EVALUATION AND OPTIMIZATION OF GROWTH AND CITRIC ACID PRODUCTION BY Yarrowia lipolytica NRRL Y-1095 USING GLYCEROL AS CARBON SOURCE AS AN ALTERNATIVE TO USE BIODIESEL BYPRODUCT

The aim of the present study was to optimize growth and citric acid production by Yarrowia lipolytica NRRL Y-1095 using glycerol as the sole carbon source, like an alternative to use biodiesel glycerol, a promising and cheap carbon source. Fermentations were performed in Erlenmeyer flasks to optimize growth and citrate production from glycerol. The fermented broth was analyzed by HPLC equipped with a UV and RI detector to evaluate isocitrate, citrate and glycerol consumption. The growth medium was optimized in flasks and in batch fermentation. The present study have optimized media conditions for the growth phase of Yarrowia lipolityca NRRL Y-1095 using experimental design and surface response methodology, obtaining 6.18 g. l(-1) of dry cell weight (DCW) and up to 22 g. l(-1) DCW in bioreactor after 96 h. Six fermentations were performed in a feed batch reactor with varying aeration and agitation. Dissolved oxygen was an important factor and a 0.5 yield of citric acid was obtained from feed batch fermentation, where up to 59 g. l-1 of citric acid was obtained. Glycerol is a cheap alternative to citric acid production since biodiesel glycerol production is growing rapidly and becoming an environmental problem.