Comparative trace element and organic growth factor requirements of five hansenula species

A comparative response of specific trace elements and organic growth factors for the growth of five Hansenula species (H. anomala, H. beijerinckii, H. ciferrii, H. polymorpha and H. sydowiorum) has been studied. Out of twenty three trace elements tested, Fe, Zn, Mn and Cu were found to be essential for the growth of all yeast species studied here, whereas the rest of the elements exhibited variable essentiality. From fifteen organic growth factors tested, thiamine, biotin, pyridoxine and inositol are the most commonly required growth factors by the yeasts, whereas the rest of the organic growth factors showed variable essentiality. All species of yeasts investigated required different concentrations of trace elements and organic growth factors for their optimum growth. Concentrations higher than the optimum have been found to be inhibitory for the growth of all the yeasts studied.