Biological control of postharvest diseases of apples,peaches and nectarines by Bacillus subtilis S16 isolated from halophytes rhizosphere

Penicillium expansum, Botrytis cinerea and Colletotrichum acutatum are the most common postharvest pathogens of apples, peaches and nectarines. In this study, 96 bacteria were isolated from halophytes rhizosphere and assayed for biocontrol activity under in vitro conditions. Among the 96 isolates tested, isolate S16 effectively inhibited the growth of P. expansum, B. cinerea and C. acutatum. The isolate S16 has reduced 78.33±1.53 to 82.98±2.13% of disease severity in apples, peaches and nectarines. Matrix-assisted laser desorption ionisation-time of flight mass spectrometry of the antifungal compounds revealed three lipopeptide complexes, namely surfactins, iturins and fengycins. Lipopeptides and hydrolytic enzymes produced by the isolate S16 play an important role in the antifungal activity. Polymerase chain reaction analysis using ituD, srfAD, fenD and fenE gene-specific primers showed that the isolate S16 carry sequences similar to ituD, srfAD, fenD and fenE genes. Based on the 16S rDNA sequencing, the effective isolate S16 was identified as Bacillus subtilis.     

Unusual Biosynthesis and Structure of Locillomycins from Bacillus subtilis 916

Three families of Bacillus cyclic lipopeptides—surfactins, iturins, and fengycins—have well-recognized potential uses in biotechnology and biopharmaceutical applications. This study outlines the isolation and characterization of locillomycins, a novel family of cyclic lipopeptides produced by Bacillus subtilis 916. Elucidation of the locillomycin structure revealed several molecular features not observed in other Bacillus lipopeptides, including a unique nonapeptide sequence and macrocyclization. Locillomycins are active against bacteria and viruses. Biochemical analysis and gene deletion studies have supported the assignment of a 38-kb gene cluster as the locillomycin biosynthetic gene cluster. Interestingly, this gene cluster encodes 4 proteins (LocA, LocB, LocC, and LocD) that form a hexamodular nonribosomal peptide synthetase to biosynthesize cyclic nonapeptides. Genome analysis and the chemical structures of the end products indicated that the biosynthetic pathway exhibits two distinct features: (i) a nonlinear hexamodular assembly line, with three modules in the middle utilized twice and the first and last two modules used only once and (ii) several domains that are skipped or optionally selected.     

Genetic analysis of the biosynthesis of non-ribosomal peptide- and polyketide-like antibiotics, iron uptake and biofilm formation by Bacillus subtilis A1/3

The Bacillus subtilis strain A1/3 shows exceptionally diverse antibiotic capacities compared to other B. subtilis strains. To analyze this phenomenon, mutants for the putative pantotheinyltransferase gene ( pptS), and for several genes involved in non-ribosomal peptide synthesis and polyketide synthesis were constructed and characterized, using bioassays with blood cells, bacterial and fungal cells, and mass spectrometry. Among at least nine distinct bioactive compounds, five antibiotics and one siderophore activity were identified. The anti-fungal and hemolytic activities of strain A1/3 could be eliminated by mutation of the fen and srf genes essential for the synthesis of fengycins and surfactins. Both pptS - and dhb -type mutants were defective in iron uptake, indicating an inability to produce a 2,3-dihydroxybenzoate-type iron siderophore. Transposon mutants in the malonyl CoA transacylase gene resulted in the loss of hemolytic and anti-fungal activities due to the inhibition of bacillomycin L synthesis, and this led to the discovery of bmyLD-LA-LB* genes. In mutants bearing disruption mutations in polyketide ( pksM - and/or pksR -like) genes, the biosynthesis of bacillaene and difficidins, respectively, was inactivated and was accompanied by the loss of discrete antibacterial activities. The formation of biofilms (pellicles) was shown to require the production of surfactins, but no other lipopeptides, indicating that surfactins serve specific developmental functions.Communicated by A. Kondorosi     

Cyclic lipopeptide profile of the plant-beneficial endophytic bacterium Bacillus subtilis HC8

