Characterization and In Vitro Study of L-Methioninase from Red Algae Symbiont Bacteria Eucheuma spinosum as Anticancer and Antioxidant Materials

L-methioninase has recently gained significant attention, particularly for its potential as an anticancer agent. The biodiversity of marine organisms, particularly the red alga Eucheuma spinosum, holds promising potential as a source of anticancer compounds, as supported by toxicity data from several previous studies. This research aimed to isolate the L-methioninase enzyme from symbiotic bacteria of the red macroalga Eucheuma spinosum collected from Pajukukang District, Bantaeng, Indonesia, for use as an anticancer and antioxidant agent. Screening and identification of bacterial isolates revealed the species Providencia stuartii strain ES 2 (1). Fractionation using ammonium sulfate revealed the highest enzyme activity in fraction F3 (60–80%), with 26.6524U/mL and a specific activity of 7.2326U/mg. The optimal L-methioninase enzyme activity was observed at pH 7, 40°C, and 30 minutes of incubation time. Metal ions such as Ca²⁺, Mg²⁺, and Co²⁺ acted as enzyme activators. The brine shrimp lethality test (BSLT) using Artemia salina Leach shrimp larvae and antioxidant tests by the DPPH method yielded an LC50 value of 149.23ppm and an IC50 value of more than 1800ppm. This classifies it as toxic and indicates strong potential for anticancer applications, but not as an antioxidant material