Bacteriocin-like Inhibitory Substance Research Articles

Kinetic modeling of bacteriocin-like inhibitory substance secretion by Pediococcus acidilactici Kp10 and its stability in food manufacturing conditions.

This paper deliberates the modelling and validation of bacteriocin-like inhibitory substance (BLIS) secretion by Pediococcus acidilactici Kp10 at different agitation speeds in a stirred tank bioreactor. A range of models namely the re-parameterised logistic, Luedeking-Piret and maintenance energy were assessed to predict the culture performance of the said bacterium. Growth of P. acidilactici Kp10 was enhanced with increased agitation speed up to 600rpm while BLIS secretion was maximum at 400rpm but decreased at higher agitation speed. Growth of P. acidilactici aptly subscribed to the re-parameterised logistic model while BLIS secretion and lactose consumption fitted well with the Luedeking-Piret model. The models revealed a relationship between growth of the bacterium and BLIS secretion. Bacterial growth and BLIS secretion were largely affected by the agitation speed of the stirred tank bioreactor which regulated the oxygen transfer to the culture. BLIS secretion by P. acidilactici Kp10 was however enhanced in oxygen-limited culture. The study also assessed BLIS from the perspective of its stability when subjected to factors such as temperature, pH and detergents. Results showed that BLIS produced by this strain was not affected by heat (at 25-100°C for 20min and at 121°C for 15min), surfactant (Tween 40, 60 and 80 and urea), detergents (up to 1% SDS), organic solvents (50% each of acetone, methanol and ethanol) and stable in a wide range of pH (2-10). The above information are pertinent with reference to commercial applications of this bacterial product in food manufacturing which invariably involve various sterilization processes and subjected to a wide pH range.

Bacteriocin-like inhibitory substance (BLIS) activity of Streptococcus macedonicus MBF10-2 and its synergistic action in combination with antibiotics.

To characterize the bacteriocin-like inhibitory-substances (BLIS) activity of Streptococcus macedonicus MBF10-2 [named BLIS(MBF10-2)], a bacteriocinogenic strain isolated from an Indonesian tofu byproduct. BLIS(MBF10-2) was obtained by culturing the bacterium, and standard deferred antagonism assays were used to demonstrate its activity. The antibacterial testing of fractions collected by filtration using 3-30kDa cut-off membrane sizes were carried out by performing well diffusion method. The growth of Micrococcus luteus, Streptococcus pyogenes, Lactococcus lactis, Leuconostoc mesenteroides and Weissella confusa were inhibited by BLIS(MBF10-2). Interestingly, BLIS-containing fractions obtained from sequential application on ultrafiltration membranes indicated that this bacterium Streptococcus macedonicus MBF10-2 could produces at least two antimicrobial peptides activities, one of which is likely to be a lantibiotic peptide. Potential synergistic activity against certain Gram-positive (but not Gram-negative) species when partnered with antibiotics (ampicillin, tetracycline or kanamycin) were observed. Combination of some BLIS(MBF10-2) active fractions with antibiotics (ampicillin, tetracycline or kanamycin) could demonstrate synergistic activities against certain Gram-positive species.

Bacteriocin-like inhibitory activities of seven Lactobacillus delbrueckii subsp. bulgaricus strains against antibiotic susceptible and resistant Helicobacter pylori strains.

In this study, anti-Helicobacter pylori activity of seven Lactobacillus delbrueckii subsp. bulgaricus (GLB) strains was evaluated by four cell-free supernatant (CFS) types. The GLB strains produced heat-stable bacteriocin-like inhibitory substances (BLISs) with a strong anti-H. pylori activity and some neutralized, catalase- and heat-treated CFSs inhibited >83% of the test strains. Bacteriocin-like inhibitory substance production of GLB strains can render them valuable probiotics in the control of H. pylori infection.

