Co-metabolism of substrates by Pseudomonas aeruginosa NG4 regulates biosurfactant production

Abstract

As compared to chemical surfactants, biosurfactants exhibit a more significant impact in various sectors due to their degradability, stability, and other specific physicochemical properties. Biosurfactant production by Pseudomonas aeruginosa NG4 was studied by co-metabolism of 1% glucose (wv⁻¹) and 1% CG (vv⁻¹) with different time intervals. The addition of Glucose (0h) + CG (24 h) (1:1, wv⁻¹, vv⁻¹) to the culture medium resulted in 4.23 gL^-1 of biosurfactant production. An enhancement of about 4.75-fold in the yield was observed. The time period of incubation of CG in the feed was optimized to be 24 h after the initiation of fermentation with glucose. Among the several nitrogen sources used in this study, sodium nitrate produced more biosurfactant than the others. Biochemical characterization through FTIR and LC-MS of biosurfactant reflected the presence of mono- and di-rhamnolipids. Therefore, this study highlights the ability of P. aeruginosa NG4 to increase biosurfactant production by co-utilizing substrates.