Characterization of Target Organisms from Environmental Origin for Rapid Bioremediation of Hexamine

Abstract

The non-aromatic, heterocyclic hexamine is one of the most refractory pollutants in some industrial effluents and food-grade plastics. This compound and its derivatives harm human health with limited options for eco-friendly biological treatment. This study reports the characterization of two rapid hexamine-removing bacterial isolates, Micromonospora citrea SRCHD01 and Micrococcus luteus SRCHD02, from wastewater of Hexamine producing plant at Vishakapatnam, India. The former is a structured biofilm former while the latter is a weak biofilm former with both isolates dividing faster under immobilized conditions. Isolate SRCHD01 could reduce 200 mg/L hexamine to 84.91 mg/L in 24 h with associated Chemical Oxygen Demand (COD) reduction of 99% from an initial concentration of 8028.93 mg/L within 120 h, making it the fastest hexamine-removing bacteria reported till date. The investigation opens a new avenue for studying the bioremediation of hexamine in biofilm reactors ensuring environmental protection.

Keywords:

• Hexamine
• doubling time
• immobilization
• chemical oxygen demand
• bioremediation

Acknowledgements

The authors acknowledge Tripura University for providing the necessary infrastructure for conducting the experiments including the Scanning Electron Microscopy at its Central Instrumentation Centre. The authors acknowledge Prof. Lalit Mohan Gantayet for suggesting to work on hexamine removal and contacting the industry for the effluent; Mr Rajesh Madhogaria of Kanoria Chemicals and Industries Limited, Visakhapatnam, India for arranging for industrial sample collection and providing the baseline data on the wastewater collected; Prof Ashoke Ranjan Thakur for collecting the sample from Vishakhapatnam and transporting to Kolkata. The authors also acknowledge the project trainees of Department of Microbiology of Tripura University who have been associated with different parts of the work.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The fellowship of the research scholar was supported by University Grants Commission- Department of Atomic Energy, Government of India under the CRS scheme [UGC-DAE-CSR-KC/CRS/19/TE07/1069/1085 dt 10.05.2019] during the tenure of the work.