Antibacterial activity of a bacteriocin-like inhibitory substance produced by bacillus sp. From halophilic environment

Antibacterial activity of a bacteriocin-like inhibitory substance produced by bacillus sp. From halophilic environment

Isolation and Preliminary Characterization of A Bacteriocin-Producer Bacillus Strain Inhibiting Methicillin Resistant Staphylococcus Aureus

In a multivalent approach to discover new antimicrobial substance, a total of 160 Bacilli were isolated from termitarium soil, characterized on the basis of their morphological and physiological characters and screened for their antimicrobial activity by agar well diffusion method against certain drug resistant pathogenic bacteria such as Staphylococcus aureus, Methicillin resistant Staphylococcus aureus and common food contaminating bacteria Listeria monocytogenes. After preliminary screening, sixteen isolates showed inhibitory activity against test pathogens. Among them Bacillus isolate TSH58 exhibited maximum inhibitory activity against MRSA, Staphylococcus aureus and Listeria monocytogenes. Based on morphological, physiological, biochemical and 16S rDNA characteristics isolate TSH58 was identified as a member of the Bacillus cereus species group. Various nutrient sources and culture conditions were optimized, the partially purified antimicrobial metabolite was subjected to various treatments such as heat, pH and proteolytic enzymes. Complete loss in the activity observed when the crude metabolite was treated with proteolytic enzymes suggesting its proteinaceous nature and termed as bacteriocin like inhibitory substance (BLIS). Minimal inhibitory concentration of the partially purified bacteriocin determined by microtiter plate assay was 80 μg/ml for MRSA and 40 μg/ml for L. monocytogenes. Tricine SDS PAGE analysis revealed that the partially purified bacteriocin produced by the Bacillus strain TSH58 had an apparent molecular weight of about 4.0 KDa.

Inhibitory substances production by Lactobacillus plantarum ST16Pa cultured in hydrolyzed cheese whey supplemented with soybean flour and their antimicrobial efficiency as biopreservatives on fresh chicken meat

Cheese whey, the main byproduct of the dairy industry, is one of the most worrisome types of industrial waste, not only because of its abundant annual global production but also because it is a notable source of environmental pollution. However, cheese whey can serve as a raw material for the production of biocomposites. In this context, in this study, we assayed the production of a bacteriocin-like inhibitory substance (BLIS) and lactate by culturing Lactobacillus plantarum ST16Pa in hydrolyzed fresh cheese whey. The process was improved by studying the enzymatic hydrolysis of cheese whey as well as its supplementation with soybean flour under microaerophilic or anaerobic conditions. Thus, the highest values of BLIS (7367.23 arbitrary units [AU]/mL) and lactate yield (Ylactate/lactose=1.39g/g) were achieved after addition of 10g/L soybean flour in microaerophilia. These conditions were successfully scaled up in a bioreactor because during complete anaerobiosis at 150rpm, L. plantarum ST16Pa attained considerable cell growth (3.14g/L), lactate concentration (14.33g/L), and BLIS activity (8082.56AU/mL). In addition, the cell-free supernatant resulting from this bioprocess showed high biopreservative efficiency in chicken breast fillets artificially contaminated with Enterococcus faecium 711 during 7days of refrigerated storage, thus indicating the potential use of this BLIS as a biopreservative in the food industry.

Antimicrobial activity of partially characterized analytes fromBacillus pumilus(B2)

This study was carried out to characterize the antimicrobial substance produced by the strain of Bacillus pumilus (B2) obtained from Novozymes Biologicals Inc. to compare its antimicrobial activity by agar well diffusion assay and bacteriocin activity assay via critical dilution method against seven different strains of Vibrio spp., specifically V. alginolyticus (A01), V. cholerae (C01), V. fluvialis (F01, F02), V herveyii (H), V. mimicus (M01), V. parahaemolyticus (P01) and V. vulnificus (V01, V02). All Vibrio spp. were isolated from the hemolymph and intestine of the white faeces disease-infected moribund pacific white-leg shrimp Litopenaeus vannamei (Boone 1931) and one strain (V. harveyi) from its diseased postlarva. The cell-free neutralized supernatant (CFNS) of B2 showed moderate thermo-stability being stable up to 70°C for 60 min with, however, reducing activity above 80°C for 20 min. B2 antimicrobials showed a stable activity within the pH ranging from 6 to 10 at room temperature and at 4°C, while residual antimicrobial activity of crude CFNS showed tolerance to salinity up to 7% of sodium chloride below 4°C. No B2 activity was obtained while exposed to proteolytic enzyme, such as proteinase k and pepsin, while its activity kept stable exposed to lipase. Initial B2 characterization for antimicrobial substance in CFNS revealed proteinaceous in nature owing to activity loss against proteolytic enzymes and no lipid moiety activity against lipase, which could be categorized as bacteriocin-like inhibitory substance having potential application against several strains of Vibrio spp. in aquaculture.

