Screening Of Lactic Acid Bacteria Research Articles

In Vitro Screening of Lactic Acid Bacteria with RAW264.7 Macrophages and the Immunoregulatory Mechanism

Lactic acid bacteria (LAB) are commonly consumed as probiotics to improve gut barrier function and boost the immune system. This study aimed to screen LAB with high immunomodulatory activity using RAW264.7 macrophages. According to the results, Limosilactobacillus reuteri AUc2301 was selected from 84 screened strains that can stimulate RAW264.7 cell proliferation. Limosilactobacillus reuteri AUc2301 significantly enhanced the phagocytosis activity of RAW264.7 cells. In the ELISA test, Limosilactobacillus reuteri AUc2301 significantly promoted the release of interleukin-6, IL-1β, the tumor necrosis factor, and nitric oxide in RAW264.7 macrophages. In addition, Limosilactobacillus reuteri AUc2301 significantly inhibited the excessive release of IL-6, IL-1β, TNF-α, prostaglandin E2 as well as NO and the high expression of cyclooxygenase-2 in RAW264.7 macrophages induced by lipopolysaccharide. In further mechanism studies, Limosilactobacillus reuteri AUc2301 could regulate the nuclear factor-κB signaling pathway in RAW264.7 macrophages. Collectively, the screened Limosilactobacillus reuteri AUc2301 showed good immunomodulatory activity in vitro, and it has the potential to be developed as a novel probiotic.

Malolactic fermentation in lingonberry juice and its use as a preservative

Lingonberry is a common wild berry that is often sold as jams and beverages. It naturally contains high amounts of the weak acid preservative benzoic acid making it an interesting ingredient for shelf-life extension. Despite this, their use as a raw ingredient is limited by the inherently intense sour taste. This study aimed to improve the taste of lingonberry juice by subjecting it to malolactic fermentation in order to reduce the sourness, and to investigate the benzoic acid in lingonberries as a natural preservative in juice blends by determining the microbial stability. After initial screening of lactic acid bacteria, a Lactiplantibacillus plantarum strain was used as the starter for subsequent investigations. Upon raising the pH, all malic acid was completely converted to lactic acid after seven days. The fermented juice was mixed with blackcurrant juice in different proportions. Challenge tests of the blends showed Listeria monocytogenes could not grow in any juice samples, while Candida albicans only grew in the pure blackcurrant juice. Aspergillus brasiliensis growth was delayed in all samples containing benzoic acid in a concentration-dependent manner. The sourness and astringency were substantially reduced in the juice with added L. plantarum compared to the unfermented juice.

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.

Growth Control of Listeria monocytogenes in Raw Sausage via Bacteriocin-Producing Leuconostoc carnosum DH25.

The current study addresses the critical issue of Listeria monocytogenes growth in raw sausage/meat products leading to human infections, most commonly listeriosis, which is known for its high fatality rate. This research focuses on the isolation, identification, and screening of lactic acid bacteria from various meat and fish products in Switzerland. In total, 274 lactic acid bacteria strains were isolated from 30 different products and were screened for their ability to inhibit Listeria monocytogenes growth, with 51 isolates demonstrating anti-Listeria activity at 8 °C, 15 °C, 25 °C, and 37 °C. Further experiments, using a meat model and a raw sausage challenge test, demonstrated that Leuconostoc carnosum DH25 significantly inhibited Listeria monocytogenes growth during the ripening and storage of the tested meat/sausage. This inhibitory effect was found to be attributed to the bacteriocins produced by Leuconostoc carnosum DH25 rather than factors like pH or water activity. The stability of the anti-Listeria substances was examined, revealing their resistance to temperature and pH changes, making Leuconostoc carnosum DH25 a promising protective culture for raw sausages. The genome sequencing of this strain confirms its safety, with no antibiotic resistance genes or virulence factors detected, and reveals the presence of the structural genes for the production of the bacteriocin LeucocinB-Ta11a. This study underscores the potential of LAB strains and their bacteriocins as effective tools for enhancing food safety and preventing Listeria monocytogenes growth in meat products, offering valuable insights into biocontrol strategies in the food industry.

