
FR-008/candicidin is a heptaene macrolide with established antifungal activity, produced by Streptomyces sp. FR-008 as a complex mixture of compounds. Here, six components (FR-008-I to -VI) of the FR-008/candicidin complex were determined; III, V, and VI were confirmed as natural products, principally differing from each other at C-3 and C-9, while the other three were believed to originate from the respective conversions of the natural ones in vitro. Inactivation of KR21 and DH18, respectively, abolished production of V carrying a C-3 hydroxyl, and VI carrying a C-9 methylene. Combined inactivation created a mutant producing only III, with a C-3 ketone and a C-9 hydroxyl, and having antifungal activity superior to V and comparable to VI. Incomplete activities of KR21 and DH18 were, therefore, unambiguously identified as being involved in structural variations of FR-008 complex. 相似文献
2.
A fed-batch culture system with constant feeding (glucose 80 g L−1, 0.25 ml min−1) was used to study the influence of glucose on cell dry weight and exopolysaccharides production from submerged Tremella fuciformis spores in a 5-L stirred-tank bioreactor. The results showed that high levels of cell mass (9.80 g L−1) and exopolysaccharides production (3.12 g L−1) in fed-batch fermentation were obtained after 1 h of feeding, where the specific growth rate (μ) and exopolysaccharides yield on substrate consumed (YP/S) were 0.267 d−1 and 0.14 g g−1. Unlike batch fermentation, maximal cell mass and exopolysaccharides production merely reached 7.11 and 2.08 g L−1; the specific growth rate (μ) and exopolysaccharides yield on substrate consumed (YP/S) were 0.194 d−1 and 0.093 g g−1, respectively. It is concluded that the synthesis of exopolysaccharides can be promoted effectively when feeding glucose
at a late exponential phase. 相似文献
3.
Organizational and mutational analysis of a complete FR-008/candicidin gene cluster encoding a structurally related polyene complex 总被引:9,自引:0,他引:9
The complete gene cluster for biosynthesis of a polyene complex, FR-008, spans 137.2 kb of the genome of Streptomyces sp. FR-008 consisting of six genes for a modular PKS and 15 additional genes. The extensive similarity to the partially characterized candicidin gene cluster in Streptomyces griseus IMRU3570, especially for genes involved in mycosamine biosynthesis, prompted us to compare the compounds produced by Streptomyces sp. FR-008 and Streptomyces griseus IMRU3570, and we found that FR-008 and candicidin complex are identical. A model for biosynthesis of a set of four structurally related FR-008/candicidin compounds was proposed. Deletion of the putative regulatory genes abolished antibiotic production, while disruption of putative glycosyltransferase and GDP-ketosugar aminotransferase functionalities led to the productions of a set of nonmycosaminated aglycones and a novel polyene complex with attachment of altered sugar moiety, respectively. 相似文献
4.
A feeding technology that was suitable for improving the nisin production by Lactococcus lactis subsp. lactis W28 was established. The effects of initial sucrose concentration (ISC) in the fermentation broth, feeding time, and feeding
rate on the fermentation were studied. It was observed that a fed-batch culture (ISC = 10 g l−1) with 100 ml sucrose solution (190 g l−1) being evenly fed (9–10 ml h−1) into the fermenter after 3-h fermentation gave the best performance in terms of biomass and nisin yield. Under these conditions,
the total biomass and the total nisin yield were approximately 23% and 51% higher than those in batch fermentation, respectively.
When the sucrose concentration was controlled at 5–10 g l−1 in variable volume intermittent fed-batch fermentation (VVIF) with ISC = 10 g l−1, the total biomass and the total nisin yield were 29% and 60% above those in batch fermentation, respectively. The VVIF proved
to be effective to eliminate the substrate inhibition by maintaining sucrose at appropriate levels. It is also easy to be
scaled up, since various parameters involved in industrial production were taken into account. 相似文献
5.
