Efficient production of ectoine using isolated <i>Halomonas smyrnensis</i> IIIM VA-6 at the reduced salinity approach

This study optimizes sustainable ectoine production in reduced salinity and minimal media to meet demands in pharmaceuticals, food, and cosmetics, isolating a halophilic bacterium 99.1% similarity to Halomonas smyrnensis from Sambhar Salt Lake. Optimization of ectoine production was performed using the one-variable-at-a-time method and response surface methodology, assessing variables such as carbon and nitrogen sources, incubation time, pH, temperature, inoculum density, agitation rate, and salinity. High-performance liquid chromatography confirmed total ectoine production, which increased from 0.54 to 6.5 g/l, a 12.03-fold enhancement compared to initial unoptimized conditions. The optimal ectoine yield by H. smyrnensis IIIM VA-6 was achieved after 72 h under conditions of 5% (w/v) salinity, 2.5 % monosodium glutamate, pH 5.0, 10.0 g/l lactose, and 250 rpm agitation, and characterized by Fourier transform infrared spectroscopy, nuclear magnetic resonance, and liquid chromatography mass spectrometry. This study represents a significant improvement in sustainable production of ectoine under reduced salinity conditions using a halophilic strain.