Activity Of Lactic Acid Bacteria Research Articles

Antagonistic Effects of Lactic Acid Bacteria Isolated from Ethiopian Traditional Fermented Foods and Beverages Against Foodborne Pathogens.

Lactic acid bacteria (LAB) found in Ethiopian traditional fermented foods and beverages have potential antagonistic effects against foodborne pathogens due to their capacity to produce various antimicrobial metabolites. This study evaluated the antagonistic activity of LAB isolated from Ethiopian traditional fermented foods and beverages against foodborne pathogens and characterized their antimicrobial substances. A total of 180 traditional fermented foods and beverages were collected, and the antagonistic activities of LAB were evaluated against selected foodborne pathogens. The effects of pH, temperature, enzymes, and food additives on the antagonistic effects of cell-free supernatant produced by LAB were investigated. LAB identification and characterization were conducted using an integrated phenotypic approach and MALDI TOF MS spectrum analysis, and data were analyzed using one-way ANOVA and Tukey post hoc analysis. A total of 956 LAB were isolated, of which seventeen (17 LAB) isolates of Pediococcus pentosaceus (Pc. pentosaceus (n = 7)), Pediococcus acidilactici (Pc. acidilactici (n = 2)), Enterococcus faecium (Ec. faecium (n = 6)), and Lactococcus lactis (Lc. lactis (n = 2)) were screened for antagonistic activity based on their ability to produce bacteriocins, probiotic activity, and preservative potential. Pc. pentosaceus JULABB16, Pc. pentosaceus JULABB01, and Ec. faecium JULABBr39 showed strong antagonistic activity against all pathogens, with mean inhibition zone diameters ranging from 23.50 to 35.50mm. Lc. lactis, Pc. pentosaceus, Pc. acidilactici, and Ec. faecium produced bioactive metabolites that were sensitive to proteolytic enzymes and capable of withstanding high temperatures (80-100°C) and acid concentrations (pH 2-10). The CFS produced by Lc. lactis, Pc. pentosaceus, Pc. acidilactici, and Ec. faecium showed the most impending antagonistic activity against all pathogens. The bioactive substances produced by LAB isolates had promising effects against food spoilage and pathogenic bacteria, making them potential natural food preservatives.

Genetic Identification and Technological Potential of Indigenous Lactic Acid Bacteria Isolated from Alheira, a Traditional Portuguese Sausage.

Alheira is a naturally fermented meat sausage traditionally made in the Portuguese region of Trás-os-Montes. Lactic acid bacteria (LAB) are the dominant microorganisms in alheira and can endow it with various technological properties. This study aimed (1) to characterize technological features and in vitro antimicrobial activity of LAB isolated from alheira, and (2) to reveal associations between such phenotypic characteristics and the isolates species identified through amplification and sequencing of the 16S ribosomal gene. Sixty-two LAB isolates were identified and Enterococcus (E.) faecium corresponded to 32.3% of isolates, followed by Leuconostoc (L.) mesenteroides (19.4%) and Latilactobacillus (Lb.) sakei (17.7%), aligning with previous research on traditional Portuguese fermented meat sausages. The phenotypic analysis of LAB isolates indicated diverse acidification capacities, proteolytic activities, and inhibitory effects against foodborne pathogens Listeria (L.) monocytogenes, Salmonella (S.) Typhimurium and Staphylococcus (S.) aureus. Overall, lactobacilli displayed high inhibition activity against the pathogens S. aureus, L. monocytogenes, and S. Typhimurium. Although the mechanisms for the inhibition of pathogen growth need to be further elucidated, these findings enhance our understanding of LAB diversity and functionality in alheira sausages, contributing to product safety and quality.

