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LUND UNIVERSITY LIBRARIES

Concentration of Proteins and Decrease of Salt Content in a Hydrolyzed Fermentation Broth Using Membrane Filtration

Sjökvist, Linnea LU (2023) KETM05 20231
Chemical Engineering (M.Sc.Eng.)
Abstract
Membrane filtration was used to concentrate proteins and decrease the salt concentration in a hydrolyzed fermentation broth. The broth was a by-product from the bacterial production and extraction of polyhydroxyalkanoates (PHA), that can be used to produce biobased plastics.

3 ultrafiltration-membranes, RC70PP, GR70PP and ETNA10PP from Alfa Laval Corporate AB, were evaluated at varying cross-flow velocities (CFV) of 0.3-0.5 m/s and transmembrane pressures (TMP) of 1-9 bar. High flux rates were measured, >100 L/m2h at CFV = 0.5 m/s and TMP 3-9, and the protein retention was >80% for RC70PP and >90% for GR70PP and ETNA10PP. Due to a limited amount of broth being available, it was necessary to dilute it before using it as feed in the... (More)
Membrane filtration was used to concentrate proteins and decrease the salt concentration in a hydrolyzed fermentation broth. The broth was a by-product from the bacterial production and extraction of polyhydroxyalkanoates (PHA), that can be used to produce biobased plastics.

3 ultrafiltration-membranes, RC70PP, GR70PP and ETNA10PP from Alfa Laval Corporate AB, were evaluated at varying cross-flow velocities (CFV) of 0.3-0.5 m/s and transmembrane pressures (TMP) of 1-9 bar. High flux rates were measured, >100 L/m2h at CFV = 0.5 m/s and TMP 3-9, and the protein retention was >80% for RC70PP and >90% for GR70PP and ETNA10PP. Due to a limited amount of broth being available, it was necessary to dilute it before using it as feed in the study. This dilution appears to have significantly affected the filtration process, as there was a notable disparity between the results from this study and the results in the following concentration studies.

Concentration studies were conducted with RC70PP and GR70PP, where the original, non-diluted broth was concentrated until a volume reduction of 90% was reached. Much lower flux rates, generally <20 L/m2h, were measured for both membranes. A high protein retention was achieved, of 97.1 % for RC70PP and 98.3 % for GR70PP. Both RC70PP and GR70PP measured fluxes around 5 L/m2h after the 90 % volume reduction, but due to unintentionally using a more concentrated feed in the study with GR70PP, the final protein concentration in the retentate was approximately doubled compared to the retentate of RC70PP. From this, the conclusion was drawn that GR70PP performed the best, as the flux was similar as when using RC70PP, but at a higher concentration of solutes. Diafiltration was performed with RC70PP with a diafiltration factor of 5 and this successfully decreased the conductivity in the retentate with approximately 50%, but it was at the cost of a small protein loss. (Less)
Popular Abstract (Swedish)
Det är möjligt att tillverka plast från socker med hjälp av bakterier, och även om detta bara görs på en relativt liten skala idag så kommer tillverkningen av biobaserad plast troligtvis öka väsentligt de kommande decennierna. Denna typen av plast tillverkas på förnybara råvaror, och är därför ett bra alternativ till plast som är baserad på fossila råvaror, som petroleum. För att öka hållbarheten av processen, både ekonomiskt och miljömässigt, är det bra att utnyttja så mycket av råmaterialet som möjligt, och ta tillvara på både huvudprodukten och biprodukter som produceras.

Biobaserad plast går att tillverka med många olika metoder, och en metod är att bakterier omvandlar socker till polymerer som heter polyhydroxialkanoater (PHA),... (More)
Det är möjligt att tillverka plast från socker med hjälp av bakterier, och även om detta bara görs på en relativt liten skala idag så kommer tillverkningen av biobaserad plast troligtvis öka väsentligt de kommande decennierna. Denna typen av plast tillverkas på förnybara råvaror, och är därför ett bra alternativ till plast som är baserad på fossila råvaror, som petroleum. För att öka hållbarheten av processen, både ekonomiskt och miljömässigt, är det bra att utnyttja så mycket av råmaterialet som möjligt, och ta tillvara på både huvudprodukten och biprodukter som produceras.

Biobaserad plast går att tillverka med många olika metoder, och en metod är att bakterier omvandlar socker till polymerer som heter polyhydroxialkanoater (PHA), som sedan extraheras ur bakterierna, renas upp och bearbetas till olika produkter. Ett företag i Lund, Bioextrax AB, tillverkar PHA och använder inga farliga kemikalier i processen, vilket gör att lösningen som är kvar efter PHA har blivit upprenad är en näringsrik blandning av bl.a. vatten, protein, fetter och överblivna celldelar.
I detta examensarbete har membranfiltrering används för att koncentrera lösningen som ursprungligen var väldigt utspädd. Slutmålet med projektet var att den koncentrerande lösningen ska torkas för att användas som t.ex. kosttillskott eller djurfoder. Tre membran av olika material testades och jämfördes med varandra. I slutändan gav alla membranen ganska lika resultat, och det var möjligt att koncentrera lösningen 10 gånger, och behålla majoriteten av proteinet. (Less)
Please use this url to cite or link to this publication:
author
Sjökvist, Linnea LU
supervisor
organization
course
KETM05 20231
year
type
H2 - Master's Degree (Two Years)
subject
keywords
Membrane filtration, ultrafiltration, PHA, polyhydroxyalkanoates, chemical engineering
language
English
id
9139488
date added to LUP
2023-10-09 15:06:47
date last changed
2023-10-09 15:06:47
@misc{9139488,
  abstract     = {{Membrane filtration was used to concentrate proteins and decrease the salt concentration in a hydrolyzed fermentation broth. The broth was a by-product from the bacterial production and extraction of polyhydroxyalkanoates (PHA), that can be used to produce biobased plastics.

3 ultrafiltration-membranes, RC70PP, GR70PP and ETNA10PP from Alfa Laval Corporate AB, were evaluated at varying cross-flow velocities (CFV) of 0.3-0.5 m/s and transmembrane pressures (TMP) of 1-9 bar. High flux rates were measured, >100 L/m2h at CFV = 0.5 m/s and TMP 3-9, and the protein retention was >80% for RC70PP and >90% for GR70PP and ETNA10PP. Due to a limited amount of broth being available, it was necessary to dilute it before using it as feed in the study. This dilution appears to have significantly affected the filtration process, as there was a notable disparity between the results from this study and the results in the following concentration studies.

Concentration studies were conducted with RC70PP and GR70PP, where the original, non-diluted broth was concentrated until a volume reduction of 90% was reached. Much lower flux rates, generally <20 L/m2h, were measured for both membranes. A high protein retention was achieved, of 97.1 % for RC70PP and 98.3 % for GR70PP. Both RC70PP and GR70PP measured fluxes around 5 L/m2h after the 90 % volume reduction, but due to unintentionally using a more concentrated feed in the study with GR70PP, the final protein concentration in the retentate was approximately doubled compared to the retentate of RC70PP. From this, the conclusion was drawn that GR70PP performed the best, as the flux was similar as when using RC70PP, but at a higher concentration of solutes. Diafiltration was performed with RC70PP with a diafiltration factor of 5 and this successfully decreased the conductivity in the retentate with approximately 50%, but it was at the cost of a small protein loss.}},
  author       = {{Sjökvist, Linnea}},
  language     = {{eng}},
  note         = {{Student Paper}},
  title        = {{Concentration of Proteins and Decrease of Salt Content in a Hydrolyzed Fermentation Broth Using Membrane Filtration}},
  year         = {{2023}},
}