title: Optimization of a medium for enhancing nicotine biodegradation by Ochrobactrum intermedium DN2.
abstract: OBJECTIVE
  To optimize a medium for nicotine degradation by Ochrobactrum intermedium DN2 in presence of yeast extract, glucose and Tween 80 using response surface methodology (RSM).
  
  
  RESULTS
  In this study, the effects of yeast extract, glucose and Tween 80 on nicotine degradation were investigated in flasks using a novel nicotine-degrading bacterium, O. intermedium DN2. A full factorial central composite design was applied in the design of experiments and in the analysis of the experimental data. The results showed that the most significant variable influencing nicotine degradation was yeast extract, followed by glucose, and then Tween 80. Moreover these three factors interacted with each other and combined to produce positive effects on nicotine degradation. The experimental data also allowed the development of an empirical model (P < 0.0001) describing the inter-relationship between independent and dependent variables. By solving the regression equation, the optimal values of the variables were determined as: yeast extracts 0.094%, glucose 0.101% and Tween 80 0.080%. Using the medium obtained, about 1,220 mg l(-1) of nicotine was degraded (95.55%) within 10 h at the specific biodegradation of 116.59 mg l(-1) h(-1) in 30-l bioreactor containing 25-l tobacco extract.
  
  
  CONCLUSIONS
  An optimal medium of nicotine degradation by the strain DN2 was obtained.
  
  
  CONCLUSIONS
  RSM proved to be reliable in developing the model, optimizing factors and analysing interaction effects. The results provide better understanding on the interactions between yeast extract, glucose and Tween 80 for nicotine biodegradation.
authors.affiliation: College of Food Science and Technology, Nanjing Agricultural University, Key Laboratory of Food Processing and Quality Control of Ministry of Agriculture, Nanjing, China.
authors.forename: Y J
authors.initials: YJ
authors.lastname: Yuan
authors.forename: Z X
authors.initials: ZX
authors.lastname: Lu
authors.forename: L J
authors.initials: LJ
authors.lastname: Huang
authors.forename: X M
authors.initials: XM
authors.lastname: Bie
authors.forename: F X
authors.initials: FX
authors.lastname: Lü
authors.forename: Y
authors.initials: Y
authors.lastname: Li
mesh_terms: D001673:Biodegradation, Environmental; D003470:Culture Media; D005947:Glucose / Q000494:pharmacology; D008954:Models, Biological; D009538:Nicotine / Q000032:analysis / Q000378:metabolism*; D018722:Nicotinic Agonists / Q000378:metabolism; D042041:Ochrobactrum / Q000378:metabolism*; D011136:Polysorbates / Q000494:pharmacology; D013501:Surface-Active Agents / Q000494:pharmacology; D015003:Yeasts / Q000378:metabolism
chemical_list: D003470:Culture Media; D018722:Nicotinic Agonists; D011136:Polysorbates; D013501:Surface-Active Agents; D009538:Nicotine; D005947:Glucose