A circular economy approach: A new formulation based on a lemon peel medium activated with lactobacilli for sustainable control of post-harvest fungal rots in fresh citrus fruit

The aim of the study was to develop an effective bio-formulation for preventing post-harvest fungal rots in fresh citrus fruit through a multi-step process that includes isolation and characterization of lactic acid bacteria (LABs) from citrus fruit peel, selection of LAB strains with high antifungal activity, chemical characterization of cell free supernatants (CFS), formulation of a lemon peel powdery-based medium (LM) activated with LAB fermentates, chemical characterization of fermented LM, and evaluation of the efficacy of the new bio-formulation against blue mold. Thirteen LABs were recovered from the rind of citrus fruit and identified by the peptide mass fingerprinting method. The antifungal activity of LABs, isolated from citrus fruit, as well as cell free supernatants (CFSs), obtained from their liquid cultures, was tested against diverse plant pathogenic fungi and oomycetes, using the dual-culture overlay and the diffusion agar assays, respectively. Two isolates designated as N3B2 and M2B2, both identified as Lactiplantibacillus plantarum, were selected among the others for their relevant antifungal activity. Both isolates showed a broad spectrum antagonistic activity comprising also major postharvest pathogens of citrus fruit, such as Penicillium digitatum and P. italicum, the causal agents of green and blue moulds, respectively, Alternaria alternata, Colletotrichum gloeosporioides, C. karsti, Phytophthora citrophthora and Ph. nicotianae. The N3B2 and M2B2 isolates were used as starter cultures to ferment a lemon peel powder medium enriched with a nutrient water solution (LM). The two formulations obtained by fermenting LM with the N3B2 and M2B2 isolates showed a strong in vitro inhibitory activity on the same broad range of pathogens used in the preliminary screening of LABs. Moreover, the two LM-based formulations reduced the severity of blue mold infection and inhibited the sporulation of P. italicum on artificially inoculated lemon fruit. The chemical analysis of LM-based bioformulations revealed their antifungal activity was very probably due to the LAB-derived acidic components, including lactic, acetic, DL-3-phenyllactic, 3-4-dihydroxyhydrocinnamic, salicylic acid vanillic acids. These innovative LM-based bioformulations activated with LAB-derived antifungal compounds will be exploited as edible and biodegradable fruit coatings to prolong the shelf-life and prevent post-harvest rots of fresh citrus fruit.

Gut Microbiome Derived Lactic Acid Bacteria (GM-d-LAB) from Dwarf Goats (Capra aegagrus hircus) Inhibit the Resident Multiple Antibiotics Resistance Bacterial pathogens

Background: The global health threat posed by antimicrobial resistance (AMR) has created an urgent need for developing alternative treatment methods. Probiotics, especially Lactic Acid Bacteria (LAB), are gaining interest in this context, as they demonstrate health-enhancing effects and potent antimicrobial activities. The intestines of goats could be a potential origin for developing new probiotics applications in animal feed and human health. Hence this study was carried out to determine the antibiotic resistance profiles of LAB and pathogens within the intestines of Nigerian dwarf goats (Capra aegagrus hircus), the antimicrobial activity of LAB against resident MDR pathogens, and subsequent identification of bioactive LAB isolated from goat faeces in Nigeria as potential probiotics in animal feed and human health.
 Method: Selective isolation of the LAB was carried out using de Mann Rogosa Sharpe (MRS) agar while enteric pathogens were isolated on MacConkey agar. Preliminary identification was carried out based on Gram reaction, and morphological, colonial, and biochemical characteristics of each isolate. Antibiotic susceptibility profiles of all isolates were determined using the Kirby-Bauer disc diffusion method. The agar overlay method was used to test the most resistant LAB isolates for antimicrobial activity against enteric pathogens. Selected LAB isolates were identified by 16SrRNA sequencing. 
 Results: The antibiotics susceptibility profile showed that a majority (77%) of LAB isolates and minimal (҇≤10%) of enteric pathogens demonstrated resistance to at least three classes of antibiotics, indicating a pattern of multi-drug resistance. Over half (62%) of these LAB isolates displayed significant antimicrobial activity against at least five of the resident-resistant pathogens, illustrating their potential role in controlling these pathogens. The sequencing results identified the most active LAB isolates, revealing a mix of strains including Pediococcus lolli (46%), Pediococcus pentosaceus (23%), Weissella confusa (8%), Enterococcus faecium (8%), Enterococcus hirae (8%), and Lactobacillus sanfranciscensis (8%).
 Conclusion: The discovery of a diverse range of LAB strains in goat intestines with significant antimicrobial activity against resident enteric pathogens is valuable. This finding suggests the potential use of these bacteria as natural alternatives to traditional antibiotics, especially in the context of growing AMR in animal husbandry.

