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Chemostat study of citric acid production from glycerol by Yarrowia lipolytica

Paper ID Volume ID Publish Year Pages File Format Full-Text
24105 43497 2011 4 PDF Available
Title
Chemostat study of citric acid production from glycerol by Yarrowia lipolytica
Abstract

The aim of the study was to examine how the dilution rate and the chemical composition of the production medium impacts on the synthesis of citric acid by the Yarrowia lipolytica strain Wratislavia AWG7 from glycerol in a chemostat culture. The yeast Y. lipolytica Wratislavia AWG7, an acetate (acet−) and morphological (fil−) mutant, was cultured in a nitrogen- and phosphorus-limited medium at the dilution rate of 0.009–0.031 h−1 in the chemostat. Under steady-state conditions, the increase in the dilution rate was paralleled by the decrease in citric acid concentration (from 86.5 to 51.2 g L−1), as well as by the increase in the volumetric rate (from 0.78 to 1.59 g L−1 h−1) and specific rate (from 0.05 to 0.18 g g−1 h−1) of citric acid production. The yield of the production process varied from 0.59 to 0.67 g g−1.In a 550-h continuous culture of the yeast test, at a dilution rate of 0.01 h−1, in a medium with enhanced concentrations of carbon, nitrogen and phosphorus sources, the concentration of citric acid, the concentration of biomass and the volumetric rate of citric acid production were 97.8 g L−1, 22.2 g L−1 and 0.98 g L−1 h−1, respectively. The yield of the process decreased to 0.49 g g−1. The number of dead cells did not exceed 1% while that of the budding cells accounted for about 20%. Owing to the low content of isocitric acid and polyols, the fermentation process was characterized by a high purity.This study has produced the following finding: the double mutant Y. lipolytica AWG7 is an effective citric acid producer, with the ability to preserve its properties unchanged during the long run of the continuous chemostat process. This is a valued technological feature of such mutants.

Keywords
Chemostat; Citric acid; Glycerol; Yarrowia lipolytica
First Page Preview
Chemostat study of citric acid production from glycerol by Yarrowia lipolytica
Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Biotechnology - Volume 152, Issues 1–2, 10 March 2011, Pages 54–57
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering