Phycobiliprotein (PB) produced by cyanobacteria exhibits an anti-inflammatory effect and anti-cancer effect, and is expected to be applied as pharmaceuticals. In this study, a PB-containing solution ...from Nostoc commune was concentrated and separated by an ultrafiltration (UF) membrane module (nominal molecular weight limit (NMWL) 150 kDa, 30 kDa and 10 kDa). When the PB-containing solution was permeated through an UF membrane module of NMWL 10 kDa at 0.07 MPa, the total protein content was concentrated up to 10 times in 30 minutes. To simulate the change in the concentration for the concentrate in the scaled-up treatment, the parameters of the formed cake layer were determined by a mathematical model. The concentration performance of the UF membrane modules was evaluated using the obtained parameters, indicating that the 150 kDa NMWL UF membrane modules were able to concentrate 100 liters of PB-containing solution by 10 times in 15 hours. The 30 kDa and 10 kDa NMWL UF membrane modules showed the possibility of PB separation, as well as protein concentration. The productivity of PB calculated by flux and selectivity was highest for the 30 kDa NMWL UF membrane module.
Phycobiliprotein (PB) produced by cyanobacteria exhibits an anti-inflammatory effect and anti-cancer effect, and is expected to be applied as pharmaceuticals. In this study, a PB-containing solution ...from Nostoc commune was concentrated and separated by an ultrafiltration (UF) membrane module (nominal molecular weight limit (NMWL) 150 kDa, 30 kDa and 10 kDa). When the PB-containing solution was permeated through an UF membrane module of NMWL 10 kDa at 0.07 MPa, the total protein content was concentrated up to 10 times in 30 minutes. To simulate the change in the concentration for the concentrate in the scaled-up treatment, the parameters of the formed cake layer were determined by a mathematical model. The concentration performance of the UF membrane modules was evaluated using the obtained parameters, indicating that the 150 kDa NMWL UF membrane modules were able to concentrate 100 liters of PB-containing solution by 10 times in 15 hours. The 30 kDa and 10 kDa NMWL UF membrane modules showed the possibility of PB separation, as well as protein concentration. The productivity of PB calculated by flux and selectivity was highest for the 30 kDa NMWL UF membrane module.
An intensive combined treatment for removing 4-chlorophenol, consisting of its oxidation with soluble soybean peroxidase and hydrogen peroxide in a continuous tank reactor, followed by purification ...of the effluent in an ultrafiltration membrane module in series, is studied for the first time. The influence of the operational variables on the conversion was evaluated, and removal percentages of 90% or more were obtained for some of the conditions assayed. Using a bisubstrate Ping-Pong kinetics for the enzymatic reaction, a design model was proposed for the whole system. The model was solved by numerical calculation and the parameters were obtained by fitting the experimental data by means of an error minimization algorithm. The good results obtained for fitting the experimental data (7.76% typical deviation) confirm the validity of the model.
The objective of this research was to design an efficient continuously operated membrane reactor with a separation unit for egg white protein (EWP) hydrolysis and production of hydrolysates with ...improved antioxidant properties. For this purpose, a mechanically stirred tank reactor coupled with the polyethersulfone ultrafiltration module with a molecular weight cutoff of 10 kDa was employed. Several proteolytic enzymes have been tested in order to obtain the best quality of peptide-based formulations intended for human consumption. Among protease from Bacillus licheniformis (Alcalase), protease from Bacillus amyloliquefaciens (Neutrase), and protease from papaya latex (papain), the highest degree of hydrolysis (DH), as well as the best antioxidant properties of obtained hydrolysates, was achieved with Alcalase. The effects of operating variables such as enzyme/substrate (E/S) ratio, impeller speed, and permeate flow rate were further studied using response surface methodology (RSM) and Box–Behnken experimental design. Results obtained in RSM analysis confirmed that over the studied range E/S ratio, impeller speed and permeate flow rate had the significant effect on the DH and reactor capacity. The effects of different impeller geometries were also studied and four-bladed propeller stirrer enabled the highest DH. Antioxidant properties were analyzed by the 2,2-diphenyl-1-picrylhydrazyl (DPPH), by the 2,2′-azino-bis-(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS) radical scavenging activity, and by the linear voltammetry methods. Results show that the use of Alcalase in the membrane reactor system is of potential interest for the EWP hydrolysis and obtaining value-added egg products.
In this work the feasibility of the recovery of a commercial sample of citrus pectin from model solutions using a temperature- and pressure-controlled bench-top ultrafiltration (UF) plant equipped ...with a ceramic tubular, 20
kDa nominal molecular weight cut-off (NMWCO), UF membrane module, was assessed.
