A biorefinery approach to microbial oil production from glycerol by Rhodotorula glutinis

Eleni E. Karamerou, Constantinos Theodoropoulos, Colin Webb

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

The use of biodiesel-derived glycerol as a carbon source for microbial oil production is a biorefinery engineering strategy that aims to reduce the glycerol surplus and make the microbial oil process more cost-effective. In this work, glycerol was used as the sole carbon source for the cultivation of the oleaginous yeast Rhodotorula glutinis along with only yeast extract as a nutrient supply and without pH control. Shake-flask cultivations showed that the specific growth rate and glycerol consumption of Rhodotorula glutinis were higher at lower glycerol concentrations (≤40 g L−1), while higher C/N atom ratios enhanced oil content. The present study extends the knowledge on the influence of the aeration rate and oxygen supply in cellular growth rate and microbial oil production, providing a wiser use of glycerol as an attempt to further reduce process costs. Cultivations at different air flow rates were performed in a 2 L bioreactor and showed that a low aeration rate of 0.5 L min−1 gave the best glycerol and nitrogen uptake rates, resulting in the highest growth (5.3 g L−1) and oil mass fraction (33% of the dry cell weight). A further 68% increase in cellular growth (16.8 g L−1) and a 34% oil mass fraction of the dry cell weight was achieved after applying a feeding strategy targeting combined growth and oil production.

Original languageEnglish
Pages (from-to)113-122
Number of pages10
JournalBiomass and Bioenergy
Volume89
Early online date30 Jan 2016
DOIs
Publication statusPublished - 30 Jun 2016

Keywords

  • Aeration rate
  • C/N ratio
  • Fed-batch
  • Oleaginous yeast
  • Oxygen uptake rate
  • Single cell oil

ASJC Scopus subject areas

  • Forestry
  • Renewable Energy, Sustainability and the Environment
  • Agronomy and Crop Science
  • Waste Management and Disposal

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