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D-stat culture for studying the metabolic shifts from oxidative metabolism to lipid accumulation and citric acid production in Yarrowia lipolytica

Paper ID Volume ID Publish Year Pages File Format Full-Text
23262 43426 2014 7 PDF Available
Title
D-stat culture for studying the metabolic shifts from oxidative metabolism to lipid accumulation and citric acid production in Yarrowia lipolytica
Abstract

•We determined each N/C ratio leading to TAG accumulation and excretion of citrate.•TAG accumulation in Yarrowia without excreting citrate is possible from glucose.•Specific enzyme activities were followed up during the D-stat.•A strong increase in ACL, ACC and ME was observed at the onset of TAG accumulation.

Lipid accumulation in oleaginous yeasts is triggered by nutrient imbalance in the culture medium between the carbon source in excess and the nitrogen source in limiting concentration. However Yarrowia lipolytica when cultivated on glucose as the sole carbon source, mainly produces citric acid upon nitrogen limitation over lipid accumulation (only 5–10% triacylglycerol). Therefore for developing bioprocess for the production of triacylglycerol from renewable carbon source as glucose it is of first importance to control this imbalance in order to avoid citric acid production during TAG accumulation.Using D-stat cultivation system, where the N/C was linearly decreased using a constant change rate we were able to identify the N/C ratio inducing TAG accumulation (0.085 Nmol Cmol−1) and citric acid (0.021 Nmol Cmol−1). We therefore demonstrated that it was possible to accumulate lipids without excretion citric acid as long as the N/C was within this indicated range. Moreover enzyme specific activities measurement during the D-stat indicated that ATP-citrate lyase, malic enzyme and acetyl-coA carboxylase were strongly induced at the onset of lipid accumulation and showed different patterns when citric acid was excreted.Our results give relevant information for future industrial bioprocess development concerning the production of lipids using renewable carbohydrate substrates as an alternative way to produce synthons for fuel or chemical industry. By controlling the N/C over the fermentation process on glucose Y. lipolytica can accumulate lipids without excreting citric acid.

Keywords
Yarrowia lipolytica; Lipid accumulation; D-stat; Nitrogen limitation; Citric acid production
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D-stat culture for studying the metabolic shifts from oxidative metabolism to lipid accumulation and citric acid production in Yarrowia lipolytica
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Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Biotechnology - Volume 170, 20 January 2014, Pages 35–41
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us