**4. Conclusions**

As a conclusion, in-situ bio-fabrication of Ag-NPs in alkaline treated*C. pentandra* fiber as supporting materials were successfully assembled using *E. spiralis* extract and AgNO3 solution. This method also is significant to control the bioavailability and bioactivity of Ag-NPs in the antibacterial and dye reduction catalytic application. In addition, the incorporation of Ag-NPs in the *C. pentandra* fiber can control the adverse effect of nanoscale of Ag-NPs by strong association of Ag-NPs with the negatively charged of functional group in the cellulose of *C. pentandra* fiber. The TGA analysis also shows that the possible mechanism of loading of Ag-NPs into treated *C. pentandra* fiber occurred at cellulose region and alkaline treatment helped to expose more cellulose region for loading of Ag-NPs into *C. pentandra* fiber. The characterization studies clearly showed the significant of *E. spiralis* extract as reducing and stabilizing agents added for loading of Ag-NPs on the *C. pentandra* fiber surface. The prepared *C. pentandra*/Ag-NPs also exhibited good antibacterial activity towards both Gram-positive and Gram-negative bacteria *S. aureus, E. faecalis, E. coli* and *P. vulgaris*. *C. pentandra*/Ag-NPs also display the ability as catalytic activity towards the Rhodamine B and methylene blue dyes. The *C. pentandra*/Ag-NPs have potential as a promising nanomaterial for biomedical applications such as for wound healing and coating of biomaterials, wastewater treatment, food packaging and textile in the wide range of microorganism.

**Author Contributions:** Synthesis, experimental works and writing original draft, W.K.A.W.M.K.; supervision, review and editing, K.S.; dye catalytic analysis or interpretation of data, review and editing, N.W.C.J.; Sample characterization, N.A.O.; antibacterial analysis or interpretation of data, review and editing, N.M.H. and S.D.J. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Acknowledgments:** The authors would like to express sincere gratitude to the Universiti Teknologi Malaysia for financial support under research university grants (Grants No. #4B422, #15H73, #20H33 and #20H55). All authors are thankful to Malaysia–Japan International Institute of Technology (MJIIT) of UTM for providing an excellent research environment to complete this work.

**Conflicts of Interest:** The authors declare no conflict of interest.
