Isolation of a potential probiotic strain Bacillus amyloliquefaciensLPB‐18 and identification of antimicrobial compounds responsible for inhibition of food‐borne pathogens

Abstract

This study was carried out to screen a potential probiotic microbe with broad‐spectrum antagonistic activity against food‐borne pathogens and identify the antimicrobial compounds. Based on morphological and molecular analysis, a new Bacillus strain with the ability to produce effective antimicrobial agents was isolated from the breeding soil of earthworms and identified as having a close evolutionary footprint to Bacillus amyloliquefaciens . The antimicrobial substances produced by B. amyloliquefaciens show effective inhibition of Aspergillus flavus and Fusarium oxysporum in an agar diffusion assay. Antimicrobial agents were identified as a series of fengycin and its isoforms (fengycin A and fengycin B) after being submitted to RT‐HPLC and MALDI‐TOF MS analyses. To evaluate the probiotic activity of the B. amyloliquefaciens , antibiotic safety and viability of the isolated strain in a simulated gastrointestinal environment were carried out. The safety test result revealed that strain LPB‐18 is susceptible to multiple common antibiotics. Moreover, acidic condition and bile salts assay were carried out, and the results revealed that it couble be a potential probiotic microbe B. amyloliquefaciens LPB‐18 is good choice for biological strains in agricultural commodities and animal feedstuffs.

Peeling back the many layers of competitive exclusion

“…This led to bio-prospecting for intestinal bacteria species for their production of inhibitory VFAs ( Hinton et al, 1991 ). Antimicrobial production has also been used to select candidate probiotics; however, most have failed to reduce Salmonella colonization ( Pan et al, 2008 ; Grant et al, 2018 ; Lu et al, 2023 ). There has also been considerable focus on microbes that produce bacteriocins ( Grant et al, 2018 ; Angelopoulou et al, 2019 ; Khan et al, 2020 ).…”

Food safety and biological control; genomic insights and antimicrobial potential of Bacillus velezensis FB2 against agricultural fungal pathogens

“…Prior to isolation, 1g soil was heated at 80˚C for 20 minutes in order to kill non-spore forming bacteria [25]. Then, dilutions of the treated soil sample were prepared and plated on Luria-Bertani (LB) agar medium (g/L: Tryptone 10, Sodium chloride 5, Yeast extract 5, Agar 15) and incubated at 30˚C for 48 hours [26]. Morphologically distinct Bacillus like colonies were purified by streak plate method on LB agar.…”

Overview of Probiotic Strains of Weizmannia coagulans, Previously Known as Bacillus coagulans, as Food Supplements and Their Use in Human Health

“…On the other hand, some spore-forming bacteria are commensals. Some are important soil bacteria, plant and animal commensals that fix nitrogen, produce protective volatile organic compounds, and are used in bioremediation, such as Bacillus subtilis, Bacillus thuringiensis, Bacillus amyloliquefaciens, Bacillus velezensis, and Bacillus pumilus [15][16][17][18][19][20][21]. The thermophilic Geobacillus stearothermophilus (previously Bacillus stearothermophilus) is commonly used as a biological indicator of sterilization [22,23].…”