title: Understanding the role of clay minerals in the chromium(VI) bioremoval by Pseudomonas aeruginosa CCTCC AB93066 under growth condition: microscopic, spectroscopic and kinetic analysis.
abstract: Laboratory batch experiments were conducted to investigate the role of clay minerals, e.g., kaolinite and vermiculite, in microbial Cr(VI) reduction by Pseudomonas aeruginosa under growth condition in glucose-amended mediums as a method for treating Cr(VI)-contaminated subsurface environment such as soil. Our results indicated that glucose could acted as an essential electron donor, and clay minerals significantly enhanced microbial Cr(VI) reduction rates by improving the consumption rate of glucose and stimulating the growth and propagation of P. aeruginosa. Cr(VI) bioreduction by both free cells and clay minerals-amended cells followed the pseudo-first-order kinetic model, with the latter one fitting better. The mass balance analyses and X-ray photoelectron spectroscopy analysis found that Cr(VI) was reduced to Cr(III) and the adsorption of total chromium on clay minerals-bacteria complex was small, implying that Cr(VI) bioremoval was not mainly due to the adsorption of Cr(VI) onto cells or clay minerals or clay minerals-cells complex but mainly due to the Cr(VI) reduction capacity of P. aeruginosa under the experimental conditions studied (e.g., pH 7). Atomic force microscopy revealed that the addition of clay minerals (e.g. vermiculite) decreased the surface roughness of Cr(VI)-laden cells and changed the cell morphology and dimension. Fourier transform infrared spectroscopy revealed that organic matters such as aliphatic species and/or proteins played an important role in the combination of cells and clay minerals. Scanning electron microscopy confirmed the attachment of cells on the surface of clay minerals, indicating that clay minerals could provide a microenvironment to protect cells from Cr(VI) toxicity and serve as growth-supporting materials. These findings manifested the underlying influence of clay minerals on microbial reduction of Cr(VI) and gave an understanding of the interaction between pollutants, the environment and the biota.
authors: School of Environment and Energy, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou, 510006, People's Republic of China.
authors: Chunxi
authors: C
authors: Kang
authors: School of Environment and Energy, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou, 510006, People's Republic of China. pppxwu@scut.edu.cn.|The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou, 510006, People's Republic of China. pppxwu@scut.edu.cn.|Guangdong Provincial Engineering and Technology Research Centre for Environmental Risk Prevention and Emergency Disposal, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou, 51006, People's Republic of China. pppxwu@scut.edu.cn.
authors: Pingxiao
authors: P
authors: Wu
authors: School of Environment and Energy, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou, 510006, People's Republic of China.
authors: Yuewu
authors: Y
authors: Li
authors: School of Environment and Energy, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou, 510006, People's Republic of China.
authors: Bo
authors: B
authors: Ruan
authors: School of Environment and Energy, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou, 510006, People's Republic of China.
authors: Liping
authors: L
authors: Li
authors: School of Environment and Energy, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou, 510006, People's Republic of China.|QuangBinh University, QuangBinh, Vietnam.
authors: Lytuong
authors: L
authors: Tran
authors: School of Environment and Energy, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou, 510006, People's Republic of China.|The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou, 510006, People's Republic of China.|Guangdong Provincial Engineering and Technology Research Centre for Environmental Risk Prevention and Emergency Disposal, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou, 51006, People's Republic of China.
authors: Nengwu
authors: N
authors: Zhu
authors: School of Environment and Energy, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou, 510006, People's Republic of China.|The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou, 510006, People's Republic of China.|Guangdong Provincial Engineering and Technology Research Centre for Environmental Risk Prevention and Emergency Disposal, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou, 51006, People's Republic of China.
authors: Zhi
authors: Z
authors: Dang
mesh_terms: D000538:Aluminum Silicates / Q000737:chemistry*; D061249:Batch Cell Culture Techniques; D001673:Biodegradation, Environmental; D002274:Carcinogens, Environmental / Q000378:metabolism; D002857:Chromium / Q000378:metabolism*; D000077215:Clay; D005947:Glucose / Q000378:metabolism; D007700:Kinetics; D018625:Microscopy, Atomic Force; D056951:Photoelectron Spectroscopy; D011550:Pseudomonas aeruginosa / Q000254:growth & development* / Q000378:metabolism / Q000648:ultrastructure; D012989:Soil Pollutants / Q000378:metabolism*
chemical_list: D000538:Aluminum Silicates; D002274:Carcinogens, Environmental; D012989:Soil Pollutants; D002857:Chromium; C074702:chromium hexavalent ion; D005947:Glucose; D000077215:Clay
keywords: Bioreduction; Bioremediation; Chromium(VI); Clay minerals; Pseudomonas aeruginosa