Phenolic compounds or phenols are a group of aromatic compounds that comprises a hydroxyl
group (OH) that is directly bonded to an aromatic ring. Phenols are injurious to organisms even
at even low concentrations with many of them are categorized as dangerous pollutants because of
their likely harm to human well-being. This review attempts to discuss the various merits and
demerits of immobilization matrices employed for phenol-degrading microorganisms’
immobilization. One of several key points of cellular immobilization is the capacity to protect
bioremediation agents towards toxic levels of specific toxicants and safeguarding from predatory
microorganisms. However, this shielding course of action should never impede the diffusion of
substrates into the pores of the immobilization structure. In the end the choice of a particular
immobilization method will strongly hinge on aspects of economy, safety and efficacy.
Most components of petroleum oily sludge (POS) are toxic, mutagenic and cancer-causing. Often bioremediation using microorganisms is hindered by the toxicity of POS. Under this circumstance, phytoremediation is the main option as it can overcome the toxicity of POS. Cajanus cajan a legume plant, was evaluated as a phyto-remediating agent for petroleum oily sludge-spiked soil. Culture dependent and independent methods were used to determine the rhizosphere microorganisms' composition. Degradation rates were estimated gravimetrically. The population of total heterotrophic bacteria (THRB) was significantly higher in the uncontaminated soil compared to the contaminated rhizosphere soil with C. cajan, but the population of hydrocarbon-utilizing bacteria (HUB) was higher in the contaminated rhizosphere soil. The results show that for 1 to 3% oily sludge concentrations, an increase in microbial counts for all treatments from day 0 to 90 d was observed with the contaminated rhizosphere CR showing the highest significant increase (p