共查询到20条相似文献,搜索用时 15 毫秒
1.
Islem Younes Olfa Ghorbel-Bellaaj Rim Nasri Moncef Chaabouni Marguerite Rinaudo Moncef Nasri 《Process Biochemistry》2012,47(12):2032-2039
Different crude microbial proteases were applied for chitin extraction from shrimp shells. A Box–Behnken design with three variables and three levels was applied in order to approach the prediction of optimal enzyme/substrate ratio, temperature and incubation time on the deproteinization degree with Bacillus mojavensis A21 crude protease. These optimal conditions were: an enzyme/substrate ratio of 7.75 U/mg, a temperature of 60 °C and an incubation time of 6 h allowing to predict 94 ± 4% deproteinization. Experimentally, in these optimized conditions, a deproteinization degree of 88 ± 5% was obtained in good agreement with the prediction and larger than values generally given in literature. The deproteinized shells were then demineralized to obtain chitin which was converted to chitosan by deacetylation and its antibacterial activity against different bacteria was investigated. Results showed that chitosan dissolved at 50 mg/ml markedly inhibited the growth of most Gram-negative and Gram-positive bacteria tested. 相似文献
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A Marino S Mustacchi D Puntillo A Senatore 《Bollettino della Società italiana di biologia sperimentale》1985,61(2):171-174
Sterols of three Basidiomycetes were determined. The main sterol was ergosta-5,7,22-trien-3 beta-ol, accompanied by other closely related sterols. Cholesterol was found only in trace amounts. 相似文献
3.
Johanna Rytioja Kristiina Hildén Jennifer Yuzon Annele Hatakka Ronald P. de Vries Miia R. M?kel? 《Microbiology and molecular biology reviews》2014,78(4):614-649
SUMMARY
Basidiomycete fungi subsist on various types of plant material in diverse environments, from living and dead trees and forest litter to crops and grasses and to decaying plant matter in soils. Due to the variation in their natural carbon sources, basidiomycetes have highly varied plant-polysaccharide-degrading capabilities. This topic is not as well studied for basidiomycetes as for ascomycete fungi, which are the main sources of knowledge on fungal plant polysaccharide degradation. Research on plant-biomass-decaying fungi has focused on isolating enzymes for current and future applications, such as for the production of fuels, the food industry, and waste treatment. More recently, genomic studies of basidiomycete fungi have provided a profound view of the plant-biomass-degrading potential of wood-rotting, litter-decomposing, plant-pathogenic, and ectomycorrhizal (ECM) basidiomycetes. This review summarizes the current knowledge on plant polysaccharide depolymerization by basidiomycete species from diverse habitats. In addition, these data are compared to those for the most broadly studied ascomycete genus, Aspergillus, to provide insight into specific features of basidiomycetes with respect to plant polysaccharide degradation. 相似文献4.
Zahra-Beagom Mokhtari-Hosseini Ashrafalsadat Hatamian-Zarmi Jaber Mohammadnejad Bahman Ebrahimi-Hosseinzadeh 《Preparative biochemistry & biotechnology》2013,43(7):662-670
AbstractChitin and chitosan with unique properties and numerous applications can be produced from fungus. The production of chitin and chitosan from the mycelia of an Iranian Ganoderma lucidum was studied to improve cell growth and chitin productivity. Inoculum size and initial pH as two effective variables on the growth of G. lucidum and chitin production were optimized using response surface method (RSM) by central composite design (CCD). The results verified the significant effect of these two variables on the cell growth and chitin production. In optimum conditions, including pH?=?5.7 and inoculum size of 7.4%, the cell dry weight was 5.91?g/L and the amount of chitin production was 1.08?g/L with the productivity of 0.083?g/(L day). The produced chitin and chitosan were characterized using XRD and FTIR. Moreover, the antibacterial activity of the produced chitosan was investigated and compared with the commercial chitosan. The results showed that the produced chitin and chitosan had suitable quality and the Iranian G. lucidum would be a great source for safe and high-quality chitin and chitosan production. 相似文献
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N. I. Vasyukova G. I. Chalenko N. G. Gerasimova E. A. Perekhod O. L. Ozeretskovskaya A. V. Il’ina V. P. Varlamov A. I. Albulov 《Applied Biochemistry and Microbiology》2000,36(4):372-376
Water-soluble low-molecular-weight (3–10 kDa) chitosan obtained by enzymatic degradation of high-molecular-weight chitosan,
as well as its deaminated derivatives, can be used as elicitors of resistance to late blight in potato. 相似文献
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A method with the combined advantages of soil particle washing, selective inhibitors, and an indicator substrate was developed to isolate saprophytic basidiomycetes from soil. Organic particles were washed from soil and plated on a medium containing lignin, guaiacol, and benomyl, which reduced mold growth and allowed detection of basidiomycetes producing laccase or peroxidase. The 64 soil samples yielded 67 basidiomycete isolates, representing 51 groups on the basis of morphology and physiology. This method should facilitate investigations into the biodiversity of soil basidiomycetes and yield organisms that are useful in bioremediation of soils contaminated with pesticides or other recalcitrant aromatic compounds. 相似文献
9.
