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1
Content available Studies of polypropylene membrane fouling during microfiltration of broth with Citrobacter freundii bacteria
Gryta M., Waszak M., Tomaszewska M.
Polish Journal of Chemical Technology
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2015
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Vol. 17, nr 4
56--64
EN
In this work a fouling study of polypropylene membranes used for microfiltration of glycerol solutions fermented by Citrobacter freundii bacteria was presented. The permeate free of C. freundii bacteria and having a turbidity in the range of 0.72–1.46 NTU was obtained. However, the initial permeate flux (100–110 L/m2h at 30 kPa of transmembrane pressure) was decreased 3–5 fold during 2–3 h of process duration. The performed scanning electron microscope observations confirmed that the filtered bacteria and suspensions present in the broth formed a cake layer on the membrane surface. A method of periodical module rinsing was used for restriction of the fouling influence on a flux decline. Rinsing with water removed most of the bacteria from the membrane surface, but did not permit to restore the initial permeate flux. It was confirmed that the irreversible fouling was dominated during broth filtration. The formed deposit was removed using a 1 wt% solution of sodium hydroxide as a rinsing solution.
2
Content available The study of glycerol-based fermentation and broth downstream by nanofiltration
Gryta Marek, Markowska-Szczupak Agata, Grzechulska-Damszel Joanna, Bastrzyk Justyna, Waszak Marta
Polish Journal of Chemical Technology
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2014
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Vol. 16, nr 4
117--122
EN
In this work, the glycerol fermentation was carried out using Citrobacter freundii bacteria. The influence of glycerol and metabolites concentrations, and the pH changes on the efficiency of 1,3-propanediol production, during batch and fed-batch processes, was presented. The nanofiltration was used for the separation of obtained post-fermentation solutions. The resulted 1,3-PD solutions were significantly desalted, which may facilitate further downstream processes during 1,3-PD production.
3
Content available The application of ultrafiltration for separation of glycerol solution fermented by bacteria
Tomczak W., Gryta M.
Polish Journal of Chemical Technology
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2013
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Vol. 15, nr 3
115-120
EN
A biotechnological synthesis generated a fermentation broth containing the dissociated forms of organic compounds and residual mineral salts. An effective method of selective removal of the ionic species and organic compounds from solutions comprises nanofiltration and reverse osmosis. Ultrafiltration (UF) was used in this work as a pre-treatment method for the preparation of feed for these processes. The UF study was carried out with a real broth, which was obtained using Citrobacter freundii bacteria for the fermentation of glycerol solutions, resulting in the UF permeate with turbidity below 0.1 NTU. However, a significant decline of the permeate flux was observed during the UF process. The influence of the transmembrane pressure on the fouling intensity of used ceramic membranes was investigated. A periodical membrane cleaning was carried out by rinsing with water and a 1 wt % solution of sodium hydroxide. The applied cleaning procedures permitted to restore the initial permeate flux.
4
Content available Evaluation of fouling potential of nanofiltration membranes based on the dynamic contact angle measurements
Gryta M., Bastrzyk J., Lech D.
Polish Journal of Chemical Technology
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2012
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Vol. 14, nr 3
97-104
EN
In this work the studies were performed on the intensity of fouling of the membrane NF90 and NF270 depending on the value of dynamic contact angle, previously determined for these membrane. The NF membranes were used for the separation of broth obtained during the fermentation of glycerol by Lactobacilluscasei bacteria. The measurements of dynamic contact angle were carried out using the Wilhelmy plate method. Taped membranes samples (support layer to support layer), wetted for 2 days in deionized water prior to testing, were used to study the contact angle of top layer and its organic fouling. Using deionized water; the contact angle values equal to 27-30o and 53-57o for NF270 and NF90, respectively, were obtained. As a consequence of adsorption of organic compound on the membrane surfaces, the contact angle obtained for both fouled membranes was about 55-56o, and this value was closer to the contact angle of non-fouled NF90 membrane. Therefore, the NF90 membrane was more resistant to organic fouling during the separation of broth.
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