Lactic Acid Bacteria Strains Research Articles

Reduction of malic acid in bilberry juice by Lactiplantibacillus plantarum-mediated malolactic fermentation

AbstractBilberries (Vaccinium myrtillus) are the most common wild berries in Northern Europe. A substantial amount of the berries are picked with the objective to extract highly valued products such as anthocyanins. A smaller amount of the bilberries is used to make jams and drinks, and these are generally restricted to the domestic market. One reason is the sour taste, partly as a result of the high content of malic acid. By using certain strains of lactic acid bacteria with the ability to convert malic acid to lactic acid, the taste is predicted to be more pleasant. This process is called malolactic fermentation, and historically it has mostly been used in winemaking. After testing five different starter cultures, we identified that the strain, Lactiplantibacillus plantarum LP58, can rapidly convert malic acid to lactic acid without any loss of sugar or citric acid, which strongly indicates a successful malolactic acid fermentation. As it has been reported that other strains of L. plantarum can be used as biopreservative agents, the resulting product was also tested in terms of microbial safety after prolonged storage, and by means of metagenome sequencing. The obtained product was quite tolerant to microbial growth, but this observation was rather due to an initial heat treatment than the addition of lactobacilli. Potentially, starter cultures with documented biopreservative activity can be combined with L. plantarum LP58 to obtain a more stable product. Until then, the fermented bilberry juice must be processed and preserved like non-fermented bilberry products.

Bacteriocinogenic Lacticaseibacillus paracasei strains from Inner Mongolian fermented milk efficiently control pathogenic bacteria in model cheddar-like cheese

Bacteriocins produced by lactic acid bacteria (LAB) consist of a wide range of antimicrobial proteins or peptides which can be used as bio-preservatives to control food-borne pathogens. In this study, bacteriocinogenic LAB strains were isolated from fermented milk in Inner Mongolia, China. These strains exhibited high antimicrobial activity and were identified as Lacticaseibacillus paracasei. The sensitivity of their antimicrobial activity to protease K implies the possible existence of bacteriocins within the culture. Selected L. paracasei strains were subjected to whole genome sequencing and the bacteriocin biosynthetic gene clusters were identified in-silico. To further verify the antimicrobial properties of the isolated strains in controlling food pathogens in model Cheddar-like cheese, they were used as adjunct starter cultures in cheese contaminated with Bacillus cereus and Listeria monocytogenes. The results showed that each of the five strains carries a minimum of three bacteriocins biosynthetic gene clusters. All L. paracasei strains exhibited the ability to inhibit B. cereus and L. monocytogenes and caused a significant log reduction of pathogens during cheese ripening. Additionally, the isolated strains improved cheese texture and flavor to varying degrees. In conclusion, the indigenious L. paracasei present in milk could play an important role in pathogen control and the quality improvement of Cheddar-like cheeses.

Lactic acid production from cashew apple bagasse, an agro-industrial waste, and its application in the enzymatic synthesis of polylactic acid

The use of cashew apple bagasse hemicellulose hydrolysate (CABH) to produce lactic acid by two strains of lactic acid bacteria, Lactobacillus plantarum FJ05311 and L. plantarum FJ05315, was evaluated. The application of cashew apple bagasse (CAB) would enhance the establishment of a biorefinery from this agro-industrial residue since its main compounds, cellulose, hemicellulose, and lignin, can be used to obtain several bioproducts. The influence of essential parameters was studied for the production of LA. The CABH contained mainly glucose and xylose at concentrations of approximately 40 g/L and 20 g/L, respectively. The process conducted at 30 °C, 100 rpm, and using the culture in the final of the growth phase (inoculum time of 24 h for LAB07 and 20 h for LAB14) and urea as nitrogen source enhanced the LA production for both strains, LAB07 and LAB14, reaching 24.3 g/L. The produced LA was used to synthesize polylactic acid (PLA) for the enzymatic route using lipase B from Candida antarctica (CALB). Then, the production of PLA from cashew apple bagasse hydrolysate is a sustainable alternative to produce a biodegradable polymer with many industrial applications and obtaining personal protective equipment to use in the current and future pandemics.

