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1.
Folia Microbiol (Praha) ; 63(4): 467-478, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29423709

RESUMO

Efficient hydrolysis of holocellulose depends on a proper balance between cellulase (endoglucanase, exoglucanase, ß-glucosidase) and xylanase activities. The present study aimed to induce the production of cellulases and xylanases using liquid cultures (one, two, three, and four fungal strains on the same bioreactor) of wild strains of Trichoderma harzianum, Aspergillus niger, and Fusarium oxysporum. The strains were identified by amplification and analysis of the ITS rDNA region and the obtained sequences were deposited in Genbank. Enzymes (endoglucanase, exoglucansae, ß-glucosidase, and xylanase activities) and the profile of extracellular protein isoforms (SDS-PAGE) produced by different fungal combinations (N = 14) were analyzed by Pearson's correlation matrix and principal component analysis (PCA). According to our results, induction of endoglucanase (19.02%) and ß-glucosidase (6.35%) were obtained after 4 days when A. niger and F. oxysporum were cocultured. The combination of A. niger-T. harzianum produced higher endoglucanase in a shorter time than monocultures. On the contrary, when more than two strains were cultured in the same reactor, the relationships of competition were established, trending to diminish the amount of enzymes and the extracellular protein isoforms produced. The xylanase production was sensible to stress produced by mixed cultures, decreasing their activity. This is important when the aim is to produce cellulase-free xylanase. In addition, exoglucanase activity did not change in the combinations tested.


Assuntos
Ascomicetos/crescimento & desenvolvimento , Ascomicetos/metabolismo , Reatores Biológicos/microbiologia , Celulases/biossíntese , Técnicas de Cocultura , Microbiologia Industrial/métodos , Ascomicetos/enzimologia , Ascomicetos/isolamento & purificação , Aspergillus niger/enzimologia , Aspergillus niger/crescimento & desenvolvimento , Aspergillus niger/isolamento & purificação , Aspergillus niger/metabolismo , Biomassa , Celulases/metabolismo , Celulose/metabolismo , Fermentação , Proteínas Fúngicas/biossíntese , Proteínas Fúngicas/metabolismo , Fusarium/enzimologia , Fusarium/crescimento & desenvolvimento , Fusarium/isolamento & purificação , Fusarium/metabolismo , Interações Microbianas/fisiologia , Trichoderma/enzimologia , Trichoderma/crescimento & desenvolvimento , Trichoderma/isolamento & purificação , Trichoderma/metabolismo , Xilosidases/biossíntese , Xilosidases/metabolismo
2.
Appl Microbiol Biotechnol ; 101(3): 1189-1201, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27743044

RESUMO

The use of synthetic dyes for laccase induction in vivo has been scarcely explored. We characterized the effect of adding different synthetic dyes to liquid cultures of Pycnoporus sanguineus on laccase production. We found that carminic acid (CA) can induce 722 % and alizarin yellow 317 % more laccase than control does, and they promoted better fungal biomass development in liquid cultures. Aniline blue and crystal violet did not show such positive effect. CA and alizarin yellow were degraded up to 95 % during P. sanguineus culturing (12 days). With this basis, CA was selected as the best inducer and used to evaluate the induction of laccase on solid-state fermentation (SSF), using sugarcane bagasse (SCB) as substrate, in an attempt to reach selective delignification. We found that laccase induction occurred in SSF, and a slight inhibition of cellulase production was observed when CA was added to the substrate; also, a transformation of SCB under SSF was followed by the 13C cross polarization magic angle spinning (CPMAS) solid-state nuclear magnetic resonance (NMR). Results showed that P. sanguineus can selectively delignify SCB, decreasing aromatic C compounds by 32.67 % in 16 days; O-alkyl C region (polysaccharides) was degraded less than 2 %; delignification values were not correlated with laccase activities. Cellulose-crystallinity index was increased by 27.24 % in absence of CA and 15.94 % when 0.01 mM of CA was added to SCB; this dye also inhibits the production of fungal biomass in SSF (measured as alkyl C gain). We conclude that CA is a good inducer of laccase in liquid media, and that P. sanguineus is a fungus with high potential for biomass delignification.


