Macro-morphological characterization and kinetics of <i>Mortierella alpina</i> colonies during batch cultivation

<div><p>An effective method for research of macro-morphological characterization and its kinetics was developed by studying the macro-morphological characteristics of <i>Mortierella alpina</i>, an oleaginous zygomycete widely used to produce lipids rich in PUFA, in function of culture medium composition and to link morphological features of fungus with the level of lipid production. A number of distinct morphological forms including hollow pellets, fluffy pellets and freely dispersed mycelia were obtained by changing the fermentation factors. By fitting a Logistic curve, the maximum specific growth rate (<i>μ</i>_max)was obtained, which determined the final mycelia morphology. <i>μ</i>_max of 0.6584 in three kind of morphological forms is the more appropriate. According to the Luedeking-Piret equation fitting, <i>α</i>≠0 and <i>β</i>≠0, lipid production was partially associated with the hyphal growth, fluffy pellets which turn glucose into lipidwas more effective than the other two kinds of morphological forms.</p></div

The detailed process of the growth rate and lipid accumulation rate at every day for each morphology.

<p>The detailed process of the growth rate and lipid accumulation rate at every day for each morphology.</p

Time course of glucose concentration, dry cell weight (DCW) and lipid production in shake flask cultures inoculated under different morphology.

<p>a Glucose concentration, b Dry cell weight, c lipid production. Solid square symbol reflect hollow pellets, solid circle reflect fluffy pellets, solid diamond reflect dispersed filaments.</p

Several distinct macro-morphological forms of <i>M</i>. <i>alpina</i> under different culture medium.

<p>a Fluffy pellets (glucose of 100g/l), b Fluffy pellets cover by slender filamentous (peptone), c Dispersed filaments (yeast extract or corn steep liquor), d Hollow pellets around a little filaments (peptone/yeast extract(3:1)), e Dispersed mycelia (peptone/yeast extract (2:1)). The specific image of mycelia was carried out by the stereoscopic microscope equipped with a monochrome CCD camera at 10X 0.8 times.</p

Lipid production, biomass and morphology of <i>M</i>. <i>alpina</i> with different nitrogen sources (means± SD).

<p>Lipid production, biomass and morphology of <i>M</i>. <i>alpina</i> with different nitrogen sources (means± SD).</p

The kinetic parameters of fermentation process cultivated with each distinct morphology.

<p>The kinetic parameters of fermentation process cultivated with each distinct morphology.</p