MICROBIOLOGICAL PROCESSES IN THE LUCERNE HAYLAGE UNDER INOCULATION WITH LACTIC ACID BACTERIA

Objective. To characterize the effect of lactic acid bacteria (LAB) on the quantitative and qualitative composition of the groups of microorganisms in the lucerne haylage after their introduction. Methods. Microbiological (cultivation of microorganisms on various media, determination of their viability, measurement of osmotolerance, determination of the amount of lactic acid during cultivation on skimmed sterile milk), microscopic, laboratory experiments on the lucerne haying with a dry matter (DM) content of 46 % and 37 % with and without inoculation with LAB strains, statistical. Results. Lucerne was inoculated with monocultures of Lactobacillus sp. LH42, Lactobacillus sp. LH43, Lactobacillus sp. LH47, L. plantarum КТ-L18/1 osmotolerant strains, which showed tolerance to 2 %, 4 %, 6.5 % sodium chloride in 100 % of cases. The best indicators in terms of active and titrated acidity were found in cultures of Lactobacillus sp. LН47, L. plantarum КТ-L18/1. The inoculation of LAB into the haylage ecosystem at Day 15 of fermentation resulted in an increase in the number of LAB compared to the untreated control. At Day 45 of lucerne haying, the number of LAB decreased and was registered at the level from 1 to 100 billion CFU/g at a 46 % DM content and at the level from 0.01 to 10 billion CFU/g at a 37 % DM content. The greatest development of clostridia in the lucerne haylage in experiments was reported at Day 3 with a sharp decrease in their number at Day 45. The influence of Lactobacillus sp. LH 43, Lactobacillus sp. LH 47, L. plantarum KT-L18/1 on the reduction of the growth of the number of clostridia both at a 46 % and 37 % DM content at the end of the fermentation period was shown. A higher number of yeasts was established at a lower (37 %) content of DM in the haylage. A fungistatic effect was established in variants with LAB inoculation versus the control variant. The relationship between the dynamics of decreasing active acidity (pH) and the dynamics of microbiota development has been shown. Conclusion. Inoculation of the studied strains of lactic acid bacteria into high-protein lucerne haylage mass contributed to an order of magnitude increase in the number of LAB versus the control variant, suppression of the development of clostridia, yeasts and a rapid decrease in active acidity, which confirms data about the effect of LAB-based inoculants on the fermentation of plant raw materials by adjusting the composition of groups of microorganisms

Selection and evaluation of lactic acid bacteria from chicken feces in Thailand as potential probiotics.

Lactic acid bacteria (LAB) are widely used as probiotics in poultry production due to their resilience to low pH and high bile salt concentrations, as well as their beneficial effects on growth performance and antagonistic activity against enteric pathogens. However, the efficacy of probiotics depends on strain selection and their ability to colonize the host's intestine. This study aimed to select, identify, and evaluate LAB strains isolated from chicken feces in Thailand for potential use as probiotics in the chicken industry. LAB strains were isolated from 58 pooled fresh fecal samples collected from chicken farms in various regions of Thailand, including commercial and backyard farms. Gram-positive rods or cocci with catalase-negative characteristics from colonies showing a clear zone on MRS agar supplemented with 0.5% CaCO3 were identified using MALDI-TOF mass spectrometry. The LAB isolates were evaluated for acid (pH 2.5 and pH 4.5) and bile salt (0.3% and 0.7%) tolerance. Additionally, their cell surface properties, resistance to phenol, antimicrobial activity, hemolytic activity, and presence of antimicrobial resistance genes were determined. A total of 91 LAB isolates belonging to the Pediococcus, Ligilactobacillus, Limosilactobacillus, and Lactobacillus genera were obtained from chicken feces samples. Backyard farm feces exhibited a greater LAB diversity compared to commercial chickens. Five strains, including Ligilactobacillus salivarius BF12 and Pediococcus acidilactici BF9, BF14, BYF20, and BYF26, were selected based on their high tolerance to acid, bile salts, and phenol. L. salivarius BF12 and P. acidilactici BF14 demonstrated strong adhesion ability. The five LAB isolates exhibited significant cell-cell interactions (auto-aggregation) and co-aggregation with Salmonella. All five LAB isolates showed varying degrees of antimicrobial activity against Salmonella strains, with P. acidilactici BYF20 displaying the highest activity. None of the LAB isolates exhibited beta-hemolytic activity. Whole genome analysis showed that L. salivarius BF12 contained ermC, tetL, and tetM, whereas P. acidilactici strains BF9 and BF14 carried ermB, lnuA, and tetM. The selected LAB isolates exhibited basic probiotic characteristics, although some limitations were observed in terms of adhesion ability and the presence of antibiotic resistance genes, requiring further investigation into their genetic location. Future studies will focus on developing a probiotic prototype encapsulation for application in the chicken industry, followed by in vivo evaluations of probiotic efficacy.

