title: Biostimulation by methanol enables the methylotrophic yeasts Hansenula polymorpha and Trichosporon sp. to reveal high formaldehyde biodegradation potential as well as to adapt to this toxic pollutant.
abstract: The methylotrophic yeasts Hansenula polymorpha and Trichosporon sp. revealed enhanced biodegradation capability of exogenously applied formaldehyde (Fd) upon biostimulation achieved by the presence of methanol, as compared to glucose. Upon growth on either of the above substrates, the strains proved to produce the activity of glutathione-dependent formaldehyde dehydrogenase-the enzyme known to control the biooxidative step of Fd detoxification. However, in the absence of methanol, the yeasts' tolerance to Fd was decreased, and the elevated sensitivity was especially pronounced for Trichosporon sp. Both strains responded to the methanol and/or Fd treatment by increasing their unsaturation index (UI) at xenobiotic levels below minimal inhibitory concentrations. This indicated that the UI changes effected from the de novo synthesis of (poly) unsaturated fatty acids carried out by viable cells. It is concluded that the yeast cell response to Fd intoxication involves stress reaction at the level of membranes. Fluidization of the lipid bilayer as promoted by methanol is suggested as a significant adaptive mechanism increasing the overall fitness enabling to cope with the formaldehyde xenobiotic via biodegradative pathway of C1-compound metabolism.
authors: Faculty of Horticulture, University of Agriculture in Kraków, Al. 29 Listopada 54, 31-425 Krakow, Poland.
authors: Paweł
authors: P
authors: Kaszycki
authors: Tomasz
authors: T
authors: Walski
authors: Nancy
authors: N
authors: Hachicho
authors: Hermann J
authors: HJ
authors: Heipieper
mesh_terms: D001711:Biotransformation; D002462:Cell Membrane / Q000187:drug effects / Q000502:physiology; D004785:Environmental Pollutants / Q000378:metabolism / Q000633:toxicity; D005231:Fatty Acids, Unsaturated / Q000378:metabolism; D005557:Formaldehyde / Q000378:metabolism* / Q000633:toxicity; D005947:Glucose / Q000378:metabolism; D008560:Membrane Fluidity / Q000187:drug effects; D000432:Methanol / Q000378:metabolism*; D010843:Pichia / Q000187:drug effects* / Q000378:metabolism* / Q000502:physiology; D013312:Stress, Physiological; D014250:Trichosporon / Q000187:drug effects* / Q000378:metabolism* / Q000502:physiology
chemical_list: D004785:Environmental Pollutants; D005231:Fatty Acids, Unsaturated; D005557:Formaldehyde; D005947:Glucose; D000432:Methanol