title: Time dependent influx and efflux of phenol by immobilized microbial consortium.
abstract: Phenol, like many other organic solvents, is toxic to micro-organisms even at low concentrations. However, some micro-organisms can withstand this toxicity to a certain concentration. To observe the uptake mechanism of phenol, bacteria were isolated from a petroleum refinery effluent and identified. Study was carried out to understand the effect of varying sub-lethal concentrations of phenol, on all the isolated individual bacterial cultures. Out of the bacteria isolated, Serratia liquefaciens was found to tolerate phenol concentration up to 1500 mg l(-1). A microbial consortium of the isolated bacteria was formulated and immobilized. Individual cultures were also immobilized and uptake of phenol by the immobilized micro-organisms was observed in a nutrient-rich and nutrient-stressed medium containing phenol as a sole source of carbon. A time-dependent uptake of phenol was exhibited by the micro-organisms in nutrient-stressed medium, after which a sudden increase in phenol concentration occurred in the extracellular medium, till it reached back to the initial concentration. This was attributed to an active efflux mechanism adopted by the micro-organisms to withstand the toxic shock.
authors.affiliation: Microbiology Division, Centre For Biochemical Technology Delhi University Campus, New Delhi, India.
authors.forename: Alka
authors.initials: A
authors.lastname: Sharma
authors.forename: Deepa
authors.initials: D
authors.lastname: Kachroo
authors.forename: Rita
authors.initials: R
authors.lastname: Kumar
mesh_terms: D000222:Adaptation, Physiological; D002244:Carbon / Q000378:metabolism; D004202:Disinfectants / Q000493:pharmacokinetics*; D007700:Kinetics; D019800:Phenol / Q000493:pharmacokinetics*; D012705:Serratia / Q000302:isolation & purification / Q000502:physiology*
chemical_list: D004202:Disinfectants; D019800:Phenol; D002244:Carbon