Effect ofppsdisruption and constitutive expression ofsrfAon surfactin productivity, spreading and antagonistic properties ofBacillus subtilis168 derivatives

Abstract

Aims: To analyse the effects of plipastatin operon disruption and constitutive expression of surfactin operon in Bacillus subtilis 168 on surfactin productivity, in vitro invasive growth and antagonism against fungi. Methods and Results: The srfA native promoter was replaced by the constitutive promoter PrepU in B. subtilis 168 after integration of a functional sfp gene. Moreover, the plipastatin synthesis was further disrupted in the B. subtilis 168 derivatives. In liquid media, an earlier and higher expression of PrepU, than that found with PsrfA, led to a specific surfactin production fivefold higher after 6 h of culture. On solid media, not only the invasive growth and the haemolytic activity but also the antifungal activity of the constitutive strains were improved when compared to the parental strain BBG111. As expected, the disruption of the plipastatin operon strongly reduced in vitro antifungal properties but, interestingly, enhanced specific surfactin production (1·47 g g−1 of biomass), spreading behaviour and haemolytic activity of the strains. Conclusions: This work demonstrates for the first time the interdependency of surfactin and plipastatin regarding their biosynthesis as well as their influence on the biological activities of the producing strain. Significance and Impact of the Study: The constitutive overproduction of surfactin enhances the invasive growth and the in vitro antagonistic activity of the mutant strain. Both properties are known to play an important role in the biocontrol of plant diseases. Plipastatin operon disruption increases the surfactin productivity of mutant strains. These mutants are interesting for use in continuous bioprocesses for surfactin production or in bioremediation.

Microbial competition between Bacillus subtilis and Staphylococcus aureus monitored by imaging mass spectrometry

“…, a concentration that is in agreement with previous findings (Coutte et al, 2010). A similar observation of directional release of surfactin and consequent S. aureus inhibition was made with a B. subtilis isolate from human skin (Fig.…”

ESI LC-MS and MS/MS Characterization of Antifungal Cyclic Lipopeptides Produced by <b><i>Bacillus subtilis </i></b>XF-1

“…It is possible that there is little to no production under current cultivating conditions. This seems to be consistent with the results of a previous study showing that fengycin production inhibits surfactin production [Coutte et al, 2010]. However, the details of the regulation of gene expression in this specific strain need further investigation.…”

Surfactin and Other Lipopeptides from Bacillus spp.

“…Presence of polypropylene carriers in a batch culture ) or use of a polypropylene membrane (Coutte et al 2010a) to aerate bioreactors (bubbleless process see Sect. 6) increases the biosynthesis of fengycin.…”

“…Firstly obtained by random mutagenesis (Lin et al 1998;Yoneda et al 2002), overproducing mutants were then constructed by promoter exchange. The four main promoters used are P repU (Tsuge et al 2001a;Leclère et al 2005;Coutte et al 2010a), P xyl (Fickers et al 2009), P spac (Sun et al 2009) and P amyQ (Ongena et al 2007). Disruption mutants were also obtained by introducing resistance genes into synthetase operons (Coutte et al 2010a).…”