Preliminary evidence of the role of hydrogen peroxide in the degradation of benzo[a]pyrene by a non-white rot fungus Fusarium solani.
In order to study the enzymatic mechanisms involved in the successive steps of BaP degradation by a Deuteromycete fungus Fusarium solani, we developed an indirect approach by using inhibitors of enzymes. We used either specific inhibitors of peroxidases (i.e. salicylhydroxamic acid) and of cytochrome P-450 (i.e. piperonyl butoxyde) or inhibitors of both enzymes (i.e. potassium cyanide). Surprisingly, no expected decrease of BaP degradation was observed with most inhibitors tested. On the contrary, more BaP was degraded. Only butylated hydroxytoluene, which acts as a free radical scavenger, inhibited BaP degradation. The inhibition of these enzymes, which use H(2)O(2) as a cosubstrate, might have resulted in an increase of hydrogen peroxide availability in the fungal cultures. This enhancement could induce formation of reactive oxygen species (ROS) which might be the agents that initiate benzo[a]pyrene oxidation. This study proposed a hypothetic alternative metabolic pathway involved in PAH metabolism by Fusarium solani.
Veignie
Etienne
E
Université du Littoral-Cote d'Opale, 50 rue Ferdinand Buisson, BP 699, F-62228 Calais, France.
Rafin
Catherine
C
Woisel
Patrice
P
Cazier
Fabrice
F
D000975:Antioxidants / Q000378:metabolism; D001564:Benzo(a)pyrene / Q000378:metabolism*; D001673:Biodegradation, Environmental; D002084:Butylated Hydroxytoluene / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D003521:Cyclopropanes / Q000378:metabolism; D065607:Cytochrome P-450 Enzyme Inhibitors; D004791:Enzyme Inhibitors / Q000378:metabolism*; D005670:Fusarium / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000378:metabolism*; D010544:Peroxidases / Q000037:antagonists & inhibitors; D010882:Piperonyl Butoxide / Q000378:metabolism; D011190:Potassium Cyanide / Q000378:metabolism; D012457:Salicylamides / Q000378:metabolism
D000975:Antioxidants; D003521:Cyclopropanes; D065607:Cytochrome P-450 Enzyme Inhibitors; D004791:Enzyme Inhibitors; D012457:Salicylamides; D002084:Butylated Hydroxytoluene; D001564:Benzo(a)pyrene; C067351:cyclopropylamine; C005703:salicylhydroxamic acid; D006861:Hydrogen Peroxide; D010544:Peroxidases; D010882:Piperonyl Butoxide; D011190:Potassium Cyanide