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- Butylina, Svetlana, et al.
(author)
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Fractionation of whey-derived peptides using a combination of ultrafiltration and nanofiltration
- 2006
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In: Journal of Membrane Science. - : Elsevier. - 0376-7388 .- 1873-3123. ; 280:1-2, s. 418-426
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Journal article (peer-reviewed)abstract
- This paper describes the fractionation and further isolation and characterisation of peptides and proteins present in sweet whey by means of ultrafiltration using a regenerated cellulose membrane with a nominal molar mass cut-off value of 10 kg/mol and nanofiltration through sulphonated polyether sulphone membrane with a cut-off of 1 kg/mol. The concentration of whey proteins was done below the critical flux. The sieving coefficients for the whey components (proteins, lactose and salts) were estimated. Whey proteins were completely rejected by the ultrafiltration membrane. Size exclusion chromatography (SEC) and matrix-assisted laser desorption ionisation time-of-flight (MALDI-TOF) mass spectrometry were used to evaluate the molar masses of the peptide fractions that were present in the whey permeates. Nanofiltration of whey permeates obtained after ultrafiltration was conducted at two pH values (9.5 and 3.0) that corresponded to the different charged states of the membrane and of the peptides. The transmission of peptides, amino acids and lactose was found to be mainly affected by the permeability of the fouling layer. The selectivity of the nanofiltration membranes toward peptides compared to lactose was calculated as 0.82 and 6.81 at pH 9.5 and 3.0, respectively.
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| 2. |
- Butylina, Svetlana, et al.
(author)
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Separation of nucleoprotein complexes with antioxidant activity from yeast Saccharomyces cerevisiae
- 2007
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In: Separation and Purification Technology. - : Elsevier BV. - 1383-5866 .- 1873-3794. ; 53:1, s. 64-70
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Journal article (peer-reviewed)abstract
- In this study, complexes of nucleic acids and acidic nuclear proteins were isolated from baker's yeast cells of Saccharomyces cerevisiae by mild alkaline extraction followed by precipitation with acetic acid. The optimal composition of the buffer applied for extraction of nucleoprotein complexes was determined. The high and low molar mass fractions of the nucleoprotein complexes were separated using cross-flow microfiltration through track-etched membranes. The molar masses were determined by intrinsic viscosity measurements and the molar mass distribution in nucleoprotein complexes was studied by gel permeation chromatography. The protein component of the nucleoprotein complexes was purified on a strongly basic anion exchange resin. The high molar mass nucleoprotein complexes could induce the growth of culture cells of S. cerevisiae exposed to ultraviolet irradiation or treated with hydrogen peroxide
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