Hossein Amani Mohammad Reza Mehrnia Mohammad Hossein Sarrafzadeh Manouchehr Haghighi Mohammad Reza Soudi 《Applied biochemistry and biotechnology》2010,162(2):510-523
There is a lack of fundamental knowledge about the scale up of biosurfactant production. In order to develop suitable technology
of commercialization, carrying out tests in shake flasks and bioreactors was essential. A reactor with integrated foam collector
was designed for biosurfactant production using Bacillus subtilis isolated from agricultural soil. The yield of biosurfactant on biomass (Y
p/x), biosurfactant on sucrose (Y
p/s), and the volumetric production rate (Y) for shake flask were obtained about 0.45 g g−1, 0.18 g g−1, and 0.03 g l−1 h−1, respectively. The best condition for bioreactor was 300 rpm and 1.5 vvm, giving Y
x/s, Y
p/x, Y
p/s, and Y of 0.42 g g−1, 0.595 g g−1, 0.25 g g−1, and 0.057 g l−1 h−1, respectively. The biosurfactant maximum production, 2.5 g l−1, was reached in 44 h of growth, which was 28% better than the shake flask. The obtained volumetric oxygen transfer coefficient
(K
L
a) values at optimum conditions in the shake flask and the bioreactor were found to be around 0.01 and 0.0117 s−1, respectively. Comparison of K
L
a values at optimum conditions shows that biosurfactant production scaling up from shake flask to bioreactor can be done with
K
L
a as scale up criterion very accurately. Nearly 8% of original oil in place was recovered using this biosurfactant after water
flooding in the sand pack. 相似文献
6.
Mathiazhakan Kuttiraja Ayed Dhouha Rajeshwar Dayal Tyagi 《Applied biochemistry and biotechnology》2018,184(4):1332-1346
The objective of this research was to investigate the kinetics of lipid production by Yarrowia lipolytica SKY7 in the crude glycerol-supplemented media with and without the control of pH. Lipid and citric acid production were improved with the pH control condition. There was no significant difference observed in the biomass concentration with or without the pH control. In the pH-controlled experiments, the biomass and lipid concentration reached 18 and 7.78 g/L, (45.5% w/w), respectively, with lipid yield (Yp/s) of 0.179 g/g at 60 h of fermentation. The lipid production was directly correlated with growth and the process was defined as growth associated. After 60 h of fermentation, the lipid degradation was noticed in the pH-controlled reactor whereas it occurred after 84 h in the pH-uncontrolled reactor. Apart from lipid, citric acid was produced as the major extracellular product in both fermentations but the much lower concentration in uncontrolled pH. Based on the experimental results, it is evident that controlling the pH will enhance the lipid production by 15% compared to pH-uncontrolled fermentation. 相似文献
7.
Junpei Zhou Huoqing Huang Kun Meng Pengjun Shi Yaru Wang Huiying Luo Peilong Yang Yingguo Bai Bin Yao 《Applied biochemistry and biotechnology》2010,160(5):1277-1292
A bacterial strain, Streptomyces sp. TN119, was isolated from the gut of Batocera horsfieldi larvae and showed xylanolytic activity. A degenerate primer set was designed based on the base usage of G and C in Actinobacteria xylanase-coding sequences belonging to the glycosyl hydrolases family 10 (GH 10), and used to clone the partial xylanase
gene from Streptomyces sp. TN119. A modified thermal asymmetric interlaced (TAIL)-PCR specific for high-GC genes, named GC TAIL-PCR, was developed
to obtain the full-length xylanase gene (xynA119; 1089 bp). Rich in GC content (67.8%), xynA119 encodes a new GH 10 xylanase (XynA119), which shares highest identity (48.8%) with an endo-1,4-β-xylanase from Cellulosimicrobium sp. HY-12. Recombinant XynA119 was expressed in Escherichia coli BL21 (DE3) and purified to electrophoretic homogeneity. The enzyme showed maximal activity at pH 6.5 and 60 °C, was stable
at pH 4.0 to 10.0 and 50 °C, was resistant to most chemicals (except for Cu2+, Mn2+, Ag+, Hg2+ and SDS) and trypsin, and produced simple products. The specific activity, K
m, V
max, and k
cat using oat-spelt xylan as substrate were 57.9 U mg−1, 1.0 mg ml−1, 74.8 μmol min−1 mg−1, and 49.2 s–1, respectively. 相似文献
8.
