title: Vibrating membrane filtration for recovery and concentration of insect killing nematodes.
abstract: New experimental data are reported that demonstrate the use of a novel vibrating membrane filter (VMF) for the combined recovery and concentration of two species of nematodes, S. feltiae and P. hermaphrodita, from mature liquid fermentation cultures. The disk membrane module had a working surface area of 0.2 m(2) and was operated at a constant flow rate of 0.2 m(3) h(-1). The recovery of the viable nematodes from the spent media and nonviable nematodes was assisted by an independently imposed oscillatory motion of the disk assembly, which produced an intense shear field at the membrane surface with calculated mean values on the order of 10(4) s(-1). Adult (nonviable) nematodes in the fermentation culture were preferentially dissolved in a detergent (sodium dodecylsulfate) and successfully separated from the juveniles using the VMF equipment. Permeate fluxes on the order of 15 to 30 L/m(2/)h were achieved for an operating transmembrane pressure of 800 mbar. Industrial-scale liquid fermentation for the manufacture of nematodes as biopesticides produces the viable nematode life stages in low-concentration suspension containing large quantities of spent media and other waste material. The VMF equipment provided a flexible operation for separation, cleaning, and concentration of viable nematodes from the fermentation broths.
authors.affiliation: Advanced Centre for Biochemical Engineering, Department of Biochemical Engineering, University College London, Torrington Place, London WC1E 7JE, United Kingdom. p.shamlou@ucl.ac.uk
authors.forename: J A
authors.initials: JA
authors.lastname: Wilson
authors.forename: J
authors.initials: J
authors.lastname: Postlethwaite
authors.forename: J D
authors.initials: JD
authors.lastname: Pearce
authors.forename: G
authors.initials: G
authors.lastname: Leach
authors.forename: G J
authors.initials: GJ
authors.lastname: Lye
authors.forename: P Ayazi
authors.initials: PA
authors.lastname: Shamlou
mesh_terms: D000818:Animals; D005285:Fermentation; D005374:Filtration / Q000295:instrumentation / Q000379:methods; D007313:Insecta / Q000472:pathogenicity*; D008567:Membranes, Artificial; D009348:Nematoda / Q000469:parasitology* / Q000502:physiology; D010572:Pest Control, Biological / Q000295:instrumentation / Q000379:methods; D014732:Vibration
chemical_list: D008567:Membranes, Artificial