Biodegradation of plasticizers by Rhodotorula rubra.
The degradation of plasticizers by the yeast Rhodotorula rubra J-96-1 (American Type Culture Collection 9449) in the presence of glucose was studied. The plasticizers included the commonly used bis-2-ethylhexyl adipate (B(EH)A), dioctyl phthalate (DOP), and dioctyl terephthalate (DOTP), and the less commonly used dipropylene glycol dibenzoate (D(PG)DB) and diethylene glycol dibenzoate (D(EG)DB). The proposal had been made that the latter two plasticizers be used as alternatives to the first three, which have been associated with negative environmental impacts. The degradation of D(PG)DB or D(EG)DB led to a significant increase in solution toxicity, which was associated with the production of metabolites resulting from the incomplete breakdown of the plasticizers. The toxic metabolites in the D(PG)DB system were identified as isomers of dipropylene glycol monobenzoate. A pathway for the formation of this metabolite was proposed. The metabolite observed when D(EG)DB was being degraded was tentatively identified as diethylene glycol monobenzoate by analogy to the D(PG)DB system. In contrast, no metabolites were observable and toxicity did not increase in the media during the degradation of B(EH)A, DOP, or DOTP by R. rubra. Collectively, these results do not support the use of D(PG)DB and D(EG)DB as environmentally safe alternatives to B(EH)A, DOP, or DOTP.
Gartshore
James
J
Department of Chemical Engineering, McGill University, 3610 University Street, Montreal, Quebec H3A 2B2, Canada.
Cooper
David G
DG
Nicell
Jim A
JA
D001565:Benzoates / Q000737:chemistry / Q000378:metabolism / Q000633:toxicity; D001673:Biodegradation, Environmental; D005285:Fermentation; D005658:Fungi / Q000145:classification / Q000378:metabolism; D008401:Gas Chromatography-Mass Spectrometry; D005947:Glucose / Q000032:analysis / Q000378:metabolism; D010776:Photobacterium / Q000187:drug effects; D010795:Phthalic Acids / Q000737:chemistry / Q000378:metabolism / Q000633:toxicity; D010968:Plasticizers / Q000737:chemistry / Q000378:metabolism* / Q000633:toxicity; D012248:Rhodotorula / Q000378:metabolism*; D018675:Toxicity Tests / Q000379:methods
D001565:Benzoates; D010795:Phthalic Acids; D010968:Plasticizers; D005947:Glucose