Xiaolin Pei Qiuyan Wang Xiaofeng Qiu Longbin Ying Junhua Tao Tian Xie 《Applied biochemistry and biotechnology》2010,162(5):1423-1434
2-Deoxyribose-5-phosphate aldolase (DERA) catalyzes a sequential aldol reaction useful in synthetic chemistry. In this work,
the effect of a feeding strategy on the production of a thermophilic DERA was investigated in fed-batch cultures of recombinant
Escherichia coli BL21 (pET303-DERA008). The predetermined specific growth rate (μ
set) was evaluated at 0.20, 0.15, and 0.10 h−1, respectively. The DERA concentration and volumetric productivity were associated with μ
set. The cells synthesized the enzyme most efficiently at μ
set = 0.15 h−1. The maximum enzyme concentration (5.12 g/L) and total volumetric productivity (0.256 g L−1 h−1) obtained were over 10 and five times higher than that from traditional batch cultures. Furthermore, the acetate concentration
remained at a relatively low level, less than 0.4 g/L, under this condition which would not inhibit cell growth and target
protein expression. Thus, a specific growth rate control strategy has been successfully applied to induce fed-batch cultures
for the maximal production of the thermophilic 2-deoxyribose-5-phosphate aldolase. 相似文献
9.
Agbaje Lateef Julius K. Oloke Evariste B. Gueguim Kana Solomon O. Oyeniyi Olukemi R. Onifade Ayokunmi O. Oyeleye Olabiyi C. Oladosu 《Chemical Papers》2008,62(6):635-638
Increasing awareness of the importance of fructooligosaccharides (FOS) as ingredients of functional foods has led to intensive
search of new sources of fructosyltransferases (FTase), enzymes responsible for the conversion of sucrose to fructooligosaccharides.
A local strain of Rhizopus stolonifer isolated from spoilt orange fruit with high fructosyltransferase activity (U
t) of 12.31–45.70 U mL−1 during a fermentation period of 24–120 h is herein reported. It showed low hydrolytic activity (U
h) in the range of 0.86–1.78 U mL−1 during the same period. FOS yield of 34 % (1-kestose, GF2, nystose, GF3) was produced by FTase obtained from a 72 h-old culture using 60 g of sucrose per 100 mL of the substrate. When the isolate
was grown in a defined submerged medium, its pH dropped sharply from the intial value of 5.5 to 1.0 within 24 h, and this
value was maintained throughout the fermentation. The biomass content ranged from 8.8 g L−1 at 24 h of fermentation to reach the maximum of 10 g L−1 at 72 h. It was reduced to 5.6 g L−1 at the end of 120 h of fermentation. This report represents the first reference to a strain of Rhizopus as a source of FTase for the production of FOS. The high U
t/U
h ratio shown by this isolate indicates that it may be a good strain for the industrial and commercial production of FOS. However,
there is a need of further optimization of the bioprocess to increase the conversion efficiency of sucrose to FOS by the enzyme. 相似文献
10.
Valduga E Valério A Treichel H Furigo Júnior A Di Luccio M 《Applied biochemistry and biotechnology》2009,157(1):61-69
With the objective of determining the kinetic behavior (growth, substrate, pH, and carotenoid production) and obtain the stoichiometric
parameters of the fermentative process by Sporidiobolus salmonicolor in synthetic and agroindustrial media, fermentations were carried out in shaken flasks at 25°C, 180 rpm, and initial pH of
4.0 for 120 h in the dark, sampling every 6 h. The maximum concentrations of total carotenoids in synthetic (913 μg/L) and
agroindustrial (502 μg/L) media were attained approximately 100 h after the start of the fermentative process. Carotenoid
bioproduction is associated with cell growth and the ratio between carotenoid production and cell growth (Y
P/X) is 176 and 163 μg/g in the synthetic and agroindustrial media, respectively. The pH of the agroindustrial fermentation medium
varied from 4.2 to 8.5 during the fermentation. The specific growth rate (μ
X) for S. salmonicolor in synthetic and agroindustrial media was 0.07 and 0.04 h−1, respectively. The synthetic medium allowed for greater productivity, obtaining maximum cell productivity (P
x) of 0.08 g L−1 h−1 and maximum total carotenoid productivity (P
car) of 14.2 μg L−1 h−1. Knowledge of the kinetics of a fermentative process is of extreme importance when transposing a laboratory experiment to
an industrial scale, as well as making a quantitative comparison between different culture conditions. 相似文献
11.
