RESUMO
Bacterial degradation of crude oil is a promising strategy for reducing the concentration of hydrocarbons in contaminated environments. In the first part of this study, we report the enrichment of two bacterial consortia from deep sediments of the Gulf of Mexico with crude oil as the sole carbon and energy source. We conducted a comparative analysis of the bacterial community in the original sediment, assessing its diversity, and compared it to the enrichment observed after exposure to crude oil in defined cultures. The consortium exhibiting the highest hydrocarbon degradation was predominantly enriched with Rhodococcus (75%). Bacterial community analysis revealed the presence of other hydrocarbonoclastic members in both consortia. In the second part, we report the isolation of the strain Rhodococcus sp. GOMB7 with crude oil as a unique carbon source under microaerobic conditions and its characterization. This strain demonstrated the ability to degrade long-chain alkanes, including eicosane, tetracosane, and octacosane. We named this new strain Rhodococcus qingshengii GOMB7. Genome analysis revealed the presence of several genes related to aromatic compound degradation, such as benA, benB, benC, catA, catB, and catC; and five alkB genes related to alkane degradation. Although members of the genus Rhodococcus are well known for their great metabolic versatility, including the aerobic degradation of recalcitrant organic compounds such as petroleum hydrocarbons, this is the first report of a novel strain of Rhodococcus capable of degrading long-chain alkanes under microaerobic conditions. The potential of R. qingshengii GOMB7 for applications in bioreactors or controlled systems with low oxygen levels offers an energy-efficient approach for treating crude oil-contaminated water and sediments.
Assuntos
Petróleo , Rhodococcus , Petróleo/metabolismo , Golfo do México , Alcanos/metabolismo , Hidrocarbonetos/metabolismo , Rhodococcus/metabolismo , Biodegradação AmbientalRESUMO
Soil fungi were evaluated regarding their ability to degrade lignin-related compounds by producing the ligninolytic enzymes. Lignosulfonic and tannic acids were used as sole carbon sources during 30 days under microaerobic and very-low-oxygen conditions. The fungi produced lignin-peroxidase, manganese-peroxidase and laccase . Expressive degradations was observed by C18 reversed-phase HPLC, indicating the biodegradation potential of these fungi, showing more advantages than obligate anaerobes to decontaminate the environment when present naturally.
Fungos isolados de solo foram avaliados quanto à habilidade em degradarem compostos derivados de lignina pela produção de enzimas ligninolíticas. Os ácidos lignosulfônicos e tânico foram usados separadamente como única fonte de carobono para cultivo dos fungos em 30 dias sob condições microaeróbias. Os fungos foram capazes de crescer e usar tais compostos como fonte de carbono e mostraram produção de lignina-peroxidase, manganês-peroxidase e lacase. Degradações expressivas dos ácidos lignosulfônico e tânico foram verificadas por Cromatografia Liquida de Alta Eficiência (CLAE), indicando grande potencial de uso em processos de biorremediação de macromoléculas aromáticas similares à lignina em ambientes naturais sob condições baixas de oxigenação.