Achieving the Best Yield in Glycolipid Biosurfactant Preparation by Selecting the Proper Carbon/Nitrogen Ratio

Abstract

Pseudomonas aeruginosa RS29, the native biosurfactant‐producing strain isolated from the oil fields of Assam, India was used to investigate the influence of the carbon nitrogen ratio on production of the biosurfactant. The biosurfactant producing ability of the strain was measured based on surface tension (ST) reduction of the culture medium and the emulsification (E24) index. Production was greatly influenced by the sources of nitrogen and carbon as well as the carbon to nitrogen (C/N) ratio. Sodium nitrate was the best nitrogen source and the water miscible carbon source, glycerol was observed as the best carbon source for maximum biosurfactant production. The C/N ratio 12.5 allowed the maximum production of biosurfactant by the RS29 strain. At this C/N ratio, 55 % ST of the culture medium was reduced by the produced biosurfactant. Concentrations of crude and rhamnolipid biosurfactant obtained at this particular C/N ratio were 5.6 and 0.8 g/l respectively. The RS29 strain was novel as it was able to produce a sufficient amount of biosurfactant utilizing a much lower amount of the water miscible carbon source, glycerol. Extraction of the biosurfactant by a chloroform–methanol (2:1) mixture was the best method to obtain the highest biosurfactant from the culture medium of the strain. The biosurfactant was confirmed as a mixture of mono and di‐rhamnolipid congeners, Rha–C10–C10–CH3 being the most abundant one. The biosurfactant was a good foaming and emulsifying agent.

Biosurfactant production by <italic>Pseudomonas aeruginosa</italic>in kefir and fish meal

“…Primarily, the amounts of the produced microbial surfactants depend on to the producer organism and factors like carbon and nitrogen sources, trace elements, and production conditions ( Patel and Desai, 1997 ). In the literature, there are studies focusing rhamnolipid production using different carbon sources ( Soberon-Chavez et al , 2005 ; Da Silva et al , 2009 ; Amani et al , 2013 ; Rikalovic et al , 2013 ; Saikia et al , 2014 ).…”

Surfactin from Bacillus velezensis H2O‐1: Production and Physicochemical Characterization for Postsalt Applications

“…Temperature is one of the physicochemical parameters that most influences lipopeptide production (Inès and Dhouha, 2015). In this study, we found that the optimal temperature for surfactin production by B. velezensis H2O-1 is about 30 C, i.e., a temperature commonly used for the production of surfactin by B. subtilis (Fisher and Sonenshein, 1991;Saikia et al, 2014).…”

“…The concentrations of these enzymes depend directly on the concentration of ammonia present in the culture medium. If nitrate is used as the sole source of nitrogen, it must first be reduced to ammonia and then enter the glutamate‐glutamine pathway (Saikia et al, ). Therefore, nitrate assimilation is slower, leading to low cell growth and, in the case of NaNO 3 , low surfactin production.…”

Glycolipid biosurfactants: main properties and potential applications in agriculture and food industry

“…Various reports have been published in recent past years on the cost reduction of glycolipid production via the substitution of high-cost medium ingredients by complex agro-industrial wastes. Many renewable resources such as agro-industrial waste, hydrocarbon wastes and vegetable oils have been used as the sole source of carbon for biosurfactant wileyonlinelibrary.com/jsfa 112,113 Cristallization Sophorolipid 96,114 production either by solid state fermentation or submerged fermentation. Several bacterial, 76,81,82 yeast, 25,83 fungal 84 and actinobacteria 11,60 strains were screened as glycolipid biosurfactant producers.…”