Metabolite repression inhibits degradation of benzo[a]pyrene and dibenz[a,h]anthracene by Stenotrophomonas maltophilia VUN 10,003.
Large inocula of Stenotrophomonas maltophilia VUN 10,003 were used to investigate bacterial degradation of benzo[a]pyrene and dibenz[a,h]anthracene. Although strain VUN 10,003 was capable of degrading 10-15 mg (-1) of the five-ring compounds in the presence of pyrene after 63 days, further addition of pyrene after degradation of the five-ring polycyclic aromatic hydrocarbons (PAHs) ceased did not stimulate significant decreases in the concentration of benzo[a]pyrene or dibenz[a,h]anthracene. However, pyrene was degraded to undetectable levels 21 days after its addition. The amount of benzo[a]pyrene and dibenz[a,h]anthracene degraded by strain VUN 10,003 was not affected by the initial concentration of the compounds when tested at 25-100 mg l(-1), by the accumulation of by-products from pyrene catabolism or a loss of ability by the cells to catabolise benzo[a]pyrene or dibenz[a,h]anthracene. Metabolite or by-product repression was suspected to be responsible for the inhibition: By-products from the degradation of the five-ring compounds inhibited their further degradation.
Juhasz
A L
AL
Centre for Bioprocessing and Food Technology, Victoria University of Technology, Melbourne City, Melbourne, Australia.
Stanley
G A
GA
Britz
M L
ML
D001551:Benz(a)Anthracenes / Q000378:metabolism*; D001564:Benzo(a)pyrene / Q000378:metabolism*; D001673:Biodegradation, Environmental; D001711:Biotransformation; D011084:Polycyclic Aromatic Hydrocarbons / Q000378:metabolism; D020615:Stenotrophomonas maltophilia / Q000378:metabolism*
D001551:Benz(a)Anthracenes; D011084:Polycyclic Aromatic Hydrocarbons; D001564:Benzo(a)pyrene; C026486:1,2,5,6-dibenzanthracene