RESUMO
OBJECTIVES: Microalgae cell wall affects the recovery of lipids, representing one of the main difficulties in the development of biofuel production. This work aimed to test a new method based on melittin peptide to induce a cellular disruption in N. oleoabundans. RESULTS: Neochloris oleoabundans cells were grown at 32 °C in the presence of a high concentration of nitrate-phosphate, causing a cell disruption extent of 83.6%. Further, a two-fold increase in lipid recovery following melittin treatment and solvent extraction was observed. Additionally, it was possible to verify the effects of melittin, both before and after treatment on the morphology of the cells. Scanning electron microscopy (SEM) and confocal images of the melittin-treated microalgae revealed extensive cell damage with degradation of the cell wall and release of intracellular material. CONCLUSIONS: Melittin produced a selective cell wall rupture effect in N. oleoabundans under some culture conditions. These results represent the first report on the effect of melittin on lipid recovery from microalgae.
Assuntos
Clorófitas , Microalgas , Meliteno/farmacologia , Meliteno/metabolismo , Clorófitas/metabolismo , Peptídeos/metabolismo , LipídeosRESUMO
El objetivo del presente estudio fue evaluar la producción de blastosporas y conidios de diferentes aislados nativos de México del hongo entomopatógeno Isaria fumosorosea y de una cepa de colección mediante diferentes técnicas de propagación. En la producción de blastosporas se utilizaron 2 medios de cultivo líquidos (sumergidos), uno a base de casaminoácidos y el otro a base de peptona de colágeno como fuentes de nitrógeno, con glucosa como fuente de carbono en ambos. Para la producción de conidios, los hongos se cultivaron en agar papa dextrosa, a partir de esos cultivos se prepararon suspensiones de 1 x 10(6) conidios/ml para inocular matraces con caldo dextrosa Sabouraud, para iniciar así la fase líquida del cultivo bifásico, denominado también precultivo. Posteriormente con el precultivo y las suspensiones de conidios se inocularon bolsas con granos de arroz, que se incubaron durante 14 días para el cultivo bifásico y para la fermentación sólida, respectivamente. El aislado HIB-23 fue el que logró la más elevada concentración de blastosporas obtenida en el cultivo sumergido: 4,90 x 10(8) blastosporas/ml en el medio casaminoácidos; y en el medio con peptona de colágeno se obtuvieron 2,15 x 10(8) blastosporas/ml. La máxima producción de conidios en fermentación sólida la logró la cepa Pfr-612 (1,58 x 10(9) conidios/g), mientras que la máxima en cultivo bifásico correspondió al aislado HIB-30 (9,00 x 10(6) conidios/g). La fermentación sólida resultó ser el método más efectivo, con un promedio de 1,09 x 10(9) conidios/g, mientras que el cultivo bifásico fue el menos efectivo, con un promedio de 2,76 x 10(6) conidios/g. Para la producción de blastosporas en los medios sumergidos no se obtuvo diferencia significativa alguna.
The aim of this study was to evaluate the production of blastospores and conidia of different native isolates and a strain of Isaria fumosorosea using different propagation techniques. Two liquid culture media of casamino acids and peptone as nitrogen sources and glucose as carbon source for both media cultures were respectively used in the production of blastospores, while for the production of conidia, the fungi were grown in potato dextrose agar; from these cultures, solutions of conidia to a concentration of 1 x 10(6) per milliliter were prepared to inoculate flasks with Sabouraud dextrose broth for the liquid phase of the biphasic culture, also known as preculture. Subsequently, rice grain bags were inoculated with the preculture and the conidia solutions, which were incubated for 14 days for solid fermentation and biphasic culture, respectively. The HIB-23 isolate recorded a concentration of 4.90 x 10(8) blastospores/ml in the casamino acid medium, while a concentration of 2.15 x 10(8) blastospores/ml was obtained in the peptone collagen medium. For the Pfr-612 strain, the conidia production in solid-state fermentation was 1.58 x 10(9) conidia/g, and for HIB-30 in the biphasic culture of 9.00 x 10(6) conidia/g. Solid-state fermentation proved to be the most effective method with an average of 1.09 x 10(9) conidia/g, whereas the biphasic culture was the least effective method with 2.76 x 10(6) conidia/g; no significant difference was reported for the submerged production media.
Assuntos
Esporos Fúngicos , Hypocreales , Meios de Cultura , Fermentação , MéxicoRESUMO
The aim of this study was to evaluate the production of blastospores and conidia of different native isolates and a strain of Isaria fumosorosea using different propagation techniques. Two liquid culture media of casamino acids and peptone as nitrogen sources and glucose as carbon source for both media cultures were respectively used in the production of blastospores, while for the production of conidia, the fungi were grown in potato dextrose agar; from these cultures, solutions of conidia to a concentration of 1×106 per milliliter were prepared to inoculate flasks with Sabouraud dextrose broth for the liquid phase of the biphasic culture, also known as preculture. Subsequently, rice grain bags were inoculated with the preculture and the conidia solutions, which were incubated for 14 days for solid fermentation and biphasic culture, respectively. The HIB-23 isolate recorded a concentration of 4.90×108 blastospores/ml in the casamino acid medium, while a concentration of 2.15×108 blastospores/ml was obtained in the peptone collagen medium. For the Pfr-612 strain, the conidia production in solid-state fermentation was 1.58×109 conidia/g, and for HIB-30 in the biphasic culture of 9.00×106 conidia/g. Solid-state fermentation proved to be the most effective method with an average of 1.09×109 conidia/g, whereas the biphasic culture was the least effective method with 2.76×106 conidia/g; no significant difference was reported for the submerged production media.
Assuntos
Hypocreales , Esporos Fúngicos , Meios de Cultura , Fermentação , MéxicoRESUMO
In this work, we examined the production of infective zoospores of Lagenidium giganteum in four culture media, and the larvicidal activity of the cultures was determined against Aedes aegypti larvae, as well as the effect of polymer encapsulation. Medium containing sunflower seed extract showed the greatest production of zoospores, 5.92×10(6) zoospores/ml after six days of fermentation at 25±2°C and 150rpm shaking. This culture tested against A. aegypti 1st stage larvae caused different mortality rates at 24, 48 and 72h posttreatment. The LC(50) obtained was 43.9, 41.1 and 42.9µl of total culture/ml, at 24, 48 and 72h posttreatment respectively, while the culture grown in medium with soybean meal showed 3-5 times higher LC(50) values. Finally, the total culture including mycelium, zoospores and presporangia formulated with 2.5% pectin showed significantly higher mortality rates, around 100% more than the unformulated culture, whose values were from 40 to 1% at 3, 6, 9, and 12d posttreatment in the bioassays carried out in the laboratory to determine residual activity.
