Open AccessCitric acid production from sucrose by recombinant Yarrowia lipolytica using semicontinuous fermentation
Author(s) -
Moeller Lucie,
Zehnsdorf Andreas,
Aurich Andreas,
Barth Gerold,
Bley Thomas,
Strehlitz Beate
Publication year - 2013
Publication title -
engineering in life sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.547
H-Index - 57
eISSN - 1618-2863
pISSN - 1618-0240
DOI - 10.1002/elsc.201200046
Subject(s) - yarrowia , citric acid , sucrose , fermentation , yeast , food science , yeast extract , chemistry , fed batch culture , biochemistry , bioreactor , yield (engineering) , biology , organic chemistry , materials science , metallurgy
The genetically modified yeast strain Yarrowia lipolytica H222‐S4(p67ICL1)T5 is able to utilize sucrose as a carbon source and to produce citric and isocitric acids in a more advantageous ratio as compared to its wild‐type equivalent. In this study, the effect of pH of the fermentation broth (pH 6.0 and 7.0) and proteose‐peptone addition on citric acid production by the recombinant yeast strain were investigated. It was found that the highest citric acid production occurred at pH 7.0 without any addition of proteose‐peptone. Furthermore, two process strategies (fed‐batch and repeated fed‐batch) were tested for their applicability for use in citric acid production from sucrose by Y. lipolytica . Repeated fed‐batch cultivation was found to be the most effective process strategy: in 3 days of cycle duration, approximately 80 g/L citric acid was produced, the yield was at least 0.57 g/g and the productivity was as much as 1.1 g/Lh. The selectivity of the bioprocess for citric acid was always higher than 90% from the very beginning of the fermentation due to the genetic modification, reaching values of up to 96.4% after 5 days of cycle duration.