The Melibiase Activity of Lactic Acid Bacteria Isolated From Yellow Ogi: A Fermented Cereal Gruel.

The Melibiase Activity of Lactic Acid Bacteria Isolated From Yellow Ogi: A Fermented Cereal Gruel.

ANTIMYCOTIC ACTIVITY OF THE ISOLATES OF LACTOBACTERIA FROM WA-TER AND MUSSELS OF BLACK SEA

Aim. Determination of the presence of antimycotic activity and its level in thirteen lactobacteria isolates from Black Sea water and mussels. Methods. Antimycotic activity of lactic acid bacteria (LAB) isolates was tested by agar diffusion method in 24-well plates. To determine character of action the plates were incubated for 7 days at 25 °C. Results. For the first time antimycotic activity of marine LAB from Odesa coast was estimated. The majority of the tested isolates of lactobateria exhibited antimycotic activity of high level completely inhibiting (in 100%) as mycelium growth as well as spore formation of Penicillium expansum UKM F-575 and Aspergillus niger UKM F-16706 on second day of the study. Four isolates (M.5.1, M.5.2, M.7.1, M.7.2) showed lower antimycotic activity (from 0 to 75%). Eight LAB isolates from seawater (W.1.1, W.1.2, W.1.3, W.1.4, W.1.5, W.1.дк, W.2.3, W.2.4) and one isolate from mussel liquor (M4.1) completely inhibited mycelial growth and sporulation of P. expansum UКМ F-575 and A. niger UКМ F-16706 even within seven days indicating fungicidal character of action. Conclusions. The most of tested LAB isolates from Black Sea exhibited high antimycotic activity against P. expansum UКМ F-575 and A. niger UКМ F-16706 indicator strains. The most active lactobacteria isolates were W.1.1, W.1.2, W.1.3, W.1.4, W.1.5, W.1.дк, W.2.3, W.2.4 isolated from Black Sea water and M4.1 – from mussel liquor. The character of the revealed antimycotic activity was determined as fungicidal.

Pathogenic Biofilm Removal Potential of Wild-Type Lacticaseibacillus rhamnosus Strains.

The emergence of antimicrobial resistance remains one of the greatest public health concerns. Biofilm formation has been postulated as a mechanism of microbial pathogens to resist antimicrobial agents. Lactic Acid Bacteria (LAB) and their metabolites have been proposed to combat bacterial biofilms due to their antimicrobial activity. In this vein, the aim of the present study was to investigate the biofilm removal potential of cell-free supernatants (CFSs) of five wild-type Lacticaseibacillus rhamnosus strains, isolated from Greek natural products, in comparison to the commercially available L. rhamnosus GG strain, against biofilms formed by common foodborne pathogens (Salmonella Enteritidis, Salmonella Typhimurium, Escherichia coli, Listeria monocytogenes, and Staphylococcus aureus). The biofilm removal activity of LAB was assessed on a two-day-old mature biofilm using a microtiter plate-based procedure. Both non-neutralized and neutralized CFSs removed biofilms in a concentration-dependent manner. The biofilm removal activity of the non-neutralized CFSs was significantly higher compared to the neutralized CFSs, as expected, with ranges of 60-89% and 30-80%, respectively. The biofilm removal efficiency of L. rhamnosus OLXAL-3 was significantly higher among the wild-type L. rhamnosus strains tested (20-100% v/v). In conclusion, our results suggest the great potential of the application of wild-type L. rhamnosus strain' CFSs as effective natural agents against pathogenic bacterial biofilms.

Isolation, Identification and Antibacterial Activity of Lactic Acid Bacteria Isolated from Dairy Products against some Pathogenic Bacteria

Isolation, Identification and Antibacterial Activity of Lactic Acid Bacteria Isolated from Dairy Products against some Pathogenic Bacteria

Lactic acid bacteria (Leuconostoc mesenteroides) as bioprotective agents against some pathogenic fungi in common bean

