Effects of amino acid on morphological development and nucleus formation of arachidonic acid-producing filamentous micro-organism, Mortierella alpina.

Aims: Effects of amino acid on morphological development and nucleus formation of arachidonic acid-producing filamentous micro-organism, Mortierella alpina were investigated using flow-through chamber. Methods and Results: Mortierella alpina CBS 754·68 was cultivated in flow through chamber using nutrient-rich, minimal and specific amino acid-containing minimal media. To investigate the effect of amino acid on morphological parameters either 0·28 g l−1 alanine, 0·53 g l−1 sodium glutamate one hydrate or 0·42 g l−1 valine was added to the minimal medium. In a flow-through chamber, the growth of hyphal elements and nucleus formation of arachidonic acid-producing fungus M. alpina were studied on-line, using image analysis techniques. When the Ala- and Val-containing media were used, the hyphal growth units (HGUs) were 90·2 and 86·7 μm per tip, respectively, which were 2·4-fold higher than that in the nutrient-rich medium, indicating that Ala and Val stimulate the elongation of hyphae. The specific nucleus formation rates were Glu->Val-containing media>minimal and nutrient-rich media>Ala-containing medium. The nucleus doubling times in Glu- and Val-containing media were 1·9 and 2 h, respectively, which were not significant different. Conclusions: Ala and Val stimulate the elongation of M. alpina hyphae, and nucleus formation rates were Glu->Val->Ala-containing media. Significance and Impact of the Study: Formation of fungal morphology and nucleus were shown using the flow-through chamber coupled with image analysis, which making possible to discuss the relationship between mycelial morphology and nucleus formation of M. alpina. [ABSTRACT FROM AUTHOR]