Laboratoire de Procédés Biologiques, Génie Enzymatique et Microbien (ProBioGEM, UPRES EA 1026), Polytech'Lille, IUT A, Université des Sciences et Technologies de Lille, Boulevard Paul, Villeneuve d'Ascq Cedex, France.
J Appl Microbiol. 2010 Aug;109(2):480-491. doi: 10.1111/j.1365-2672.2010.04683.x. Epub 2010 Jan 22.
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.
The srfA native promoter was replaced by the constitutive promoter P(repU) 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 P(repU), than that found with P(srfA), 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.
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.
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.
分析枯草芽孢杆菌 168 中 plipastatin 操纵子缺失和 surfatin 操纵子组成型表达对 surfatin 生产力、体外侵袭性生长和抗真菌作用的影响。
在整合功能性 sfp 基因后，将 srfA 天然启动子替换为枯草芽孢杆菌 168 中的组成型启动子 P(repU)。此外，在枯草芽孢杆菌 168 衍生物中进一步破坏了 plipastatin 的合成。在液体培养基中，与 P(srfA)相比，P(repU)更早且更高的表达导致培养 6 小时后特异性 surfatin 产量提高了五倍。在固体培养基上，与亲本菌株 BBG111 相比，组成型菌株的侵袭性生长和溶血活性以及抗真菌活性都得到了改善。正如预期的那样，plipastatin 操纵子的缺失强烈降低了体外抗真菌特性，但有趣的是，它增强了菌株的特异性 surfatin 生产（1.47 g g(-1) 生物质）、扩展行为和溶血活性。
这项工作首次证明了 surfactin 和 plipastatin 之间在生物合成以及它们对产生菌株的生物活性的影响方面存在相互依存关系。
组成型过表达 surfatin 增强了突变株的侵袭性生长和体外拮抗活性。这两种特性都被认为在植物病害的生物防治中起着重要作用。Plipastatin 操纵子缺失增加了突变株的 surfatin 生产力。这些突变体在连续生物过程中用于 surfatin 生产或生物修复很有趣。