Short Communication: Diversity of indigenous LAB from kefir grains cultured in goat milk based on phenotypic characteristics for probiotic candidates

Abstract. Wulansari PD, Rahayu N, Kusuma RJ, Sukarno AS. 2023. Short Communication: Diversity of indigenous LAB from kefir grains cultured in goat milk based on phenotypic characteristics for probiotic candidates. Biodiversitas 24: 6389-6395. Kefir grain is the starter of kefir products containing the symbiotic compound of lactic acid bacteria (LAB) and yeast. Microbial diversity in kefir grain is affected by multiple factors that include the origin of microbiota, upkeep, storage, and types of milk. Goat milk exhibits various superior properties in composition or characteristics. These have inspired the present study to obtain the local isolates from LAB derived from native Indonesian kefir grain produced and revitalized using goat milk. This study aimed to obtain local LAB isolates from kefir grain through phenotypic identification and characterization. The morphology of phenotypic identification consisted of macroscopic, microscopic, and biochemical identification. Based on macroscopic and microscopic observation, the isolates were milky white, circular, entire edge, smooth and shiny surface with convex elevation, coccus/basil shaped, Gram-positive, negative catalase, non-motile, non-spore, non-producing CO2, heterofermentative/homofermentative, able to ferment various carbohydrates, growing at 37 and 45°C, pH 4.4, and salinity level of 6.5%. A scientific approach enabled to obtaining of several LAB strains, namely nine isolates of Lactococcus and seven isolates of Lactobacillus. It takes genotypic identification to promote the identification process up to the species level.

Soybean hull polysaccharides affect the physicochemical properties and lactic acid bacteria proliferation in plant‐based yogurt

AbstractAs a by‐product of soybean processing, soybean hulls contain soybean hull polysaccharides (SHPS). This study aims to develop a plant‐based yogurt with SHPS addition and assess the consequences of SHPS on the physicochemical properties and growth of lactic acid bacteria (LAB) in yogurts. The study investigated the water holding capacity (WHC), microstructure, rheological properties, texture, pH, organoleptic attributes, volatile compounds, flavor profile, and LAB population. The findings reveal that the addition of SHPS significantly impacted these properties. SHPS improved the physicochemical properties, increased the level of flavor compounds, and improved the organoleptic properties of yogurt. Yogurt with 0.6% SHPS demonstrated superior WHC, texture, rheological properties, and the highest organoleptic evaluation scores. However, when SHPS additions exceeded 0.6%, WHC, texture, and rheological properties of the yogurts decreased. Furthermore, SHPS‐added yogurts contained more LAB compared to yogurt without SHPS. LAB grew better in media with SHPS than in media without glucose. Streptococcus thermophilus grew best among the LAB strains. This study highlights the potential of SHPS in yogurt production and its promising applications in fermented food products.

Lactic Acid Bacteria isolated from traditional and innovative alheiras as potential biocontrol agents