Isolation, characterization and screening of lactic acid bacteria (Lab) from fruits for the production of probiotic beverage

Isolation, characterization and screening of lactic acid bacteria (Lab) from fruits for the production of probiotic beverage

Screening of Lactic Acid Bacteria from Oysters for Antibacterial Activity Against Selected Pathogens

Lactic acid bacteria (LAB) are among the important groups of bacteria and considered as probiotics development. LAB is mostly isolated from the gastrointestinal tract (GIT) from organism such as oyster. Oyster belongs in to class Bivalvia which live in estuaries area. The purpose of research was to isolate and screened for antibacterial activity against selected pathogens. The LAB was isolated by pour plate method using MRSA (De Man, Rogosa, Sharpe Agar) as selection media for LAB. Then, LAB was screened by an agar diffusion assay for antibacterial activity. The result showed that four isolates (TR-01; TR-02; TR-03 and TR-04) have inhibitory activity against pathogens including E. coli, Salmonella enterica, Staphylococcus aureus, Bacillus cereus. Therefore, it is needed further assay to selected 4 isolates as potential probiotics.

Screening Lactic Acid Bacteria from Seaweed for Plant Milk Fermentation: A Preliminary Research

A fascinating opportunity for screening lactic acid bacteria with the potential to ferment plant-based milk production exists in seaweed, a rich source of microbial variety. In this work, marine-derived lactic acid bacteria (LAB) will be identified and used to improve plant milk fermentation, paving the path for healthy and sustainable dairy substitutes. The methods applied in this research including the LAB isolation and identification by performing gram and catalase test. Then, the lactic acid bacteria transferred to fermentation in both plant and dairy milk to observe the ability to ferment plant-based products. It is resulted that the bacteria isolated can ferment the plant-based milk better than the dairy milk, suggesting that the potential of marine lactic acid bacteria to be applied in plant milk-based fermentation.

Gut Microbiome Analysis and Screening of Lactic Acid Bacteria with Probiotic Potential in Anhui Swine.

With the widespread promotion of the green feeding concept of "substitution and resistance", there is a pressing need for alternative products in feed and breeding industries. Employing lactic acid bacteria represents one of the most promising antimicrobial strategies to combat infections caused by pathogenic bacteria. As such, we analyzed the intestinal tract of Anhui local pig breeds, including LiuBai Pig, YueHei Pig, and HuoShou Pig, to determine the composition and diversity of intestinal microbiota using 16S rRNA. Further, the functionality of the pigs' intestinal microbiota was studied through metagenomic sequencing. This study revealed that lactic acid bacteria were the primary contributors to the functional composition, as determined through a species functional contribution analysis. More specifically, the functional contribution of lactic acid bacteria in the HuoShou Pig group was higher than that of the LiuBai Pig and YueHei Pig. Subsequently, the intestinal contents of the HuoShou Pig group were selected for the screening of the dominant lactic acid bacteria strains. Out of eight strains of lactic acid bacteria, the acid-production capacity, growth curve, and tolerance to a simulated intestinal environment were assessed. Additional assessments included surface hydrophobicity, the self-aggregation capability, co-agglutination of lactic acid bacteria with pathogenic bacteria, and an in vitro bacteriostatic activity assay. Lactobacillus johnsonii L5 and Lactobacillus reuteri L8 were identified as having a strong overall performance. These findings serve as a theoretical basis for the further development of pig-derived probiotics, thereby promoting the application of lactic acid bacteria to livestock production.

Isolation and screening of lactic acid bacteria and yeast starters from ersho (traditional Ethiopian sourdoughs) and evaluation of their role in bread production

SummaryErsho is a well‐known as a source of lactic acid bacteria (LAB) and yeasts in Ethiopia. However, the utilisation of yeasts and LAB for bread production has not been previously studied. Therefore, the objective of the current study was to screen yeasts and LAB from ersho samples and determination of their bread production efficiency using a laboratory based experiment. Three LAB (1A, 13E, and 55A) and three yeasts (4A, 14D, and 54A) were screened and used to develop sourdough starters (4A13E, 14D55A, 54A1A, and 54A13E). The properties of BS4 bread made with 54A13E sourdough starter had more improved. The protein, TVC (total viable count), TFC (total fungal count), and shelf life of control bread were 13.38%, 3.1, 2.1 log cfu g−1, and 4 days, respectively. The protein, TVC, TFC, and shelf life of BS4 bread were 15.52%, 2.0, 1.4 log cfu g−1, and 7 days, respectively. Colour, texture, taste, odour, and overall acceptability mean scores of control bread were 6.6, 6.7, 6.9, 7.1, and 6.9, respectively. Colour, texture, taste, odour, and overall acceptability mean scores of BS4 bread were 8.6, 8.6, 6.4, 8.1, and 7.7, respectively. The results suggest that the use of sourdough starter in place of bakery yeast would be preferable when baking bread.

