Lipid production in batch and fed-batch cultures of Rhodosporidium toruloides from 5 and 6 carbon carbohydrates

Marilyn G. Wiebe (Corresponding Author), Kari Koivuranta, Merja Penttilä, Laura Ruohonen

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Abstract

Background: Microbial lipids are a potential source of bio- or renewable diesel and the red yeast Rhodosporidium toruloides is interesting not only because it can accumulate over 50% of its dry biomass as lipid, but also because it utilises both five and six carbon carbohydrates, which are present in plant biomass hydrolysates.Methods: R. toruloides was grown in batch and fed-batch cultures in 0.5 L bioreactors at pH 4 in chemically defined, nitrogen restricted (C/N 40 to 100) media containing glucose, xylose, arabinose, or all three carbohydrates as carbon source. Lipid was extracted from the biomass using chloroform-methanol, measured gravimetrically and analysed by GC.Results: Lipid production was most efficient with glucose (up to 25 g lipid L-1, 48 to 75% lipid in the biomass, at up to 0.21 g lipid L-1 h-1) as the sole carbon source, but high lipid concentrations were also produced from xylose (36 to 45% lipid in biomass). Lipid production was low (15-19% lipid in biomass) with arabinose as sole carbon source and was lower than expected (30% lipid in biomass) when glucose, xylose and arabinose were provided simultaneously. The presence of arabinose and/or xylose in the medium increased the proportion of palmitic and linoleic acid and reduced the proportion of oleic acid in the fatty acids, compared to glucose-grown cells.High cell densities were obtained in both batch (37 g L-1, with 49% lipid in the biomass) and fed-batch (35 to 47 g L-1, with 50 to 75% lipid in the biomass) cultures. The highest proportion of lipid in the biomass was observed in cultures given nitrogen during the batch phase but none with the feed. However, carbohydrate consumption was incomplete when the feed did not contain nitrogen and the highest total lipid and best substrate consumption were observed in cultures which received a constant low nitrogen supply.Conclusions: Lipid production in R. toruloides was lower from arabinose and mixed carbohydrates than from glucose or xylose. Although high biomass and lipid production were achieved in both batch and fed-batch cultures with glucose as carbon source, for lipid production from mixtures of carbohydrates fed-batch cultivation was preferable. Constant feeding was better than intermittent feeding. The feeding strategy did not affect the relative proportion of different fatty acids in the lipid, but the presence of C5 sugars did.

Original languageEnglish
Article number26
JournalBMC Biotechnology
Volume12
DOIs
Publication statusPublished - 30 May 2012
MoE publication typeA1 Journal article-refereed

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Batch Cell Culture Techniques
Carbon
Carbohydrates
Lipids
Biomass
Arabinose
Nitrogen
Xylose
Glucose
Fatty Acids

Keywords

  • Bio- and renewable diesel
  • Fed-batch
  • High cell density
  • Lipid
  • Rhodosporidium toruloides

Cite this

@article{756fecbd62ab438cafb42c17b645f194,
title = "Lipid production in batch and fed-batch cultures of Rhodosporidium toruloides from 5 and 6 carbon carbohydrates",
abstract = "Background: Microbial lipids are a potential source of bio- or renewable diesel and the red yeast Rhodosporidium toruloides is interesting not only because it can accumulate over 50{\%} of its dry biomass as lipid, but also because it utilises both five and six carbon carbohydrates, which are present in plant biomass hydrolysates.Methods: R. toruloides was grown in batch and fed-batch cultures in 0.5 L bioreactors at pH 4 in chemically defined, nitrogen restricted (C/N 40 to 100) media containing glucose, xylose, arabinose, or all three carbohydrates as carbon source. Lipid was extracted from the biomass using chloroform-methanol, measured gravimetrically and analysed by GC.Results: Lipid production was most efficient with glucose (up to 25 g lipid L-1, 48 to 75{\%} lipid in the biomass, at up to 0.21 g lipid L-1 h-1) as the sole carbon source, but high lipid concentrations were also produced from xylose (36 to 45{\%} lipid in biomass). Lipid production was low (15-19{\%} lipid in biomass) with arabinose as sole carbon source and was lower than expected (30{\%} lipid in biomass) when glucose, xylose and arabinose were provided simultaneously. The presence of arabinose and/or xylose in the medium increased the proportion of palmitic and linoleic acid and reduced the proportion of oleic acid in the fatty acids, compared to glucose-grown cells.High cell densities were obtained in both batch (37 g L-1, with 49{\%} lipid in the biomass) and fed-batch (35 to 47 g L-1, with 50 to 75{\%} lipid in the biomass) cultures. The highest proportion of lipid in the biomass was observed in cultures given nitrogen during the batch phase but none with the feed. However, carbohydrate consumption was incomplete when the feed did not contain nitrogen and the highest total lipid and best substrate consumption were observed in cultures which received a constant low nitrogen supply.Conclusions: Lipid production in R. toruloides was lower from arabinose and mixed carbohydrates than from glucose or xylose. Although high biomass and lipid production were achieved in both batch and fed-batch cultures with glucose as carbon source, for lipid production from mixtures of carbohydrates fed-batch cultivation was preferable. Constant feeding was better than intermittent feeding. The feeding strategy did not affect the relative proportion of different fatty acids in the lipid, but the presence of C5 sugars did.",
keywords = "Bio- and renewable diesel, Fed-batch, High cell density, Lipid, Rhodosporidium toruloides",
author = "Wiebe, {Marilyn G.} and Kari Koivuranta and Merja Penttil{\"a} and Laura Ruohonen",
year = "2012",
month = "5",
day = "30",
doi = "10.1186/1472-6750-12-26",
language = "English",
volume = "12",
journal = "BMC Biotechnology",
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TY - JOUR

T1 - Lipid production in batch and fed-batch cultures of Rhodosporidium toruloides from 5 and 6 carbon carbohydrates

AU - Wiebe, Marilyn G.