Effect of Bacteriocin-like Inhibitory Substances Produced by <i>Vaginal Lactobacilli</i> on Group B Streptococcus

Reduction of vaginal Lactobacillus population leads to overgrowth of opportunistic organisms such as Streptococcus agalactiae (Group B Streptococcus, GBS), which causes life threatening neonatal infections. The activities of bacteriocin-like inhibitory substances (BLIS) produced by Lactobacillus species isolated from the vagina of pregnant women were tested on GBS. Crude Bacteriocins were produced from seven Lactobacillus isolates using de Man Rogosa Sharpes media. Partial purification was done using ammonium sulphate saturation (90%) and dialysis methods. The antibacterial effects of the crude and partially purified BLIS were carried out by disc Agar diffusion method. The BLIS from strains R5 and L2 gave the highest and lowest inhibition zone diameter (IZD) of 16.9 mm and 12.1 mm, respectively, for the crude extracts and 18.5 mm and 14.2 mm, respectively, for the partially purified extracts. All the BLIS had their strongest activity at 30°C and decreased with increase in temperature. BLIS from strains L3 and L4 lost their activities at 100°C. The activities of all the BLIS were higher at acidic pH. The IZD of the combined crude extract was 19.06 mm, while that of the combined partially purified extracts was 21.07 mm. The combined BLIS had higher activity than each of the single compound. There were no statistical difference between the sensitivities of the partially purified BLIS and the crude BLIS (P > 0.05). The findings of this study show that BLIS produced by vaginal Lactobacilli spp. can be used as probiotics for the control of GBS and that combining the BLIS may be more effective.Keywords: Antibacterial, Group B Streptococci, Vaginal Lactobacillus

Recovery of a bacteriocin-like inhibitory substance from Pediococcus acidilactici Kp10 using surfactant precipitation

Bacteriocin is an important peptide which can be used as an anti-microbial agent in food. However, simpler and more cost-effective purification methods need to be developed compared to chromatography to enhance its commercial viability. Surfactant precipitation was employed for the first time to purify bacteriocin-like inhibitory substance (BLIS) from a fermentation broth of Pediococcus acidilactici Kp10, and the amount precipitated was investigated as a function of anionic surfactant (AOT) concentration, and pH. Protein recovery from the precipitate was accomplished using solvent extraction, and solvent type, NaCl concentration, and ionic strength of the final solution were optimised. Optimal conditions were; 1.05mM of AOT at pH 4 for precipitation, and acetone extraction (with 1mM NaCl), which resulted in an 86.3% yield, and 53.8 purification factor. This study highlighted the fact that surfactant precipitation can be used as a primary recovery method for BLIS from a complex fermentation broth.

Potential Factors Enabling Human Body Colonization by Animal Streptococcus dysgalactiae subsp. equisimilis Strains

Streptococcus dysgalactiae subsp. equisimilis (SDSE) is a pyogenic, Lancefield C or G streptococcal pathogen. Until recently, it has been considered as an exclusive animal pathogen. Nowadays, it is responsible for both animal infections in wild animals, pets, and livestock and human infections often clinically similar to the ones caused by group A streptococcus (Streptococcus pyogenes). The risk of zoonotic infection is the most significant in people having regular contact with animals, such as veterinarians, cattlemen, and farmers. SDSE is also prevalent on skin of healthy dogs, cats, and horses, which pose a risk also to people having contact with companion animals. The main aim of this study was to evaluate if there are features differentiating animal and human SDSE isolates, especially in virulence factors involved in the first stages of pathogenesis (adhesion and colonization). Equal groups of human and animal SDSE clinical strains were obtained from superficial infections (skin, wounds, abscesses). The presence of five virulence genes (prtF1, prtF2, lmb, cbp, emm type) was evaluated, as well as ability to form bacterial biofilm and produce BLIS (bacteriocin-like inhibitory substances) which are active against human skin microbiota. The study showed that the presence of genes coding for fibronectin-binding protein and M protein, as well as BLIS activity inhibiting the growth of Corynebacterium spp. strains might constitute the virulence factors which are necessary to colonize human organism, whereas they are not crucial in animal infections. Those virulence factors might be horizontally transferred from human streptococci to animal SDSE strains, enabling their ability to colonize human organism.

In vitro and in vivo cholesterol lowering ability of Lactobacillus pentosus KF923750.

