Microbial degradation of [¹⁴C]polystyrene and 1,3-diphenylbutane

Abstract

Microbial degradation of [beta-14C]polystyrene and 1,3-diphenylbutane, a compound structurally representing the smallest repeating unit of styrene (dimer), was investigated in soil and liquid enrichment cultures. Degradation rates in soil, as determined by 14CO2 evolution from applied [14C]polystyrene, varied from 1.5 to 3.0% for a 4-month period. Although relatively low, these percentages were 15 to 30 times greater than values previously reported. Enrichment cultures, containing 1,3-diphenylbutane as the only carbon souce, were used to determine the mechanisms of microbial oxidation of the polymer chain ends. Metabolism of 1,3-diphenylbutane appeared to involve the attack by a monooxygenease to form 2-phenyl-4-hydroxyphenylbutane followed by a further oxidation and subsequent fission of the benzene ring to yield 4-phenylvaleric acid and an unidentified 5-carbon fragment via the classic meta-fission pathway. Phenylacetic acid was probably formed from 4-phenylvaleric acid by subsequent beta-oxidation of the side chain, methyl-oxidation and decarboxylation. An initial examination of the population of microorganisms in the diphenylbutane enrichment cultures indicated that these oxidative reactions are carried out by common soil microorganism of the genera Bacillus, Pseudomonas, Micrococcus, and Nocardia.

Production of 3-Vinylcatechol and Physiological Properties ofPseudomonasLF-3, Which Can Assimilate Styrene in a Two-phase (Solvent-Aqueous) System

“…In the presence of yeast extract, however, a brownish precipitate accumulated for 7 days, causing high turbidity (Table II). The precipitate accumulated after maximum cell viability may be a pure and/or mixed polymer of styrene as stated by Sielicki et al 5) Pseudomonas LF-3 could use 10 % toluene as a carbon source in addition to styrene (Table II). At any concentration of toluene, neither white precipitate nor yellow color was observed, suggesting that Pseudomonas LF-3 utilized toluene via a different metabolic route from that with styrene.…”

“…4 ) Some organisms can use solvents that were provided at extremely low concentrations in general. In the case of styrene, Sielicki et al 5) reported that 14C styrene in soil was degraded by a mixed population of microorganisms. Shirai and Hisatsuka isolated 31 strains of styrene-degrading bacteria, one of which, Pseudomonas sp., produced 2-phenylethanol via styrene oxide from styrene.…”

Isolation and Identification of Styrene Assimilating Bactiria

“…6 ) Microbial degradation of styrene, however, is not well understood, as discussed by Omori et al ',8) They reported that isolated bacteria utilizing aromatic hydrocarbons did not grow on styrene when it used as the sole carbon source. Recently, Sielicki et al 9 ) obtained a mixed population of bacteria which could utilize styrene from landfill soil. The metabolites were traced and identified, and they proposed two degradative pathways for styrene: one was via p-phenethyl alcohol (P-PA) and phenylacetic acid and the other was via low-molecular-weight oligomer.…”

Growth of microorganisms on insoluble polymers: Transformation of automobile tires

“…Fletcher (1977) recently presented data that described the attachment of microbes to polystyrene, but presented no evidence for its breakdown. Sielicki et al (1978) determined polystyrene degradation by following 14C0 evolution from (14C)polystyrene, 2 but found very little degradation.…”