In a previous study (Malfanova et al. in Microbial Biotech 4:523–532, 2011), we described the isolation and partial characterization of the biocontrol endophytic bacterium B. subtilis HC8. Using thin-layer chromatography, we have detected several bioactive antifungal compounds in the methanolic extract from the acid-precipitated supernatant of HC8. In the present study, we have further analyzed this methanolic extract using liquid chromatography-mass spectrometry. Based on the comparison of retention times and molecular masses with those of known antifungal compounds, we identified three families of lipopeptide antibiotics. These include four iturins A having fatty acyl chain lengths of C14 to C17, eight fengycins A (from C14 to C18 and from C15 to C17 containing a double bond in the acyl chain), four fengycins B (C15 to C18), and five surfactins (C12 to C16). Evaluation of the antifungal activity of the isolated lipopeptides showed that fengycins are the most active ones. To our knowledge, this is the first report of an endophytic Bacillus subtilis producing all three major families of lipopeptide antibiotics containing a very heterogeneous mixture of homologues. The questions remain open which of these lipopeptides (1) are being produced during interaction with the plant and (2) are contributing to the biocontrol activity of HC8.     

Structural and functional characterization of gene clusters directing nonribosomal synthesis of bioactive cyclic lipopeptides in Bacillus amyloliquefaciens strain FZB42

The environmental strain Bacillus amyloliquefaciens FZB42 promotes plant growth and suppresses plant pathogenic organisms present in the rhizosphere. We sampled sequenced the genome of FZB42 and identified 2,947 genes with >50% identity on the amino acid level to the corresponding genes of Bacillus subtilis 168. Six large gene clusters encoding nonribosomal peptide synthetases (NRPS) and polyketide synthases (PKS) occupied 7.5% of the whole genome. Two of the PKS and one of the NRPS encoding gene clusters were unique insertions in the FZB42 genome and are not present in B. subtilis 168. Matrix-assisted laser desorption ionization-time of flight mass spectrometry analysis revealed expression of the antibiotic lipopeptide products surfactin, fengycin, and bacillomycin D. The fengycin (fen) and the surfactin (srf) operons were organized and located as in B. subtilis 168. A large 37.2-kb antibiotic DNA island containing the bmy gene cluster was attributed to the biosynthesis of bacillomycin D. The bmy island was found inserted close to the fen operon. The responsibility of the bmy, fen, and srf gene clusters for the production of the corresponding secondary metabolites was demonstrated by cassette mutagenesis, which led to the loss of the ability to produce these peptides. Although these single mutants still largely retained their ability to control fungal spread, a double mutant lacking both bacillomycin D and fengycin was heavily impaired in its ability to inhibit growth of phytopathogenic fungi, suggesting that both lipopeptides act in a synergistic manner.     

Cyclic lipopeptides from Bacillus subtilis activate distinct patterns of defence responses in grapevine

Non‐self‐recognition of microorganisms partly relies on the perception of microbe‐associated molecular patterns (MAMPs) and leads to the activation of an innate immune response. Bacillus subtilis produces three main families of cyclic lipopeptides (LPs), namely surfactins, iturins and fengycins. Although LPs are involved in induced systemic resistance (ISR) activation, little is known about defence responses induced by these molecules and their involvement in local resistance to fungi. Here, we showed that purified surfactin, mycosubtilin (iturin family) and plipastatin (fengycin family) are perceived by grapevine plant cells. Although surfactin and mycosubtilin stimulated grapevine innate immune responses, they differentially activated early signalling pathways and defence gene expression. By contrast, plipastatin perception by grapevine cells only resulted in early signalling activation. Gene expression analysis suggested that mycosubtilin activated salicylic acid (SA) and jasmonic acid (JA) signalling pathways, whereas surfactin mainly induced an SA‐regulated response. Although mycosubtilin and plipastatin displayed direct antifungal activity, only surfactin and mycosubtilin treatments resulted in a local long‐lasting enhanced tolerance to the necrotrophic fungus Botrytis cinerea in grapevine leaves. Moreover, challenge with specific strains overproducing surfactin and mycosubtilin led to a slightly enhanced stimulation of the defence response compared with the LP‐non‐producing strain of B. subtilis. Altogether, our results provide the first comprehensive view of the involvement of LPs from B. subtilis in grapevine plant defence and local resistance against the necrotrophic pathogen Bo. cinerea. Moreover, this work is the first to highlight the ability of mycosubtilin to trigger an immune response in plants.     