Composition of bacterial blends for fermentation-induced pea protein emulsion gels using multi-property screening of lactic acid bacteria

In this study, a comprehensive screening and identification process to pinpoint lactic acid bacteria (LAB) strains capable of enhancing gel firmness and elevating the flavor profile in pea protein-based protein gels was conducted, aiming to demonstrate how tailored starter cultures for specific applications can provide high-quality sensory attributes in fermented plant-based cheese. Thirteen single strains were selected from a poll of 90 different LAB based on their acidification performance, contribution to gel firmness, removal of off-flavors and production of dairy-associated volatile organic compounds. They were combined in 64 different blends of five strains each and screened again for the same parameters. Fast acidifying strains were prioritized for food preservation reasons to inhibit undesirable spoilage. Fermentation of pea protein emulsions with Streptococcus thermophilus, Lactobacillus, and Lactococcus blends resulted in a significant reduction in volatile organic compounds associated with beany and green off-flavor, a production of dairy-associated compounds, and satisfactorily contributed to gel firmness.

Screening of lactic acid bacteria from freshwater fish intestines and their effects on growth, immunity, and disease resistance in zebrafish

Screening of lactic acid bacteria from freshwater fish intestines and their effects on growth, immunity, and disease resistance in zebrafish

Screening lactic acid bacteria and yeast strains for soybean paste fermentation in northeast of China.

Soybean paste was a traditional fermented product in northeast China, mainly fermented by molds, yeast, Bacillus, and lactic acid bacteria. In this study, the safety and fermentation ability of lactic acid bacteria and yeast strains isolated from traditional soybean paste in northeast China were evaluated, and the dynamic changes of biogenic amines, aflatoxin, total acids, amino acid nitrogen, and volatile compounds were investigated during the fermentation of the traditional soybean paste. Among the tested strains, Lactiplantibacillus plantarum DPUL-J8 could decompose putrescine by 100%, and no biogenic amine was produced by Pichia kudriavzevii DPUY-J8. Lactiplantibacillus plantarum DPUL-J8 and P. kudriavzevii DPUY-J8 with strong biogenic amine degrading capacities were inoculated into the soybean paste. After 30 days of fermentation, the content of biogenic amines and aflatoxin in the fermented soybean paste declined by more than 60% and 50%, respectively. At the same time, compared with the control group without inoculation, the contents of total acid (1.29 ± 0.05 g/100 g), amino acid nitrogen (0.82 ± 0.01 g/100 g), and volatile compounds in soybean paste fermented by L. plantarum DPUL-J8 and P. kudriavzevii DPUY-J8 were significantly increased, which had a good flavor. These results indicated that the use of L. plantarum DPUL-J8 and P. kudriavzevii DPUY-J8 as starter cultures for soybean paste might be a good strategy to improve the safety and flavor of traditional Chinese soybean paste.

The potential of lactic acid bacteria isolated from ikan budu (fermented fish) to inhibit the growth of pathogenic fungi and detoxify aflatoxin B1.

Market demand for safe feed and food supply and consumer preferences for safe and healthy products are increasing. Control measures to counter threats to the feed supply need to be implemented as early as possible to prevent economic losses. Mycotoxins produced by certain groups of fungi are a problem that can disrupt the feed supply or pose a threat to the health of animals and humans. Biological control to detoxify contaminated feed ingredients can be carried out on a large scale economically. For example, lactic acid bacteria (LAB) can act as biological agents for eliminating mycotoxins. This study aimed to clarify the value of screening LAB to inhibit Aspergillus flavus growth and detoxify aflatoxin B1 (AFB1). In this study, using a completely randomized design with three replications, five isolates of LAB (LA.1, LA.6, LA.8, LA.12, and LA.22) along with their supernatants were tested qualitatively and quantitatively for their ability to counter mycotoxins using A. flavus and corn kernels. The isolates with the best activity were identified by sequencing 16S rDNA. The results showed that the five LAB isolates can inhibit the growth of A. flavus and detoxify AFB1. Among these isolates, LA.12 showed the best performance, followed by LA.22, LA.8, LA.6, and then LA.1. The sequencing results confirmed that LA.12 was Lactobacillus harbinensis strain 487. All of the isolates in this study have the potential as biological agents for detoxifying AFB1, with isolate LA.12 appearing to be the most promising biodetoxification agent for feed (AFB1 in corn) based on its ability to inhibit pathogenic fungi.

