RT journal article T1 Optimized ultrasound-assisted tryptophan extraction from Kappaphycus spp.: Enhancing bioactive compound profiling and cultivation strategies A1 Izmi, Nuzulia A1 Manikharda A1 Palma Lovillo, Miguel A1 Lideman A1 Rafi, Mohamad A1 Mareta, N. A1 Setyaningsih, Widiastuti A2 Química Analítica K1 Box behnken design; K1 Kapppaphycus alvarezii K1 Kapppaphycus striatum K1 Optimization K1 UPLC-FD AB Kappaphycus spp., a widely cultivated seaweed, is valued for its diverse bioactive compounds, including tryptophan. This study aimed to optimize and validate an ultrasound-assisted extraction (UAE) method to quantify tryptophan using a Box-Behnken design integrated with response surface methodology. The factors evaluated included solvent composition (50–90 % methanol in water), pH (2–8), ultrasound amplitude (25–75 %), and pulse duty cycle (0.2–1.0 s⁻¹). The optimized extraction variables—73 % methanol in water, pH 8, 58 % ultrasound amplitude, and a 0.8 s⁻¹ pulse duty cycle at 60 °C for 10 min—achieved high recovery (>90 %) and precision (CV <5 %). This method was applied to 36 samples of Kappaphycus alvarezii and Kappaphycus striatum, revealing significant variations in tryptophan content based on species, environmental factors, and farming methods. Notably, K. striatum from Sekotong (Lombok) cultivated via the longline method exhibited the highest tryptophan yield. The findings underscore the potential of optimized UAE for supporting seaweed biotechnology and enhancing bioactive compound production through improved cultivation strategies. PB Elsevier B.V. SN 2772-5022 YR 2025 FD 2025 LK http://hdl.handle.net/10498/38615 UL http://hdl.handle.net/10498/38615 LA eng DS Repositorio Institucional de la Universidad de Cádiz RD 08-nov-2026