Page 128 - IJB-9-3

International Journal of Bioprinting Programmable formaldehyde dehydrogenase for biodegradation formaldehyde

Therefore, the degradation of formaldehyde has become a Three-dimensional (3D) printing, also referred to as
topical social issue. In general, the methods for removing digital fabrication technology, has originated from the
formaldehyde include ventilation, plant absorption , layer-by-layer fabrication technology of 3D structures
[6]
plasma purification , adsorbent adsorption , and directly based on computer-aided design (CAD)
[7]
[8]
photocatalyst degradation [9,10] . The disadvantages of these drawing . Today, 3D printing technology is widely
[26]
methods include high cost , low efficiency , secondary used in the fields of aerospace, medicine, housing and
[9]
[11]
pollution , and other limiting factors in practical construction, automotive electronics, and clothing.
[12]
applications [13,14] , while the green methods for degrading The use of 3D printing technology can reduce costs and
formaldehyde are still under exploration. increase production speeds. The versatile, flexible, and
highly customizable characteristics can be satisfied in
Formaldehyde dehydrogenases (FDH; EC: 1.2.1.1), most sectors of industrial production . So far, a variety
[27]
which belongs to the family of zinc-containing medium- of 3D printing technologies are available for printing
chain alcohol dehydrogenases, can be found in a variety live cells and biological materials. These mainly include
of organisms . The majority of FDHs are able to oxidize inkjet printing , laser-based printing , acoustic-based
[15]
[29]
[28]
formaldehyde in the presence of β-nicotinamide adenine printing , and micro-extrusion-based bio-plotting ,
[30]
[31]
dinucleotide trihydrate (β-NAD ) and glutathione. which are widely used in tissue engineering, drug
+
However, formaldehyde dehydrogenase from Pseudomonas screening, and construction of in vitro tissue/pathological
putida (PFDH; EC: 1.2.1.46) was a glutathione-independent models . Enzymes are very important biocatalysts with
[32]
oxidoreductase, which selectively oxidizes formaldehyde to high specificity and catalytic efficiency . High stability
[33]
formic acid using NAD as an electron acceptor . In this and easy catalyst recovery are critical to the catalytic
[16]
+
process, it catalyzes the irreversible oxidation of formaldehyde industry . Some researchers have already used 3D
[34]
independent of glutathione, which is of particular interest printing to immobilize enzymes . However, there is still
[35]
for biotechnological applications. At the same time, a gap in research on the biodegradation of formaldehyde
the enzymes used to remove formaldehyde have the using 3D printing technology to immobilize PFDH.
characteristics of high efficiency, environmental friendliness, In this work, PFDH (glutathione-independent) from
and strong specificity. Therefore, PFDH is a potential green Pseudomonas putida, which acts as an excellent catalyst
method for removing formaldehyde. Compared with for the biodegradation of formaldehyde, was immobilized
free enzyme, immobilized enzymes are highly stable and using 3D printing technology, and preliminary explorations
highly recoverable, and can enable convenient downstream were made to immobilize different print objects and
processing in industrial applications . Thus, establishing different print shapes using 3D printing technology.
[17]
an effective method to improve the reusability of PFDH Through the single-factor experiment and response
has become a research focus. So far, the immobilization of surface analysis (RSM), the conditions for 3D printing of
enzymes mainly includes absorption , crosslinking , PFDH were optimized. Subsequently, the number of reuse
[18]
[19]
and self-assembly . In these immobilization methods, the cycle of immobilized enzyme with different particle sizes
[20]
free enzymes are adsorbed onto insoluble carriers through was studied. The appropriate particle sizes were selected
hydrogen bonds, hydrophobic bonds, and other physical for application experiments and further characterization.
immobilization forces. The enzymes immobilized by these The 2.5 mm FADH/calcium alginate (CA) microspheres
methods are fast, simple, and have high residual enzyme were chosen for scale-up experiments and microscopic
activity, while their active site is less likely to be destroyed characterization of the 3D-printed immobilized enzyme to
and their advanced structure is less likely to change . In explore the binding mode and spatial structure about the
[21]
previous studies, Masuda et al. fixed FDH onto phenyl- material and the enzyme. Enzymes in different shapes were
functionalized mesoporous silica to enhance the activity printed by 3D printing technology, and different printed
and stability . Yoshimoto et al. immobilized formaldehyde objects (pure enzymes, crude enzymes, and recombinant
[22]
dehydrogenase (FaDH) by encapsulation in liposomes Escherichia coli) were encapsulated in the material. These
with nicotinamide adenine dinucleotide to prove the were carried out to compare the catalytic effect to generate
enzyme thermal stability . In other respects, FDH was data conducive to the expansion of industrial applications.
[23]
also applied for the construction of biosensors, as shown by
Vianello et al. , Abu Bakar et al. , and Teiserskyte et al. . 2. Materials and methods
[16]
[24]
[25]
However, few studies have focused on the application of
FDHs for the biodegradation of formaldehyde. When it 2.1. Chemicals and materials
comes to immobilized enzymes, the choice of the right In this study, all chemicals were used directly, without
immobilization vehicle and shape is important for practical further purification. The chemicals used in this work
industrial applications. include sodium alginate (CP; Solarbio), calcium chloride
Volume 9 Issue 3 (2023) 120 https://doi.org/10.18063/ijb.695