E. de Jong

The physiology of anthracene biodegradation by the white-rot fungus Bjerkandera sp. strain BOS55.

A recently isolated white-rot strain, Bjerkandera sp. strain BOS55, displays high extracellular peroxidase activity, and rapidly degrades polycyclic aromatic hydrocarbons (PAH). In this study, the culture conditions for the biodegradation of the model PAH compound, anthracene, were optimized with respect to O2, N, and C. An additional objective was to determine if the decolorization of the polymeric ligninolytic indicator dye, Poly R-478, could be correlated to anthracene biodegradation observed under a wide range of culture conditions. The supply of O2 was found to be the most important parameter in the biodegradation of anthracene. Increasing culture aeration enhanced the biodegradation of anthracene and the accumulation of its peroxidase-mediated oxidation product anthraquinone. Decolorization of Poly R-478 was less affected by inadequate aeration. Provided that ample aeration was supplied, the degradation of anthracene under different culture conditions was strongly correlated with the ligninolytic activity as indicated by the rate of Poly R-478 decolorization. Concentrations up to 22 mM NH4+ N did not repress anthracene biodegradation and only caused a 0%–40% repression of the Poly R-478 decolorizing activity in various experiments. A cosubstrate requirement of 100 mg glucose / mg anthracene biodegraded was observed in this study.

Degradation of veratryl alcohol by Penicillium simplicissimum

SummarySeveral bacteria, yeast and fungi selectively isolated from paper-mill waste-water grew on veratryl alcohol, a key intermediate of lignin metabolism. Penicillium simplicissimum oxidized veratryl alcohol via a NAD(P)+-dependent veratryl alcohol dehydrogenase to veratraldehyde, which was further oxidized to veratric acid in a NAD(P)+-dependent reaction. Veratric-acid-grown cells contained NAD(P)H-dependent O-demethylase activity for veratrate, vanillate and isovanillate. Protocatechuate was cleaved by a protocatechuate 3,4-dioxygenase.

Significant fungal biogenesis of physiologically important chlorinated aromatics in natural environments.

Common wood-degrading fungi produce chlorinated anisyl metabolites (CAM). These compounds, which are structurally related to xenobiotic chloroaromatics, occur at high concentrations of approximately 75 mg CAM kg-1 wood or litter in the environment. In contrast to the commmonly held belief that natural haloaromatics only fullfill an antimicrobial function, we were able to demonstrate a distinct physiological role of CAM. During wood biodegradation, they are substrates for extracellular aryl-alcohol oxidases, generating H2O2 for ligninolytic enzymes.

Screening for Pah Degrading White-Rot Fungi: Bjerkandera Sp. Bos55, a Promising New Isolate

New white-rot fungal isolates were screened for their ability to degrade polycyclic aromatic hydrocarbons (PAH). The best isolate. Bjerkandera sp. BOS55, was able to remove 99.2 and 83.1% of anthracene and benzo[a]pyrene supplied at 10 mg L−1 after growing for 28 days in 10 g L−1 glucose media. Adequate culture aeration was found to be of critical importance for rapid PAH biodegradation. Bjerkandera BOS55 was also able to remove 38.5% of benzo[a]pyrene (100 mg kg−1) from artificially polluted sterilized soil after 56 days of incubation.