Efeitos da remediação térmica na comunidade microbiana de um solo tropical contaminado com hidrocarbonetos
Arquivos
Data
2022-07-26
Autores
Penna, Daniel Di Pace Soares 
Orientadores
Nakayama, Cristina Rossi
Tipo
Trabalho de conclusão de curso
Título da Revista
ISSN da Revista
Título de Volume
Resumo
O desenvolvimento de estratégias de remediação eficientes e mais sustentáveis é um desafio para a sociedade. Dentre as estratégias de remediação empregadas, a remediação térmica, que mobiliza ou remove contaminantes por meio do aquecimento do solo, tem estado cada vez mais em evidência nos últimos anos. No entanto, a influência do aquecimento sobre a microbiota do solo ou o potencial de aplicação integrada da remediação térmica e a biorremediação ainda é pouco conhecido, principalmente em ambientes tropicais. Neste trabalho utilizamos métodos dependentes de cultivo e sequenciamento de alto desempenho do rRNA 16S para comparar a estrutura da comunidade microbiana de amostras de solo contaminadas com creosoto aquecidas a 60 °C e 100 °C em microcosmos, simulando faixas de baixa temperatura do gradiente de remediação térmica, com impacto esperado na microbiota, mas antes de sua inativação completa. O aquecimento a 60 °C reduziu a densidade de bactérias heterotróficas cultiváveis, mas as populações se recuperaram após 30 dias de incubação. O aquecimento a 100 °C inativou a comunidade heterotrófica viável. Burkholderia-Caballeronia-Paraburkholderia (BCP), Sphingobium, Clostridium-sensu-stricto-1 e Escherichia-Shigella foram os gêneros predominantes nos microcosmos. A 60 °C a abundância relativa de Sphingobium diminuiu e BCP mostrou maior dominância após 30 dias de incubação. Ambos os gêneros são conhecidos por serem capazes de degradar HPAs, mostrando que, mesmo com o impacto da temperatura talvez o solo possua redundância funcional e seja capaz de manter atividades degradantes. Concluímos que a biorremediação pode ser usada em faixas de temperatura para as quais a remediação térmica não remove ou degrada completamente os contaminantes
Development of remediation strategies with optimized efficiency and sustainability is a challenge. Among the remediation strategies available, thermal remediation, which mobilizes or removes contaminants through soil heating, has been increasingly in evidence in recent years. However, the influence of heating on soil microbiota or the potential for an integrated application of thermal and bioremediation is still poorly understood, especially in tropical environments. In this work we used culture dependent and high-throughput 16SrRNA sequencing methods to compare the microbial community structure of creosote contaminated soil samples heated at 60 °C and 100 °C in microcosms, simulating low temperature ranges of the thermal remediation gradient, with expected impact on the microbiota, but before its complete inactivation. Heating at 60 °C reduced the density of cultivable heterotrophic bacteria, but populations recovered after 30 days of incubation. Heating to 100 °C inactivated the viable heterotrophic community. Burkholderia-Caballeronia-Paraburkholderia (BCP), Sphingobium, Clostridium-sensu-stricto-1 and Escherichia-Shigella were the predominant genera in the microcosms. At 60 °C the relative abundance of Sphingobium decreased and BCP showed increased dominance after 30 days of incubation. Both genera are known to be capable of degrading PAHs, showing that, even with the impact of temperature, the soil may have functional redundancy and may maintain degrading activities. We concluded that bioremediation can be used in temperature ranges for which thermal remediation does not completely remove or degrade contaminants.
Development of remediation strategies with optimized efficiency and sustainability is a challenge. Among the remediation strategies available, thermal remediation, which mobilizes or removes contaminants through soil heating, has been increasingly in evidence in recent years. However, the influence of heating on soil microbiota or the potential for an integrated application of thermal and bioremediation is still poorly understood, especially in tropical environments. In this work we used culture dependent and high-throughput 16SrRNA sequencing methods to compare the microbial community structure of creosote contaminated soil samples heated at 60 °C and 100 °C in microcosms, simulating low temperature ranges of the thermal remediation gradient, with expected impact on the microbiota, but before its complete inactivation. Heating at 60 °C reduced the density of cultivable heterotrophic bacteria, but populations recovered after 30 days of incubation. Heating to 100 °C inactivated the viable heterotrophic community. Burkholderia-Caballeronia-Paraburkholderia (BCP), Sphingobium, Clostridium-sensu-stricto-1 and Escherichia-Shigella were the predominant genera in the microcosms. At 60 °C the relative abundance of Sphingobium decreased and BCP showed increased dominance after 30 days of incubation. Both genera are known to be capable of degrading PAHs, showing that, even with the impact of temperature, the soil may have functional redundancy and may maintain degrading activities. We concluded that bioremediation can be used in temperature ranges for which thermal remediation does not completely remove or degrade contaminants.