Abstract
OBJECTIVE: Algae contain many symbiotic bacteria, often considered pollutants in algal cultivation. Recent studies indicate that these connections enhance the longevity of both organisms. Researching the bioactive metabolites of marine bacteria has emerged as a promising strategy for drug discovery. Green algae, including Caulerpa lentillifera, have anticancer activity and possess antioxidant qualities. The research emphasizes the isolation and identification of beneficial proteins from symbiotic bacteria, particularly Caulerpa lentillifera. METHODS: The stages of the research included isolation and identification of the endophytic bacteria of the green alga symbiont C. lentillifera, isolation of protein from the bacterial symbiont, fractionation, hydrolysis, ultrafiltration of protein into peptides, and testing for activity. Screening activities used the BSLT to obtain the value of LC50, and the mitotic test of the sea urchin zygote cell Tripneustes gratilla Linn to find the value of IC50. RESULTS: The results of this study indicated that the bacterial symbiont of the algae C. lentillifera was a species of Cobetia marina strain CL2-2. The peptide with molecular weight < 3 kDa from Cobetia marina strain CL2-2 was active. The peptide was from protein deposited with 40-60% saturated ammonium sulfate and hydrolyzed using pepsin enzyme. BSLT toxicity tests indicate that peptides with a molecular weight of less than 3 kDa showed significant toxicity, indicated by an LC50 value of 4.061 ppm. In a mitotic cytotoxicity test involving sea urchin zygote cells, peptides with a molecular weight of less than 3 kDa indicated significant cytotoxic activity, resulting in an IC50 value of 7.236 μg/mL. CONCLUSION: The bioactive peptide with molecular weight of less than 3 kDa resulting from protein hydrolysis isolated from the green algae symbiont C. lentillifera has the potential as an anticancer agent.