Lipopeptides as main ingredients for inhibition of fungal phytopathogens by Bacillus subtilis/amyloliquefaciens

Some isolates of the Bacillus subtilis/amyloliquefaciens species are known for their plant protective activity against fungal phytopathogens. It is notably due to their genetic potential to form an impressive array of antibiotics including non-ribosomal lipopeptides (LPs). In the work presented here, we wanted to gain further insights into the relative role of these LPs in the global antifungal activity of B. subtilis/amyloliquefaciens. To that end, a comparative study was conducted involving multiple strains that were tested against four different phytopathogens. We combined various approaches to further exemplify that secretion of those LPs is a crucial trait in direct pathogen ward off and this can actually be generalized to all members of these species. Our data illustrate that for each LP family, the fungitoxic activity varies in function of the target species and that the production of iturins and fengycins is modulated by the presence of pathogens. Our data on the relative involvement of these LPs in the biocontrol activity and modulation of their production are discussed in the context of natural conditions in the rhizosphere.     

Suppression of Phytophthora blight on pepper (Capsicum annuum L.) by bacilli isolated from brackish environment

Bacteria of the genus Bacillus are well known to possess antagonistic activity against numerous plant pathogens. In the present study, 11 strains of Bacillus spp. were isolated from a brackish environment and assayed for biocontrol activity under in vitro and in vivo conditions. Among the 11 isolates tested, nine isolates effectively inhibited the growth of various plant pathogens, namely Phytophthora capsici, Phytophthora citrophthora, Phytophthora citricola, Phytophthora sojae, Colletotrichum coccodes, Colletotrichum gloeosporioides, Colletotrichum acutatum, Rhizoctonia solani, Fusarium solani, Fusarium graminearum, Pyricularia spp., and Monilina spp. The effective isolates were further screened for suppression of Phytophthora blight of pepper plants under greenhouse conditions. The isolate SB10 exhibited the maximum (72.2%) ability to reduce the disease incidence and increased (32.2%) the vigour index of Capsicum annuum L. plants. Antifungal compounds produced by isolate SB10 were highly thermostable (100°C for 30 min). Matrix-Assisted Laser Desorption Ionization-Time of Flight mass spectrometry of the antifungal compounds revealed three lipopeptide complexes, namely the surfactins, the iturins, and the fengycins, which are well-known antifungal compounds produced by Bacillus spp.     

Characterization of Novel Lipopeptides Produced by Bacillus tequilensis P15 Using Liquid Chromatography Coupled Electron Spray Ionization Tandem Mass Spectrometry (LC–ESI–MS/MS)

Microbes are known to interact and communicate with their neighbouring cells by releasing diverse types of low molecular weight diffusible metabolites. This paper describes the identification of iturins, fengycins and surfactins secreted by Bacillus tequilensis P15 isolated from sea coast of Jakhao, Kutch, India, using liquid chromatography coupled electron spray ionization tandem mass spectrometry. In methanol soluble fraction of acid precipitate harvested from cell free supernatant of B. tequilensis P15, 5 variants of iturins, 6 of fengycins and 39 surfactins could be identified. In particular, new surfactins with Ile/Leu at position 5 and Asp at position 6 in the peptide chain were discovered, which have not been previously reported. A novel class of novel surfactin consisting of Glu/methyl ester of Asp at position 5 in peptide chain was also identified. In addition, several linear forms of surfactins were also identified in the methanol soluble extracellular fraction of B. tequilensis P15. This is the first report on co-production of all the three classes of cyclic lipopeptides by a marine isolate B. tequilensis.     

Characterization of fungal antagonistic bacilli isolated from aerial roots of banyan (Ficus benghalensis) using intact‐cell MALDI‐TOF mass spectrometry (ICMS)

Aims

To characterize fungal antagonistic bacilli isolated from aerial roots of banyan tree and identify the metabolites responsible for their antifungal activity.

Methods and Results

Seven gram positive, endospore‐forming, rod‐shaped endophytic bacterial strains exhibiting a broad‐spectrum antifungal activity were isolated from the surface‐sterilized aerial roots of banyan tree. The isolates designated as K1, A2, A4 and A12 were identified as Bacillus subtilis, whereas isolates A11 and A13 were identified as Bacillus amyloliquefaciens using Biolog Microbial Identification System. The antifungal lipopeptides, surfactins, iturins and fengycins with masses varying in the range from m/z 900 to m/z 1550 could be detected using intact‐cell MALDI‐TOF mass spectrometry (ICMS). On the basis of mass spectral and carbon source utilization profile, all seven endophytes could be distinguished from each other. Furthermore, ICMS analysis revealed higher extent of heterogeneity among iturins and fengycins produced by B. subtilis K1, correlating well with its higher antifungal activity in comparison with other isolates.