《Bioscience, biotechnology, and biochemistry》2013,77(2):440-441
Screening tests for aspartic proteinases with milk-clotting activity were done on basidiomycetes. Crude enzymes from 6 strains had a high ratio of milk-clotting activity to caseinolytic activity. These enzymes showed acidic pH optimum for proteolytic activity and were inhibited considerably by pepstatin, a specific aspartic proteinase inhibitor. Among them, the crude enzyme from Laetiporus sulphureus was more heat-labile than the other enzymes. 相似文献
10.
Pelletier A Lemire I Sygusch J Chornet E Overend RP 《Biotechnology and bioengineering》1990,36(3):310-315
Chitosan, the deacetylated derivative of chitin, was until recently produced by hydrolysis in 50% (w/v) NaOH. Application of thermo-mechano-chemical technology to chitin deacetylation was evaluated as an alternative method of chitosan production. This process consists of a cascade reactor unit operating under reduced alkaline conditions of 10% (w/v) NaOH. Prior mercerization of chitin at 4 degrees C for 24 h was required for high deacetylation yields. Sudden decompression of the aqueous alkaline suspension of mercerized chitin resulted in near complete deacetylation of chitin. Reactor residence time was 90 s at 230 degrees C prior to decompression. The chitosan produced was characterized by elemental analysis, (13)C-NMR and enzymatic depolymerization. Enzymatic determination of the degree of acetylation of chitin/chitosan mixtures was also investigated. Relative chitinase and/or chitosanase digestibilities were shown to be strongly dependent on chitin deacetylation. Based on enzymatic digestibilities, the alkaline aqueous high shear process does not appear to produce significant secondary products. Correlation of chitosanase digestibility with percentage of deacetylation provides a simple biological assay to study chitosan composition. 相似文献
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Costas Tsioptsias Chrysoula Michailof George Stauropoulos Costas Panayiotou 《Carbohydrate polymers》2009,76(4):535-540
Supercritical point drying of gels is a common technique for the production of a specific category of nano-porous materials called aerogels. We have successfully prepared chitin aerogels by extracting the solvent from the alcogels (gels with an alcohol as the solvent) with carbon dioxide under supercritical conditions. The produced nano-porous materials exhibit the typical properties of aerogels such as high porosity, high surface area, and low density, which make them quite attractive for many applications. The use of chitin, however, is of particular interest for the production of aerogels not only for being abundant and cheap but also because it has important inherent properties such as biocompatibility, non toxicity, thermal and chemical stability. In this work we examine the influence of different parameters on the porosity characteristics of the aerogels, such as the drying conditions (temperature and pressure), the nature of the solvent, and the gel concentration. Since these aerogels collapse in liquid medium, we also investigated the possibility of their utilization as carbon aerogel precursors. 相似文献
13.
S. V. Nemtsev O. Yu. Zueva M. R. Khismatullin A. I. Albulov V. P. Varlamov 《Applied Biochemistry and Microbiology》2004,40(1):39-43
A procedure of isolation of chitin, chitosan, and water-soluble low-molecular-weight chitosan from the corpses of bees has been developed. This procedure includes deproteinization of bee corpses, discoloration of the chitin–melanin complex, deacetylation, and enzymatic hydrolysis of chitosan. 相似文献
14.