Abstract The common bean (Phaseolus vulgaris L.) is the most important edible food legume in the world. However, its cultivation encounters several phytopathogens. Our study aims to improve food quality and safety through more natural protection methods such as the use of microorganisms that allows us to avoid and minimize pesticide risks. For this purpose, we tested the antagonistic capacity of lactic acid bacteria isolated from raw goat’s milk against four fungal strains isolated from P. vulgaris var. djedida. In this study, lactic acid bacteria (LAB) (Leuconostoc mesenteroides) were screened in vitro for antifungal activity at 28 °C against Fusarium oxysporum, Botrytis cinerea, Aspergillus flavus, and Alternaria alternata. The statistical analysis of the antifungal activity of LAB showed significant differences after a seven-day period. The results of the direct confrontation on the PDA (Potato Dextrose Agar) and MRS (de Man, Rogosa, and Sharpe) Agar medium showed better inhibition by the lactic acid strain on MRS Agar medium. L. mesenteroides gave the highest inhibition rate of 57.6% for the pathogen B. cinerea and 29.1%, 33.3%, and 26.7%, respectively, for the pathogens A. alternata, B. cinerea, F. oxysporum, and A. flavus on the solid PDA medium. However, on the MRS Agar medium, inhibition rates of 88.1% and 80.5% were observed for the pathogens B. cinerea and A. flavus and a total inhibition of 100% on A. alternata and F. oxysporum in the presence of the strain L. mesenteroides. This study led to suggest that food-derived LAB strains could be selected for biotechnological application to control phytopathogenic fungi.

Investigation of Lactobacillus spp. bacteria in infants consuming breast milk and formula and determination of some probiotic characters

Objectives: It was aimed to investigate some probiotic properties of Lactic Acid Bacteria (LAB) isolated from stool samples taken from 45 healthy 0-4 month old babies, who did not take antibiotics or probiotic supplements in the last 3 months, and who did not have any health problems. Methods: Six different species were obtained from 21 isolates selected by the method of Mass Spectrometry (MALDI-TOF MS). Results: The most common strain was Lactobacillus rhamnosus with a rate of 59%, followed by Lactobacillus paracasei with a rate of 13.6%. Vancomycin, tetracycline, gentamicin, netilmicin, tobramycin, penicillin, ampicillin, teicoplanin and amikacin antibiotics were used to evaluate the antimicrobial activities of the strains. In our study, while all strains were resistant to the antibiotic amikacin, they were sensitive to tetracycline, penicillin, gentamicin, netilmicin, teicoplanin, vancomycin, ampicillin and tobramycin antibiotics. In the evaluation of the antagonistic activities of LAB, 6 different pathogens (Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 6538, Bacillus subtilis ATCC 6633, S. aureus ATCC 25923, Candida albicans ATCC 10231, Listeria monocytogenes ATCC 19111) were used and it was determined that the strains showed antimicrobial effects on all pathogenic microorganisms. Cholesterol assimilation abilities, T21 and T22 strains achieved the highest cholesterol assimilation rate of 39.1%. Conclusions: It is thought that most of the isolated strains have probiotic potential, and especially Lactobacillus gasseri T21 and L. paracasei T22 strains may be probiotic strains that can be used in the production of preparations alone or together with other Lactobacillus strains.

Quantitative tools in microbial and chemical risk assessment.

The popularity of biological origin food protection substances is driven by demands from consumers for natural and clean label product, increasing various food-related safety and health concerns and sustainability issues. Lactic acid bacteria (LAB) are most promising because they are a large group of beneficial microorganisms commonly used in food protection due to their ability to inhibit the growth of pathogenic bacteria and enhance food safety. Extensive scientific research has been conducted to understand the mechanisms by which LAB exert their protective effects in various food systems. Even though LAB activity against various food pathogens and spoilers is distinguished, use of cell-free supernatant (CFS) is still under investigation. This report is dedicated to present how qualitative measures can elaborate in new bacteria-origin food additive investigation. As part of the EU-FORA programme, the fellow was involved in the risk assessment tasks and projects which include gaining basic knowledge in predicative microbiology fundamentals, including different types of modelling strategies; delivering essential understanding about experimental design, knowledge in three specific software tools (MATLAB, GInaFiT and DMFit) and gained overall understanding what are the main differences while modelling growth or inactivation models. Secondary activities were included as a way to expand competences beyond qualitative measures to overall all activities done regarding risk assessment and build a strong network of food safety experts and professionals to continue engaging in risk assessment beyond fellowship programme.

