## 1 Introduction  
Biorefining research and exploration has consistently been one of the cutting-edge techniques as a substituting strategy for exhaustible fossil resources in light of the rising environmental challenges of fossil fuel overuse [1, 2, 3, 4, 5, 6]. Microbial fermentation, as an essential component of biorefinery engineering, provides sustainable bioenergy or chemicals by using natural biomass resources as ingredients to produce green chemical raw materials, promoting social and economic sustainability, and adhering to current carbon neutrality [7, 8]. Despite a wide range of applications, the inherent issues of conventional microbial fermentation systems, such as environmental blockage, product inhibition, and cell elution, have always been detrimental to fermentation output and efficiency. Therefore, developing an appropriate delivery system is critical to protect sensitive cells from adverse environments and improve metabolic product yield. The immobilized cell fermentation technique (IMCF) aims to constrain the cells to the water-insoluble carrier that supports cell growth and metabolism. This IMCF system can be desirable over freely suspended cells since immobilization normally promotes an improvement in metabolic performance, cell stability, and product separation during fermentation, as well as permitting repeated catalysis for adherent cells [9, 10]. In IMCF, it is crucial to establish an applicable carrier or scaffold that facilitates cell growth and the metabolism process since the surface chemistry of the immobilized carrier material can affect the activity and stability of immobilized cells [11; 12]. Diverse carriers have recently been developed for cell immobilization to achieve excellent mass transfer and long-term cell viability. [PERSON] et al. established a calcium pectate gel immobilized system to entrapped _Lactobacillus casei_ for L (+) lactic acid production from whey, and the optimized pectate-entrapped bacterial cells achieved a high lactose conversion and corking reusing ability [13]. Despite the most frequently utilized matrix in IMCF, natural materials such as Ca-alginate and pectin are solely focused on mass transfer enhancement and cell biocompatibility. Due to their low mechanical strength and susceptibility to corroded corrosion, natural carriers cannot retain stability against agitation and shear. To provide sufficient mechanical properties, inorganic mesoporous material was developed as support for the advantages of large specific surface area, narrow void distribution, and good resistance against biodegradation [14; 15; 16]. [PERSON] and colleagues absorbed _Lactobacillus rhamns_ (_L. rhamns_) in mesoporous silica-based carriers under mild conditions and the Isi-_L. rhamns_ exhibited excellent reusability for lactic acid production due to its stabilization against disruption [17]. However, this attachment approach could not efficiently capture cells and is easy to cause leakage of already immobilized cells throughout the fermentation process due to the weak binding effect. Mechanical strength in highly stable cell-carrier systems can also be enhanced through the use of other strategies, such as synthetic polymer and composite materials. [PERSON] et al. designed a 3D-printed porous nylon bead and modified the microbead with polycationic polythermimide (PEI) [18]. Such microbeads are very stable against stirring and acidic conditions, and the cell-bound microbeads may be used as inoculants even after extended storage. Nevertheless, the cells could not adhere to the 3D-printed nylon bead lack of PEI better; conversely, treatment of the beads with PEI decreased productivity due to the polycation's inhibitory action. It is still tough to immobilize cells in a polymeric porous carrier that is both mechanically robust and highly active in the culture medium environment.