Alarcón J Aguila S Arancibia-Avila P Fuentes O Zamorano-Ponce E Hernández M 《Zeitschrift für Naturforschung. C, Journal of biosciences》2003,58(1-2):62-64
Pleurotus ostreatus strains were cultured in liquid medium and on wheat straw. The yields of lovastatin were compared. 相似文献
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Smirnov SA Koroleva OV Gavrilova VP Belova AB Klyachko NL 《Biochemistry. Biokhimii?a》2001,66(7):774-779
Laccases from the Basidiomycetes Coriolus hirsutus, Coriolus zonatus, Cerrena maxima, and Coriolisimus fulvocinerea have been isolated and purified to homogeneity and partially characterized. The kinetics of oxidation of different methoxyphenolic compounds by the fungal laccases has been studied. As laccase substrates, such methoxyphenolic compounds as 4-hydroxy-3,5-dimethoxycinnamic acid (sinapinic acid), 4-hydroxy-3-methoxycinnamic acid (ferulic acid), and 2-methoxyphenol (guaiacol) were used. The stoichiometries of the enzymatic reactions were determined: guaiacol and sinapinic acid are one-electron donors and their oxidation apparently results in the formation of dimers. It was established that k
cat/K
m, which indicates the effectiveness of catalysis, increases in the series guaiacol, ferulic acid, and sinapinic acid. This fact might be connected with the influence of substituents of the phenolic ring of the substrates. This phenomenon was established for fungal laccases with different physicochemical properties, amino acid composition, and carbohydrate content. This suggests that all fungal laccases possess the same mechanism of interaction between organic substrate electron donors and the copper-containing active site of the enzyme and that this interaction determines the observed values of the kinetic parameters. 相似文献
17.
Kurita K 《Marine biotechnology (New York, N.Y.)》2006,8(3):203-226
Chitin and chitosan, typical marine polysaccharides as well as abundant biomass resources, are attracting a great deal of
attention because of their distinctive biological and physicochemical characteristics. To fully explore the high potential
of these specialty biopolymers, basic and application researches are being made extensively. This review deals with the fundamental
aspects of chitin and chitosan such as the preparation of chitin and chitosan, crystallography, extent of N-acetylation, and some properties. Recent progress of their chemistry is then discussed, focusing on elemental modification
reactions including acylation, alkylation, Schiff base formation and reductive alkylation, carboxyalkylation, phthaloylation,
silylation, tosylation, quaternary salt formation, and sulfation and thiolation. 相似文献
18.
TRACEY MV 《The Biochemical journal》1955,61(4):579-586
19.
Two new N-glucosylated indole alkaloids were isolated from fruiting bodies of the basidiomycete Cortinarius brunneus (Pers.) Fr. The structures were elucidated by means of the spectroscopic data. Additionally, the very recently reported compounds N-1-beta-glucopyranosyl-3-(carboxymethyl)-1H-indole (3) and N-1-beta-glucopyranosyl-3-(2-methoxy-2-oxoethyl)-1H-indole (4) could be detected. Compound 3 is the N-glucoside of the plant-growth regulator 1H-indole-3-acetic acid (IAA), but, in contrast, it does not exhibit auxin-like activity in an Arabidopsis thaliana tap root elongation assay. 相似文献
20.
Riviere T Diedhiou AG Diabate M Senthilarasu G Natarajan K Verbeken A Buyck B Dreyfus B Bena G Ba AM 《Mycorrhiza》2007,17(5):415-428
Ectomycorrhizal (ECM) fungi have a worldwide distribution. However, the ecology of tropical ECM fungi is poorly documented,
limiting our understanding of the symbiotic associations between tropical plants and fungi. ECM Basidiomycete diversity was
investigated for the first time in two tropical rain forests in Africa (Western Upper Guinea) and in Asia (Western Ghats,
India), using a fragment of the mitochondrial large subunit rRNA gene to type 140 sporocarps and 54 ectomycorrhizas. To evaluate
taxonomic diversity, phylogenetic analyses were performed, and 40 sequences included from identified European specimens were
used as taxonomic benchmarks. Five clades were recovered corresponding to six taxonomic groups: boletoids, sclerodermatoids,
russuloids, thelephoroids, and a clade grouping the Amanitaceae and Tricholomataceae families. Our results revealed that the
Russulaceae species display a great diversity with several putative new species, especially in Guinea. Other taxonomic issues
at family/section levels are also briefly discussed. This study provides preliminary insights into taxonomic diversity, ECM
status, and biogeographic patterns of ECM fungi in tropical two rain forest ecosystems, which appear to be as diverse as in
temperate and boreal forests. 相似文献