Total Lactic Acid Bacteria (LAB) and Antioxidant Activity of Goat's Milk Yoghurt with The Addition Of Red Bran During Refrigeration Storage

Background: Goat milk yogurt is a functional food made from processed food of animal origin with the help of LAB fermentation, which is healthy for the body. The utilization of red rice bran flour as an additional ingredient in making yogurt can increase the level of antioxidant activity and become a food fiber content in yogurt. Purpose: This study aims to determine the effect of refrigerated storage temperatures (4℃) of goat milk yogurt with the addition of red rice bran flour on total LAB and antioxidant activity. Methods: Using a CRD with five treatments and four replications. The treatment included 0, 1, 2, 3, and 4 weeks of storage. Each treatment group will be calculated for total LAB using the TPC method and antioxidant activity testing using the DPPH method. The data obtained were analyzed using the One Way ANOVA Test followed by the Duncan Test to determine the effect between treatment groups. Results: The results showed that storage time significantly affected (p<0.01) total LAB and antioxidant activity. The results of total LAB successively from 0 to 4 weeks of storage were 8,0 x 108 CFU/ml, 7,8 x 107 CFU/ml, 7,6 x 107 CFU/ml, 6,4 x 106 CFU/ml, and 6,3 x 106 CFU/ml. The results of antioxidant activity successively from 0 to 4 weeks of storage were 534,29 mg/ml, 443,96 mg/ml, 358,61 mg/ml, 282,32 mg/ml, and 230,88 mg/ml. Conclusion: Goat’s milk yogurt with the addition of brown rice bran flour is recommended to be consumed for up to 2 weeks of storage.

Isolation and Evaluation of the Probiotic Activity of Lactic Acid Bacteria Isolated from Pickled Brassica juncea (L.) Czern. et Coss.

The naturally occurring lactic acid bacteria can be isolated from various sources. Pickled Brassica juncea (L.) Czern. et Coss. was used to isolate lactic acid bacteria (LAB). This study was conducted to compare the probiotic properties of probiotics isolated from pickled Vietnamese cabbage with some commercial strains of probiotics available on the Vietnamese market. The results showed that two strains (Lactobacillus fermentum and Lactiplantibacillus plantarum) isolated from pickled Vietnamese cabbage and three commercial strains of probiotics (Bacillus subtilis, Bacillus clausii, Lactobacillus acidophilus) all showed probiotic properties. Probiotic properties were evaluated through the ability to survive in low pH, pepsin, pancreatin, and bile salt media, the hydrophobicity of the bacteria, the antibiotic resistance, and the resistance to pathogenic bacteria. The isolated strain Lactiplantibacillus plantarum had fewer probiotic properties than Bacillus subtilis but more than the two commercial strains Bacillus clausii and Lactobacillus acidophilus, and the isolated Lactobacillus fermentum showed the fewest probiotic properties of the five strains.

Technological Interest and Antimicrobial Activity of Lactic Acid Bacteria Isolated from Date Paste of the Ghers Variety (Bechar, South-West of Algeria)

Background: Dates are high nutritional value fruits. They are the basis of many traditional products and compose several oases by-products. Among these products, date paste represents a form of conservation widely practiced in Algeria to valorize common date’s surplus production for commercial purposes. Methods: First, microbiological analysis was carried out to isolate lactic acid bacteria (LAB) from date’s paste and microbial contaminants from both date fruit by-products according to standard microbiological methods before investigating the technological characteristics attributed to the isolated LAB. Second, the antimicrobial effect was evaluated through three different techniques. Result: Nine microbial contaminants were isolated from date paste and date extract, while eight LAB strains were isolated from date paste, which belong to the Streptococci and Leuconostoc strains. The SLM1 strain revealed a good acidifying power going up to 5.13 g/L of lactic acid within 6 hours of incubation compared to the other LAB strains. A moderate to strong antibacterial effect ranging up to a 20 mm zone of inhibition was revealed against bacterial contaminants. In decreasing order, the antifungal effect was significant against Penicillium sp, Aspergillus niger and A. flavus. The isolated lactic strains of streptococci could be good candidates for food preservation by extending the shelf life of foods and improving their nutraceutical and hygienic quality.

