Identification of Non-Ribosomal Peptide Synthetase Modifications Involved in Surfactin Production and Quorum-sensing Operon of Bacillus subtilis MJ01 Isolated from Oil-Contaminated Soil

Abstract

The isolation of native microorganism that produced biosurfactants in order to oil pollutants bioremediation and hydrophobic oil hydrocarbons availability inter soil texture has become important issues in bioremediation technology. Surfactin is one of the biosurfactants with more application that produced by Bacillus subtilis strains could overcome these problems. Thus in this study, we investigated operon which involved in surfactin biosynthesis and its regulator comQXPA operon due to a high level of surfactin biosynthesis by B. subtilis MJ01 isolated from oil contaminated soil based on comparative genomics approaches. Surfactin operon localized and compared among six genomes of close relative strains and MJ01 indicated that missense point mutations on genes of surfactin operon were existence. These mutations affected NPRS protein AMP-binding domain that responsible to bind amino acid to correct the situation on surfactin peptide ring. It seems that lack of hemolytic and anti-microbial function of MJ01 surfactin was due to the creation of missense mutation and modifications in the surfactin biosynthesis NPRS enzyme structure. Moreover, srf genes expression regulated by comQXPA‏ quorum sensing operon. MJ01 Quorum sensing operon rearrangement showed that part of the comQ gene was extended into comX gene and these genes had overlap region. Results suggested that in MJ01 genome has been occurred specific combination of QS genes organization. Despite high similarity of three genes comQXP‏ among MJ01 with BEST7613 and other subtilis strains group, comA gene showed high identity with spizizenii strains group‏.