Modeling of Xanthophyllomyces dendrorhous growth on glucose and overflow metabolism in batch and fed-batch cultures for astaxanthin production

Yuan Shuai Liu, Jianyong Wu

Research output: Journal article publicationJournal articleAcademic researchpeer-review

19 Citations (Scopus)

Abstract

An astaxanthin-producing yeast Xanthophyllomyces dendrorhous ENM5 was cultivated in a liquid medium containing 50 g/L glucose as the major carbon source in stirred fermentors (1.5-L working volume) in fully aerobic conditions. Ethanol was produced during the exponential growth phase as a result of overflow metabolism or fermentative catabolism of glucose by yeast cells. After accumulating to a peak of 3.5 g/L, the ethanol was consumed by yeast cells as a carbon source when glucose in the culture was nearly exhausted. High initial glucose concentrations and ethanol accumulation in the culture had inhibitory effects on cell growth. Astaxanthin production was partially associated with cell growth. Based on these culture characteristics, we constructed a modified Monod kinetic model incorporating substrate (glucose) and product (ethanol) inhibition to describe the relationship of cell growth rate with glucose and ethanol concentrations. This kinetic model, coupled with the Luedeking-Piret equation for the astaxanthin production, gave satisfactory prediction of the biomass production, glucose consumption, ethanol formation and consumption, and astaxanthin production in batch cultures over 25-75 g/L glucose concentration ranges. The model was also applied to fed-batch cultures to predict the optimum feeding scheme (feeding glucose and corn steep liquor) for astaxanthin production, leading to a high volumetric yield (28.6 mg/L) and a high productivity (5.36 mg/L/day).
Original languageEnglish
Pages (from-to)996-1004
Number of pages9
JournalBiotechnology and Bioengineering
Volume101
Issue number5
DOIs
Publication statusPublished - 1 Dec 2008

Keywords

  • Diauxic growth
  • Ethanol inhibition
  • Fed-batch culture
  • Kinetic model
  • Overflow metabolism

ASJC Scopus subject areas

  • Biotechnology
  • Bioengineering
  • Applied Microbiology and Biotechnology

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