Biomonitoring of biosurfactant production by green fluorescent protein‐marked Bacillus subtilis W1012

Abstract

AbstractBACKGROUND: Biosurfactant production was investigated using two strains of Bacillus subtilis, one being a reference strain (B. subtilis 1012) and the other a recombinant of this (B. subtilis W1012) made able to produce the green fluorescent protein (GFP).RESULTS: Batch cultivations carried out at different initial levels of glucose (G0) in the presence of 10 g L−1 casein demonstrated that the reference strain was able to release higher levels of biosurfactants in the medium at 5.0≤G0≤10 g L−1 (Bmax = 104–110 mg L−1). The recombinant strain exhibited slightly lower levels of biosurfactants (Bmax = 90–104 mg L−1) but only at higher glucose concentrations (G0 ≥ 20 g L−1). Under these nutritional conditions, the fluorescence intensity linked to the production of GFP was shown to be associated with the cell concentration even after achievement of the stationary phase.CONCLUSION: The ability of the genetically‐modified strain to simultaneously overproduce biosurfactant and GFP even at low biomass concentration makes it an interesting candidate for use as a biological indicator to monitor indirectly the biosurfactant production in bioremediation treatments. Copyright © 2008 Society of Chemical Industry