Lactobacillus pentosus KF923750 was characterised for probiotic related properties and then characterised for cholesterol uptake in vitro as well as in vivo using rabbits fed a high-cholesterol diet. The survival percentage of L. pentosus KF923750 was 100% at pH 3, 52.18% at pH 2 and 36.21% at pH 2 plus pepsin. Similarly, this strain appeared resistant to bile (0.1% [98.42%], 0.3% [88.52%], 0.5% [75.60%] and 1% [71.15%]), after 4 h exposure. Moreover, L. pentosus KF923750 controlled growth of Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 25923 through the production of a bacteriocin-like inhibitory substance and anti-adhesive capabilities. L. pentosus KF923750 was non-cytotoxic to eukaryotic cells but sensitive to some antibiotics. Compared with rabbits fed a high-cholesterol diet but without L. pentosus KF923750 supplementation, the plasma total cholesterol, low-density lipoprotein cholesterol and triglycerides levels were significantly decreased in L. pentosus KF923750-fed rabbits by 11.54, 16.00 and 18.00%, respectively, with no significant change in high-density lipoprotein cholesterol levels. The histological sections of livers revealed lesions in all the rabbits that were fed a high-cholesterol diet, but these were less pronounced in rabbits ingesting L. pentosus KF923750. This study highlights the potential of lactobacilli, such as L. pentosus KF923750, in the treatment or prevention of hypercholesterolemia.

Influence of Oral Probiotic Streptococcus salivarius K12 on Ear and Oral Cavity Health in Humans: Systematic Review

Traditionally, probiotics are linked to the good health of the intestine and most clinical studies focus on that field. Evidence of oral probiotic use for ear and oral cavity disease prevention with impact on human health is limited. This work reviews existing studies and literature on Streptococcus salivarius K12 as an oral probiotic and effects of S. salivarius K12 on human ear and oral cavity human health. The studies were accessed via database searches: MEDLINE, PubMed, and Elsevier. The search included/focused on/encompassed publications from 2003 to 2016 with keywords related to K12 Streptococcus salivarius, bacteriocin-like inhibitory substances (BLIS) K12, probiotic K12 salivarius, and K12 probiotic health effects. Only a small amount of studies was identified: the total of 68 studies was identified, 35 of which were relevant after screening, and 9 were included in the final analysis. Very little literature is available about the association/correlation between/connection/interrelation of S. salivarius K12 with/and human ear and oral cavity health. S. salivarius K12 may have a role in reducing the occurrence and/or severity of secretory otitis media (SOM) and also in prevention of streptococcal and viral pharyngotonsillitis in children. Research highlights that S. salivarius K12 has shown promising results in treatment of halitosis, but data are still deficient. Further studies need to be initiated to improve understanding of the association of oral probiotic S. salivarius K12 with human ear and oral cavity health.

Anti-Listeria Activity of Lactic Acid Bacteria in Two Traditional Sicilian Cheeses.

Listeria monocytogenes is a pathogen frequently found in dairy products, and its growth is difficult to control. Bacteriocin-like inhibitory substances (BLIS), produced by lactic acid bacteria (LAB), having proven in vitro anti-Listeria activity, could provide an innovative approach to control L. monocytogenes; however, this application needs to be evaluated in vivo. In this study, twenty LAB strains isolated from different Sicilian dairy environments were tested for control of growth of L. monocytogenes in three different experimental trials. First, raw and UHT milk were inoculated with LAB strains alone, and LAB strains mixed with L. monocytogenes. Second, mini-cheeses containing LAB and/or L. monocytogenes were produced. Third, two traditional Sicilian cheeses inoculated with a multi-strain LAB mixture combined with L. monocytogenes were produced. The addition of BLIS produced by LAB to milk and in mini-cheese production was unable to inhibit the growth of L. monocytogenes. However, an anti-Listeria effect was observed in the Pecorino Siciliano cheeses, where, after 15 days of ripening, the cheeses with added LAB had fewer L. monocytogenes compared to the control cheeses with no added LAB, while in the Vastedda della valle del Belìce cheeses, the multi-strain LAB mixture completely prevented the growth of L. monocytogenes.

Quantitative analyses of the bacterial microbiota of rearing environment, tilapia and common carp cultured in earthen ponds and inhibitory activity of its lactic acid bacteria on fish spoilage and pathogenic bacteria.

