Biotechnological and Biomedical Applications of Magnetically Stabilized and Fluidized Beds - Porous Media: Applications in Biological Systems and Biotechnology - page 460

and medical applications of MSFBs; examples of this are as follows: sep-
aration of proteins (Cocker et al. 1997; Seibert et al. 1998; Tanyolac and
Ozdural 2000; Tong and Sun 2003; Ozkara et al. 2004; Ding and Sun
2005; Safarik and Safarikova 2004; Turkmen et al. 2006; Yao et al. 2006),
antibody removal/processing and antibiotics production (Webb et al. 1996;
Al-Qodah 2000), fermentation and cell/enzyme immobilization (Ivanova et al.
1996; Al-Qodah and Al-Hassan 2000; Bahar and Celebar 2000; Bohm and
Pittermann 2000; Al-Qodah and Al-Shannag 2006; Qiu et al. 2006; Van Hee
et al. 2006; Betancor and Luckarift 2008), processing of high-value substances
(e.g., plant cell culture processing) (Al-Qodah and Al-Shannag 2006), bilirubin
removal (Uzun and Denizli 2006), cell separation (Qiu et al. 2006; Al-Qodah
and Al-Shannag 2007; Karatas et al. 2007), immunoglobulin G depletion and
erythrocyte fractionation ( Ozkara et al. 2004; Karatas et al. 2007; Ozturk
et al. 2007), bioanalytical techniques (e.g., continuous anity chromatogra-
phy) (Cocker et al. 1997; Turkmen et al. 2006; Yao et al. 2006; Ozturk et al.
2007), water treatment by enzymes (Arica 2000), and nucleic acids purification
(Hultman et al. 1989; Yamaura et al. 2004).
All these applications will be detailed in Section 12.5.
12.3 MSBs and MFBs
12.3.1 Principles of MSBs and MFBs
A MFB is a device in which a bed of particles suffers the influence of an exter-
nal magnetic field. This magnetic field may act axially or transversely to the
flow (the former is more usual, although some authors defend the latter as
being the most effective configuration (Hristov 2006a; Augusto et al. 2008)).
The interparticle forces between the particles forming the bed are increased
by the action of this magnetic field because it stimulates the appearance of a
magnetic force between them (as the bed is formed by ferromagnetic or strong
paramagnetic particles or by agglomerates presenting strong magnetic char-
acteristics), leading to an enhancement of the properties and eciency of the
fluidized beds. Distinguishing between MFBs and MSBs is not an easy task
and, indeed, this distinction is not accepted by all the scientific community.
However, the majority of researchers consider that the MFBs include the sta-
bilized beds, establishing that MSBs are fluidized beds in which the bubbling
effect, usually present in ordinary fluidized beds, is suppressed (this suppres-
sion is due to the influence of the magnetic field and thus of the interparticle
magnetic forces), thus “stabilizing” the bed. This bubbling effect is not always
present in MFBs, and therefore the definition of MFBs includes the cases of
MSBs, the cases where the field is not uniform, and even uncommon applica-
tions such as the magnetic valve for solids (MVS) (Zhang et al. 1984) and the