From a selection of seven traditional and 14 innovative alheiras, 491 lactic acid bacteria (LAB) were isolated and tested for their antimicrobial activity against several food-borne pathogens. Among these, six strains revealed antimicrobial activity through potential bacteriocin production against 14 Listeria monocytogenes strains, Enterococcus faecalis ATCC 29212, Clostridium sporogenes ESB050, and Clostridium perfringens ESB054.Through whole genome sequencing (WGS), these strains were identified as Lactiplantibacillus plantarum (2), Leuconostoc mesenteroides (1), and Pediococcus acidilactici (3). Furthermore, several orthologues of class II bacteriocins genes were identified, including Plantaricin E, Plantaricin F, Pediocin PA, Enterocin X, Leucocin A, and Coagulin A. No virulence or antibiotic resistance genes’ orthologues were detected by WGS analysis. However, the selected LAB strains showed variable phenotypic patterns related to virulence genes and antibiotic resistance when assessed through classical methodologies. None of these strains demonstrated the production of biogenic amines, gelatinase or DNase. Additionally, no hemolytic activity or lipase enzyme production was observed. However, only Lpb. plantarum 9A3 was sensitive to all tested antibiotics and was thus chosen for further examination. The bacteriocins produced by Lpb. plantarum (9A3) exhibited stability across a broad range of conditions, including temperatures from 4 to 100 °C, pH values ranging from 2 to 8, exposure to surfactants and detergents (Tween 20 and 80, SDS, EDTA 0.1, 2 and 5 mM, urea and sodium deoxycholate), and enzymes (papain and catalase). Their maximum activity (AU/mL = 12,800) against four L. monocytogenes strains was observed between 21 and 36 h of growth of Lbp. plantarum 9A3, indicating a bacteriostatic mode of action. Therefore, this strain appears to be a robust candidate for potential application as a protective strain to be used in the food industry. Not only is it safe, but it also produces stable bacteriocins (harbouring genes encoding for the production of three) effectively inhibiting significant pathogens such as L. monocytogenes and C. perfringens.

Microbial network and fermentation modulation of Napier grass and sugarcane top silage in southern Africa.

Feed shortage in the tropics is a major constraint to the production of livestock products such as milk and meat. In order to effectively utilize of local feed resources, the selected lactic acid bacteria (LAB) strain was used to prepare Napier grass and sugarcane top silage. The results showed that the two silages inoculated with LAB formed a co-occurrence microbial network dominated by Lactiplantibacillus during the fermentation process, regulated the microbial community structure and metabolic pathways, and improved the silage fermentation quality. This is of great significance for alleviating feed shortage and promoting sustainable production of livestock.

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.

Kinetics of Phosphate Ions and Phytase Activity Production for Lactic Acid-Producing Bacteria Utilizing Milling and Whitening Stages Rice Bran as Biopolymer Substrates.

A study evaluated nine kinetic data and four kinetic parameters related to growth, production of various phytase activities (PEact), and released phosphate ion concentration ([Pi]) from five lactic acid bacteria (LAB) strains cultivated in three types of media: phytate (IP6), milling stage rice bran (MsRB), and whitening stage rice bran (WsRB). Score ranking techniques were used, combining these kinetic data and parameters to select the most suitable LAB strain for each medium across three cultivation time periods (24, 48, and 72 h). In the IP6 medium, Lacticaseibacillus casei TISTR 1500 exhibited statistically significant highest (p ≤ 0.05) normalized summation scores using a 2:1 weighting between kinetic and parameter data sets. This strain also had the statistically highest levels (p ≤ 0.05) of produced phosphate ion concentration ([Pi]) (0.55 g/L) at 72 h and produced extracellular specific phytase activity (ExSp-PEact) (0.278 U/mgprotein) at 48 h. For the MsRB and WsRB media, Lactiplantibacillus plantarum TISTR 877 performed exceptionally well after 72 h of cultivation. It produced ([Pi], ExSp-PEact) pairs of (0.53 g/L, 0.0790 U/mgprotein) in MsRB and (0.85 g/L, 0.0593 U/mgprotein) in WsRB, respectively. Overall, these findings indicate the most promising LAB strains for each medium and cultivation time based on their ability to produce phosphate ions and extracellular specific phytase activity. The selection process utilized a combination of kinetic data and parameter analysis.

Antilisterial activity of raw sheep milk from two native Epirus breeds: Culture-dependent identification, bacteriocin gene detection and primary safety evaluation of the antagonistic LAB biota

