**4. Biotechnological applications**

The immobilization of different biomolecules in magnetic material has been used for several biotechnological applications in biomedicine [5], environment [43], and food industry [22] (**Figure 3**). At present, magnetic bio-derivatives have found potential uses in biodiesel production. Knowing it as a renewable, biodegradable, noninflammable, and nontoxic product, the biodiesel has been studied as an attractive substitute to the diesel fuel based on petroleum. Lipase immobilized on magnetic particles has been used to produce biodiesel by enzymatic transesterification [44, 45]. Moreover, magnetic microreactors employing immobilized enzymes are widely investigated to study and manipulate bioprocesses. For instance, the prediction of pharmaceutical response in animal models could be avoided by using enzymatic microreactors in culture systems. The authors advice reading the review article to find more information about magnetic enzyme microreactors [46].

**39**

**Figure 3.**

*Magnetic Bio-Derivatives: Preparation and Their Uses in Biotechnology*

Biocompatibility, specificity, ability to recognize other molecules, and operational stability presented by biomolecules such as enzymes [2], carbohydrates [21], antibodies [47], antigens [48], peptides [49], DNA [50], and glycoprotein [20], among others, are properties that make biomolecules attractive to biotechnological applications. The possibility of reuse, the easy removal of the magnetic bio-derivative from the reaction medium, the greater stability of the biomolecule, the high productivity, and the low-cost of production are some of the advantages of the immobilization.

Considering the above, the topics below exhibit the most recent developments in

our research group. Applications such as trypsin purification, obtaining of antioxidant peptides, affinity purification of antithrombin, high sucrolytic activity by

**4.1 Trypsin purification using magnetic particles of azocasein-iron composite**

**4.2 Optimization of** *Penicillium aurantiogriseum* **protease immobilization on** 

In this work, magnetic nanoparticles coated with polyaniline were used to immobilize protease from *Penicillium aurantiogriseum* and applied to the production

**magnetic nanoparticles for antioxidant peptides' obtainment**

The purpose of this work was to develop a trypsin purification strategy based on affinity binding with ferromagnetic particles of azocasein composite (mAzo) [4]. Trypsin was purified when the fish crude extract (2 mL) obtained from intestines of fish Nile tilapia (*Oreochromis niloticus*) was exposed to the magnetic bio-derivate (mAzo: 100 mg) for 2 h, removed from the reaction medium with the aid of a magnetic field, and washed with buffer (0.1 M Tris-HCl) seven times to remove unbound protein and three times under high ionic strength (3 M NaCl) to leach off the protein. The specific activity of the free enzyme present in the crude extract was 60-fold lower than that of the preparation. The optimum performance suggests that the mAzo composite, besides being reused, can be applied to purify trypsin from other sources.

invertase, and purification of glycoproteins are discussed.

*Major biotechnological uses of the magnetic bio-derivatives.*

*DOI: http://dx.doi.org/10.5772/intechopen.85748*

*Magnetic Bio-Derivatives: Preparation and Their Uses in Biotechnology DOI: http://dx.doi.org/10.5772/intechopen.85748*

*Applied Surface Science*

Magnetization measurement

X-ray diffraction (XRD)

Electronic microscopy (SEM and TEM)

Thermal gravimetric analysis (TGA)

*Some parameters provided by the technique.*

Mössbauer spectroscopy (MS)

*a*

**Table 1.**

*bio-derivative.*

**Technique Information** 

**type**

Qualitative and quantitative

Qualitative and quantitative

TGA can also be employed to determine the degree of functionalization of the support, the effectiveness of the immobilization method, and structural information of biomolecule after the immobilization [40]. An attractive nanobiocatalyst consisting of α-amylase (AA) immobilized on magnetic nanoparticles (MNP@SiO2) functionalized with naringin (NA) was proposed [33]. The functionalization and immobilization processes were assessed by TGA analysis. The results for the MNP@SiO2/NA (without enzyme) and MNP@SiO2/NA/AA (with enzyme) showed that the major weight loss was associated with the removal of the organic moieties. Moreover, the difference in weight loss between these samples was used to evidence the α-amylase immobilization. In order to conclude this section, **Table 1** exhibits a summary with the main information about the physicochemical techniques above described. The reader can use the information contained therein to evaluate the desired parameters. It is important to mention that these techniques can be applied in both magnetic materials with and without the biomolecule. Moreover, other techniques can also be

*Main features of some physicochemical techniques to characterize a magnetic material or magnetic* 

**Parametera Easy** 

Quantitative Saturation magnetization, remanent

crystalline size

Qualitative Specific to differentiate between

Quantitative Mass change in processes such as

dehydration

magnetization, and coercivity

Chemical composition, crystallinity degree, crystalline phase, and

iron oxide phases (e.g., magnetite, maghemite, and hematite)

Particle size, morphology, size distribution, and shape

oxidation, decomposition, and

**access to technique?**

Yes

Yes

No

Yes

Yes

The immobilization of different biomolecules in magnetic material has been used for several biotechnological applications in biomedicine [5], environment [43], and food industry [22] (**Figure 3**). At present, magnetic bio-derivatives have found potential uses in biodiesel production. Knowing it as a renewable, biodegradable, noninflammable, and nontoxic product, the biodiesel has been studied as an attractive substitute to the diesel fuel based on petroleum. Lipase immobilized on magnetic particles has been used to produce biodiesel by enzymatic transesterification [44, 45]. Moreover, magnetic microreactors employing immobilized enzymes are widely investigated to study and manipulate bioprocesses. For instance, the prediction of pharmaceutical response in animal models could be avoided by using enzymatic microreactors in culture systems. The authors advice reading the review article to find more information about magnetic enzyme

performed to characterize a magnetic bio-derivative.

**4. Biotechnological applications**

**38**

microreactors [46].

**Figure 3.** *Major biotechnological uses of the magnetic bio-derivatives.*

Biocompatibility, specificity, ability to recognize other molecules, and operational stability presented by biomolecules such as enzymes [2], carbohydrates [21], antibodies [47], antigens [48], peptides [49], DNA [50], and glycoprotein [20], among others, are properties that make biomolecules attractive to biotechnological applications. The possibility of reuse, the easy removal of the magnetic bio-derivative from the reaction medium, the greater stability of the biomolecule, the high productivity, and the low-cost of production are some of the advantages of the immobilization.

Considering the above, the topics below exhibit the most recent developments in our research group. Applications such as trypsin purification, obtaining of antioxidant peptides, affinity purification of antithrombin, high sucrolytic activity by invertase, and purification of glycoproteins are discussed.

#### **4.1 Trypsin purification using magnetic particles of azocasein-iron composite**

The purpose of this work was to develop a trypsin purification strategy based on affinity binding with ferromagnetic particles of azocasein composite (mAzo) [4]. Trypsin was purified when the fish crude extract (2 mL) obtained from intestines of fish Nile tilapia (*Oreochromis niloticus*) was exposed to the magnetic bio-derivate (mAzo: 100 mg) for 2 h, removed from the reaction medium with the aid of a magnetic field, and washed with buffer (0.1 M Tris-HCl) seven times to remove unbound protein and three times under high ionic strength (3 M NaCl) to leach off the protein. The specific activity of the free enzyme present in the crude extract was 60-fold lower than that of the preparation. The optimum performance suggests that the mAzo composite, besides being reused, can be applied to purify trypsin from other sources.
