Expression of nisin in Scenedesmus acutus and evaluation of its antimicrobial activity.

OBJECTIVES

The study aimed to express a synthetic nisin gene in the nucleus of the green microalga Scenedesmus acutus UTEX 72 and evaluate its antimicrobial activity in vitro against Staphylococcus aureus (ATCC 29213), Enterococcus faecalis (ATCC 29212), and Listeria monocytogenes (ATCC 19118).

RESULTS

Nuclear transformation of S. acutus was achieved through co-culture with Agrobacterium tumefaciens. PCR analysis confirmed the presence of the Nis gene in the transformant lines, while ELISA quantified the total protein content. Results showed that nisin was predominantly expressed in the total soluble protein fraction, with the highest yield reaching 2.24 µg/µl. Antimicrobial assays demonstrated growth inhibition in all three tested Gram-positive bacteria. S. aureus and L. monocytogenes were inhibited after 60 min of exposure to 14.3 µg/ml of transgenic nisin, whereas E. faecalis needed 55 µg/ml and 180 min for inhibition. No antimicrobial activity was observed with wild-type S. acutus total soluble protein.

CONCLUSIONS

Nisin was successfully expressed in the nucleus of S. acutus, exhibiting antimicrobial activity against S. aureus, L. monocytogenes, and E. faecalis. These findings highlight S. acutus as a promising platform for the production of transgenic antimicrobial peptides, offering a potential alternative for combating pathogenic bacteria.