Factors affecting rhamnolipids production by Pseudomonas Aeruginosa LBI

Abstract

This paper presents the results from study investigating the capacity of Pseudomonas aeruginosa LBI growing on several carbon (Hydrophilic substrate) and nitrogen sources. The carbon source (2%) studied were: glycerol, manitol, fructose, glucose, lactose and the nitrogen sources (2; 3; 4 and 5%) were: NaNO3, NH4NO3, (NH4)2SO4 and (NH2)2CO. At the 96 h of fermentation, the medium with glycerol as a carbon source reached 7.9 g/L of rhamnolipids and 1.2 g/L cellular protein. The surface tension reduction was 38.46 % for glycerol as a carbon source. The NaNO3 at 3% was the best concentration for rhamnolipids production (7.35 g/L) and cellular protein (1.12 g.L). The influences of metal ions [FeSO4.7H2O (0.001 g/L, 0.005 g/L and 0.1 g/L)] and MgSO4.7H2O (0.001 g/L, 0.005 g/L and 0.1 g/L)] on ramnolipids production were studied. Fe2+ had a negative influence on the studied concentrations while Mg2+ had a positive influence when its concentration was increased.