The First Step of Biodegradation of 7-Hydroxycoumarin in 7HK4 Depends on an Alcohol Dehydrogenase-Type Enzyme.

Coumarins are well known secondary metabolites widely found in various plants. However, the degradation of these compounds in the environment has not been studied in detail, and, especially, the initial stages of the catabolic pathways of coumarins are not fully understood. A soil isolate 7HK4 is able to degrade 7-hydroxycoumarin (umbelliferone) via the formation of 3-(2,4-dihydroxyphenyl)propionic acid, but the enzymes catalyzing the α-pyrone ring transformations have not been characterized.

Biodegradation of 7-Hydroxycoumarin in 7HK4 via -Hydroxylation of 3-(2,4-Dihydroxyphenyl)-propionic Acid.

A gene cluster, denoted as , required for the degradation of 3-(2,4-dihydroxyphenyl)-propionic acid has been cloned from 7-hydroxycoumarin-degrading 7HK4 (DSM 107615), and sequenced. Bioinformatic analysis shows that the operon encodes a flavin-binding hydroxylase (HcdA), an extradiol dioxygenase (HcdB), and a putative hydroxymuconic semialdehyde hydrolase (HcdC). The analysis of the recombinant HcdA activity in vitro confirms that this enzyme belongs to the group of -hydroxylases.

Airborne fungi in industrial environments--potential agents of respiratory diseases.

Investigations on airborne fungi in a poultry house, a swinery, a feed preparing and storing house, a grain mill, a wooden panel producing factory, and organic waste recycling facilities have been carried out in Lithuania. Low concentrations of fungal spores were detected in the wooden panel producing factory, the swinery, the feed preparing and storing house, and the poultry house; moderate concentrations were found in the organic waste recycling facilities; high concentrations were revealed at the grain mill. Species of Aspergillus oryzae, A.

Enzymatic activities of Aspergillus fumigatus strains isolated from the air at waste landfills.

Out of 15 Aspergillus fumigatus strains isolated from the air at waste landfills, all revealed cellulolytic and lipolytic activities. Eleven out of 15 strains showed very strong cellulolytic properties, as assessed by the viscosimetric test for endo-1,4-beta-glucanase activity (EGA). None of the examined strains revealed a well-expressed proteolytic activity.