Prospecting Ulva lactuca seaweed in Java Island, Indonesia, as a candidate resource for industrial applications

Ulva is an unutilized green seaweed that grows in the intertidal zone around the coast of Java Island, Indonesia. In this study, U. lactuca samples collected from three regions in south of Java Island (Cihara, Surade, and Tepus) were studied in terms of their chemical composition, physical properties and its bioactivity, to determine the best regions for establishing seaweed industries. The chemical characteristics differed significantly among different regions, where the seaweed from Tepus, Surade and Cihara had the highest content of protein (22.93%), carbohydrate (61.58%), and mineral (28.72%), respectively. The amino acids were dominated with L-aspartic acid and L-glutamic acid. All U. lactuca samples contained abundant pigments, such as chlorophylls and carotenoids, especially samples from Tepus. The highest content of crude ulvan was found in Surade seaweed (26.9%). Chemical and physical analyses showed the presence of S = O and C–O–S functional groups in ulvan, a sulfated polysaccharide unique to Ulva sp., with thermal degradation up to 220 °C. Crude ulvan from Surade and Tepus seaweed exhibited bioactivity to support proliferation of fibroblast cells at 100 and 1000 ppm, respectively. Based on the properties of U. lactuca, Tepus and Surade were identified as potential sites to establish aquaculture and/or processing industries.