Author/Editor     Lanišnik-Rižner, Tea; Romih, Rok
Title     Growth media effects on morphology and 17beta.HSD activity in the fungus Curvularia lunata
Type     članek
Source     Annals of microbiology
Vol. and No.     Letnik 57, št. 4
Publication year     2007
Volume     str. 635-43
ISSN     1590-4261
Language     eng
Abstract     The filamentous fungus Curvularia lunata has enzymatic activities of biotechnological significance. Its lla-hydroxylase activity produces hydrocortisone, and its 17-ketosteroid reductase (17beta-HSD) activity is important in the production of 17beta-hydroxysteroids. We have examined the effects of different media on the 17beta-HSD activity, and on the morphology and ultrastructure of C. lunata in the search for a correlation between high enzymatic activity, morphology and ultrastructure. The highest 17beta-HSD activity per dry weight of C, lunata was seen in Czapek medium, while more product per volume was formed in malt extract broth. In all growth media tested, the highest 17beta-HSD activity coincided with the exponential phase of growth. In Czapek broth medium, fungal hyphae formed pellets, while in malt extract and yeast nitrogen base broth media, the fungus formed branched hyphae dispersed throughout the media. Scanning electron microscopy revealed differences in the thickness of hyphal cells; those of the fungus grown in Czapek and yeast nitrogen base media were much thicker than those in malt extract medium. Transmission electron microscopy showed melanized cell walls in the fungus grown in malt extract and Czapek media, but not in yeast nitrogen base medium. Our results show that the C. lunata with the highest 17beta-HSD activity grow as dispersed, melanized mycelia with thin hyphae.
Descriptors     ASCOMYCETES
17-KETOSTEROIDS
OXIDOREDUCTASES
CULTURE MEDIA
MICROSCOPY, ELECTRON
POLYMERASE CHAIN REACTION