## 2 Organic-Inorganic Hybrid Nanofibers
### Conventional HNFs Immobilized Enzymes  
HNFs can be obtained by mixing metal ions, phosphate, and enzyme solutions and allowing them to co-incubate. Among the various enzyme nanoflowers studied, there has been a significant focus on single-enzyme HNFs, with enzymes such as laccase [49], lipase [50], horseradish peroxidase (HRP) [51], glucose oxidase (GOx) [52], \(\alpha\)-amylase [53], urease (Ur) [54], and papain [55] being successfully prepared in the form of single-enzyme HNFs [3] (see Table 1). \begin{table}
\begin{tabular}{c c c c c} \hline
**Enzyme** & **Metal Ions** & **Applications** & **Improved Performance** & **Ref.** \\ \hline \(\omega\)-Transaminase & Co2\({}^{*}\) & Production of chiral amines & Enhanced reusability & [56] \\ \hline lipase & Zn2\({}^{+}\) & \begin{tabular}{c} Regioselective acylation of \\ arbutin \\ \end{tabular} & Enhanced reusability & [57] \\ \hline L-arabinose isomerase & Mn2\({}^{+}\) & Synthesis of \(D\)-tagatose & \begin{tabular}{c} Enhanced reusability and \\ storage stability \\ \end{tabular} & [58] \\ \hline Lactoperoxidase & Cu2\({}^{+}\) & \begin{tabular}{c} Detection of dopamine and \\ epinephrine \\ \end{tabular} & \begin{tabular}{c} Enhanced activity, pH \\ stability, and reusability \\ \end{tabular} & [59] \\ \hline Lipase from thermomyces & \begin{tabular}{c} \\ Lanuginosus \\ \end{tabular} & Ca2\({}^{+}\) & Proof of concept & \begin{tabular}{c} 21.7 times more catalytic \\ activity and \\ thermal stability than a free \\ enzyme \\ \end{tabular} & [60] \\ \hline Phosphotriesterase & Co2\({}^{+}\)\& Mn2\({}^{+}\) & \begin{tabular}{c} Use in nerve agent (GD and \\ VX) degradation \\ \end{tabular} & \
\begin{tabular}{c} Enhanced stability and \\ reusability \\ \end{tabular} & [61] \\ \hline Burkholderia cepacia & Ag\({}^{+}\)/Fe2\({}^{+}\)/Cu2\({}^{+}\)/Au3\({}^{+}\) & Proof of concept & Enhanced stability & [62] \\ \hline Aldehyde/ketone reductase &
\begin{tabular}{c} Synthesis of (S)-1-(2,6- \\ dichloro-3-fluorophenyl) \\ ethyl alcohol \\ \end{tabular} & Enhanced thermal stability & [63] \\ \hline \end{tabular}
\end{table} 
Table 1: Summary of HNF applications and enhanced performance. In the majority of reported cases, hybrid nanoflowers (HNFs) exhibit higher catalytic activity compared to the corresponding free enzymes. This phenomenon can be attributed to the following reasons [2; 15; 50]: (1) Increased surface area: The larger surface area of nanoflowers facilitates the enrichment of substrates around the enzyme, thereby enhancing the catalytic efficiency. (2) Metal Activation: Certain metal enzymes can be activated by the metal ions present in the nanoflowers. (3) Conformational favorability: Enzymes immobilized through coordination bonds in nanoflowers can maintain a conformation favorable for catalysis. The enhanced stability observed in HNFs is attributed to the interaction between the rigid inorganic precipitate and the flexible enzyme. This interaction provides a rigid framework for the enzyme, reducing the degree of conformational change. As a result, it prevents enzyme denaturation under extreme conditions, improving the stability of the enzyme in complex environments and under various conditions [60; 71]. In practical production processes, single-enzyme HNFs may not be suitable when multiple enzymes are involved in a reaction. Single-enzyme HNFs struggle to rapidly remove unstable intermediates, hindering the progress of the reaction. In contrast, multi-enzyme HNFs, based on the simultaneous immobilization of multiple enzymes, prove more effective. The co-immobilization of enzymes not only reduces the cost of repetitive operations but also brings enzymes closer together. This proximity facilitates the transfer of intermediates between different enzymes in cascade reaction systems [72; 73]. [PERSON] et al. reported the co-immobilization of cellulase, endoglucanase, and \(\beta\)-glucosidase to prepare multi-enzyme HNFs (ECG-NFs) for the one-pot conversion of cellulose to glucose.