title: Surface tailored organobentonite enhances bacterial proliferation and phenanthrene biodegradation under cadmium co-contamination.
abstract: Co-contamination of soil and water with polycyclic aromatic hydrocarbon (PAH) and heavy metals makes biodegradation of the former extremely challenging. Modified clay-modulated microbial degradation provides a novel insight in addressing this issue. This study was conducted to evaluate the growth and phenanthrene degradation performance of Mycobacterium gilvum VF1 in the presence of a palmitic acid (PA)-grafted Arquad® 2HT-75-based organobentonite in cadmium (Cd)-phenanthrene co-contaminated water. The PA-grafted organobentonite (ABP) adsorbed a slightly greater quantity of Cd than bentonite at up to 30mgL(-1) metal concentration, but its highly negative surface charge imparted by carboxylic groups indicated the potential of being a significantly superior adsorbent of Cd at higher metal concentrations. In systems co-contained with Cd (5 and 10mgL(-1)), the Arquad® 2HT-75-modified bentonite (AB) and PA-grafted organobentonite (ABP) resulted in a significantly higher (72-78%) degradation of phenanthrene than bentonite (62%) by the bacterium. The growth and proliferation of bacteria were supported by ABP which not only eliminated Cd toxicity through adsorption but also created a congenial microenvironment for bacterial survival. The macromolecules produced during ABP-bacteria interaction could form a stable clay-bacterial cluster by overcoming the electrostatic repulsion among individual components. Findings of this study provide new insights for designing clay modulated PAH bioremediation technologies in mixed-contaminated water and soil.
authors: Future Industries Institute (formerly Centre for Environmental Risk Assessment and Remediation), University of South Australia, Mawson Lakes, SA 5095, Australia; Indian Council of Agricultural Research (ICAR), Indian Institute of Soil Science, Bhopal, India.
authors: Asit
authors: A
authors: Mandal
authors: Future Industries Institute (formerly Centre for Environmental Risk Assessment and Remediation), University of South Australia, Mawson Lakes, SA 5095, Australia; Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE), ACT Building, University of Newcastle, Callaghan, NSW 2308, Australia.
authors: Bhabananda
authors: B
authors: Biswas
authors: Future Industries Institute (formerly Centre for Environmental Risk Assessment and Remediation), University of South Australia, Mawson Lakes, SA 5095, Australia; Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE), ACT Building, University of Newcastle, Callaghan, NSW 2308, Australia. Electronic address: binoy.sarkar@unisa.edu.au.
authors: Binoy
authors: B
authors: Sarkar
authors: Indian Council of Agricultural Research (ICAR), Indian Institute of Soil Science, Bhopal, India.
authors: Ashok K
authors: AK
authors: Patra
authors: Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE), ACT Building, University of Newcastle, Callaghan, NSW 2308, Australia; Global Centre for Environmental Remediation (GCER), Faculty of Science and Information Technology, University of Newcastle, Callaghan, NSW 2308, Australia. Electronic address: ravi.naidu@newcastle.edu.au.
authors: Ravi
authors: R
authors: Naidu
mesh_terms: D001419:Bacteria / Q000378:metabolism*; D001546:Bentonite / Q000737:chemistry*; D001673:Biodegradation, Environmental; D002104:Cadmium / Q000032:analysis / Q000378:metabolism*; D010616:Phenanthrenes / Q000032:analysis / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000378:metabolism*
chemical_list: D010616:Phenanthrenes; D014874:Water Pollutants, Chemical; D002104:Cadmium; D001546:Bentonite
keywords: Bioremediation; Clay-bacterial interaction; Heavy metal; Modified clay; Polycyclic aromatic hydrocarbon (PAH)