scholarly journals Fractionation of Glycomacropeptide from Whey Using Positively Charged Ultrafiltration Membranes

Foods ◽  
2018 ◽  
Vol 7 (10) ◽  
pp. 166 ◽  
Author(s):  
Abhiram Arunkumar ◽  
Mark Etzel
Keyword(s):  
Polymer Brushes ◽  
Cheese Whey ◽  
Fold Increase ◽  
Membrane System ◽  
Attractive Alternative ◽  
Salt Tolerant ◽  
Water Addition ◽  
Ultrafiltration Membranes ◽  
Charged Ultrafiltration Membranes ◽  
Positively Charged

Fractionation of the bovine glycomacropeptide (GMP) from the other proteins in cheese whey was examined using ultrafiltration membranes surface modified to contain positively charged polymer brushes made of polyhexamethylene biguanide. By placing a strong positive charge on a 1000 kDa ultrafiltration membrane and adjusting the pH of whey close to the isoelectric point of GMP, a 14-fold increase in selectivity was observed compared to unmodified membranes. A one stage membrane system gave 90% pure GMP and a three-stage rectification system gave 97% pure GMP. The charged membrane was salt-tolerant up to 40 mS cm−1 conductivity, allowing fractionation of GMP directly from cheese whey without first lowering the whey conductivity by water dilution. Thus, similarly sized proteins that differed somewhat in isoelectric points and were 50–100 fold smaller than the membrane molecular weight cut-off (MWCO), were cleanly fractionated using charged ultrafiltration membranes without water addition. This is the first study to report on the use of salt-tolerant charged ultrafiltration membranes to produce chromatographically pure protein fractions from whey, making ultrafiltration an attractive alternative to chromatography for dairy protein fractionation.

Use of Negatively-Charged Ultrafiltration Membranes

1980 ◽  
pp. 605-608 ◽  
Author(s):  
D. Bhattacharyya ◽  
M. G. Balko ◽  
C. Cheng ◽  
S. E. Gentry
Keyword(s):  
Ultrafiltration Membranes ◽  
Charged Ultrafiltration Membranes

Pilot plant study on the performance and optimization of submerged membranes for taste and odor removal

2002 ◽  
Vol 2 (2) ◽  
pp. 185-192 ◽  
Author(s):  
L. Schideman ◽  
V.L. Snoeyink ◽  
B.J. Mariñas ◽  
M. Kosterman
Keyword(s):  
Lake Michigan ◽  
System Modeling ◽  
Cost Effective ◽  
Membrane System ◽  
Pilot Scale ◽  
Attractive Alternative ◽  
Beneficial Effects ◽  
Ideal Mixing ◽  
Taste And Odor ◽  
Cake Layer

Hybrid sorption-membrane processes are an attractive alternative for meeting a range of water treatment goals in a single process that is compact and cost-effective. This study investigated the performance and optimization of a hybrid sorption-membrane process using powdered activated carbon (PAC) and submerged-style membranes for odor control. Specifically, this study focused on the removal of 2-methylisoborneol (2-MIB) from a Lake Michigan source water and investigated the effects of PAC dose, dosing method, backwash interval, and aeration. Adsorption performance was predicted using a mathematical model, and tested using a pilot-scale, submerged membrane system. Modeling continuously dosed PAC performance agreed well with pilot results, but pulse dosed PAC performance was overestimated by the model. Non-ideal mixing effects were identified as important factors in explaining the pulse dosing results. Pilot results with aeration and pulse dosing were also overestimated by the model. It is hypothesized that aeration disturbs the PAC cake layer that forms on the membrane, and thus eliminates the beneficial effects that this cake layer can have on adsorption. Extending backwash intervals from 30 to 180 minutes with continuous dosing increased the percent removal of 2-MIB by up to 30% in both the model predictions and pilot results. This study highlights some important considerations in the design of full-scale systems and future mathematical models.

scholarly journals Adaptive Evolution of a Lactose-Consuming Saccharomyces cerevisiae Recombinant