Several total recycle tests allowed the assessment of the effects of transmembrane pressure difference (Δ
P), feed superficial velocity (
v
S
) and solute concentration (
c
BR) in the ranges of 0.4–4.2
bar, 4–6
m
s
−1, and 2.2–30.4
kg
m
−3, respectively, on the permeation flux under a constant process temperature of 50
°C.
As
c
BR increased from about 2.2 to 10
kg
m
−3 the limiting permeation flux (
J
P∞) almost linearly decreased from 125–195 to about 25–40
dm
3
m
−2
h
−1, these values depending on
v
S
. For
c
BR rising from ∼10 to 31
kg
m
−3,
J
P∞ was almost constant or slightly tended to decline. The change in slope of the plot
J
P∞-vs.-log(
c
BR) was attributed to the transition from turbulent to laminar regime.
Two dimensionless empirical regressions among the modified Sherwood, Reynolds and Schmidt numbers, valid in the laminar or turbulent flow regime, enabled the estimation not only of the
J
P∞ values detected here in the total recycle mode, but also of the permeation fluxes observed by Pritchard et al. M. Pritchard, R. Field, J.A. Howell, The ultrafiltration of viscous liquids, J. Membr. Sci. 102 (1995) 223–235 using a polyethersulphone, 65-kDa NMWCO, tubular module operating at 45
°C, Δ
P
=
2.5
bar and different feed superficial velocities (1.3–2.7
m
s
−1) with about 21% deviation. Moreover, such relationships yielded satisfactory simulation of two other independent validation tests performed in the batch mode with an average percentage error between the theoretical and experimental fluxes of 15%.
The wall shear stress is determined at the surface of a plane sheet of ‘Plexiglas’, taking the place of a membrane, using an electrochemical method. Several microelectrodes are mounted flush to this ...plate and maps of shear stress and flow regime are determined for several inlet and outlet systems. The experimental measurements emphasize the same heterogeneity of wall shear stress for all the configurations investigated. Furthermore, whatever the configuration, the study of the turbulence features of the flow shows a transition flow regime in the range of Reynolds numbers investigated. The comparison of wall shear stresses and turbulent intensity rates obtained for each inlet/outlet system allows the determination of the best configuration.
Recently, the amount of natural waters contaminated with petroleum products, which enter surface sources together with wastewater, has increased. Therefore, the issues of natural water purification ...of petroleum products are given great importance. Purification of natural waters from petroleum products is possible by sorption and ultrafiltration methods. Kazan State University of Architecture and Engineering conducted research on the purification of natural waters from petroleum products in adsorption filters using various sorbents, as well as membrane separators with ultrafiltration modules from various manufacturers. As a loading of sorption filters, it is recommended to use activated charcoal as a sorbent that is optimal in terms of price and quality of water purification. The membrane modules manufactured in Europe and the United States, have a high cleaning effect from petroleum products and a sufficiently high productivity. However, they are extremely expensive.
In this work an experimental procedure was established to assess the main engineering parameters characterizing the ultrafiltration (UF) recovery of a commercial sample of sodium alginate from model ...solutions, using both a laboratory-scale and a pilot-scale plant equipped with ceramic tubular UF membrane modules.
Several total recycle tests were performed in the laboratory-scale plant so as to assess the effects of transmembrane pressure difference (Δ
P), feed superficial velocity (
v
S
) and solute concentration (
c
BR) in the ranges of 0.5–4.5
bar, 4–10
m/s, and 3–22
kg
m
−3, respectively, on the permeation flux under a constant process temperature of 50
°C.
As
c
BR increased from approximately 3 to 7
kg
m
−3, the limiting permeation flux (
J
P∞) decreased almost linearly from 140 to 320
dm
3
m
−2
h
−1 (depending on
v
S
) to about 40
dm
3
m
−2
h
−1, the latter value being independent of
v
S
. The change in slope of the plot
J
P∞-vs.-log(
c
BR) was shown to be due to the transition from turbulent to laminar flow.
Two empirical dimensionless correlations relating the modified Sherwood, Reynolds and Schmidt numbers, valid in the laminar or turbulent flow regime, enabled prediction of the permeation flux of two independent batch mode validation tests at high and low initial feed solute concentrations to within <10%. The correlations were also used to estimate the permeation flux for other UF tests, performed previously in a pilot-scale plant equipped with a commercial ceramic tubular membrane module operating in either batch or total recycle mode at 60
°C and high or low transmembrane pressure, with an accuracy of 5.6–15.2%.
The two empirical correlations should be suitable as design tools for further scaling-up of the UF process under study.
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