In vitro screening and probiotic evaluation of anti-obesity and antioxidant lactic acid bacteria

In this study, an in vitro screening method for lactic acid bacteria (LAB) with anti-obesity and antioxidant effects was developed. We first screened high cholesterol-lowering LAB from the traditional fermented food water kefir. Among the screened LAB, there were 12 strains with a cholesterol degradation rate over of 60%. The 12 strains were ranked from highest to lowest cholesterol degradation ability, and the top five strains were selected for subsequent tests to determine their ability to lower triglycerides, inhibit α-amylase and α-glucosidase, and LAB with great anti-obesity and antioxidant effects were screened in vitro by determining their ability to inhibit Enterobacter cloacae and their antioxidant activity. A comprehensive evaluation model was then combined with principal component analysis: Y = 0.513Y1+0.229Y2+0.137Y3+0.121Y4. Lactobacillus rhamnosus S51, Lactobacillus plantarum S184, and Lactobacillus fermentum S7 had better anti-obesity and antioxidant potential. The cholesterol-lowering ability of S51 was 69.90%, the triglyceride-lowering ability was 53.72%, α-amylase, and α-glucosidase inhibiting ability was 69.97% and 31.49%, respectively, and Enterobacter cloacae inhibiting ability was 3.43 cm. Its IC scavenging ability of DPPH free radical was 90.47%, which was equivalent to 27.98 μg/mL Trolox standard solution, the CFE scavenging capacity for hydroxyl radicals was 60.99%, and the total reducing power of CFE was equivalent to 513.37 μmol/L l-cysteine hydrochloride. S51, S184, and S7 were eligible for probiotic conditions. The results of the study provide a theoretical basis for the screening of LAB with anti-obesity and antioxidant effects in vitro.

The Occurrence of Folate Biosynthesis Genes in Lactic Acid Bacteria from Different Sources.

Lactic acid bacteria (LAB) are known to produce folate. However, this ability is highly strain-dependent. Folate synthesis in specific LAB strains is affected by the availability of folate, which can be consumed by other LAB under certain conditions. Moreover, differences in folate synthesis capabilities are related to the presence of folate biosynthesis-related genes and regulation of this pathway. As basic information to better understand the regulation of folate biosynthesis among different LAB species and strains, folate biosynthetic genes were screened and identified in folate-producing and non-folate-producing LAB isolated from various local food sources in Indonesia. The extracellular folate productivity amounts of the isolates were analyzed using high-performance liquid chromatography with a diode array detector (HPLC-DAD). Eleven of the thirteen tested LAB isolates had all of the eight genes involved in folate biosynthesis (folE, folQ, folB, folK, folP, folC1, folA and folC2). Furthermore, these isolates produced extracellular folate ranging from 10.37 to 31.10 µg/mL. In contrast, two non-folate-producing isolates lacked several folate biosynthetic genes, such as folQ, folP and folA, which is possibly the reason for their inability to synthesize folate de novo. Phylogenetic tree construction revealed that the folate biosynthetic genes (excluding folK and folP) from six distinct species of folate-producing LAB isolates were monophyletic with homologous genes from other LAB species in the database. In this study, the distribution of folate biosynthetic genes in various LAB species was determined. The findings from this research support the use of folate biosynthesis marker genes in the genotypic screening for folate-producing LAB.

Selection Of Lactic Acid Bacteria as Starter Culture for Cocoa Fermentation (Theobroma Cacao L.)

