scholarly journals Changes in antagonistic activity of lactic acid bacteria induced by their response to technological factors

2015 ◽  
Vol 24 (4) ◽  
Author(s):  
Dovile Jonkuviene ◽  
Joana Šalomskienė ◽  
Asta Abraitienė ◽  
Irena Mačionienė ◽  
Jūratė Repečkienė ◽  
...  

This study examined the changes in antagonistic activity of selected lactic acid bacteria (LAB) in response to technological factors used in food production. The antimicrobial activity of 12 selected LAB strains was assessed against the bacterial and fungal strains using the agar well diffusion method. Sodium chloride (NaCl) 6.5–8.0%, glucose 20-30% and pH 4.0, pH 8.0 and higher were the most crucial factors in reducing the spectra of the microorganisms antagonized. Heating at 80 °C or 100 °C had a greater negative impact than 63 °C on the antifungal activity of LAB. Freezing at –72 °C eliminated the antifungal activity, or it changed from fungicidal to fungistatic. Although each LAB demonstrated the ability to retain antimicrobial activity induced by various technological factors, Lactococcus lactis 768/5 was superior in retaining high antimicrobial activity against tested indicator strains.

2015 ◽  
Vol 18 (2-3) ◽  
pp. 87-91
Author(s):  
Ionela Sârbu ◽  
◽  
Tatiana Vassu ◽  
Ileana Stoica ◽  
Carmen Chifiriuc ◽  
...  

Objective. The main objective of this study was to select lactic acid bacteria strains with antimicrobial activity and to identify and characterize the antimicrobial compounds. Methods. In this study we tested the antimicrobial activity of 153 lactic bacteria strains by disk diffusion method against 6 microbial pathogenic strains isolated from patients with urinary and vaginal infections. Results. Antimicrobial test results revealed that most of lactic acid bacteria strains exhibited high antimicrobial activity against pathogenic microorganisms. For most of lactic bacteria strains antimicrobial activity has been correlated with the production of organic acids and only for two strains with the biosynthesis of bacteriocins. Bacteriocin produced by Lactococcus (Lc.) lactis F2a strain presented a broad spectrum of activity and high activity (51,200 AU/ml) compared with bacteriocins isolated from Lactobacillus (Lb.) paracasei ssp. paracasei JR strain (400 AU/ml). The stability tests of bacteriocin revealed that the bacteriocin produced by Lc. lactis F2a strain, it is stable at acid pH while exposure for long time to 600C causes a drastic decrease in bacteriocin activity. Conclusions. Lactic bacteria strains showed a high antimicrobial activity against both prokaryotic and eukaryotic pathogen strains. Two bacterial strains have bacteriocins. Bacteriocins isolated from Lc. lactis F2a strain showed a high activity and a broad spectrum of action.


2020 ◽  
Vol 21 (4) ◽  
Author(s):  
Usman Pato ◽  
YUSMARINI YUSUF ◽  
SHANTI FITRIANI ◽  
NIA NAIDYA JONNADI ◽  
MIMI SRI WAHYUNI ◽  
...  

The use of natural preservatives called bacteriocin derived from lactic acid bacteria (LAB) is one way of preventing food from being contaminated by pathogenic microorganisms such as L. monocytogenes (LM). The aims of this study were to evaluate the ability of LAB isolated from dadih to inhibit the growth of LM and to obtain the antimicrobial components that play a role in inhibiting the growth of LM. The antimicrobial activity of the supernatant obtained from 12 strains of dadih LAB was determined using the paper disk diffusion method. The results showed that the supernatant from the 12 LAB strains was able to inhibit the growth of LM with various inhibition zones. However, out of the 12 LABs, only 9 strains were found to have an inhibition zone of more than 3.5 mm.  The antimicrobial compounds of 9 strains were tested and it was found that the antimicrobial compounds of strains R-8, R-14 and R-49 were derived from lactic acid. In addition, 6 strains namely R-43, R-32, R-19, R-55, R-45 and R-41 were derived from bacteriocin based on their sensitivity to pH, heat and enzyme treatments. Crude bacteriocin derived from 6 LAB strains inhibited the growth of LM, and the highest antimicrobial activity was obtained in Streptococcus faecalis subsp. liquefaciens R-55 with an average inhibition zone of 13.87 mm. Bacteriocin produced by strain R-55 can be used as natural preservatives for the prevention of food-borne disease caused by LM.


