title: Quantifying mold biomass on gypsum board: comparison of ergosterol and beta-N-acetylhexosaminidase as mold biomass parameters.
abstract: Two mold species, Stachybotrys chartarum and Aspergillus versicolor, were inoculated onto agar overlaid with cellophane, allowing determination of a direct measurement of biomass density by weighing. Biomass density, ergosterol content, and beta-N-acetylhexosaminidase (3.2.1.52) activity were monitored from inoculation to stationary phase. Regression analysis showed a good linear correlation to biomass density for both ergosterol content and beta-N-acetylhexosaminidase activity. The same two mold species were inoculated onto wallpapered gypsum board, from which a direct biomass measurement was not possible. Growth was measured as an increase in ergosterol content and beta-N-acetylhexosaminidase activity. A good linear correlation was seen between ergosterol content and beta-N-acetylhexosaminidase activity. From the experiments performed on agar medium, conversion factors (CFs) for estimating biomass density from ergosterol content and beta-N-acetylhexosaminidase activity were determined. The CFs were used to estimate the biomass density of the molds grown on gypsum board. The biomass densities estimated from ergosterol content and beta-N-acetylhexosaminidase activity data gave similar results, showing significantly slower growth and lower stationary-phase biomass density on gypsum board than on agar.
authors.affiliation: Department of General Microbiology, University of Copenhagen, 2100 Copenhagen, Denmark. mreeslev@mycometer.dk
authors.forename: M
authors.initials: M
authors.lastname: Reeslev
authors.forename: M
authors.initials: M
authors.lastname: Miller
authors.forename: K F
authors.initials: KF
authors.lastname: Nielsen
mesh_terms: D000362:Agar; D001230:Aspergillus / Q000201:enzymology / Q000254:growth & development* / Q000378:metabolism; D018533:Biomass; D002133:Calcium Sulfate / Q000378:metabolism; D003252:Construction Materials; D003470:Culture Media; D004875:Ergosterol / Q000378:metabolism*; D009172:Mycology / Q000379:methods; D013191:Stachybotrys / Q000201:enzymology / Q000254:growth & development* / Q000378:metabolism; D001619:beta-N-Acetylhexosaminidases / Q000378:metabolism*
chemical_list: D003470:Culture Media; D000362:Agar; D001619:beta-N-Acetylhexosaminidases; D002133:Calcium Sulfate; D004875:Ergosterol