Characterization of Potential Probiotic Activity of Lactic Acid Bacteria Isolated from Camel Colostrum by Biochemical and Molecular Methods.

A total of 60 isolates of lactic acid bacteria (LAB) were isolated from Jordanian camel colostrum using biochemical and molecular methods. Two dominant species were identified, and they were Lactobacillus salivarius and Enterococcus faecium. The entire 60 isolated LAB were tested for their acidity and bile tolerance, antimicrobial activity, and antibiotic sensitivity to test their potential probiotic activity. All 60 isolates were tolerant to different pH concentrations (2, 3, 4, 5, 6, 7, 8, 9, and 10) with different survival rates (%). The entire isolates were also tolerant to different bile salt concentrations (0.2, 0.4, 0.6, 0.8, 1, 2, and 3) with different bile resistance (%). All isolates have a different range of antimicrobial activity against Staphylococcus aureus, E. coli, and Salmonella typhimurium. The 60 isolates were almost sensitive to ampicillin, amoxicillin, and clarithromycin when different concentrations were used except some isolates of intermediate resistance. Only 6% of the isolates were resistant to clarithromycin at a concentration of 15 µg per disc.

Activity of Lactic Acid Bacteria (LAB) from the intestines of vannamei shrimp (Lithopenaeus vannamei) in inhibiting the growth of Vibrio harveyi

Lactic Acid Bacteria (LAB) is a bacterium that has been widely used as a probiotic because it can inhibit the growth of pathogenic bacteria. Lactic acid bacteria are usually found in the digestive tract of both humans and animals. In this study, isolates of Lactic Acid Bacteria from the intestines of vannamei shrimp (Litopenaeus vannamei) were isolated from traditional ponds in Bangkalan. Antibacterial activity testing was carried out on Vibrio harveyi, and then the suspected isolates of LAB were identified using a biochemical test referring to the book Identification of Cowan and Steel 1992. Isolation of LAB using pour plate using MRS Agar media enriched with CaCO3 1%. Antibacterial activity test using Kirby Baurer method with disc diffusion technique. The results of the characterization of LAB contained in the intestines of vannamei shrimp were obtained as many as four isolates. Antibacterial activity test of LAB against Vibrio harveyi obtained the highest inhibition zone, namely isolate 2 with a diameter of 4.25 ± 1.77 mm, and was included in the weak category because it was less than 5 mm. The results of bacterial identification using biochemical tests showed that the three isolates were bacteria from the genus Pediococcus and one isolate was a bacterium from the genus Gemella.

Fungal inhibition by lactic acid bacteria (LAB) is modulated in vitro by cocoa fermentation-related conditions: towards a biocontrol of fungi in processing cocoa

Fungal growth impair strongly the quality of processed cocoa, leading to low crops value for farmers and manufacturers. The antifungal activity of lactic acid bacteria (LAB) from fermenting cocoa was analyzed and the conditions of fungal inhibition were evaluated. Fungi were isolated from stored fermented and dried cocoa beans on sabouraud plate medium. The results showed that, LAB strongly inhibit fungi isolated from fermented cocoa beans notably Mucors and Aspergilli, with Lactobacillus plantarum inducing the stronger inhibition whereas Leuconostoc mesenteroides produced a weaker inhibition. Acids production assayed by HPLC was found to be not related to antifungal activity, since LAB strains producing strong antifungal activity were not necessarly the best acid producers. Maximum fungal inhibition occured at 35 °C in Lactobacillus plantarum and Leuconostoc mesenteroides but also at 30 °C in Lactobacllus casei. Likewise, a narrow acidic pH range (3.0-4.0) allowed full expression of fungal inhibtion in LAB analyzed that decreased progressively toward pH 7.0 and failed at alkalin pH. However, sucrose even at high content (8%) was found to have no effect on antifungal activity of LAB, but its bioconversion product glucose and fructose decreased this activity when concentrations were set at 6 et 2 %, respectively. All together, the results suggest that, LAB may effectively exert fungal inhibition in a narrow timing of cocoa fermentation, with pulp contained sugars as metabolic regulators of this inhibition. These results may contribute to a better management of LAB as starter culture for an efficient inhibition of fungal growth and prevention of cocoa contamination from mycotoxins.
 Key Words : Antifungal activity ; lactic acid bacteria ; cocoa fermentation ; inhibition variation; pH and temperature ; sugars content.

