title: Interfacial interaction between methyl parathion-degrading bacteria and minerals is important in biodegradation.
abstract: In the present study, the influence of kaolinite and goethite on microbial degradation of methyl parathion was investigated. We observed that the biodegradation process was improved by kaolinite and depressed by goethite. Calorimetric data further showed that the metabolic activities of degrading cells (Pseudomonas putida) were enhanced by the presence of kaolinite and depressed by the presence of goethite. A semipermeable membrane experiment was performed and results supported the above observations: the promotive effect of kaolinite and the inhibition of goethite for microbial degradation was not found when the bacteria was enclosed by semipermeable membrane and had no direct contact with these minerals, suggesting the important function of the contact of cellular surfaces with mineral particles. The relative larger particles of kaolinite were loosely attached to the bacteria. This attachment made the cells easy to use the sorbed substrate and then stimulated biodegradation. For goethite, small particles were tightly bound to bacterial cells and limited the acquisition of substrate and nutrients, thereby inhibiting biodegradation. These results indicated that interfacial interaction between bacterial cells and minerals significantly affected the biodegradation of pesticides.
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China.
authors.forename: Gang
authors.initials: G
authors.lastname: Zhao
authors.forename: Qiaoyun
authors.initials: Q
authors.lastname: Huang
authors.forename: Xingmin
authors.initials: X
authors.lastname: Rong
authors.forename: Peng
authors.initials: P
authors.lastname: Cai
authors.forename: Wei
authors.initials: W
authors.lastname: Liang
authors.forename: Ke
authors.initials: K
authors.lastname: Dai
mesh_terms: D000327:Adsorption; D001673:Biodegradation, Environmental / Q000187:drug effects; D001692:Biological Transport / Q000187:drug effects; D007306:Insecticides / Q000378:metabolism*; D058085:Iron Compounds / Q000494:pharmacology*; D007616:Kaolin / Q000494:pharmacology*; D007700:Kinetics; D008567:Membranes, Artificial; D008743:Methyl Parathion / Q000378:metabolism*; D008903:Minerals / Q000494:pharmacology*; D010316:Particle Size; D010539:Permeability; D016958:Pseudomonas putida / Q000187:drug effects* / Q000502:physiology; D013816:Thermodynamics
chemical_list: D007306:Insecticides; D058085:Iron Compounds; D008567:Membranes, Artificial; D008903:Minerals; C094886:goethite; D007616:Kaolin; D008743:Methyl Parathion