Francis Reuben Paul A. Padayao, Owen Brylle L. Acosta, Rosanna I. Ramos, Reyna Marie Therese S. Sanchez, Mary Hannah Rose A. Padayao, Jonie C. Yee, Kenji Arakawa, Norman G. Quilantang
The targeted fermentation of marine seaweed by indigenous microbial isolates offers a promising approach to unlock novel bioactivities and diversify the chemical repertoire of seaweed-derived products. This study investigated the fermentation of the red seaweed Halymenia durvillei using its indigenous Bacillus species, namely B. altitudinis (FHB1), B. australimaris (FHB2), and B. safensis (FHBS), to assess improvements in biological activities and chemical complexity. Overall enhancement in antibacterial, anthelmintic, and radical scavenging activities was observed in fermented H. durvillei (FHB1, FHB2, and FHBS) compared to the unfermented control (UFH). Notably, FHBS exhibited the most potent bioactivity in all the assays performed. Chemical profiling by ESI-MS/MS revealed a significant increase in chemical diversity in FHBS relative to UFH, identifying 45 unique compounds, including bioactive surfactin clusters, menaquinones, astaxanthin, deoxyspergualin, and various fatty acids and esters, which are likely contributors to the observed enhanced bioactivity. These results suggest that indigenous seaweed-associated Bacillus species contribute to the biotransformation and release of bioactive compounds in H. durvillei, emphasizing the potential of indigenous microbial fermentation as a tool for developing functional marine bioproducts. Microbial bioprocessing, therefore, represents a transformative and sustainable approach in marine biotechnology, significantly enhancing the pharmacological potential of seaweed. © 2025 The Authors
Applied Microbiology and Molecular Biology Laboratory, Department of Biology, University of San Carlos, Cebu City, 6000, Philippines; Department of Mathematics and Natural Sciences - Biology, Cebu Institute of Technology-University, Cebu City, 6000, Philippines; Department of Molecular Biotechnology, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, 739-8526, Japan
