title: [Flocculating activity of Penicillium purpurogenum EL-02 and its flocculating activity].
abstract: OBJECTIVE
  To isolate, identify and characterize a fungus with flocculating activity.
  
  
  METHODS
  We used gradient dilution, plaque distribution and 18S rDNA analysis to isolate and identify a fungus with flocculating activity. We used high-speed centrifugation, ultrasonication and qualitative test to determine the nature of flocculating active substances.
  
  
  RESULTS
  We isolated a flocculating active fungi and identified it as Penicillium purpurogenum. Ultrasonication test confirmed that the flocculating activity was primarily in the fermentation supernatant. We explored the flocculating activity curve and found that 4 days was the optimum fermentation time for accumulating flocculating active substances. The strain flocculating activity remains unchanged when pH varied from 2 to 11 and temperature varied from -70 degrees C to 100 degrees C. We finally identified the flocculating active substances as saccharides.
  
  
  CONCLUSIONS
  We isolated a flocculating active strain P. purpurogenum EL-02, and identified its flocculating active products as saccharides.
authors.affiliation: Institute of Seawater Desalination and Multipurpose Utilization, SOA, Tianjin 300192, China. yushanzhang@hotmail.com
authors.forename: Yushan
authors.initials: Y
authors.lastname: Zhang
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
authors.forename: Jianan
authors.initials: J
authors.lastname: Hao
authors.forename: Xiuzhi
authors.initials: X
authors.lastname: Zhang
authors.forename: Yu
authors.initials: Y
authors.lastname: Cheng
mesh_terms: D050260:Carbohydrate Metabolism; D005285:Fermentation; D005427:Flocculation; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D010407:Penicillium / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D012988:Soil Microbiology; D013696:Temperature