Changes in the microbial community during bioremediation of gasoline-contaminated soil

Abstract

We aimed to verify the changes in the microbial community during bioremediation of gasoline-contaminated soil. Microbial inoculants were produced from successive additions of gasoline to municipal solid waste compost (MSWC) previously fertilized with nitrogen-phosphorous. To obtain Inoculant A, fertilized MSWC was amended with gasoline every 3 days during 18 days. Inoculant B received the same application, but at every 6 days. Inoculant C included MSWC fertilized with N–P, but no gasoline. The inoculants were applied to gasoline-contaminated soil at 10, 30, or 50 g/kg. Mineralization of gasoline hydrocarbons in soil was evaluated by respirometric analysis. The viability of the inoculants was evaluated after 103 days of storage under refrigeration or room temperature. The relative proportions of microbial groups in the inoculants and soil were evaluated by FAME. The dose of 50 g/kg of inoculants A and B led to the largest CO2 emission from soil. CO2 emissions in treatments with inoculant C were inversely proportional to the dose of inoculant. Heterotrophic bacterial counts were greater in soil treated with inoculants A and B. The application of inoculants decreased the proportion of actinobacteria and increased of Gram-negative bacteria. Decline in the density of heterotrophic bacteria in inoculants occurred after storage. This reduction was bigger in inoculants stored at room temperature. The application of stored inoculants in gasoline-contaminated soil resulted in a CO2 emission twice bigger than that observed in uninoculated soil. We concluded that MSWC is an effective material for the production of microbial inoculants for the bioremediation of gasoline-contaminated soil.

Mycobacterial Response to Organic Solvents and Possible Implications on Cross-Resistance With Antimicrobial Agents

“…However, the water solubility of MTBE, its high mobility in the environment and low biodegradability, has led to a widespread contamination of groundwater and soil ( Bonjar, 2005 ; Abbaspour et al, 2013 ). The encouragement for the use of ethanol as gasoline additive and as biofuel, made by several governments, also increased the number of ethanol-based fuel spills and environmental contamination with repercussions on microbial communities ( Nelson et al, 2010 ; Leal et al, 2017 ). The ability of Mycobacterium strains to degrade such compounds and their presence in contaminated soil ( Johnson et al, 2004 , Johnsen et al, 2007 ; Ohkubo et al, 2009 ) justifies the assessment of the adaptation of M. vaccae to these compounds.…”

Biorremediação De Solos E Águas Contaminados Com Hidrocarbonetos: Revisão De Literatura

“…Um desses acidentes foi em janeiro de 2012, um derramamento no mar ocasionado devido à uma operação de transbordo de uma monoboia da Transpetro, atingiu a praia em Tramandaí, RS. O acidente derramou cerca de 1,2 milhões de litros de óleo no mar (LEAL et al, 2016).…”

“…xilenos, são moléculas com alta toxicidade, pois eles possuem um potencial mutagênico, teratogênico e carcinogênico (LEAL et al, 2016). O benzeno, por exemplo, é considerado uma substância cancerígena e hemotóxica, essa classificação é decorrente de sua metabolização.…”

“…Os BTEX são moléculas lipossolúveis o que possibilita o aumento da continuidade desses compostos no meio ambiente, sendo assim, dificulta a biodegradação natural (LEAL et al, 2016).…”

Candida pseudoglaebosa and Kodamaea ohmeri are capable of degrading alkanes in the presence of heavy metals

“…Although bacteria are known to grow by using petroleum as the sole carbon source in the presence of HMs (Cd 2+ , Pb 2+ , As 2+ , and Hg 2+ ) , this characteristic has not been shown for yeasts. Nevertheless, fungal communities constitute a considerable portion of hydrocarbonoclastic microorganisms involved in the degradation of alkanes and aromatic hydrocarbons in soil polluted by petroleum products . Saccharomycetales yeasts have been frequently isolated from these environments, including Candida , Yarrowia , and Pichia .…”