Antimicrobial properties of lactic acid bacteria from fermented palm sap against E. coli and S. aureus growth

Palm sap produced from tapping can be a growing place for lactic acid bacteria (LAB). Palm sap has a lot of carbohydrate content, such as sucrose, fructose, and glucose, which can be a source of nutrition for the growth of microorganisms such as LAB). The result of LAB metabolism that is formed can be in the form of organic acid acids that can act as antimicrobial compounds. LAB have been isolated from fermented palm sap. This study aimed to determine the antibacterial properties of LAB from the fermentation of palm sap against E. coli and S. aureus using the well-agar diffusion method and the paper disc diffusion method. The study showed that LAB isolates (Lactobacillus A1, A6, B12, C1, and C4) and cell-free supernatants have antibacterial activity against E. coli and S. aureus. LAB antibacterial properties using cells with a clear zone diameter against E. coli ranges from 8.03 to 0.58 mm, and S. aureus inhibition zone diameter ranges from 9.13 to 11.16 mm. The antimicrobial activity of LAB using cell-free supernatants against E. coli ranges from 4.59 to 5.01 mm, and the diameter of the inhibitory zone against S. aureus ranges from 4.34 to 5.79 mm. From these results, LAB isolated from fermented palm sap can potentially be probiotics.

Identification and Antimicrobial Activity of Lactic Acid Bacteria Isolated from Tualang Bee Honey

Malaysia tualang honey usually collected from the combs of Asia rock bees (Apis dorsata), which build their hives high up in the tualang tree (Koompassia excelsa). Tualang honey is used commonly as a medicinal product and as food in Malaysia. LAB strains have been discovered to exhibit antimicrobial properties even though especially in Malaysia, the research on LAB found from honey are still scarce. The study was conducted to isolate and identify lactic acid bacteria (LAB) from Tualang honey bee from East Coast Peninsular Malaysia. The Tualang honey identified LAB strains were further tested against several pathogenic bacteria by using well-diffusion method. The LAB were primarily identified by colony morphology, microscopy of Gram`s stain, biochemical tests and 16s rRNA sequencing method. 10 isolates LAB that has been identified as Leuconostoc mesenteroides (5 isolates), Lactobacillus kunkeei (4 isolates), and Lactobacillus farraginis (1 isolates) were selected for the characterization of antimicrobial agents produced by LAB. It was found that from 10 isolates, 5 isolates exhibited strong antimicrobial activity against Staphylococcus epidermidis and Pseudomonas aeruginosa results in excellent inhibition zones diameters larger than 15 mm. This study indicated that lactic acid bacteria isolated from Tualang honey has potential antimicrobial activity against pathogenic bacteria and can be further characterized for health benefits and potential use in food industry at Malaysia.
 Keywords: Tualang Honey, LAB, pathogen, 16s rRNA sequencing, antimicrobial activity.

A Comprehensive Review of Bioactive Compounds from Lactic Acid Bacteria: Potential Functions as Functional Food in Dietetics and the Food Industry.

Lactic acid bacteria (LAB) are beneficial microbes known for their health-promoting properties. LAB are well known for their ability to produce substantial amounts of bioactive compounds during fermentation. Peptides, exopolysaccharides (EPS), bacteriocins, some amylase, protease, lipase enzymes, and lactic acid are the most important bioactive compounds generated by LAB activity during fermentation. Additionally, the product produced by LAB is dependent on the type of fermentation used. LAB derived from the genera Lactobacillus and Enterococcus are the most popular probiotics at present. Consuming fermented foods has been previously connected to a number of health-promoting benefits such as antibacterial activity and immune system modulation. Furthermore, functional food implementations lead to the application of LAB in therapeutic nutrition such as prebiotic, immunomodulatory, antioxidant, anti-tumor, blood glucose lowering actions. Understanding the characteristics of LAB in diverse sources and its potential as a functional food is crucial for therapeutic applications. This review presents an overview of functional food knowledge regarding interactions between LAB isolated from dairy products (dairy LAB) and fermented foods, as well as the prospect of functioning LAB in human health. Finally, the health advantages of LAB bioactive compounds are emphasized.