Assuntos
Celulose/metabolismo , Corantes/farmacologia , Lacase/biossíntese , Lignina/metabolismo , Pycnoporus/efeitos dos fármacos , Pycnoporus/enzimologia , Compostos Azo/metabolismo , Compostos Azo/farmacologia , Biomassa , Carmim/metabolismo , Carmim/farmacologia , Corantes/metabolismo , Meios de Cultura/química , Indução Enzimática , Fermentação , Lacase/metabolismo , Pycnoporus/metabolismo
3.
Folia Microbiol (Praha) ; 61(2): 137-42, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26233233

RESUMO

The aim was to determine which specific regions of the visible light spectrum were responsible for the induction or inhibition of laccase in Pycnoporus sanguineus. Cultures were exposed to various bandwidth lights: blue (460 nm), green (525 nm), white (a combination of 460 and 560 nm), red (660 nm), and darkness. The results indicate that short wavelengths strongly inhibit the production of laccase: green (3.76 ± 1.12 U/L), blue (1.94 ± 0.36 U/L), and white (1.05 ± 0.21 U/L) in proportions of 85.8, 92.6, and 96.0%, respectively; whereas long wavelengths inhibit laccase production only partially i.e., red light (14.05 ± 4.79 U/L) in a proportion of 46.8%. Maximum activity was induced in absence of visible light (30 °C, darkness), i.e., 30.76 ± 4.0 U/L. It is concluded that the production of laccase in P. sanguineus responds to light stimuli [measured as wavelengths and lx] and that it does so inversely. This can be explained as an ecological mechanism of environmental recognition, given that P. sanguineus develops inside lignocellulose structures in conditions of darkness. The presence of short wavelength light (460-510 nm) would indicate that the organism finds itself in an external environment, unprovided of lignin, and that it is therefore unnecessary to secrete laccase. This possible new regulation in the laccase production in P. sanguineus has important biotechnological implications, for it would be possible to control the production of laccase using light stimuli.


Assuntos
Proteínas Fúngicas/antagonistas & inibidores , Lacase/antagonistas & inibidores , Pycnoporus/enzimologia , Pycnoporus/efeitos da radiação , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Lacase/genética , Lacase/metabolismo , Luz , Pycnoporus/genética
4.
Electron. j. biotechnol ; 18(4): 327-332, July 2015. graf, tab
Artigo em Inglês | LILACS | ID: lil-757872

RESUMO

Background Ethanol has been pointed out as a laccase inducer. However, there are controversial reports about its efficiency with some fungi. In this study, we hypothesized that ethanol laccase induced in Pycnoporus sanguineus depends on nitrogen nutriment conditions. To prove this, we assessed laccase production in submerged cultures of P. sanguineus, with different nitrogen concentrations and with, or without ethanol added in a factorial designed experiment. Results In order to analyze the effects of factors on the response variables, a factorial ANOVA, and response-surface models were performed. It was found that the nitrogen source was the main factor that affected laccase production in P. sanguineus. The treatments with yeast extract (2 g/L) and ethanol (3 g/L) induced the highest laccase activity (31.01 ± 4.9 U/L), while the treatments with urea reached the lowest activity (less than 1.6 U/L). Ethanol had positive and synergic effects on laccase production, in accordance with the surface response model, as long as simple nitrogen sources (urea) were not available. Conclusions We suggest that laccase in P. sanguineus is regulated by a catabolic nitrogen repression mechanism; laccase activity is strongly inhibited by urea used as nitrogen source and it decreases when the amount of urea increases; contrarily, a synergic positive effect was observed between yeast extract and ethanol on laccase production.


Assuntos
Lacase/biossíntese , Etanol/metabolismo , Pycnoporus/enzimologia , Nitrogênio/análise , Leveduras , Análise de Variância , Monofenol Mono-Oxigenase , Etanol/análise
8.
Washington, D.C; Pan Américan Health Organization; 1996. s.p (PAHO. Scientific Públication, 560).
Monografia em Inglês | LILACS | ID: lil-377016
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