title: Enhanced degradation of phenol by Sphingomonas sp. GY2B with resistance towards suboptimal environment through adsorption on kaolinite.
abstract: The effects of clay minerals on microbial degradation of phenol under unfavorable environmental conditions were investigated. Degradation of phenol by Sphingomonas sp. GY2B adsorbed on kaolinite, montmorillonite, and vermiculite were evaluated in comparison with free bacteria under optimal conditions. Kaolinite was found to be the most effective in accelerating degradation rate (reducing the degradation time) as well as improving degradation efficiency (increasing the percentage of phenol degraded), with GY2B/kaolinite complex achieving a degradation efficiency of 96% within 6 h. GY2B adsorbed on kaolinite was more competent than free GY2B in degradation under conditions with high phenol concentrations and at alkaline pH. Kaolinite reduced the time required for degradation by 8-12 h and improved the degradation efficiency by as much as 82% at high phenol concentrations. Meanwhile, the GY2B/kaolinite complex reduced the degradation time by 24 h and improved the degradation efficiency by 46% at pH 12. The improvement was partially due to the buffering effects of kaolinite. It was also shown that Cr(VI) and kaolinite synergistically enhanced the degradation by GY2B, with Cr(VI) and kaolinite both increasing the degradation rate and kaolinite being primarily responsible for enhanced degradation efficiency. These results showed one of the common clay minerals, kaolinite, is able to significantly improve the microbial degradation performance, and protect microorganisms against unfavorable environment. Kaolinite can collaborate with Cr(VI) to further improve the microbial degradation performance. It is implied that clay minerals have great potential to be applied in enhancing the biodegradation of phenol.
authors.affiliation: School of Environment and Energy, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou 510006, PR China.
authors.forename: Beini
authors.initials: B
authors.lastname: Gong
authors.affiliation: School of Environment and Energy, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou 510006, PR China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, Guangzhou 510006, PR China; Guangdong Provincial Engineering and Technology Research Centre for Environment Risk Prevention and Emergency Disposal, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou 510006, PR China. Electronic address: pppxwu@scut.edu.cn.
authors.forename: Pingxiao
authors.initials: P
authors.lastname: Wu
authors.affiliation: School of Environment and Energy, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou 510006, PR China.
authors.forename: Zhujian
authors.initials: Z
authors.lastname: Huang
authors.affiliation: School of Environment and Energy, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou 510006, PR China.
authors.forename: Yuewu
authors.initials: Y
authors.lastname: Li
authors.affiliation: School of Environment and Energy, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou 510006, PR China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, Guangzhou 510006, PR China.
authors.forename: Zhi
authors.initials: Z
authors.lastname: Dang
authors.affiliation: School of Environment and Energy, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou 510006, PR China.
authors.forename: Bo
authors.initials: B
authors.lastname: Ruan
authors.affiliation: School of Environment and Energy, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou 510006, PR China.
authors.forename: Chunxi
authors.initials: C
authors.lastname: Kang
authors.affiliation: School of Environment and Energy, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou 510006, PR China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, Guangzhou 510006, PR China; Guangdong Provincial Engineering and Technology Research Centre for Environment Risk Prevention and Emergency Disposal, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou 510006, PR China.
authors.forename: Nengwu
authors.initials: N
authors.lastname: Zhu
mesh_terms: D000327:Adsorption; D000538:Aluminum Silicates / Q000737:chemistry; D001546:Bentonite / Q000737:chemistry; D001673:Biodegradation, Environmental; D002857:Chromium / Q000737:chemistry*; D000077215:Clay; D004785:Environmental Pollutants / Q000032:analysis* / Q000378:metabolism; D007616:Kaolin / Q000737:chemistry*; D019800:Phenol / Q000032:analysis* / Q000378:metabolism; D010636:Phenols / Q000378:metabolism; D020578:Sphingomonas / Q000254:growth & development* / Q000378:metabolism
chemical_list: D000538:Aluminum Silicates; D004785:Environmental Pollutants; D010636:Phenols; D002857:Chromium; D001546:Bentonite; C003760:vermiculite; C074702:chromium hexavalent ion; D007616:Kaolin; D019800:Phenol; D000077215:Clay
keywords: Cr(VI); Kaolinite; Sphingomonas sp. GY2B; Substrate concentration; Synergy