This research aims to select the potential lactic acid bacteria (LAB) for starter culture for cocoa beans fermentation. The bio-control activity against mycotoxigenic fungi were also evaluated. The indigenous LAB was analized from Sukabumi cocoa beans fermentation by spontaneous method for four days (96 hours). The preliminary screening of LAB were observed by clear zone forming, morphology characterization and catalase activity. The LAB were screened for their ability to resist acidity, ethanol, and heat, and their ability to produce high acid and antifungal. The antifungal capability was antagonistic assays to Aspergillus ochraceus IPBCC 88.033 on Potato Dextrose Agar (PDA) medium. The result showed that the selected acid bacteria isolate, H 2.34, were antifungal-producing strains, and resist acidity, ethanol and heat, which was suitable property for starter culture and biopreservation agent. The study demonstrated the selection of local Indonesian LAB from Sukabumi fermented cocoa bean to observe the potential of isolate as a starter culture and biopreservation agent

Studying the physiological and biochemical properties of lactic bacteria cultures in the creation of sourdough for bread

The article presents the results of screening lactic acid bacteria cultures of the genus Lactobacillus and Pediococcus from the collection of Kazakh Scientific Research Institute of Processing and Food Industry, previously isolated from wheat grain, flour, rye starter cultures, as well as kumis and shubat. For a comprehensive assessment of probiotic properties of the selected 7 strains of lactic acid bacteria, their physiological and biochemical properties were studied: acid-forming, antagonistic activity, saccharolytic profile, resistance to various concentrations of bile, sodium chloride, growth at different pH values, antibiotic resistance. As a result of strains screening 5 most active cultures of lactic acid bacteria were selected for inclusion in the sourdough for bread: Limosilactobacillus pontis 9K3, Limosilactobacillus fermentum 3Ш1, Lb. paracasei 82, Lb. paracasei 114, Lacticaseibacillus paracasei 126.The selection criteria were high enzymatic, acid-forming, proteolytic and antagonistic activity of the strains against opportunistic and pathogenic microflora (B. subtilis ATCC 6633, Escherichia coli-1257, Staphylococcus sp.209-P, Salmonella Typhimurium). We show that this result of the analysis indicates the prospects of using a consortium of these cultures to obtain a probiotic starter culture for bakery products. This, in turn, will increase production efficiency, ensure the quality and safety of food products in the baking industry.

Isolation and Characterization of Lactic Acid Bacteria from Fermented Milk Produced in Jimma Town, Southwest Ethiopia, and Evaluation of their Antimicrobial Activity against Selected Pathogenic Bacteria.

Raw milk is usually contaminated with pathogenic bacteria. Fermentation of milk is important to inhibit the growth of contaminants, spoilage, and pathogenic bacteria. The objective of this study was to isolate lactic acid bacteria from fermented milk and evaluate their antimicrobial activity against selected pathogenic bacteria. Laboratory-based experimental study design was conducted from May-July, 2021.Three samples of Ergo (each of 250 ml) were collected from Jimma town. Lactic acid bacteria (LAB) isolates were identified through integrated phenotypic techniques. Further identification was conducted through using API 50 CHL strips. Antimicrobial activities (AMAs) of LAB isolates were tested against clinical isolates of E. coli, S. aureus, and Salmonella spp. using agar well diffusion method. The data were analyzed by using SPSS software version 21 and Microsoft Excel spreadsheet. Tables and figures were applied to describe characteristics of data. Twelve LAB isolates were identified. Those LAB isolates include six Lactococcus lactis subsp. lactis, Lactobacillus acidophilus (2), Lactiplantibacillus plantarum (1), Limosilactobacillus fermentum (2), and Leuconostoc lactis (1). Based on primary screening of LAB, isolates/strains ESCIa, ESBIa, and ESCIc show strong AMA against S. aureus, E. coli, and Salmonella spp. The CFS of ESCIc showed the highest AMA against S. aureus and Salmonella spp. with a zone of inhibition of 14.12 ± 1.6 mm and 12.9 ± 3.6 mm, respectively, while ESBIa showed the highest AMA against E. coli with a zone of inhibition of 13.5 ± 2.1 mm. The CFSs of selected LAB strains were heat tolerant at varying temperatures up to 100°C. The CFSs of selected LAB strains were inactivated by proteinase enzymes, but they are not inactivated with amylase enzymes. Conclusions and Recommendation. All 12 LAB isolates exhibited antimicrobial activity against tested bacterial strains. Lactobacillus isolates showed the highest antagonistic activity on tested indicator strains. Thus, they are possible alternatives to antibiotics in the era of antimicrobial resistance. S. aureus was the most sensitive to antimicrobial effects/agents of selected LAB isolates. Consumption of fermented foods is advisable since they support the growth of healthy GIT microbiota. Fermentation serves as biopreservation of food. However, analysis of probiotic features and in vivo probiotic effects of those LAB isolates will be subject of future research/study.