Jiang L Wang J Liang S Wang X Cen P Xu Z 《Applied biochemistry and biotechnology》2010,160(2):350-359
Butyric acid has many applications in chemical, food, and pharmaceutical industries. In the present study, Clostridium tyrobutyricum ATCC 25755 was immobilized in a fibrous-bed bioreactor to evaluate the performance of butyrate production from glucose and
xylose. The results showed that the final concentration and yield of butyric acid were 13.70 and 0.46 g g−1, respectively, in batch fermentation when 30 g L−1 glucose was introduced into the bioreactor. Furthermore, high concentration 10.10 g L−1 and yield 0.40 g g−1 of butyric acid were obtained with 25 g L−1 xylose as the carbon source. The immobilized cells of C. tyrobutyricum ensured similar productivity and yield from repeated batch fermentation. In the fed-batch fermentation, the final concentration
of butyric acid was further improved to 24.88 g L−1 with one suitable glucose feeding in the fibrous-bed bioreactor. C. tyrobutyricum immobilized in the fibrous-bed bioreactor would provide an economically viable fermentation process to convert the reducing
sugars derived from plant biomass into the final bulk chemical (butyric acid). 相似文献
12.
N. S. Shaligram S. K. Singh R. S. Singhal A. Pandey G. Szakacs 《Applied biochemistry and biotechnology》2009,159(2):505-520
In the present study, compactin production by Penicillium brevicompactum WA 2315 was optimized using solid-state fermentation. The initial one factor at a time approach resulted in improved compactin
production of 905 μg gds−1 compared to initial 450 μg gds−1. Subsequently, nutritional, physiological, and biological parameters were screened using fractional factorial and Box–Behnken
design. The fractional factorial design studied inoculum age, inoculum volume, pH, NaCl, NH4NO3, MgSO4, and KH2PO4. All parameters were found to be significant except pH and KH2PO4. The Box–Behnken design studied inoculum volume, inoculum age, glycerol, and NH4NO3 at three different levels. Inoculum volume (p = 0.0013) and glycerol (p = 0.0001) were significant factors with greater effect on response. The interaction effects were not significant. The validation
study using model-defined conditions resulted in an improved yield of 1,250 μg gds−1 compactin. Further improvement in yield was obtained using fed batch mode of carbon supplementation. The feeding of glycerol
(20% v/v) on day 3 resulted in further improved compactin yield of 1,406 μg gds−1. The present study demonstrates that agro-industrial residues can be successfully used for compactin production, and statistical
experiment designs provide an easy tool to improve the process conditions for secondary metabolite production. 相似文献
13.
R. Bruce King 《Journal of mathematical chemistry》2008,44(1):5-19
The special projective linear groups PSL(2ℓ + 1) or L
2(2ℓ + 1) of order 2ℓ(2ℓ + 1)(ℓ + 1) can be used to study atomic shells of electrons with angular momentum quantum number ℓ
corresponding to the atomic p, d, f, and g shells for ℓ = 1, 2, 3, 4, respectively. For the atomic g shell the group L
2(9) is isomorphic with the alternating group A
6 on six objects of order 360 or the symmetry group of the 5-dimensional simplex, a 5-dimensional analogue of the tetrahedron
with 6 vertices and 15 edges. This leads to the subgroup chain SO(9) ⊃ SO(5) ⊃ L
2(9) for the atomic g shell analogous to the subgroup chain SO(7) ⊃ G
2 ⊃ L
2(7) ≈7
O for the atomic f shell. In the L
2(9) group only the representations of spherical harmonics or sums thereof, Γ(Yℓ), with dimensions dim Γ(Yℓ) or dim Γ(Yℓ) ± 1 divisible by 9 are found to be individually reducible to irreducible representations (irreps) or sums of irreps of L
2(9). This leads to term groupings such as S, PD, G, PF, DH, L, PK, DI, FH, M, FI, PO, DN, HK, R, etc., of increasing total
dimension for the irreps of SO(9) for various g
n
configurations in the atomic g shell. 相似文献
14.
Rosa Maria Rojas K. Petrov G. Avdeev J. M. Amarilla L. Pascual J. M. Rojo 《Journal of Thermal Analysis and Calorimetry》2007,90(1):67-72
Chromium doped spinels LiCrYMn2−YO4 (0.2≤Y≤0.8) has been synthesized by the sucrose-aided combustion procedure. The thermal behaviour, phase homogeneity and structural
characteristics of the samples were studied by thermal analysis, coupled mass spectrometry, and room-and high-temperature
X-ray diffraction methods. It was found that the ‘as prepared’ samples contained residual organic impurities undetectable
for X-ray diffraction, that burn out completely at 400°C. Samples treated between 400 and 750°C are single phase spinels,
whose crystallites size increase from 10 to 50 nm on increasing the temperature. Cr-doping enhances the thermal stability
of the spinels, which augments on increasing the Cr content Y. The enhanced thermal stability of the spinels has been accounted
for based on the high excess stabilization energy of Cr3+ in octahedral ligand field. 相似文献
15.