2018 ◽  
Vol 2 (1) ◽  
Author(s):  
Nur Khikmah Nunung Sulistyani

Candida albicans cause opportunistic infection of the oral cavity. Probiotic has health benefits, produces organic acids as anti-C. albicans. The aim of this research was to determine the antifungal activity of commercial fermented milk products against Candida and viability of bacteria in commercial fermented milk products. The antifungal activity was determined using well diffusion method. Viability of lactic acid bacteria was done by plate count method. The results show that commercial fermented milk productshas an activity of anti-C.albicans were shown by irradical zone formed around well containing fermented dairy products. Viability of lactic acid bacteria 107-1010 CFU/mL.


SCISCITATIO ◽  
2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Nur Khikmah ◽  
Nunung Sulistyani

Bakteri Asam Laktat (BAL) yang terkandung dalam susu fermentasi akan menghasilkan asam-asam organik, hidrogen peroksida, diasetil, asetaldehid, asetoin, reutinin, reuterisiklin dan bakteriosin, dapat sebagai anti-Candida. Spesies Candida non-albicans seperti C. tropicalis dan C. glabrata sebagai penyebab kandidiasis oral cenderung meningkat. Tujuan penelitian ini mengetahui aktivitas antifungi susu fermentasi komersial pada Candida non-albicans dan viabilitas bakteri asam laktat di dalam susu fermentasi komersial. Aktivitas antifungi pada Candida non-albicans dilakukan dengan metode difusi sumuran. Viabilitas bakteri asam laktat dihitung berdasarkan jumlah bakteri asam laktat sebagai jumlah bakteri total (Total Plate Count). Hasil penelitian menunjukkan bahwa susu fermentasi komersial lebih mampu menghambat C. tropicalis dibandingkan C. glabrata. Viabilitas bakteri asam laktat dalam susu fermentasi komersial 107-1010 CFU/mL. Lactic Acid Bacteria (LAB) contained in fermented milk will produce organic acids, hydrogen peroxide, diacetyl, acetaldehyde, acetoin, reutinin, reuterycline and bacteriocin, as anti-Candida. Candida non-albicans species such as C. tropicalis and C. glabrata as causes of oral candidiasis tend to increase. The aim of this research was to determine the antifungal activity of commercial fermented milk against Candida non-albicans and viability of lactic acid bacteria in commercial ermented milk. The antifungal activity was determined using well diffusion method. Viability of lactic acid bacteria is calculated as Total Plate Count. The results showed that commercial fermented milk was more able to inhibit C. tropicalis compared C. glabrata. Viability of lactic acid bacteria 107-1010 CFU/mL.


Author(s):  
ROSALINA YULIANA AYEN ◽  
ENDANG KUSDIYANTINI ◽  
SRI PUJIYANTO

Objective: This research aimed to isolate, determine the characteristics of lactic acid bacteria (LAB) of Sui Wu’u from Bajawa, Nusa Tenggara Timur and identify LAB using 16S rRNA potential as antimicrobial activity against pathogenic bacteria. Methods: Sui Wu’u which has been stored for 6 months was obtained from Bajawa district, inoculated on de Man Rogosa-Sharpe Agar (Merck) + 0.5% CaCO3, purification of LAB, characterization of selected isolates, biochemical test, tolerance test for pH, viability to test temperature, and content NaCl, determination of antimicrobial action by the agar well disk diffusion method using antibiotic (Amoxicillin) as a control and as indicator bacteria (Staphylococcus aureus and Escherichia coli) and isolation of genomic 16S rRNA; molecular identification. Results: Based on research results obtained five isolates of LAB, Gram staining the LAB isolated from Sui Wu’u showed that the isolated bacteria (bacilli and coccus) are Gram-positive, catalase-negative and the isolates have tolerance of viability at temperatures of 10°C, 45°C, and 50°C and to salinitas of 4% and 6.5%. The inhibitory zone LAB isolates (2PKT) against E. coli bacteria (20 mm) and S. aureus (12 mm), and (2PKB) against E. coli bacteria (17 mm) and S. aureus (10 mm). The two selected isolates were identified as Lactobacillus fermentum strain HB bacteria with 100% identification value and 98.93% query cover and L. fermentum strain HT with 100% identification value and 99.23% query cover. Conclusion: L. fermentum from Sui Wu’u has antibacterial activity against Staphylococcus aureus and Escherichia coli.


