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Protein enrichment of an Opuntia ficus-indica cladode hydrolysate by cultivation of Candida utilis and Kluyveromyces marxianus.

Akanni GB, du Preez JC, Steyn L, Kilian SG - J. Sci. Food Agric. (2014)

Bottom Line: Yeast cultivation more than doubled the protein content of the hydrolysate, with an essential amino acid profile superior to sorghum and millet grains.Despite its low biomass yield, its performance compared well with C. utilis.This is the first report showing that the protein content and quality of O. ficus-indica cladode biomass could substantially be improved by yeast cultivation, including a comparative evaluation of C. utilis and K. marxianus.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbial, Biochemical and Food Biotechnology, University of the Free State, Bloemfontein 9300, South Africa.

No MeSH data available.


Related in: MedlinePlus

Effect of glucose concentration on the cultivation profiles of K. marxianus (A, B) and C. utilis (C, D) in a chemically defined medium maintained at a DOT of above 30% of saturation and containing a glucose concentration of 10 (A, C) or 50 g L−1 (B, D). Symbols: biomass (); glucose (); ethanol ().
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fig03: Effect of glucose concentration on the cultivation profiles of K. marxianus (A, B) and C. utilis (C, D) in a chemically defined medium maintained at a DOT of above 30% of saturation and containing a glucose concentration of 10 (A, C) or 50 g L−1 (B, D). Symbols: biomass (); glucose (); ethanol ().

Mentions: To further investigate the low biomass yields of K. marxianus and the failure of the balances of its cultivation to close, the yeasts were grown aerobically in a chemically defined glucose-limited medium. Using an initial glucose concentration of 10 g L−1, K. marxianus and C. utilis NRRL Y-1084 exhibited µmax values of 0.78 and 0.42 h−1, respectively, with corresponding biomass yield coefficients of 0.45 and 0.50 (Fig. 3). Kluyveromyces marxianus produced a minimal amount of ethanol (0.23 g L−1) under these conditions. However, with an initial glucose concentration of 50 g L−1, the biomass yield coefficient of K. marxianus decreased to 0.15, while ethanol production increased to 8.4 g L−1 with the accumulation of lower concentrations of glycerol (1.3 g L−1), acetic acid (0.75 g L−1), acetaldehyde (0.11 g L−1) and ethyl acetate (0.25 g L−1). By contrast, the biomass yield of C. utilis remained close to the theoretical maximum, irrespective of the glucose concentration, with the production of less than 0.05 g L−1 glycerol and acetic acid but no ethanol (Fig. 3). Thus, although K. marxianus is regarded as strongly Crabtree negative, the above observations suggested a shift from a respiratory to a respiro-fermentative metabolism at the higher sugar concentration, as indicated by aerobic ethanol production and a concomitant increase in the RQ to 1.98.


Protein enrichment of an Opuntia ficus-indica cladode hydrolysate by cultivation of Candida utilis and Kluyveromyces marxianus.

Akanni GB, du Preez JC, Steyn L, Kilian SG - J. Sci. Food Agric. (2014)

Effect of glucose concentration on the cultivation profiles of K. marxianus (A, B) and C. utilis (C, D) in a chemically defined medium maintained at a DOT of above 30% of saturation and containing a glucose concentration of 10 (A, C) or 50 g L−1 (B, D). Symbols: biomass (); glucose (); ethanol ().
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4402007&req=5

fig03: Effect of glucose concentration on the cultivation profiles of K. marxianus (A, B) and C. utilis (C, D) in a chemically defined medium maintained at a DOT of above 30% of saturation and containing a glucose concentration of 10 (A, C) or 50 g L−1 (B, D). Symbols: biomass (); glucose (); ethanol ().
Mentions: To further investigate the low biomass yields of K. marxianus and the failure of the balances of its cultivation to close, the yeasts were grown aerobically in a chemically defined glucose-limited medium. Using an initial glucose concentration of 10 g L−1, K. marxianus and C. utilis NRRL Y-1084 exhibited µmax values of 0.78 and 0.42 h−1, respectively, with corresponding biomass yield coefficients of 0.45 and 0.50 (Fig. 3). Kluyveromyces marxianus produced a minimal amount of ethanol (0.23 g L−1) under these conditions. However, with an initial glucose concentration of 50 g L−1, the biomass yield coefficient of K. marxianus decreased to 0.15, while ethanol production increased to 8.4 g L−1 with the accumulation of lower concentrations of glycerol (1.3 g L−1), acetic acid (0.75 g L−1), acetaldehyde (0.11 g L−1) and ethyl acetate (0.25 g L−1). By contrast, the biomass yield of C. utilis remained close to the theoretical maximum, irrespective of the glucose concentration, with the production of less than 0.05 g L−1 glycerol and acetic acid but no ethanol (Fig. 3). Thus, although K. marxianus is regarded as strongly Crabtree negative, the above observations suggested a shift from a respiratory to a respiro-fermentative metabolism at the higher sugar concentration, as indicated by aerobic ethanol production and a concomitant increase in the RQ to 1.98.

Bottom Line: Yeast cultivation more than doubled the protein content of the hydrolysate, with an essential amino acid profile superior to sorghum and millet grains.Despite its low biomass yield, its performance compared well with C. utilis.This is the first report showing that the protein content and quality of O. ficus-indica cladode biomass could substantially be improved by yeast cultivation, including a comparative evaluation of C. utilis and K. marxianus.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbial, Biochemical and Food Biotechnology, University of the Free State, Bloemfontein 9300, South Africa.

No MeSH data available.


Related in: MedlinePlus