title: Study of the physiological characteristics of the medicinal mushroom Trametes pubescens (higher Basidiomycetes) during the laccase-producing process.
abstract: The study of the physiological characteristics of the medicinal mushroom Trametes pubescens was conducted under submerged cultures, suggesting that the laccase activity was positively correlated with oxidative level and culture conditions. Mycelial biomass and laccase activity in medium I were higher than those in medium II, which indicated that laccase activity was correlated with mycelium growth. The enhancement in mycelial biomass presented the logarithmic increase at days 6-8 and the peak value on the day 12 after inoculation. During liquid cultivation, increases in the amounts of malondialdehyde, hydrogen peroxide, and ascorbic acid were observed. In addition, the higher activities of superoxide dismutase and total antioxidative capacity still could be detected during this period. However, better ability to restrain hydroxyl free radical and catalase had a negative influence on laccase activity. It was evident that the fungal strain T. pubescens was under oxidative stress during the laccase-producing process. When the concentrations of H2O2 and Fe2+ were 3 and 30 mmol/L, respectively, the laccase activity reached to its peak at 37.21 U/L after a 14-day incubation period. It was concluded that a relationship between laccase synthesis and antioxidative capability existed in fungal cells, which could be regulated by reactive oxygen.
authors.affiliation: Institute of Microbiology, Beijing Forestry University, Beijing, People's Republic of China.
authors.forename: Jing
authors.initials: J
authors.lastname: Si
authors.forename: Bao-Kai
authors.initials: BK
authors.lastname: Cui
mesh_terms: D018533:Biomass; D002374:Catalase; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology*; D015966:Gene Expression Regulation, Fungal / Q000502:physiology*; D006861:Hydrogen Peroxide; D042845:Laccase / Q000378:metabolism*; D008315:Malondialdehyde; D018384:Oxidative Stress; D013482:Superoxide Dismutase; D055454:Trametes / Q000201:enzymology* / Q000502:physiology*
chemical_list: D008315:Malondialdehyde; D006861:Hydrogen Peroxide; D042845:Laccase; D002374:Catalase; D013482:Superoxide Dismutase