Raw milk from native small ruminant breeds in Epirus, Greece, is a valuable natural source of autochthonous lactic acid bacteria (LAB) strains with superior biotechnological properties. In this study, two bulk milks (RM1, RM2) from two local sheep yards, intended for traditional Kefalotyri cheese production, were preselected for bacteriocin-like antilisterial activity by in vitro tests. Their antagonistic LAB biota was quantified followed by polyphasic (16S rRNA gene sequencing; IGS for Enterococcus; a multiplex-PCR for Leuconostoc) identification of 42 LAB (RM1/18; RM2/24) isolates further evaluated for bacteriocin encoding genes and primary safety traits. Representative isolates of the numerically dominant mesophilic LAB were Leuconostoc mesenteroides (10) in both RMs, Streptococcus parauberis (7) in RM2, and Lactococcus lactis (1) in RM1; the subdominant thermophilic LAB isolates were Enterococcus durans (8), E. faecium (6), E. faecalis (3), E. hirae (1), E. hermanniensis (1), Streptococcus lutetiensis (2), S. equinus (1) and S. gallolyticus (1). Based on their rpoB, araA, dsr and sorA profiles, six Ln. mesenteroides strains (8 isolates) were atypical lying between the subspecies mesenteroides and dextranicum, whereas two strains profiled with Ln. mesenteroides subsp. jonggajibkimchii that is first-time reported in Greek dairy food. Two RM1 E. faecium strain biotypes (3 isolates) showed strong, enterocin-mediated antilisterial activity due to entA/entB/entP possession. One E. durans from RM1 possessed entA and entP, while additional nine RM2 isolates of the E. faecium/durans group processed entA or entP singly. All showed direct (cell-associated) antilisterial activity only, as also both S. lutetiensis strains from RM2 did strongly. Desirably, no LAB isolate was β-hemolyrtic, or cytolysin-positive, or possessed vanA, vanB for vancomycin resistance, or agg, espA, hyl, and IS16 virulence genes. However, all three E. faecalis from RM2 possessed gelE and/or ace virulence genes. In conclusion, all Ln. mesenteroides strains, the two safe, enterocin A-B-P-producing E. faecium strains, and the two antilisterial S. lutetiensis strains should be validated further as potential costarter or adjunct cultures in Kefalotyri cheese. The prevalence of α-hemolytic pyogenic streptococci in raw milk, mainly S. parauberis in RM2, requires consideration in respect to subclinical mastitis in sheep and the farm hygiene overall.

In vitro fermentation of pineapple–whey protein fermentation product on human intestinal microbiota derived from fecal microbiota transplant donors

A new fermented food by utilizing pineapple by-products and whey protein as the matrix via co-fermentation with strains of lactic acid bacteria and yeast is developed. We investigated its impact on human well-being, focusing on the bioavailability and physiological viability of the resulting pineapple–whey protein fermented product (PWF) under simulated human gastrointestinal conditions. We evaluated PWF's potential as a prebiotic using in vitro fermentation assays, revealing that its probiotic components effectively reached the colon and functioned without hindrance. This transit triggered significant release of phenolic compounds, establishing an antioxidant-rich environment during simulated digestion. In vitro fermentation experiments showcased PWF's capacity to induce short-chain fatty acid production in the intestines, alongside its ability to influence the microbial community composition. Additionally, we explored how PWF-induced alterations in the gut microbiota might impact human health. The results suggested that PWF could potentially enhance metabolic pathways in the intestinal microbiota, thereby fostering a more favorable microbial ecosystem.

Characterizing Probiotic Lactic Acid Bacteria from Buffalo Milk Fermentation (Dadih) for Beef Biopreservation

Beef is a perishable food that can be naturally preserved using antimicrobial chemicals in a procedure known as biopreservation. Probiotic bacteria, or bacteria with the ability to create antimicrobial metabolites, are known as lactic acid bacteria. Fermented foods such as dadih, or fermented buffalo milk, from West Sumatra, Indonesia, contain lactic acid bacteria. This study aims to explore the existence of probiotic lactic acid bacteria in dadih and the effectiveness of utilizing lactic acid bacteria metabolites as biopreservatives in beef for nine days at 4 °C. The DK1 strain of lactic acid bacteria showed the most antibacterial metabolite activity against Salmonella sp. (11.5 mm) and Escherichia coli (13 mm) among the three isolates examined. Probiotic characteristics set the DK1 isolate apart; resistance test results showed over 106 CFU/mL, pH 2–4, a temperature range of 25 °C to 45 °C, and 0.3% bile salt. DK1 isolates tested positive for auto-aggregation 89.2% of the time. The co-aggregation test results for Salmonella sp. and E. coli reveal 46.9% and 53.1%, respectively. The findings of the bio preservation showed that, overall, treated beef contained fewer E. coli and other microorganisms than untreated meat. Furthermore, compared to control beef, metabolite-treated meat showed a shift in hue and a lower, more constant pH value.