Conclusion

Seven fungal antagonistic bacilli were isolated from aerial roots of banyan tree, exhibiting broad spectrum of antifungal activity, among which B. subtilis K1 isolate was found to be most potent. The ICMS analysis revealed that all these isolates produced cyclic lipopeptides belonging to surfactin, iturin and fengycin families and exhibited varying degree of heterogeneity.

Significance and Impact of the study

The endophytes are considered as a potential source of novel bioactive metabolites, and this study describes the potent fungal antagonistic bacilli from aerial roots of banyan tree. The isolates described in this study have a prospective application as biocontrol agents. Also ICMS analysis described in this study for characterization of antifungal metabolites produced by banyan endophytic bacilli may be used as a high throughput tool for screening of microbes producing novel cyclic lipopeptides.     

Production of a Mixture of Fengycins with Surfactant and Antifungal Activities by <Emphasis Type="Italic">Bacillus</Emphasis> sp. MA04, a Versatile PGPR

Bacillus sp. strain MA04 a plant growth-promoting rhizobacteria (PGPR) showed hemolytic activity on blood agar plates, and the supernatant from liquid culture in nutrient broth at 24 h exhibited emulsification activity, suggesting the production of biosurfactants. In antagonist assays, the supernatant showed antifungal activity against phytopathogenic fungi such as Penicillium expansum, Fusarium stilboides, Sclerotium rolfsii y Rhizoctonia solani, finding a reduction of mycelial growth of all fungi tested, ranging from 35 to 69%, this activity was increased with time of culture, accomplishing percentages of inhibition up to 85% with supernatants obtained at 72 h. Then, the crude biorsurfactant (CB) was isolated from the supernatant in order to assay its antagonistic effect on the phytopathogens previously tested, finding an increase in the inhibition up to 97% at 500 mg/L of CB. The composition of CB was determined by infrared spectroscopy, identifying various functional groups related to lipopeptides, which were purified by high-performance liquid chromatography and analyzed by MALDI-TOF/TOF–MS, revealing a mixture of fengycins A and B whose high antifungal activity is been widely recognized. These results show that PGPR Bacillus sp. MA04 could also contribute to plant health status through the production of metabolites with antimicrobial activity.     

Mass spectrometry identification of antifungal lipopeptides from Bacillus sp. BCLRB2 against Rhizoctonia solani and Sclerotinia sclerotiorum

This work aims to characterize the bioactive molecules produced by an antagonistic Bacillus sp. strain BCLRB2 isolated from healthy leaves of olive tree against Rhizoctonia solani and Sclerotinia sclerotiorum. The bacterial strain isolated showed a high and persistent antifungal activity against the two pathogens. The free-cell supernatant showed also a high antifungal activity against R. solani and at a lower extent against S. sclerotiorum. The partial purification of the antifungal substances with methanol gradient applied to C18 column binding the Bacillus BCLRB2 culture supernatant showed that the 20% and 60% methanol fractions had a high and specific activity against S. sclerotiorum and R. solani, respectively. The mass spectrometry identification of the compounds in the fraction specifically active against S. sclerotiorum revealed the presence of bacillomycin D C16 as a major lipopeptide. The fraction specifically active against R. solani contained bacillomycin D C15 and 2 unknown lipopeptides. The 80% methanol fraction had a moderate and a broad spectrum activity against the two pathogens and consisted from two iturin D (C13 and C14) as a major lipopeptides.     

New approach for the detection of non-ribosomal peptide synthetase genes in Bacillus strains by polymerase chain reaction

Bacillus strains produce non-ribosomal lipopeptides that can be grouped into three families: surfactins or lichenysins, iturins and fengycins or plispastatins. These biosurfactants show a broad spectrum of biological activities. To detect strains able to produce these lipopeptides, a new polymerase chain reaction screening approach was developed using degenerated primers based on the intraoperon alignment of adenylation and thiolation nucleic acid domains of all enzymes implicated in the biosynthesis of each lipopeptide family. The comparative bioinformatics analyses of each operon led to the design of four primer pairs for the three families taking into account the differences between open reading frames of each synthetase gene. Tested on different Bacillus sp. strains, this technique was used successfully to detect not only the expected genes in the lipopeptide producing strains but also the presence of a plispastatin gene in Bacillus subtilis ATCC 21332 and a gene showing a high similarity with the polyketide synthase type I gene in the B. subtilis ATCC 6633 genome. It also led to the discovery of the presence of non-ribosomal peptide synthetase genes in Bacillus thuringiensis serovar berliner 1915 and in Bacillus cereus LMG 2098. In addition, this work highlighted the differences between the fengycin and plipastatin operon at DNA level.     