Hiroaki Watanabe 《Tetrahedron letters》2006,47(9):1399-1402
The biosynthetic pathway of a potent antifungal agent, FR-900848, has been examined by administration of several 13C-labeled precursors to Streptoverticillium fervens HP-891. Although none of the 13C-labeled acetate was incorporated into FR-900848, the labeling pattern of FR-900848 derived from d-[U-13C6]glucose revealed that the fatty acid backbone of FR-900848 has been biosynthesized via a polyketide pathway. These unusual results strongly show that the major pathway to provide acetyl-CoA in this microorganism is glycolysis. Feeding experiments with d-[U-13C6]glucose, [1,3-13C2]glycerol, and l-[Me-13C]methionine provided information on the biosynthetic origin of structurally unusual parts (polycyclopropane and aminonucleoside) in this antibiotic. 相似文献
16.
Application of a pH Feedback-Controlled Substrate Feeding Method in Lactic Acid Production 总被引:1,自引:0,他引:1
Substrate concentration in lactic acid fermentation broth could not be controlled well by traditional feeding methods, including
constant, intermittent, and exponential feeding methods, in fed-batch experiments. A simple feedback feeding method based
on pH was proposed to control pH and substrate concentration synchronously to enhance lactic acid production in fed-batch
culture. As the linear relationship between the consumption amounts of alkali and that of substrate was concluded during lactic
acid fermentation, the alkali and substrate in the feeding broth were mixed together proportionally. Thus, the concentration
of substrate could be controlled through the adjustment of pH automatically. In the fed-batch lactic acid fermentation with
Lactobacillus lactis-11 by this method, the residual glucose concentration in fermentation broth was controlled between 4.1 and 4.9 g L−1, and the highest concentration of lactic acid, maximum cell dry weight, volumetric productivity of lactic acid, and yield
were 96.3 g L−1, 4.7 g L−1, 1.9 g L−1 h−1, and 0.99 g lactic acid per gram of glucose, respectively, compared to 82.7 g L−1, 3.31 g L−1, 1.7 g L−1 h−1, and 0.92 g lactic acid per gram of glucose in batch culture. This feeding method was simple and easily operated and could
be feasible for industrial lactic acid production in the future. 相似文献
17.
采用高温熔融法制备Eu3+?Tb3+共掺杂SiO2?B2O3?Na2O?Y2O3?P2O5前驱体玻璃。对前驱体玻璃粉末进行差示扫描量热(DSC)分析,确定玻璃陶瓷样品的热处理温度。前驱体玻璃热处理后,采用X射线衍射(XRD)和扫描电镜(SEM)分析可知前驱体玻璃中有Na3.6Y1.8(PO4)3晶粒析出。利用荧光光谱对玻璃陶瓷样品的发光性能进行表征,同时分析了Tb3+离子的荧光衰减曲线,确定Eu3+、Tb3+离子的发光机理以及能量传递过程。通过对Eu3+?Tb3+共掺杂玻璃陶瓷样品的发射光谱采集并用色坐标软件和色温计算程序,获得玻璃陶瓷样品的色坐标和相关色温。 相似文献
18.
Pinheiro AD Rocha MV Macedo GR Gonçalves LR 《Applied biochemistry and biotechnology》2008,148(1-3):227-234
A commercial strain of Saccharomyces cerevisiae was used for the production of ethanol by fermentation of cashew apple juice. Growth kinetics and ethanol productivity were
calculated for batch fermentation with different initial sugar (glucose + fructose) concentrations. Maximal ethanol, cell,
and glycerol concentrations were obtained when 103.1 g L−1 of initial sugar concentration was used. Cell yield (Y
X/S) was calculated as 0.24 (g microorganism)/(g glucose + fructose) using cashew apple juice medium with 41.3 g L−1 of initial sugar concentration. Glucose was exhausted first, followed by fructose. Furthermore, the initial concentration
of sugars did not influence ethanol selectivity. These results indicate that cashew apple juice is a suitable substrate for
yeast growth and ethanol production. 相似文献
19.
