Multiple Pathways in the Degradation of Dibenzothiophene by Mycobacterium aromativorans Strain JS19b1(T)

作者：Seo Jong Su^*

来源：Journal of the Korean Society for Applied Biological Chemistry, 2012, 55(5): 613-618.

DOI：10.1007/s13765-012-2106-5

• dibenzothiophene
• dioxygenation
• meta-cleavage
• monooxygenation
• Mycobacterium aromativorans JS19b1(T)

Mycobacterium aromativorans JS19b1(T), isolated from a polycyclic aromatic hydrocarbon (PAH)-contaminated site in Hilo, Hawaii, USA, was studied for its degradation of dibenzothiophene (DBT) as a sole carbon source. Strain JS19b1(T) degraded 100% of DBT (40 mg/L) within 11 days incubation through branched metabolic pathways, including dioxygenation on C-1,2 and C-3,4 positions and monooxygenation on sulfur atom. The metabolites were isolated and identified by gas chromatography-mass spectrometry. Dibenzothiophene-5,5'-dioxide was transformed from sulfur oxidation of DBT. Cis-dibenzothiophene dihydrodiols were detected as initial dioxygenation products. Two ring cleavage products of dibenzothiophene diols were detected as trans-4-(3-hydroxybenzo[b]thiophen-2-yl)-2-oxobut-3-enoic acid and trans-4-(2hydroxy-benzo[b]thiophen-3-yl)-2-oxobut-3-enoic acid, which could be produced by meta-cleavage of dibenzothiophene-1,2-diol and dibenzothiophene-3,4-diol, respectively. The detection of benzothienopyranone strongly supported that M aroma tivorans JS19b1(T) can degrade DBT through 1,2- and/or 3,4-dioxygenations followed by meta-cleavage. The ring cleavage products were further transformed into 2,2'-dithiosalicylic acid via 2-mercaptobenzoic acid. These results suggested that strain JS19b1(T) has diverse lateral dioxygenase and metabolic enzyme systems. The diverse DBT metabolic pathways in JS19b1(T) gave a new insight to the bacterial degradation of aromatic compounds.

• 出版日期2012-10