Elucidated potential of immobilized Janibacter sp. for saline wastewater phenol removal

Phenolic compounds are commonly found in industrial effluents and can be hazardous to organisms even at low concentrations. Over the years, researchers have demonstrated that bioremediation is a cost-effective and environmentally friendly alternative to physicochemical approaches used to remove phenol. The aim of this study was to investigate the removal of phenol from saline wastewaters by a halotolerant strain of the genus Janibacter. For this purpose, bacterial cells were immobilized on different supports, from which mica and zeolite were ultimately chosen due to their higher removal efficiency. The wet weight of immobilized cells per 1 g of mica and zeolite was 0.51 and 0.48 g, respectively. Free cells consumed 100 mg/L of phenol in 88 h, while immobilized cells used it in 40 h. Immobilized cells revealed a higher thermostability and could operate over a wider pH range and salinity. Unlike free cells, immobilized cells could remove 700 mg/L of phenol and could be reused for at least nine cycles. Interestingly the phenol removal efficiency of zeolite-immobilized cells remained unchanged after 4 months of storage at 4 and - 20 degrees C, which could be of great advantage for industrial applications. Complete destruction of phenol was observed through the meta pathway comprising phenol hydroxylase and catechol 2,3-dioxygenase enzymes.

Automated summary

The study focused on using a halotolerant strain of the genus Janibacter to remove phenol from saline wastewaters, showing that bacterial cells immobilized on mica and zeolite had higher removal efficiency, better thermostability, wider operating range, and longer reuse potential. The process involved complete destruction of phenol through the meta pathway involving phenol hydroxylase and catechol 2,3-dioxygenase enzymes, with zeolite-immobilized cells showing consistent efficiency even after 4 months of storage at low temperatures.