Comparison of three different lactic acid bacteria-fermented proteins on RAW 264.7 osteoclast and MC3T3-E1 osteoblast differentiation

Osteoporosis is a state of bone weakening caused by an imbalance in osteoblast and osteoclast activity. In this study, the anti-osteoporotic effects of three proteins fermented by lactic acid bacteria (LAB) were assessed. Commercial proteins sodium caseinate (SC), whey protein isolate (WPI), and soy protein isolate (SPI) were fermented by LAB strains for 48 h. The fermented products (F-SC, F-WPI, and F-SPI, respectively) were used in an in vitro osteoclast and osteoblast-like cell model to assess their effects on bone health. Despite no difference in the results of TRAP staining of RANKL-induced osteoclastogenesis, F-WPI and F-SPI were effective in normalizing the altered gene expression of osteoclastogenesis markers such as TRAP, Nfatc1, RANK, and ATP6v0d. F-SPI was also effective in modulating osteoblasts by enhancing the expression of the osteoblastogenesis markers T1Col, Col2a, and OSX to levels higher than those in the SPI group, indicating that protein characteristics could be enhanced through bacterial fermentation. Moreover, these boosted effects of F-SPI may be involved with isoflavone-related metabolism during LAB-fermentation of SPI. These results demonstrate the potential of LAB-fermented proteins as dietary supplements to prevent bone loss. However, further understanding of its effects on balancing osteoblasts and osteoclasts and the underlying mechanisms is needed.

Improvement of Key Molecular Events Linked to Alzheimer's Disease Pathology Using Postbiotics.

In the past 50 years, life expectancy has increased by more than 20 years. One consequence of this increase in longevity is the rise of age-related diseases such as dementia. Alzheimer's disease (AD) is the most common form of dementia, accounting for 60-70% of cases. AD pathogenesis is not restricted to the neuronal compartment but includes strong interactions with other brain cells, particularly microglia triggering the release of inflammatory mediators, which contribute to disease progression and severity. There is growing evidence revealing the diverse clinical benefits of postbiotics in many prevalent conditions, including neurodegenerative diseases. Here, we tested the ability of bacterial conditioned media (BCM) derived from selected lactic acid bacteria (LAB) strains to regulate core mechanisms relevant to AD pathophysiology in the microglia cell line BV-2. Levilactobacillus brevis CRL 2013, chosen for its efficient production of the neurotransmitter GABA, and Lactobacillus delbrueckii subsp. lactis CRL 581, known for its anti-inflammatory properties, were selected alongside Enterococcus mundtii CRL 35, a LAB strain that can significantly modulate cytokine production. BCM from all 3 strains displayed antioxidant capabilities, reducing oxidative stress triggered by beta-amyloid oligomers (oAβ1-42). Additionally, BCM effectively mitigated the expression of inflammatory cytokines, namely, TNF-α, IL-1β, and IL-6 triggered by oAβ1-42. Furthermore, our study identified that BCM from CRL 581 inhibit the activity of acetylcholinesterase (AChE), a crucial enzyme in AD progression, in both human erythrocytes and mouse brain tissues. Notably, the inhibitory effect was mediated by low-molecular-weight components of the BCM. L. delbrueckii subsp. lactis CRL 581 emerged as a favorable candidate for production of postbiotics with potential benefits for AD therapy since it demonstrated potent antioxidant activity, reduction of cytokine expression, and partial AChE inhibition. On the other hand, E. mundtii CRL 35 showed that the antioxidant activity failed to inhibit AChE and caused induction of iNOS expression, rendering it unsuitable as a potential therapeutic for AD. This study unveils the potential benefits of LAB-derived postbiotics for the development of new avenues for therapeutic interventions for AD.

Characterization of Lactic Acid Bacteria and Yeast from Grains as Starter Cultures for Gluten-Free Sourdough.

