Antibiotic resistance has become one of the world’s most severe problems because of the overuse of antibiotics. Antibiotic-resistant bacteria are more difficult to kill and more expensive to treat. Researchers have been studied on antibiotic alternatives such as antimicrobial peptides and lipopeptides. A functional bacteria MB01 producing lipopeptides which can be used as bacteriostat was isolated from the Bohai Sea sediments, which had been identified as Bacillus licheniformis by the morphological, physiological, and biochemical identification and 16s rDNA sequence. The lipopeptides produced by MB01 were determined to be cyclic surfactin homologs by LC-ESI-MS structural identification after crude extraction and LH-20 chromatography. [M+H]+ m/z 994, 1008, 1022, and 1036 were all the characteristic molecular weight of surfactin homologs. CID analysis revealed that the molecular structure of the lipopeptides was Rn-Glu1-Leu/Ile2-Leu3-Val4-Asp5-Leu6-Leu/Ile7. The lipopeptides showed well resistance to UV light and the change of pH and temperature.

A two-step ultrafiltration and liquid chromatography-electronic spray ionization-tandem mass spectrometry (LC–ESI–MS/MS) were applied to investigate the nature of lipopeptides in the methanol extract harvested from marine Bacillus megaterium. The structure of lipopeptide homologs were characterized by using collision-induced dissociation mass spectrometry analysis. Collectively, two kinds of linear fengycin A and B with a double bond were characterized for the first time besides the popular cyclic fengycin A and B with the difference in the amino acid at position 6 of the peptide moiety. It is worth noting that two kinds of linear isoforms of surfactins and two kinds of cyclic isoforms of esperin with a smaller peptide ring formed by the fifth l-Asp and β-hydroxy fatty acid were also separated and identified in addition to the all seven kinds of cyclic isoforms of surfactins. Only one analogue (bacillomycin D) of iturin family was identified in this research. To our best knowledge, this is the first report that more than 40 variants of lipopeptides from one strain of Bacillus were identified using our potent purification and identification methods.Electronic supplementary materialThe online version of this article (doi:10.1186/s13568-016-0252-6) contains supplementary material, which is available to authorized users.

Aflatoxins are highly carcinogenic, teratogenetic, and morbigenous secondary metabolites of Aspergillus flavus and A. parasiticus that can contaminate multiple staple foods, such as peanut, maize, and tree nuts. In this study, Zygosaccharomyces rouxii was screened out and identified from fermented soy paste-one kind of traditional Chinese food-to detoxify aflatoxin B 1 (AFB 1 ) by aerobic solid state fermentation in peanut meal. The optimal degradation condition was chosen from single factor experiment, and the most effective detoxification rate was about 97%. As for liquid fermentation, we tested the binding ability of Z. rouxii, and the highest binding rate reached was 74.3% (nonviable cells of Z. rouxii) in phosphate-buffered saline (PBS). Moreover, the biotransformation of AFB 1 through fermentation of Z. rouxii in peanut meal was further verified by liquid chromatography/mass spectrometry (LC/MS). According to TIC scan, after fermentation by Z. rouxii, the AFB 1 in peanut meal was prominently degraded to the lowering peaks of AFB 1 . Additionally, m/s statistics demonstrated that AFB 1 may be degraded to some new products whose structural properties may be different from AFB 1 , or the degradation products may be dissolved in the aqueous phase rather than the organic phase. As far as we know, this is the first report indicating that the safe strain of Z. rouxii has the ability to detoxify AFB 1 .

The overuse of antibiotics makes its detection very significant for human health. New facile methods and high‐performance sensory materials will be urgently needed for detection of antibiotics. Unfortunately, there are few reports on fluorescence enhancement of antibiotics detection. Herein, based on the modulability of the coordination mode, we proposed two MOFs with different coordination modes based on different metal ions: Zn‐MOF (1) and Cd‐MOF (2). The fluorescence of 1 and 2 can be efficiently and selectively quenched by nitrofuran antibiotics (nitrofurazone, NFZ and furazolidone, FZD) and chloramphenicol (CAP), respectively. Particularly, the matched energy levels between 2 and enrofloxacin (ENR) enables 2 with turn‐on sensing for ENR. Moreover, apart from the sensitivity and selectivity, 1 and 2 also have strong recyclable ability, fast response time and anti‐interference ability, which make them great potential sensory materials to detect antibiotics.

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