Surfactin is one of the most representative biosurfactants and exhibits excellent surface activity plus other biological effects. It has potential applications in microbial enhanced oil recovery, environmental bioremediation, agricultural bio-control, pharmacy, cosmetics food industries. The low yield surfactant from wild strains a key restriction for industrial applications. construction genet...

Undomesticated strains of Bacillus subtilis exhibit extensive colony spreading on certain soft agarose media: first the formation of dendritic clusters of cells, followed by spreading (pellicle-like) growth to cover the entire surface. These phases of colonization are dependent on the level of potassium ion (K(+)) but independent of flagella, as verified with a mutant with a hag gene replacemen...

An increasing number of studies have investigated the effects of nanoparticles (NPs) on microbial systems; however, few existing reports have focused on the defense mechanisms of bacteria against NPs. Whether secondary metabolism biosynthesis is a response to NP stress and contributes to the adaption of bacteria to NPs is unclear. Here, a significant induction in the surfactin production and bi...

Poly-γ-glutamic acid (γ-PGA) is an important natural biopolymer that is used widely in fields of foods, medicine, cosmetics, and agriculture. Several B. amyloliquefaciens LL3 mutants were constructed to improve γ-PGA synthesis via single or multiple marker-less in-frame deletions of four gene clusters (itu, bae, srf, and fen) encoding antibiotic substances. γ-PGA synthesis by the Δsrf mutant sh...

Bacillus subtilis DZSY21 isolated from the leaves of Eucommia ulmoides oliv. was labeled by antibiotic marker and found to effectively colonize the leaves of maize plant. Agar diffusion assays and biocontrol effect experiments showed that strain DZSY21 and its lipopeptides had antagonistic activity against Bipolaris maydis, as well as high biocontrol effects on southern corn leaf blight caused ...

The srfA operon of Bacillus subtilis functions in the biosynthesis of the lipopeptide antibiotic surfactin. On the basis of nucleotide sequence and genetic analysis, it is believed to encode three enzymes (E1A, E1B, and E2) that catalyze the incorporation of the surfactin substrate amino acids. Insertion, deletion, and amino acid substitution mutations of srfA were analyzed for subunit composit...

This work concerns the study of the enhancement of surfactin and fengycin production by B. mojavensis A21 and application of the produced product in diesel biodegradation. The influences of the culture medium and cells immobilization were studied. The highest lipopeptides production was achieved after 72 hours of incubation in a culture medium containing 30 g/L glucose as carbon source and a co...

Urokinase-type plasminogen activator (u-PA) is a serine protease that cleaves Arg561-Val562 bond in plasminogen to convert it to the active serine protease plasmin, which is involved not only in blood clot dissolution but also in a variety of physiological and pathological processes requiring localized proteolysis1). u-PA is synthesized and secreted as a single-chain zymogen form (pro-u-PA)2). ...