The present study aimed to evaluate the bacterial load of water, Nile Tilapia and common Carp intestines from earthen ponds, isolate lactic acid bacteria (LAB) and assess their antimicrobial activity against fish spoilage and pathogenic bacteria. Following enumeration and isolation of microorganisms the antimicrobial activity of the LAB isolates was evaluated. Taxonomic identification of selected antagonistic LAB strains was assessed, followed by partial characterisation of their antimicrobial metabolites. Results showed that high counts (>4 log c.f.u ml-1 or 8 log c.f.u g-1) of total aerobic bacteria were recorded in pond waters and fish intestines. The microbiota were also found to be dominated by Salmonella spp., Vibrio spp., Staphylococcus spp. and Escherichia coli. LAB isolates (5.60%) exhibited potent direct and extracellular antimicrobial activity against the host-derived and non host-derived spoilage and pathogenic bacteria. These antagonistic isolates were identified and Lactococcus lactis subsp. lactis was found as the predominant (42.85%) specie. The strains displayed the ability to produce lactic, acetic, butyric, propionic and valeric acids. Bacteriocin-like inhibitory substances with activity against Gram-positive and Gram-negative (Vibrio spp. and Pseudomonas aeruginosa) bacteria were produced by three L. lactis subsp. lactis strains. In this study, the LAB from the microbiota of fish and pond water showed potent antimicrobial activity against fish spoilage or pathogenic bacteria from the same host or ecological niche. The studied Cameroonian aquatic niche is an ideal source of antagonistic LAB that could be appropriate as new fish biopreservatives or disease control agents in aquaculture under tropical conditions in particular or worldwide in general.

Study of Synergy between Mentha pulegium Essential Oil, Honey and Bacteriocin-like Inhibitory Substance E204 against Listeria monocytogenes CECT 4032 and Escherichia coli K12

Study of Synergy between Mentha pulegium Essential Oil, Honey and Bacteriocin-like Inhibitory Substance E204 against Listeria monocytogenes CECT 4032 and Escherichia coli K12

Partial characterization of bacteriocin-like compounds from two strains of Bacillus cereus with biological activity against Paenibacillus larvae, the causal agent of American Foulbrood disease.

An Integrated Pest Management (IPM) approach is needed to ensure the sustainability of the beekeeping industry due to the increasing demand for organic honey and the reduction of dependence on antibiotics. Biocontrol agents produced by bacteria isolated from apiarian sources seem promising and able to combine with an IPM strategy. The most significant findings of this study are the characterization of bacteriocin-like compounds (BLIS) obtained from two strains of Bacillus cereus isolated from honey. Both BLIS have a narrow activity range and highly inhibit the growth of Paenibacillus larvae, the causal agent of American Foulbrood disease of honey bees.

Isolation, identification and characterization of Pediococcus pentosaceus LB44 and Weissella confusa LM85 for the presence of bacteriocin-like inhibitory substances (BLIS)

Lactic acid bacteria (LAB) were isolated from different soil samples such as dairy, garden, rhizospheric soil and sediments of lake. Thirty nine strains of bacteria were isolated using direct spreading method but only one showed the characteristics of LAB. Whereas, using accumulation with incubation method, fifty seven strains were found to be LAB out of sixty eight strains of bacteria isolated. Therefore, accumulation with incubation method was found to be more effective and faster. On the basis of higher growth and antimicrobial activity, two potential isolates LB44 and LM85 were selected for the further characterization. Strain LB44 and LM85 were identified using 16S rDNA amplification and sequencing as Pediococcus pentosaceus LB44 and Weissella confusa LM85, respectively. Cell free supernatant (CFS) of these strains showed antimicrobial activity, stability at higher temperatures, acidic pH and in the presence of organic solvents, detergents and surfactants. Antimicrobial activity was not affected by treatment with catalase and lipase but reduced after treatment with proteinase K reveals the presence of bacteriocin-like inhibitory substance in CFS. CFS inhibited the growth of other Gram-positive and Gram-negative bacteria such as Micrococcus luteus, Lactobacillus delbrueckii, L. curvatus, L. plantarum, L. acidophilus, Enterobacter cloaceae, Lactococcus lactis subsp. cremoris, L. lactis subsp. lactis, Bacillus subtilis, B. licheniformis, Salmonella typhi and Escherichia coli.

Purification of a Novel Bacteriocin-Like Inhibitory Substance Produced by Enterococcus faecium ICIS 8 and Characterization of Its Mode of Action.