Thermostable Chitosanase from Bacillus sp. Strain CK4: Cloning and Expression of the Gene and Characterization of the Enzyme

A thermostable chitosanase gene from the environmental isolate Bacillus sp. strain CK4, which was identified on the basis of phylogenetic analysis of the 16S rRNA gene sequence and phenotypic analysis, was cloned, and its complete DNA sequence was determined. The thermostable chitosanase gene was composed of an 822-bp open reading frame which encodes a protein of 242 amino acids and a signal peptide corresponding to a 30-kDa enzyme. The deduced amino acid sequence of the chitosanase from Bacillus sp. strain CK4 exhibits 76.6, 15.3, and 14.2% similarities to those from Bacillus subtilis, Bacillus ehemensis, and Bacillus circulans, respectively. C-terminal homology analysis shows that Bacillus sp. strain CK4 belongs to cluster III with B. subtilis. The gene was similar in size to that of the mesophile B. subtilis but showed a higher preference for codons ending in G or C. The enzyme contains 2 additional cysteine residues at positions 49 and 211. The recombinant chitosanase has been purified to homogeneity by using only two steps with column chromatography. The half-life of the enzyme was 90 min at 80°C, which indicates its usefulness for industrial applications. The enzyme had a useful reactivity and a high specific activity for producing functional oligosaccharides as well, with trimers through hexamers as the major products.     

Rope-Producing Strains of Bacillus spp. from Wheat Bread and Strategy for Their Control by Lactic Acid Bacteria

Two types of white wheat bread (high- and low-type loaves) were investigated for rope spoilage. Thirty of the 56 breads tested developed rope spoilage within 5 days; the high-type loaves were affected by rope spoilage more than the low-type loaves. Sixty-one Bacillus strains were isolated from ropy breads and were characterized on the basis of their phenotypic and genotypic traits. All of the isolates were identified as Bacillus subtilis by biochemical tests, but molecular assays (randomly amplified polymorphic DNA PCR assay, denaturing gradient gel electrophoresis analysis, and sequencing of the V3 region of 16S ribosomal DNA) revealed greater Bacillus species variety in ropy breads. In fact, besides strains of B. subtilis, Bacillus licheniformis, Bacillus cereus, and isolates of Bacillus clausii and Bacillus firmus were also identified. All of the ropy Bacillus isolates exhibited amylase activity, whereas only 32.4% of these isolates were able to produce ropiness in bread slices after treatment at 96°C for 10 min. Strains of lactic acid bacteria previously isolated from sourdough were first selected for antirope activity on bread slices and then used as starters for bread-making experiments. Prevention of growth of approximately 10⁴ rope-producing B. subtilis G1 spores per cm² on bread slices for more than 15 days was observed when heat-treated cultures of Lactobacillus plantarum E5 and Leuconostoc mesenteroides A27 were added. Growth of B. subtilis G1 occurred after 7 days in breads started with Saccharomyces cerevisiae T22, L. plantarum E5, and L. mesenteroides A27.     

Lipopeptides Produced by a Soil <Emphasis Type="Italic">Bacillus Megaterium</Emphasis> Strain

A soil microorganism identified as Bacillum megaterium was found to produce several antibiotics substances after growth for 20 h at 37°C in a mineral culture medium. Analysis both by electron spray ionization (ESI) and matrix-assisted laser desorption ionization—time of flight (MALDI-TOF) mass spectrometry (MS) identified these substances as lipopeptides. Predominant peaks at m/z 1,041 and m/z 1,065 revealed ions which are compatible with surfactins and lichenysins, respectively. Two other ions m/z 1,057 and m/z 1,464 were further studied by collision-induced dissociation (CID) unveiling an iturin A at the first and fengycins A and B at the second m/z peaks. The CID spectrum of the m/z 1,464 ion also suggests the existence of fengycins A and B variants in which Ile was changed to Val in the position 10 of the peptide moiety. Raw mixtures of all these compounds were also assayed for antibiotic features. The data enlighten the unusual diversity of the lipopeptide mixture produced by a sole Bacillus species.     

