RESUMO
This study was conducted to report the richness of endophytic Penicillium and Talaromyces species isolated from Tillandsia catimbauensis, a bromeliad endemic in the Brazilian tropical dry forest (Caatinga), to verify their ability to produce the enzyme L-asparaginase and to partially optimise the production of biomass and L-asparaginase of the best enzyme producer. A total of 184 endophytes were isolated, of which 52 (29%) were identified through morphological and phylogenetic analysis using ß-tubulin sequences into nine putative species, four in Penicillium and five in Talaromyces. Talaromyces diversus and T. cf. cecidicola were the most frequent taxa. Among the 20 endophytic isolates selected for L-asparaginase production, 10 had the potential to produce the enzyme (0.50-2.30 U/g), especially T. cf. cecidicola URM 7826 (2.30 U/g) and Penicillium sp. 4 URM 7827 (1.28 U/g). As T. cf. cecidicola URM 7826 exhibited significant ability to produce the enzyme, it was selected for the partial optimisation of biomass and L-asparaginase production. Results of the 23 factorial experimental design showed that the highest dry biomass (0.66 g) was obtained under pH 6.0, inoculum concentration of 1 × 108 and 1% L-proline. However, the inoculum concentration was found to be statistically significant, the pH was marginally significant and the concentration of L-proline was not statistically significant. L-Asparaginase production varied between 0.58 and 1.02 U/g and did not reach the optimal point for enzyme production. This study demonstrates that T. catimbauensis is colonised by different Penicillium and Talaromyces species, which are indicated for enzyme production studies.
Assuntos
Asparaginase/biossíntese , Endófitos/enzimologia , Proteínas Fúngicas/biossíntese , Penicillium/enzimologia , Talaromyces/enzimologia , Tillandsia/microbiologia , Asparaginase/genética , Brasil , Endófitos/genética , Endófitos/isolamento & purificação , Florestas , Proteínas Fúngicas/genética , Penicillium/genética , Penicillium/isolamento & purificação , Filogenia , Talaromyces/genética , Talaromyces/isolamento & purificaçãoRESUMO
The petroleum hydrocarbon contamination represents a worldwide problem, since its accumulation promotes a serious environmental impact. Thereby, the use of microorganisms, such as those from mangrove micro biota, as degrading agents of various carbon sources is poorly exploited in environmental remediation processes. Thus, this in vitro study evaluated the degrading potential of isolated bacteria from mangrove sediments in the degradation of petroleum hydrocarbons. Analysis of the genetic diversity using the 16S rRNA marker revealed closely related (99%) sequences with Proteobacterium, Pseudomonas and Exiguobacterium. Results showed the bacterial growth in the mineral saline medium (MSM) containing 1% petroleum or diesel, as carbon sources. This growth was determinated by optical density at 595 nm for 15 days, with sample withdrawal every 48 h. Bacterial growth indicated the hydrocarbon metabolization. However, bacteria were more efficient at degrading petroleum. Overall, experimental data displayed the potential application of these bacteria in bioremediation processes, due to their metabolic and adaptive capacities to grow in a rich hydrocarbon medium.
Los hidrocarburos de petróleo representan un problema mundial, pues su acumulación promueve un serio impacto ambiental. Así, el uso de microorganismos, por ejemplo los de la microbiota de manglares, como agentes degradadores de diversas fuentes de carbono, es poco explotado en procesos de remediación ambiental. Así, este estudio evaluó in vitro el potencial degradador de bacterias aisladas de sedimento de manglar en la degradación de hidrocarburos. El análisis genético usando el marcador 16S rRNA reveló secuencias íntimamente relacionadas (99%) con Proteobacterium, Pseudomonas y Exiguobacterium. Los resultados mostraron el crecimiento de bacterias en medio salino mineral (MSM) conteniendo petróleo o diesel al 1%, como fuentes de carbono. Este crecimiento, determinado por densidad óptica (DO) a 595 nm durante 15 días, con toma de muestras a cada 48 h, indicó la matabolización de hidrocarburos. Sin embargo, las bacterias fueron más eficientes en degradarlos. Por lo tanto, los resultados muestran la potencial aplicación de las bacterias en procesos de biorremediación por su capacidad metabólica y adaptativa de crecimiento usando hidrocarburos.