AU - Koivuranta, Kari

AU - Penttilä, Merja

AU - Ruohonen, Laura

PY - 2012/5/30

Y1 - 2012/5/30

N2 - Background: Microbial lipids are a potential source of bio- or renewable diesel and the red yeast Rhodosporidium toruloides is interesting not only because it can accumulate over 50% of its dry biomass as lipid, but also because it utilises both five and six carbon carbohydrates, which are present in plant biomass hydrolysates.Methods: R. toruloides was grown in batch and fed-batch cultures in 0.5 L bioreactors at pH 4 in chemically defined, nitrogen restricted (C/N 40 to 100) media containing glucose, xylose, arabinose, or all three carbohydrates as carbon source. Lipid was extracted from the biomass using chloroform-methanol, measured gravimetrically and analysed by GC.Results: Lipid production was most efficient with glucose (up to 25 g lipid L-1, 48 to 75% lipid in the biomass, at up to 0.21 g lipid L-1 h-1) as the sole carbon source, but high lipid concentrations were also produced from xylose (36 to 45% lipid in biomass). Lipid production was low (15-19% lipid in biomass) with arabinose as sole carbon source and was lower than expected (30% lipid in biomass) when glucose, xylose and arabinose were provided simultaneously. The presence of arabinose and/or xylose in the medium increased the proportion of palmitic and linoleic acid and reduced the proportion of oleic acid in the fatty acids, compared to glucose-grown cells.High cell densities were obtained in both batch (37 g L-1, with 49% lipid in the biomass) and fed-batch (35 to 47 g L-1, with 50 to 75% lipid in the biomass) cultures. The highest proportion of lipid in the biomass was observed in cultures given nitrogen during the batch phase but none with the feed. However, carbohydrate consumption was incomplete when the feed did not contain nitrogen and the highest total lipid and best substrate consumption were observed in cultures which received a constant low nitrogen supply.Conclusions: Lipid production in R. toruloides was lower from arabinose and mixed carbohydrates than from glucose or xylose. Although high biomass and lipid production were achieved in both batch and fed-batch cultures with glucose as carbon source, for lipid production from mixtures of carbohydrates fed-batch cultivation was preferable. Constant feeding was better than intermittent feeding. The feeding strategy did not affect the relative proportion of different fatty acids in the lipid, but the presence of C5 sugars did.

AB - Background: Microbial lipids are a potential source of bio- or renewable diesel and the red yeast Rhodosporidium toruloides is interesting not only because it can accumulate over 50% of its dry biomass as lipid, but also because it utilises both five and six carbon carbohydrates, which are present in plant biomass hydrolysates.Methods: R. toruloides was grown in batch and fed-batch cultures in 0.5 L bioreactors at pH 4 in chemically defined, nitrogen restricted (C/N 40 to 100) media containing glucose, xylose, arabinose, or all three carbohydrates as carbon source. Lipid was extracted from the biomass using chloroform-methanol, measured gravimetrically and analysed by GC.Results: Lipid production was most efficient with glucose (up to 25 g lipid L-1, 48 to 75% lipid in the biomass, at up to 0.21 g lipid L-1 h-1) as the sole carbon source, but high lipid concentrations were also produced from xylose (36 to 45% lipid in biomass). Lipid production was low (15-19% lipid in biomass) with arabinose as sole carbon source and was lower than expected (30% lipid in biomass) when glucose, xylose and arabinose were provided simultaneously. The presence of arabinose and/or xylose in the medium increased the proportion of palmitic and linoleic acid and reduced the proportion of oleic acid in the fatty acids, compared to glucose-grown cells.High cell densities were obtained in both batch (37 g L-1, with 49% lipid in the biomass) and fed-batch (35 to 47 g L-1, with 50 to 75% lipid in the biomass) cultures. The highest proportion of lipid in the biomass was observed in cultures given nitrogen during the batch phase but none with the feed. However, carbohydrate consumption was incomplete when the feed did not contain nitrogen and the highest total lipid and best substrate consumption were observed in cultures which received a constant low nitrogen supply.Conclusions: Lipid production in R. toruloides was lower from arabinose and mixed carbohydrates than from glucose or xylose. Although high biomass and lipid production were achieved in both batch and fed-batch cultures with glucose as carbon source, for lipid production from mixtures of carbohydrates fed-batch cultivation was preferable. Constant feeding was better than intermittent feeding. The feeding strategy did not affect the relative proportion of different fatty acids in the lipid, but the presence of C5 sugars did.

KW - Bio- and renewable diesel

KW - Fed-batch

KW - High cell density

KW - Lipid

KW - Rhodosporidium toruloides

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U2 - 10.1186/1472-6750-12-26

DO - 10.1186/1472-6750-12-26

M3 - Article

C2 - 22646156

AN - SCOPUS:84861567451

VL - 12

JO - BMC Biotechnology

JF - BMC Biotechnology

SN - 1472-6750

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