With the increasing number of people affected by gluten consumption-related diseases, adhering to a gluten-free (GF) diet is the most effective preventive measure. Herein, we aimed to isolate and characterize the functional properties of autochthonous lactic acid bacteria (LAB) and yeast from various GF sourdoughs to determine their suitability in starter cultures for sourdough preparation. Three LAB, Weissella confusa BAQ2, Lactobacillus brevis AQ2, Leuconostoc citreum YC2, and Saccharomyces cerevisiae BW1, were identified. The isolated LAB exhibited greater TTA, faster acidification rates, and higher acid tolerance than commercial LAB. W. confusa BAQ2 exhibited the highest EPS production, W. confusa BAQ2 and L. brevis AQ2 showed high maltose utilization, and S. cerevisiae BW1 exhibited the highest CO2 production rate. Accordingly, all four microbial strains were mixed for the starter culture. The sourdough prepared with starter cultures exhibited differences in gas production depending on fermentation time, which influenced the volume of GF bread dough. GF bread prepared with fermented sourdough exhibited a 16% higher specific volume and enhanced crumb firmness and elasticity than that prepared using non-fermented sourdough. Thus, autochthonous LAB strains isolated from various GF sourdoughs can be used together to improve the quality of sourdough bread, demonstrating their potential for use in starter cultures for GF sourdough production.

Patulin removal and biopreservation of apple by three lactic acid bacteria strains isolated from foods

ABSTRACTPenicillium expansum contamination and patulin production can occur at various stages of the food chain, leading to detrimental effects on the quality and shelf life of food. Consequently, it is imperative to develop safe and efficient methods to control fungal growth and prevent mycotoxin contamination. The use of lactic acid bacteria (LAB) for food biopreservation has become one of the most promising alternatives. In this study, we investigated the antifungal activity of three LAB strains, namely Lactiplantibacillus plantarum 4F, Lactiplantibacillus plantarum 4JC, and Lacticaseibacillus paracasei 3MI3 against Penicillium expansum, and we further evaluated their biopreservative potential using apple as a food model against the blue mould. Moreover, their ability to remove patulin (10 µg/mL) from MRS broth and apple juice was also examined. The mechanism involved in this decontamination was investigated using scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS) and fourier transform infrared spectroscopy (FTIR). It was found that in vitro antifungal activity of the three strains was validated in vivo. All strains were able to reduce patulin from MRS medium, notably L. plantarum4F exhibited the highest rate of reduction (88.18%). This particular strain eliminated patulin from juice, with a reduction of 87.26%. The C = O, C–H, and N–H were the main functional groups engaged in patulin adsorption indicated by FTIR and SEM-EDS. Furthermore, in terms of morphological changes, SEM analysis revealed that bacterial cell wall became irregular. This research provides evidence of control of blue Penicilium growth on apple and patulin removal using antifungal LAB strains.

Screening of Wild Lactobacillus Plantarum Found in Brine Solution of Naturally Fermented Cucumbers

Fermentation has been used as a simple technique for preserving vegetables since ancient days. This research work aimed to isolate, characterize, and identify wild Lactobacillus plantarum found in a brine solution (8% w/v NaCl) of naturally fermented cucumber. Cucumber samples were naturally fermented at ambient temperature for 14 days in a brine solution, in which lactic acid bacteria (LAB) were then cultured (37℃, 48 h) within 24 h for 3, 5, 7, 10, and 14 days. Seventeen different LAB strains were isolated and identified within the different time intervals of fermentation using morphological, biochemical API 50 CHL, PCR verification using Lactobacillus subspecies-specific genes primer, and 16S rRNA gene sequencing. The API confirmed strains were further verified by PCR to be L. plantarum subsp. plantarum M23 based on the amplified gene fragment separation by gel electrophoresis and gene sequencing. After 24 h of fermentation, the most dominant LAB-identified strains were Leuconostoc mesenteroides, Tetragenococcus halophilus, and L. plantarum M23, respectively. Starting from the fifth day of fermentation, L. plantarum M23 controlled the fermentation process as the dominant LAB. The drop in the pH value was significant (from 6.8 to 3.18) due to the variations in the LAB strains throughout the 14 days of fermentation. Further investigation will be carried out to study the production of plantaricin, which has great importance in food biopreservation.

Context matters: environmental microbiota from ice cream processing facilities affected the inhibitory performance of two lactic acid bacteria strains against Listeria monocytogenes.

Antilisterial LAB strains have been proposed as biological control agents for application in food processing environments. However, the effect of resident food processing environment microbiota on the performance on antilisterial LAB strains is poorly understood. Our study shows that the presence of microbiota collected from ice cream processing facilities' environmental surfaces can affect the attachment and inhibitory effect of LAB strains against L. monocytogenes. Further studies are therefore needed to assess whether individual microbial taxa affect antilisterial properties of LAB strains and to characterize the underlying mechanisms.