Biosurfactant-Producing Denitrifying Bacteria in Marine Petroleum-Contaminated Environmental Sites

Denitrifying bacteria are ubiquitously distributed in marine ecosystems and especially widespread in hydrocarbon-contaminated systems. Their unique flexible respiratory mechanism and ability to degrade a broad range of aliphatic, aromatic, and polycyclic aromatic hydrocarbons enable them to withstand varying oxygen fluxes prevalent in oil-contaminated sites. This chapter emphasizes the significance of denitrifying bacteria in hydrocarbon-contaminated environments. It elucidates the various mechanisms adopted by denitrifying bacteria to degrade hydrocarbons including aliphatic, aromatic, and polycyclic aromatic hydrocarbons and adapt effectively to oxygen fluxes prevalent in petroleum-contaminated systems. In order to facilitate hydrocarbon degradation, denitrifying bacteria produce amphiphilic metabolites like biosurfactants and bioemulsifiers. Such surface-active compounds isolated from indigenous bacteria have received increasing interest over the past few decades due to their important applications in bioremediation projects designed to combat oil spills and in handling, transportation, and recovery of oil. This chapter focuses on the significance of biosurfactant-producing denitrifying bacteria in marine petroleum-contaminated sites for effective use in bioremediation studies.