2021 ◽  
Vol 924 (1) ◽  
pp. 012082
Author(s):  
F Hayati ◽  
T Yuliana ◽  
T Rialita

Abstract Food preservation by chemical preservatives addition is not recommended in large quantities. However, lactic acid bacteria (LAB) metabolites can be used as a safe alternative. LAB can produce a type of antimicrobial peptide known as bacteriocin. One source of LAB that can be used as a bacteriocin-producing candidate is dadih, a traditional fermented buffalo milk product from West Sumatra, Indonesia. In this study, eight bacterial isolates isolated from dadih were identified using the catalase test and Gram straining and obtained 6 isolates that were taken as LAB. An antimicrobial activity test was carried out using the diffusion method on LAB liquid isolates suspension and crude bacteriocins from the six isolates. The isolates with the highest antimicrobial activity were DK8, the diameter of inhibiting zone of liquid isolates was 15.75 mm (Salmonella sp.), 14.25 mm (Escherichia coli), and 12.25 mm (Staphylococcus aureus). Meanwhile, the diameter of crude bacteriocin inhibition of DK 8 isolates was 8 mm (Salmonella sp.). 8 mm (E. coli), and 8.5 mm (S. aureus). Furthermore, 16S rRNA sequencing confirmed DK8 as Lactobacillus pentosus.


2020 ◽  
Vol 9 (1) ◽  
pp. 96
Author(s):  
Made Juli Antari ◽  
Ni Nyoman Puspawati ◽  
Putu Ari Sandhi Wipradnyadewi

The aim of the research was to find the potency of Lactic Acid Bacteria isolated from breast milk on inhibiting Listeria monocytogenes FNCC 0156 and to find the magnitude of lactic acid bacteria from breast milk in inhibiting L. monocytogenes FNCC 0156. This reseach consists of two phase: antimicrobial activity of lactic acid bacteria from breast milk and activity of bacteriocin against L. monocytogenes FNCC 0156. Isolate used in this research was A1, A3, A6, A8, A9, B3, B7, B8, and B10b. Antimicrobial activity of lactic acid bacteria from breast milk against L. monocytogenes FNCC 0156 was performed cell free supernatant, cell free neutral supernatant, and cell free neutral heated supernatant. The test was performed by well-agar diffusion method and contact method. The activity of bacteriocin was carried out according to the optimum incubation time of bacteriocin production in cell free heated neutral supernatant. The highest antimicrobial activity was supernatant treatment by well-agar diffusion method and contact method showed by isolate A1 with inhibition diameter of 10.60 mm and a decrease of 1.66 log cycle. The highest antimicrobial activity was neutral supernatant treatment by well-agar diffusion method and contact method showed by isolate B8 with inhibition diameter of 5.11 mm and increased only by 0.18 log cycle. The highest antimicrobial activity on the heated neutral supernatant treatment by well-agar diffusion method and contact method showed by isolate A6 with inhibition diameter of 0.85 mm and a decrease of 0.48 log cycle. The two isolates of cell free neutral heated supernatant treatment was isolate A6 and isolate B8 suspected to have bacteriocin compounds was then continued with isolation of bacteriocin. The result of the second phase showed that optimum time for bacteriocin production of isolate A6 was 36 hours and B8 was 60 hours. The highest antimicrobial activity of bacteriocin was showen by isolate A6 with an average inhibition diameter of 5.36 mm, followed by B8 with an average inhibition diameter of 2.44 mm. Keywords: lactic acid bacteria, breast milk, Listeria monocytogenes FNCC 0156, antimicrobial activity, bacteriocin


Foods ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2267
Author(s):  
Anna Łepecka ◽  
Piotr Szymański ◽  
Sylwia Rutkowska ◽  
Kinga Iwanowska ◽  
Danuta Kołożyn-Krajewska

The aim of this study was to determine the impact of environmental conditions on the antimicrobial properties of 21 lactic acid bacteria strains in the selected indicator bacteria. To assess the antimicrobial activity of the whole bacteria culture (WBC), the agar well diffusion method was used. The interference of LAB strains with the growth of the selected indicator bacteria was evaluated by incubating co-cultures in the food matrix. Based on the conducted research, it was found that environmental conditions have a significant impact on the antimicrobial activity of lactic acid bacteria strains. The highest antimicrobial activity was recorded under optimal conditions for the development of LAB, the incubation time being different depending on the indicator strain used. The tested LAB strains were characterized by a high ability to inhibit indicator strains, especially in the food matrix. These results led us to further characterize and purify the antimicrobial compound produced by lactic acid bacteria taking into account changing environmental conditions.