Isolation, Characterization, and Effect on Biofilm Formation of Bacteriocin Produced by Lactococcus lactis F01 Isolated from Cyprinus carpio and Application for Biopreservation of Fish Sausage.

The aim of this work was the screening of bacteriocin-producing LABs isolated from fish, the selection of promising/prominent strain(s), the characterization of the bacteriocin produced, and the evaluation of its potential to be used as biopreservative(s). Amplification and sequencing of the 16S rRNA gene of the bacteriocin-producing strain was performed. Then a partial purification of the produced bacteriocin, using a combination of ammonium sulfate and chloroform-methanol precipitation, was done. Its molecular weight was determined by SDS-PAGE. In addition, the action spectrum, the hemolysis test, and its ability to inhibit biofilm formation were analyzed. A total of 88 isolates of lactic acid bacteria (LAB) including one bacteriocin producer, which was identified as Lactococcus lactis F01, were collected. The bacteriocin was partially purified with an estimated yield of 40%. Regarding the SDS-PAGE profile, the secreted bacteriocin has molecular weight of about 3.5 kDa and was identified as class I bacteriocin. The antimicrobial test showed that the bacteriocin inhibits pathogenic and/or spoilage bacteria, 10 Gram-positive and 16 Gram-negative bacterial species. Moreover, it can inhibit biofilm formation from 1.3% (Escherichia coli) to 63.92% (Pseudomonas aeruginosa ATCC15692) depending on the strain. The hemolytic activity of novel bacteriocin was observed at the concentration of 10 μg/ml of bacteriocin crude extract, which was 0.7 ± 0.0029%. In addition, it exhibited good thermal and pH stability with retained antibacterial activity of 85.25% after treatment at 121°C for 20 min, as well as at a pH range between 2.0 and 10.0. Moreover, this bacteriocin showed the ability to inhibit the growth of bacterial culture load in fish sausage stored at 8°C for 28 days. Considering the results obtained, bacteriocin could be potentially exploited as an alternative to chemical preservatives or as a substitute for antibiotics.

Isolation and Screening of Lactic Acid Bacteria From Sumbawa Buffalo Milk (Bubalus bubalis) as Potential Starter Cultures

The Sumbawa buffalo (Bubalus bubalis) is one of the ruminant livestock in Indonesia that not only contributes to fulfilling meat requirements but also milk. Besides containing nutrients that are very beneficial for human health, buffalo milk is also a potential source of lactic acid bacteria (LAB) with technological and functional properties. Lactic acid bacteria have been utilized as starter cultures in various fermented products. This study aimed to isolate LAB from Sumbawa buffalo milk and to identify the potential isolate as a starter culture. The screening of LAB as a starter culture was based on some technological properties, including proteolytic activity, lipolytic activity, exopolysaccharide (EPS) production, antibacterial activity, antibiotic sensitivity, hemolytic activity, and acidification activity Data were analyzed statistically using one-way ANOVA and Tukey’s post hoc test at a 5% significance level. A total of 21 isolates were isolated from fresh buffalo milk, with a LAB total was 4.7x105 CFU.mL-1. All the isolates were characterized as Gram-positive with cocci-shaped. The SA8 isolate was selected as the most potential candidate as a starter culture because it has fulfilled the criteria such as the highest proteolytic activity, the lowest lipolytic activity, producing EPS, potential antagonistic activity against Bacillus cereus, Escherichia coli, and Salmonella Typhi, and sensitivity to cefazolin, intermediate to erythromycin and cinoxacin, non-pathogen, as well as the most rapid acidification activity. The SA8 isolate was identified as Enterococcus lactis with a similarity level of 99.99% towards strain BT159. This indigenous LAB was a potential starter culture of Sumbawa fermented buffalo milk to increase the diversification of products derived from buffalo milk.