Microbial Production of Tenuazonic Acid Analogues

Abstract
The fungus Alternaria tenuis normally produces tenuazonic acid (3-acetyl-5-secbutyltetramic acid). On supplementation of the culture substrate with l -valine and l -leucine, the organism formed two new tetramic acids, 3-acetyl-5-isopropyltetramic acid and 3-acetyl-5-isobutyltetramic acid, respectively. l -Phenylalanine was not utilized by the organism as a tetramic acid precursor.