Purification and characterization of macrolactins and amicoumacins from Bacillus licheniformis BFP011: a new source of food antimicrobial substances

Nida Arbsuwan,Wisarut Payoungkiattikun,Pisan Sirithorn,Sakda Daduang,Nisachon Jangpromma,Apisak Dhiravisit,Young Tae Hahm,Lorenz Kurt Neubert,Sompong Klaynongsruang

doi:10.1080/19476337.2017.1337047

Abstract

ABSTRACTIn this study, Bacillus licheniformis BFP011 has been cultivated for producing antimicrobial compounds, which were concentrated from the crude supernatant and purified using thin-layer chromatography. The antimicrobial activity was investigated in the presence of several organic solvents and detergents, and inhibiting effects to various Gram-negative and Gram-positive human pathogenic and food spoilage bacteria were observed. Three bands (F4, F5 and F6) showing antimicrobial activity against Salmonella typhi ATCC 5784 were subjected to reversed-phase high-performance liquid chromatography purification. Two peaks of fraction F5, F5-P3 and F5-P4, showed 100% inhibition against S. typhi ATCC 5784. The contained mixture of antimicrobial compounds consists of macrolactins and amicoumacins, which induced the collapse and breaking of S. typhi ATCC 5784 cell membranes in a time-dependent manner. Taken collectively, the results indicate that these compounds may represent promising candidates for the development of food preservative agents of natural origin, as well as novel antimicrobial drug candidates against multiresistant bacterial strains.

Highlights

Throughout half a century, numerous industrially important species belonging to the genus of Bacillus have been discovered (Nascimento & Martins, 2006; Sun et al, 2015; Suwanmanon & Hsieh, 2014) and found to be valuable for genetic and biochemical studies
Partial purification of crude BFP011 supernatant by Thin-layer chromatography (TLC) technique A previous study conducted in our lab demonstrated that the antimicrobial substances of B. licheniformis BFP011 produced in stationary phase cultures might be secondary metabolites (Arbsuwan et al, 2014)
The five major peaks in the LC chromatogram for fraction F5-P4 (Figure 5 (a)) were associated with mass peaks [M + H]+ at m/z ratios of 485.36 (Figure 5(b)), 402.21 (Figure 5(c)), 437.23 (Figure 5 (d)), 569.31 (Figure 5(e)) and 662.22 (Figure 5(f)), which were identified as 7-O-malonyl macrolactin A, macrolactin A (Romero-Tabarez et al, 2006), macrolactin M (Nagao, Adachi, Sakai, Nishijima, & Sano, 2001), macrolactin B or C and, macrolactin D (Kang et al, 2012), respectively (Table 2). These results suggest that the pronounced antimicrobial activity against S. typhi ATCC 5784 is strongly dependent on the composition of macrolactins and amicoumacins in the mixture

Summary

Introduction

Throughout half a century, numerous industrially important species belonging to the genus of Bacillus have been discovered (Nascimento & Martins, 2006; Sun et al, 2015; Suwanmanon & Hsieh, 2014) and found to be valuable for genetic and biochemical studies. Have been studied in terms of the potential to produce numerous antibiotics, predominantly peptides including surfactins, fengycins and iturins (Lee et al, 2012; Oh et al, 2011; Schneider et al, 2007; Stein, 2005). Were shown to inhibit the growth of Gram-positive and Gram-negative human pathogenic bacteria and phytopathogens (Lee et al, 2012; Wu et al, 2005). Apart from peptides, polyketides are the other dominant family of secondary metabolites having antimicrobial, immunosuppressive, antitumor or other physiologically relevant bioactivities. Polyketides are widespread secondary metabolites from bacteria, only a few have been isolated and characterized from Bacillus (Schneider et al, 2007). In a recent example employing polyketides produced by B. subtilis as non-peptide-based antibiotics, including macrolactin A, 7-O-macrolactin A and 7-O-

Methods

Results

Conclusion