Cyclic Lipopeptide Biosynthetic Genes and Products,and Inhibitory Activity of Plant-Associated Bacillus against Phytopathogenic Bacteria

The antibacterial activity against bacterial plant pathogens and its relationships with the presence of the cyclic lipopeptide (cLP) biosynthetic genes ituC (iturin), bmyB (bacillomycin), fenD (fengycin) and srfAA (surfactin), and their corresponding antimicrobial peptide products have been studied in a collection of 64 strains of Bacillus spp. isolated from plant environments. The most frequent antimicrobial peptide (AMP) genes were bmyB, srfAA and fenD (34-50% of isolates). Most isolates (98.4%) produced surfactin isoforms, 90.6% iturins and 79.7% fengycins. The antibacterial activity was very frequent and generally intense among the collection of strains because 75% of the isolates were active against at least 6 of the 8 bacterial plant pathogens tested. Hierarchical and correspondence analysis confirmed the presence of two clearly differentiated groups. One group consisted of Bacillus strains that showed a strong antibacterial activity, presented several cLPs genes and produced several isoforms of cLPs simultaneously, mainly composed of B. subtilis and B. amyloliquefaciens, although the last one was exclusive to this group. Another group was characterized by strains with very low or none antibacterial activity, that showed one or none of the cLP genes and produced a few or none of the corresponding cLPs, and was the most heterogenous group including B. subtilis, B. licheniformis, B. megaterium, B. pumilus, B. cereus and B. thuringiensis, although the last two were exclusive to this group. This work demonstrated that the antagonistic capacity of plant-associated Bacillus against plant pathogenic bacteria is related to the presence of cLP genes and to the production of the corresponding cLPs, and it is mainly associated to the species B. subtilis and B. amyloliquefaciens. Our findings would help to increase the yield and efficiency of screening methods to obtain candidate strains to biocontrol agents with a mechanism of action relaying on the production of antimicrobial cLPs.     

Interactions between Fengycin and Model Bilayers Quantified by Coarse-Grained Molecular Dynamics

Bacteria, particularly of the genus Bacillus, produce a wide variety of antifungal compounds. They act by affecting the lipid bilayers of fungal membranes, causing curvature-induced strain and eventual permeabilization. One class of these, known as fengycins, has been commercialized for treating agricultural infections and shows some promise as a possible antifungal pharmaceutical. Understanding the mechanism by which fengycins damage lipid bilayers could prove useful to the future development of related antifungal treatments. In this work, we present multi-microsecond-long simulations of fengycin interacting with different lipid bilayer systems. We see fengycin aggregation and uncover a clear aggregation pattern that is partially influenced by bilayer composition. We also quantify some local bilayer perturbations caused by fengycin binding, including curvature of the lipid bilayer and local electrostatic-driven reorganization.     

Interactions between Fengycin and Model Bilayers Quantified by Coarse-Grained Molecular Dynamics

Bacteria, particularly of the genus Bacillus, produce a wide variety of antifungal compounds. They act by affecting the lipid bilayers of fungal membranes, causing curvature-induced strain and eventual permeabilization. One class of these, known as fengycins, has been commercialized for treating agricultural infections and shows some promise as a possible antifungal pharmaceutical. Understanding the mechanism by which fengycins damage lipid bilayers could prove useful to the future development of related antifungal treatments. In this work, we present multi-microsecond-long simulations of fengycin interacting with different lipid bilayer systems. We see fengycin aggregation and uncover a clear aggregation pattern that is partially influenced by bilayer composition. We also quantify some local bilayer perturbations caused by fengycin binding, including curvature of the lipid bilayer and local electrostatic-driven reorganization.     

氮源和碳源对解淀粉芽孢杆菌Q-426抗菌脂肽合成的影响

微生物来源的环状脂肽在生物农药以及医学领域极具应用潜力。通过测量抑菌活性并利用反相高效液相色谱(RP-HPLC),液相质谱联用(HPLC-MS)和串联质谱(MS/MS)技术检测抗菌脂肽组分的变化研究了氮(N)源、碳(C)源和培养基中的初始pH值对解淀粉芽孢杆菌Q-426菌株中抗菌脂肽bacillomycin D和fengycins合成的影响,从而为进一步研究它们生物合成的基因调控以及更有目的性提高产量提供理论依据。结果表明:L-组氨酸、L-赖氨酸、甘油、山梨醇以及培养基中的[OH]-均能促进脂肽bacillomycin D的合成,但它们在该实验菌株抗菌脂肽bacillomycinD合成途径中的调控靶点有所不同。