Microbial Degradation of Recalcitrant PAHs-Microbial Diversity Involving Remediation Process

Abstract

Domestic pollutants, largely due to population explosion and industrial inputs lead to the accumulation of various types of recalcitrant xenobiotic compounds (Hadibarata et al. 2009; Igwo-Ezikpe et al. 2010). As majority of them persist for longer period of time and are carcinogenic in nature, their disposal is a matter of global concern (Jain et al. 2005). Primarily, xenobiotic compounds are anonymous to living organisms and also have a tendency to get accumulated in the environment (Sinha et al. 2009). They encompass pesticides, fuels, solvents, alkanes, synthetic azo dyes, polyaromatic, nitroaromatic, chlorinated and polycyclic hydrocarbons. Amongst them, the presence of polycyclic aromatic hydrocarbons (PAHs) in the environment causes acute health hazard with their intrinsic chemical stability, high recalcitrance ability against different types of degradation and high toxicity to living organisms for their mutagenic or carcinogenic properties (Zhang et al. 2006). Apart from it, they are ubiquitous and prevail as persistent bioaccumulative toxins (PBT) (NiChadhain et al. 2006). For instance, phenanthrene, a lipophilic and relatively insoluble in water, is skin photosensitizer and mild allergenic to human (Hafez et al. 2008). It is also found as an inducer of the sister chromatid exchange process (Popp et al. 1997) and a potent inhibitor of gap-junction intercellular communications (Bláha et al. 2002).