Comparison between Different Hydrolysis Processes of Vine-Trimming Waste to Obtain Hemicellulosic Sugars for Further Lactic Acid Conversion 总被引:1,自引:0,他引:1
Moldes AB Bustos G Torrado A Domínguez JM 《Applied biochemistry and biotechnology》2007,143(3):244-256
Trimming vine shoot samples were treated with water under selected operational conditions (autohydrolysis reaction) to obtain
a liquid phase containing hemicellulose-decomposition products. In a further acid-catalyzed step (posthydrolysis reaction),
xylooligosaccharides were converted into single sugars for the biotechnological production of lactic acid using Lactobacillus
pentosus. A wide range of temperatures, reaction times, and acid concentrations were tested during the autohydrolysis–posthydrolysis
process to investigate their influence on hemicellulose solubilization and reaction products. The maximum concentration of
hemicellulosic sugars was achieved using autohydrolysis at 210 °C followed by posthydrolysis with 1% H2SO4 during 2 h. Data from autohydrolysis–posthydrolysis were compared with the results obtained at the optima conditions assayed
for prehydrolysis (3% H2SO4 at 130 °C during 15 min) based on previous works. Prehydrolysis extracted more hemicellulosic sugars from trimming vine shoots;
however, the protein content in the hydrolysates from autohydrolysis–posthydrolysis was higher. The harsher conditions assayed
during the autohydrolysis process and the higher content of protein after this treatment could induce Maillard reactions decreasing
consequently the concentration of hemicellulosic sugars in the hydrolysates. Therefore, despite the several advantages of
autohydrolysis (less equipment caused by the absence of mineral acid, less generation of neutralized sludges, and low cost
of reagents) the poor results obtained in this work with no detoxified hydrolysates (Q
P = 0.36 g/L h, Q
S = 0.79 g/L h, Y
P/S = 0.45 g/g, Y
P/Sth = 61.5 %) or charcoal-treated hydrolysates (Q
P = 0.76 g/L h, Q
S = 1.47 g/L h, Y
P/S = 0.52 g/g, Y
P/Sth = 71.5 %) suggest that prehydrolysis of trimming vine shoots with diluted H2SO4 is more attractive than autohydrolysis-posthydrolysis for obtaining lactic acid through fermentation of hemicellulosic sugars
with L. pentosus. Besides the higher hemicellulosic sugars concentration achieved when using the prehydrolysis technology, no detoxification
steps are required to produce efficiently lactic acid (Q
P = 1.14 g/L h; Q
S = 1.64 g/L h; Y
P/S = 0.70 g/g; Y
P/Sth = 92.6 %), even when vinification lees are used as nutrients (Q
P = 0.89 g/L h; Q
S = 1.54 g/L h; Y
P/S = 0.58 g/g; Y
P/Sth = 76.1 %). 相似文献
20.
Z. Branković K. Đuriš A. Radojković S. Bernik Z. Jagličić M. Jagodič K. Vojisavljevic G. Branković 《Journal of Sol-Gel Science and Technology》2010,55(3):311-316
Substituted lanthanum manganites with the general formula A1−x
B
x
MnO3 (A = La, B = Ca, Sr…) have attracted a lot of attention due to their exceptional electric and magnetic properties. In this
work, pure and Ca2+, Sr2+-doped LaMnO3 (LMO) with the concentrations of dopants 30% Ca2+ (LCMO), 30% Sr2+ (LSMO) and 15% Ca2+ + 15% Sr2+ (LCSMO) (in mol. %) were synthesized by polymerizable complex method. Bulk samples were prepared by sintering at 1300 °C
for 4 h in oxygen atmosphere. It was found that sintering in oxygen atmosphere enables preparation of single phase ceramics
with rhombohedral crystal structure. Chemically prepared fine, submicronic precursor powders provided uniform microstructure
and grain size distribution in final ceramics. As a result, pure and doped LMO ceramics with excellent microstructural and
magnetic properties were obtained. Depending on the composition, magnetic measurements showed high saturation magnetizations
(up to 93 emu/g), with values of the Curie temperature in the range 180–390 K and magnetoresistance up to 67%. 相似文献