title: Fermentative production of self-toxic fungal secondary metabolites.
abstract: Fungi are well known for their vast diversity of secondary metabolites that include many life-saving drugs and highly toxic mycotoxins. In general, fungal cultures producing such metabolites are immune to their toxic effects. However, some are known to produce self-toxic compounds that can pose production optimization challenges if the metabolites are needed in large amounts for chemical modification. One such culture, LV-2841, was identified as the lead for one of our exploratory projects. This culture was found to be a slow grower that produced trace amounts of a known metabolite, cercosporamide, under the standard flask fermentation conditions, and extensive medium optimization studies failed to yield higher titers. Poor growth of the culture in liquid media was attributed to the self-toxicity of cercosporamide to the producing organism, and the minimum inhibitory concentration (MIC) of cercosporamide was estimated to be in the range of 8-16 microg/ml. Fermentations carried out in media containing Diaion HP20 resin afforded significantly higher titers of the desired compound. While several examples of resin-based fermentations of soil streptomyces have been published, this approach has rarely been used for fungal fermentations. Over a 100-fold increase in the production titer of cercosporamide, a self-toxic secondary metabolite, was achieved by supplementing the production medium with a commercially available neutral adsorbent resin.
authors.affiliation: Biosynthetic Chemistry and Infectious Diseases, Chemical Sciences Division, Pfizer (Legacy Wyeth Research), 401 N. Middletown Road, Pearl River, NY 10965, USA. singhm@wyeth.com
authors.forename: Maya P
authors.initials: MP
authors.lastname: Singh
authors.forename: Margaret M
authors.initials: MM
authors.lastname: Leighton
authors.forename: Laurel R
authors.initials: LR
authors.lastname: Barbieri
authors.forename: Deborah M
authors.initials: DM
authors.lastname: Roll
authors.forename: Susan E
authors.initials: SE
authors.lastname: Urbance
authors.forename: Linda
authors.initials: L
authors.lastname: Hoshan
authors.forename: Leonard A
authors.initials: LA
authors.lastname: McDonald
mesh_terms: D000935:Antifungal Agents / Q000378:metabolism* / Q000633:toxicity*; D001572:Benzofurans / Q000378:metabolism* / Q000633:toxicity*; D003470:Culture Media / Q000737:chemistry; D005285:Fermentation; D005658:Fungi / Q000187:drug effects* / Q000378:metabolism*; D007475:Ion Exchange Resins / Q000378:metabolism; D008826:Microbial Sensitivity Tests; D011137:Polystyrenes / Q000378:metabolism
chemical_list: D000935:Antifungal Agents; D001572:Benzofurans; D003470:Culture Media; D007475:Ion Exchange Resins; D011137:Polystyrenes; C085452:cercosporamide; C065649:Diaion HP 20