2008 ◽  
Vol 74 (6) ◽  
pp. 1748-1756 ◽  
Author(s):  
Pedro M. R. Guimarães ◽  
Jean François ◽  
Jean Luc Parrou ◽  
José A. Teixeira ◽  
Lucília Domingues
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Copy Number ◽  
Cheese Whey ◽  
Kluyveromyces Lactis ◽  
Strain Improvement ◽  
Attractive Alternative ◽  
Evolutionary Engineering ◽  
Serial Transfer ◽  
Lactose Fermentation ◽  
Transcriptional Induction

ABSTRACT The construction of Saccharomyces cerevisiae strains that ferment lactose has biotechnological interest, particularly for cheese whey fermentation. A flocculent lactose-consuming S. cerevisiae recombinant expressing the LAC12 (lactose permease) and LAC4 (β-galactosidase) genes of Kluyveromyces lactis was constructed previously but showed poor efficiency in lactose fermentation. This strain was therefore subjected to an evolutionary engineering process (serial transfer and dilution in lactose medium), which yielded an evolved recombinant strain that consumed lactose twofold faster, producing 30% more ethanol than the original recombinant. We identified two molecular events that targeted the LAC construct in the evolved strain: a 1,593-bp deletion in the intergenic region (promoter) between LAC4 and LAC12 and a decrease of the plasmid copy number by about 10-fold compared to that in the original recombinant. The results suggest that the intact promoter was unable to mediate the induction of the transcription of LAC4 and LAC12 by lactose in the original recombinant and that the deletion established the transcriptional induction of both genes in the evolved strain. We propose that the tuning of the expression of the heterologous LAC genes in the evolved recombinant was accomplished by the interplay between the decreased copy number of both genes and the different levels of transcriptional induction for LAC4 and LAC12 resulting from the changed promoter structure. Nevertheless, our results do not exclude other possible mutations that may have contributed to the improved lactose fermentation phenotype. This study illustrates the usefulness of simple evolutionary engineering approaches in strain improvement. The evolved strain efficiently fermented threefold-concentrated cheese whey, providing an attractive alternative for the fermentation of lactose-based media.

Experiences in integrity testing ultrafiltration membranes at a large potable water treatment works

2003 ◽  
Vol 3 (5-6) ◽  
pp. 1-7
Author(s):  
S. Oxtoby
Keyword(s):  
Water Treatment ◽  
Membrane Filtration ◽  
Membrane System ◽  
Primary System ◽  
Secondary System ◽  
Ultrafiltration Membranes ◽  
Integrity Testing ◽  
Particulate Loads ◽  
Integrity Tests ◽  
The Uk

The Clay Lane Water treatment works of Three Valleys Water, in the south east of England, is currently the world’s largest ultrafiltration works with a capacity of 160 Ml/d. It utilises ultrafiltration membranes constructed as hollow fibres with a number of membrane elements in a pressure housing. The plant has been operating since spring 2001. The decision to install the system was made in anticipation of the introduction of tighter regulations on Cryptosporidium in water supplies in the UK. Once a decision was made to proceed with a membrane system the ability to monitor the integrity of the system and to repair problems became a crucial design parameter that was a critical part of membrane selection. The need to include a system affected the design of the filtration units offered by manufacturers. The available systems for integrity testing are reviewed and the reasons for selecting the system adopted are discussed. These include particle counting and the dosing of test particulate loads. The different forms of air passage integrity tests are discussed and the displaced air flow system used is described. Once a failure has been detected it must be traced so that the fault can be repaired. This procedure is described together with the techniques of pin repair of damaged fibres. At Clay Lane and other membrane filtration sites the backwash water from membrane cleaning is recovered using a secondary membrane system. Currently the secondary system operates in the same integrity testing regime as the primary system and the secondary filtrate is returned ahead of the primary membrane system. The relative merits of this system, or the alternative of adding the recovered water to the filtrate are discussed.

Plasmid DNA transmission through charged ultrafiltration membranes

2009 ◽  
Vol 344 (1-2) ◽  
pp. 123-128 ◽  
Author(s):  
Kimberly Ager ◽  
David R. Latulippe ◽  
Andrew L. Zydney
Keyword(s):  
Plasmid Dna ◽  
Ultrafiltration Membranes ◽  
Charged Ultrafiltration Membranes
Sign in / Sign up

Export Citation Format

Share Document