Enhancement of Bacillus subtilis Lipopeptide Biosurfactants Production through Optimization of Medium Composition and Adequate Control of Aeration

Table 2

Effect of the variation of organic nitrogen source on biomass and biosurfactant production by Bacillus subtilis SPB1 strain.

Organic nitrogen source	Biosurfactants (mg/L)	Biomass (10^7 CFU/mL)	*Relative biosurfactants yield (mg/10^10 CFU)
Casein hydrolysate	630±5	25±1	25.20
Beef extract	600±11	24±3	25.00
Urea	720±5	27±2	26.66
Pancreatic digest of casein	660±9	28±3	23.57
Yeast extract	660±10	27±1	24.44

*Relative biosurfactant yield was calculated as the ratio of biosurfactant (mg/L) over CFU (10¹⁰ CFU/L), both of them were determined at the end of fermentation.