Biodegradation of petroleum by bacteria isolated from fishes of Indian Ocean / Biodegradação do petróleo por bactérias isoladas de peixes do oceano Índico

In this study, oil degrading bacteria discovered from fish living near the oil ports at Karachi in Pakistan were characterized. The bacteria isolated from skin, gills, and gut in fish could consume crude oil as a source of carbon and energy. Total 36 isolates were tested using Nutrient Agar (NA) and MSA media with different crude oil concentrations (0.2%, 0.5%, 0.7%, 1%, 2%, and 5%) and 4 out of 36 isolates (two Gram positive and two Gram negative bacteria) were selected for further identification. 16S rRNA gene sequencing revealed that the isolates are related to Bacillus velezensis, Bacillus flexus, Pseudomonas brenneri and Pseudomonas azotoforman. Oil degrading potential of these bacteria was characterized by GC-MS analysis of degradation of oil components in crude oil as well as engine oil. We found that one (2, 6, 10, 14-Tetramethylpentadecane) out of 42 components in the crude oil was fully eliminated and the other oil components were reduced. In addition, 26 out of 42 oil components in the engine oil, were fully eliminated and the rest were amended. Taken together, these studies identify that B. velezensis, B. flexus, P. brenneri and P. azotoforman have high oil degrading potential, which may be useful for degradation of oil pollutants and other commercial applications.

Neste estudo, bactérias degradadoras de óleo descobertas em peixes que vivem perto dos portos de petróleo em Karachi, no Paquistão, foram caracterizadas. As bactérias isoladas da pele, guelras e intestinos dos peixes podem consumir petróleo bruto como fonte de carbono e energia. No total, 36 isolados foram testados usando Agar Nutriente (NA) e meio MSA com diferentes concentrações de óleo bruto (0,2%, 0,5%, 0,7%, 1%, 2% e 5%) e 4 de 36 isolados (dois Gram positivos e duas bactérias Gram negativas) foram selecionadas para posterior identificação. O sequenciamento do gene 16S rRNA revelou que os isolados estão relacionados a Bacillus velezensis, Bacillus flexus, Pseudomonas brenneri e Pseudomonas azotoforman. O potencial de degradação do óleo dessas bactérias foi caracterizado pela análise de GC-MS da degradação dos componentes do óleo no óleo cru, bem como no óleo do motor. Descobrimos que um (2, 6, 10, 14-tetrametilpentadecano) de 42 componentes do óleo cru foi totalmente eliminado e os outros componentes do óleo foram reduzidos. Além disso, 26 dos 42 componentes do óleo do motor foram totalmente eliminados e o restante corrigido. Juntos, esses estudos identificam que B. velezensis, B. flexus, P. brenneri e P. azotoforman têm alto potencial de degradação de óleo, o que pode ser útil para a degradação de poluentes de óleo e outras aplicações comerciais.

Remediación de residuos sólidos contaminados con Cr(vi) por un hongo filamentoso / Remediation of waste contaminated with Cr (VI) by a filamentous fungus

La biotecnología ambiental recurre a organismos capaces de reducir los niveles de metales pesados, entre ellos el Cr(VI), contenido en residuos y efluentes agroindustriales. El objetivo del trabajo fue estudiar la biorremediación de un residuo como pulpa de limón contaminada con Cr(VI) y el efecto del metal sobre el crecimiento fúngico. Se utilizaron tres hongos filamentosos como Aspergillus niger; Penicillium expansum y P. islandicum para remediar pulpa de limón (residuo) contaminada con Cr(VI) (50 mg/L) que se realizó en las siguientes condiciones de cultivo: la pulpa se suplementó con urea, 0,006; (NH4) 2SO4, 0,012; KH2PO4,0,003 y KCl, 0,001 g/ g; 105 conidios/g, a pH 2,5, 30°C y 96 h de incubación. Se estudió el efecto tóxico de diferentes concentraciones (5; 10; 20 y 50 mg/L) del metal sobre el desarrollo del hongo de mayor eficiencia de remediación (Ef. por ciento). Aspergillus niger; obtuvo mayor EF. de remediación (97 por ciento) respecto a Penicillium expansum (95 por ciento) y P. islandicum (94 por ciento), del residuo contaminado con 50 mg/L de Cr(VI). Se determinó que la presencia de Cr(VI) y no su concentración estimuló la maduración temprana (48 h) de los conidios (blancos a negros) de A. niger, sin que se observe alteraciones en el micelio con respecto al control (72h), desarrollado en la pulpa sin el metal. En conclusión, A. niger fue más resistente y presentó altas Ef. de remediación de Cr(VI) de residuos sólidos, este proceso es una alternativa a las tecnologías físico-químicas, debido que los microorganismos pueden remover selectivamente diferentes iones de zonas contaminadas.

Environmental biotechnology uses organisms capable of reducing levels of heavy metals, including the Cr (VI), contained in waste and agro-industrial effluents. The objective of this work was to study bioremediation of waste contaminated with Cr(VI) lemon pulp and the effect of the metal on the fungal growth. We used three filamentous fungi such as Aspergillus niger; Penicillium expansum and P. islandicum to remedy pulp from lemon (residue) contaminated with Cr(VI) (50 mg/L) that was conducted in the following conditions of cultivation: the pulp is supplemented with urea, 0.006; (NH4) 2SO4, 0.012; KH2PO4, 0.003 and KCl, 0.001 g / g; 105 conidia/g, at pH 2.5, 30 ° C and 96 h of incubation. We studied the toxic effect of different concentrations (5, 10, 20 and 50 mg/L) of the metal on the development of the fungus increased efficiency of remediation (Ef. percent). Aspergillus niger; obtained greater EF. remediation (97 percent) with respect to Penicillium expansum (95 percent) and P. islandicum (94 percent), 50 mg/L of Cr (VI)-contaminated waste. It was determined that the presence of Cr (VI) and not its concentration stimulated early maturation (48 h) of conidia (white on black) from A. niger, unless you observe alterations in the mycelium as compared to the control (72 h), developed in the pulp without the metal. In conclusion, A. niger was stronger and presented high Ef. remediation of Cr (VI) waste, this process is an alternative to physico-chemical technologies, due to the micro-organisms be removed selectively different ions from contaminated areas.

Selection of white-rot fungi to formulate complex and coated pellets for Reactive Orange 165 decolourization

Six strains of white-rot fungi isolated from southern Chile were evaluated for their ergosterol/biomass correlation and ligninolytic potential in solid medium to formulate pellets for Reactive Orange 165 (RO165) decolourization. The fungus Anthracophyllum discolor was selected to formulate complex pellets (fungal mycelium, sawdust, and activated carbon), coated pellets (complex pellet + alginate) and simple pellets (fungal mycelium). The activity of ligninolytic enzymes (laccase, manganese peroxidase, manganese-independent peroxidase, and lignin peroxidase) was evaluated in both the complex and coated pellets in modified Kirk medium, and the morphology of the pellets was studied using scanning electron microscopy (SEM). Complex pellets of A. discolor showed a higher enzymatic production mainly MnP (38 U L-1 at day 15) compared to coated and simple pellets. Examinations using SEM showed that both pellets produced a black core that was entrapped by a layer of fungal mycelium. Decolourization of RO165 was demonstrated with all the pellets formulated. However, the highest and fastest decolourization was obtained with complex pellets (100 percent at day 8). Therefore, complex pellets of A. discolor can be used for the biological treatment of wastewater contaminated with RO165.

XVIII Congreso Español de Toxicología / No disponible

No disponible