The aim of this work was to purify and characterize a bacteriocin-like antimicrobial substance produced by an antagonistic active strain of Enterococcus faecium. A novel bacteriocin-like inhibitory substance (BLIS) produced by the E. faecium ICIS 8 strain was purified and characterized using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and N-terminal amino acid sequencing revealed the following partial sequence: NH2-APKEKCFPKYCV. The proteinaceous nature of purified BLIS was assessed by treatment with proteolytic enzyme. Studies of the action of BLIS using bacteriological and bioluminescence assays revealed a dose-dependent inhibition of Listeria monocytogenes 88BK and Escherichia coli K12 TG1 lac::lux viability. The interaction of the BLIS with the bacterial surface led to the compensation of a negative charge value, as shown by zeta-potential measurements. Assessments of membrane integrity using fluorescent probes and atomic force microscopy revealed the permeabilization of the cellular barrier structures in both L. monocytogenes and E. coli. The novel BLIS from E. faecium ICIS 8 was characterized by a unique primary peptide sequence and exerted bactericidal activity against L. monocytogenes and E. coli by disrupting membrane integrity.

Determination of Acquired Resistance Profiles of Pseudomonas aeruginosa Isolates and Characterization of an Effective Bacteriocin-Like Inhibitory Substance (BLIS) Against These Isolates.

BackgroundThe emergence of pan-drug resistant strains (PDR) of Pseudomonas aeruginosa has led to renewed efforts to identify alternative agents, such as bacteriocins and bacteriocin-like inhibitory substances (BLISs).ObjectivesThe aims of this study were to determine the acquired resistance profiles of multidrug-resistant (MDR), extensively drug-resistant (XDR), and PDR P. aeruginosa isolates based on the revised definitions of the CDC and ECDC and to screen and characterize effective BLISs against these isolates.Patients and MaterialsIn a cross-sectional study, 96 P. aeruginosa strains were isolated during a 12-month period. The resistance profiles of these isolates were determined as MDR, XDR, and PDR, and the data were analyzed using WHONET5.6 software. A BLIS against the P. aeruginosa strains was characterized based on its physicochemical properties, size, growth curves, and production profiles.ResultsAmong the 96 isolates of P. aeruginosa, 2 (2.1%), 94 (97.9%), and 63 (65.6%) were non-MDR, MDR, and XDR, respectively, and 1 (1.1%) was PDR. The most effective antibiotics against these isolates were polymyxins and fosfomycin. A BLIS isolated from the P. aeruginosa DSH22 strain had potent activity against 92 (95.8%) of the 96 isolates. The BLIS was heat stable, (up to 100°C for 10 min), UV stable, and active within a pH range of 3 - 9. The activity of BLIS disappeared when treated with trypsin, proteinase K, and pepsin, indicating its proteinous nature. Based on its size (25 kDa), the BLIS may belong to the large colicin-like bacteriocin family. BLIS production started in the midexponential phase of growth, and the maximum level (2700 AU/mL) occurred in the late-stationary phase after 25 hours of incubation at 30°C.ConclusionsThis BLIS with broad-spectrum activity may be a potential agent for the treatment or control of drug-resistant strains of P. aeruginosa infection.

Aqueous two-phase flotation for primary recovery of bacteriocin-like inhibitory substance (BLIS) from Pediococcus acidilactici Kp10.

An aqueous two-phase flotation (ATPF) system based on polyethylene glycol (PEG) and sodium citrate (NaNO3C6H5O7·2H2O) was considered for primary recovery of bacteriocin-like inhibitory substance (BLIS) from Pediococcus acidilactici Kp10. The effects of ATPF parameters namely phase composition, tie-line length (TLL), volume ratio between the two phases (VR), amount of crude load (CL), pH, nitrogen gas flow rate (FR) and flotation time (FT) on the performance of recovery were evaluated. BLIS was mainly concentrated into the upper PEG-rich phase in all systems tested so far. The optimum conditions for BLIS purification, which composed of PEG 8000/sodium citrate, were: TLL of 42.6, VR of 0.4, CL of 22% (w/w), pH 7, average FT of 30min and FR of 20mL/min. BLIS was partially purified up to 5.9-fold with a separation efficiency of 99% under this optimal conditions. A maximum yield of BLIS activity of about 70.3% was recovered in the PEG phase. The BLIS from the top phase was successfully recovered with a single band in SDS-gel with molecular weight of about 10-15kDa. ATPF was found to be an effective technique for the recovery of BLIS from the fermentation broth of P. acidilactici Kp10.