Microbial biotransformation - cleavage of ethereal bond - in 4,5-dihydroiso
xazoles was carried out by using selected yeast Rhodotorulla rubra no. 4 an
d Aspergillus niger mold fungus. The cleavage of ethereal bond in these com
pounds afforded alcohols or phenols with a 4,5-dihydroisoxazolic group.