title: The development of a liquid formulation of Pseudoxanthomonas sp. RN402 and its application in the treatment of pyrene-contaminated soil.
abstract: OBJECTIVE
  To develop a liquid formulation of Pseudoxanthomonas sp. RN402 for prolonged storage and maintaining high survival rates and pyrene biodegradability.
  
  
  RESULTS
  Liquid formulations of RN402, designated as L-RN402, were prepared by suspending bacterial cells (10⁹ CFU ml⁻¹) in various buffers. Analysis found that phosphate buffer containing glycerol maintained high survival rate (94%) as well as pyrene biodegradability of bacteria after a 30-day storage. This L-RN402 could be stored at 30°C for at least 6 months. Bioaugmentation treatment with stored L-RN402 resulted in the complete degradation of pyrene (300 mg kg⁻¹) in soil microcosms within 4 weeks. RN402 could be detected by denaturing gradient gel electrophoresis throughout the period; moreover, real-time PCR indicated the presence of high number of nidA-containing bacteria.
  
  
  CONCLUSIONS
  A liquid formulation of RN402, an effective pyrene degrader, was developed by suspending RN402 in phosphate buffer containing 1% glycerol. This formulation could be stored at 30°C for at least 6 months and maintain high efficacy in the treatment of pyrene-contaminated soil.
  
  
  CONCLUSIONS
  This work is the first description of a liquid formulation of pyrene-degrading bacteria for prolonged storage that retains biological activity for the treatment of environmental pollutants.
authors.affiliation: Inter-department of Environmental Science, Graduate School, Chulalongkorn University, Bangkok, Thailand.
authors.forename: W
authors.initials: W
authors.lastname: Nopcharoenkul
authors.forename: P
authors.initials: P
authors.lastname: Pinphanichakarn
authors.forename: O
authors.initials: O
authors.lastname: Pinyakong
mesh_terms: D001673:Biodegradation, Environmental; D058645:Denaturing Gradient Gel Electrophoresis; D004785:Environmental Pollutants / Q000378:metabolism; D050296:Microbial Viability; D016133:Polymerase Chain Reaction; D011309:Preservation, Biological / Q000379:methods*; D011721:Pyrenes / Q000378:metabolism*; D012988:Soil Microbiology; D044166:Xanthomonadaceae / Q000502:physiology*
chemical_list: D004785:Environmental Pollutants; D011721:Pyrenes; C030984:pyrene