2020 ◽  
Author(s):  
Alazar Essayas ◽  
Sujata Pandit ◽  
Deepak Kumar Verma

AbstractThere have been incerases in antibiotic resistant strains of human pathogens and causing treatment of microbial infections difficult. These days more attention is given to seraching new antimicrobial drugs to combat pathogenic microbes. Traditional fermented cottage of Metata Ayib which is naturally enriched with lactic acid bacteria (LAB) and used to preserve cheese for long time in Northern Ethiopia, may have antimicrobial activity against various human pathogens. However, there was no scientific report on the antimicrobial activity of lactic acid bacteria isolated from Metata Ayib. The objective of this study is to evaluate antibacterial activity of lactic acid bacteria from Metata Ayib against clinical and standard human pathogens. The study was laboratory based experiment. Antibiotic production by the LAB was performed by inoculating the LAB isolates into 6.0 ml MRS medium and incubating at 30 °C. Cell free supernatants (CFS) were collected by centrifugation (10,000 rpm for 15 min at 4 °C) of the six day fermented broth cultures. The pH of the CFS was adjusted to 6.5 with 4 N NaOH to eliminate the effect of organic acids.The susceptibility of produced antibiotic against test organisms was done by growing on Muller Hinton agar in triplicate using well diffusion method and the inhibition zone was recorded. Preceddingly, MIC and MBC was determined using standard methods. The antibiotic substance exhibited antimicrobial activity towards standard and drug resistant bacteral strains with the inhibition zone ranges upto 25.33±3.21 mm. The result of MIC against tested ornaisnms showed a considerable antimicrobial activity of the antibiotic substance withn the range values 6.25% to12.5%. In addition, the result of this study showed that LAB obtained from Metata Ayib exhibits antimicrobial activity against standard and pathogenic pathogenic test bacterial species ranged from 12.5-25% of MBC value. This might be due to the production of organic acids, but also other compounds, such as ethanol, hydrogen peroxide, diacetyl, reuterin and bacteriocins. The results of this investigation can also provide baseline for information for future studies about the application of antibacterial substances produced by LAB from fermented Metata ayib.


2015 ◽  
Vol 35 (02) ◽  
pp. 164 ◽  
Author(s):  
Ema Damayanti ◽  
Ade Erma Suryani ◽  
Ahmad Sofyan ◽  
Muhammad Faiz Karimy ◽  
Hardi Julendra

Fungi contamination was a serious problem on feed industry in Indonesia. Mycotoxin was produced by contaminated fungi could decrease feed quality and it accumulation on animal caused immunosuppressive and mortality effect. The application of biological agent such as antifungal microbe was a promising solution and to be important for futher study. The objective of this research was to select lactic acid bacteria (LAB) with antifungal activity against mycotoxin producing fungi. Lactic acid bacteria were isolated from oil palm frond (OPF) silage, poultry and ruminant digestive tracts (cattle and goat). Antifungal activities of LAB was conducted by using overlay method and paper disc diffusion method of the cell free supernatant against   FNCC 6002,   FNCC 6033 and FNCC 6111. The result showed that LAB strain PDS2 from OPF silage had the highestKeywords: Animal, lactic acid bacteria, fungi, mycotoxin, oil palm frond silage ABSTRAKKontaminasi jamur dalam bahan pakan masih menjadi masalah dalam industri ternak di Indonesia. Selain karena menurunkan kualitas pakan, akumulasi mikotoksin yang dihasilkan oleh jamur kontaminan dalam tubuh ternak juga mengakibatkan efek immunosupresif yang  menyebabkan ternak mudah terserang penyakit hingga menyebabkan kematian. Penggunaan agen biologis berupa mikrobia dengan aktivitas anti jamur menjadi solusi menjanjikan dan penting untuk dikaji. Penelitian ini bertujuan untuk menyeleksi bajteri asam laktat (BAL) dengan aktivitas anti jamur penghasil mikotoksin. BAL diisolasi dari silase pelepah sawit, saluran cerna unggas dan ruminansia (kambing dan sapi).Pengujian aktivitas anti jamur dilakukan dalam secara kualitatif dengan metode dan secara kuantitatif dengan menguji daya hambat supernatan bebas sel menggunakan metode difusi kertas cakram terhadap kapang FNCC 6002,   FNCC 6033 dan   FNCC 6111. Hasil penelitian menunjukkan isolat PDS2 dari silase memiliki daya hambat yang nyata terhadap ketiga jamur uji, sedangkan isolat BAL dari saluran cerna unggas dan ruminansia tidak menunjukkan daya hambat yang nyata.Kata kunci: Anti jamur, bakteri asam laktat, saluran cerna ternak, silase


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