Production of lipopeptide biosurfactants by Bacillus atrophaeus 5-2a and their potential use in microbial enhanced oil recovery

Table 3 Dry cell weight (g L⁻¹), crude biosurfactant yield (g L⁻¹), oil spreading (cm), emulsification index (%), and surface tension (mN m⁻¹) obtained from Bacillus atrophaeus 5-2a in BB and BU media

Medium	Dry cell weight (gL⁻¹)	Crude biosurfactant yield (gL⁻¹)	Oil spreading (cm)	Emulsification index (%)	Surface tension (mN m⁻¹)	Yield (g g⁻¹)
BB	1.34 ± 0.014a	1.01 ± 0.016a	19.9 ± 0.071a	54.73 ± 0.085b	25.47 ± 0.042b	0.75
BU	0.95 ± 0.028b	0.77 ± 0.014b	19.1 ± 0.10b	59.49 ± 0.33a	26.52 ± 0.057a	0.81

Values are presented as the mean ± standard deviation (n = 3). Different superscript letters within a column indicate significant differences (P < 0.05) by Duncan’s multiple range test. BB for the fermentation medium used brown sugar, beef extract and peptone as the carbon and nitrogen sources; BU for the optimal medium used brown sugar and inorganic nitrogen urea as the carbon and nitrogen sources. The same as below, unless otherwise specified

ISSN: 1475-2859