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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

Cultivation profiles of C. utilis (A) and K. marxianus (B) with the DOT controlled above 30% of saturation in a chemically defined medium containing a sugar mixture simulating an enzymatic hydrolysate of cladode biomass.
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fig02: Cultivation profiles of C. utilis (A) and K. marxianus (B) with the DOT controlled above 30% of saturation in a chemically defined medium containing a sugar mixture simulating an enzymatic hydrolysate of cladode biomass.

Mentions: To serve as a benchmark for the performance of yeasts in the cladode hydrolysate and to investigate the low biomass yield found with K. marxianus, experiments were conducted using a chemically defined medium containing a sugar mixture simulating the composition of the cladode hydrolysate to facilitate carbon and degree of reduction balances, using a biomass composition of CH1.8O0.5 N0.2. In this medium K. marxianus had a high maximum specific growth rate (µmax) of 0.71 h−1, whereas C. utilis had a µmax value of 0.40 h−1 and a biomass yield coefficient of 0.42. By contrast, the biomass yield coefficient of K. marxianus remained low at 0.24 (Table 3). The sugar utilization profiles were similar to those in the actual cladode hydrolysate medium (Fig. 2). Although arabinose utilization by K. marxianus appeared slightly slower than in the actual hydrolysate, the volumetric rate of total sugar uptake by both yeasts was about 1.5-fold higher than in the hydrolysate. After 30 h of cultivation, K. marxianus had utilized about 88% of the total sugars and C. utilis 79%. Kluyveromyces marxianus again produced up to 6.4 g ethanol L−1 as well as ethyl acetate, acetaldehyde and acetic acid, whereas C. utilis produced glycerol and acetic acid (Fig. 2 and Table 3). In this medium both yeasts produced a substantially higher acetic acid concentration than in the actual hydrolysate. The carbon and degree of reduction balances for C. utilis cultivation closed to 97% and 94%, respectively, with a respiratory quotient (RQ) of 1.12. However, in the case of K. marxianus the carbon and degree of reduction balances closed to only 65% and 72%, respectively, and the RQ of 1.86 indicated a respiro-fermentative metabolism.


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)

Cultivation profiles of C. utilis (A) and K. marxianus (B) with the DOT controlled above 30% of saturation in a chemically defined medium containing a sugar mixture simulating an enzymatic hydrolysate of cladode biomass.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig02: Cultivation profiles of C. utilis (A) and K. marxianus (B) with the DOT controlled above 30% of saturation in a chemically defined medium containing a sugar mixture simulating an enzymatic hydrolysate of cladode biomass.
Mentions: To serve as a benchmark for the performance of yeasts in the cladode hydrolysate and to investigate the low biomass yield found with K. marxianus, experiments were conducted using a chemically defined medium containing a sugar mixture simulating the composition of the cladode hydrolysate to facilitate carbon and degree of reduction balances, using a biomass composition of CH1.8O0.5 N0.2. In this medium K. marxianus had a high maximum specific growth rate (µmax) of 0.71 h−1, whereas C. utilis had a µmax value of 0.40 h−1 and a biomass yield coefficient of 0.42. By contrast, the biomass yield coefficient of K. marxianus remained low at 0.24 (Table 3). The sugar utilization profiles were similar to those in the actual cladode hydrolysate medium (Fig. 2). Although arabinose utilization by K. marxianus appeared slightly slower than in the actual hydrolysate, the volumetric rate of total sugar uptake by both yeasts was about 1.5-fold higher than in the hydrolysate. After 30 h of cultivation, K. marxianus had utilized about 88% of the total sugars and C. utilis 79%. Kluyveromyces marxianus again produced up to 6.4 g ethanol L−1 as well as ethyl acetate, acetaldehyde and acetic acid, whereas C. utilis produced glycerol and acetic acid (Fig. 2 and Table 3). In this medium both yeasts produced a substantially higher acetic acid concentration than in the actual hydrolysate. The carbon and degree of reduction balances for C. utilis cultivation closed to 97% and 94%, respectively, with a respiratory quotient (RQ) of 1.12. However, in the case of K. marxianus the carbon and degree of reduction balances closed to only 65% and 72%, respectively, and the RQ of 1.86 indicated a respiro-fermentative metabolism.

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