Page 131 - IJB-9-3

International Journal of Bioprinting Programmable formaldehyde dehydrogenase for biodegradation formaldehyde

Figure 1. Single-factor experiments. (A) The influence of SA concentration on PFDH activity. (B) The influence of CaCl concentration on PFDH activity.
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(C) The influence of crosslinking time on PFDH activity. (D) The influence of reaction temperature on PFDH activity.

on the results of the single-factor experiments, we used are significant. The analysis showed that the PFDH activity
RSM to conduct cross-combination analysis of the four reached a maximum at the conditions of SA concentration
factors to further determine the optimal conditions for 3D = 1.6 wt%, CaCl concentration = 7.5 wt%, crosslinking
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printing immobilized PFDH/CA microspheres. The RSM time = 8 min, and temperature = 31.5°C. The relative
results are shown in Figure 2. As shown in Figure 2A, the enzyme activity predicted by software was 102%, and the
effect of two factors, SA concentration and crosslinking measured value was 103.3%, which were consistent and
time, on the interaction of PFDH activity was studied. reliable. Therefore, we used optimized conditions for 3D
Effects of SA concentration and temperature on PFDH printing immobilized PFDH to study the application of
activity are shown in Figure 2B. Similarly, Figure 2C shows formaldehyde removal, which provides an insight into the
the influence of CaCl concentration and SA concentration biological degradation of formaldehyde.
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on PFDH activity. The curves in Figure 2A–C similarly
show downward inclination, but the curve in Figure 2C 3.3. 3D-printed PFDH/CA microspheres
demonstrates huge color variation, indicating that SA As shown in Figure 3, three different sizes (1.5 mm,
concentration has more significant influence on the results. 2.5 mm, and 3.5 mm) of PFDH/CA microspheres were
As shown in Figure 2D, the effect of two factors, CaCl printed in this study based on the optimal combination
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and crosslinking time, on PFDH activity was explored. of printing conditions of RSM. The same concentration of
The results of CaCl concentration and temperature on PFDH solution was used to prepare 3D printing ink, and
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PFDH activity are shown in Figure 2E. The influence the printing needle and pressure were adjusted to prepare
of two factors, crosslinking time and temperature, on three different sizes of PFDH/CA microspheres. Therefore,
PFDH activity is demonstrated in Figure 2F. As shown in under theoretical conditions, the ink concentration of
Figure 2D–F, the trend first increases and then gradually 3D printing is the same, but more enzymes are present
decreases, with a distinct apex. The results of the RSM in printed microspheres of larger volume. Because of
showed that the model P-values of SA concentration and different crosslinking factors and particle sizes, the
CaCl concentration <0.05 indicated that the model terms activities of PFDH displayed by the three particles are also
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Volume 9 Issue 3 (2023) 123 https://doi.org/10.18063/ijb.695