Homofermentative Lactobacilli Research Articles

Ensiling conditions and changes of cannabinoid concentration in industrial hemp.

Hemp (Cannabis sativa L.) is an important source of fibre and seed oil and protein. By-products of industrial hemp fibre production, like hemp seeds and cakes, can be used as feed for all animal species as fat and protein source and the whole hemp plant (including stalk and leaves) might be a suitable fibre source for ruminants. However, a previous feeding experiment with leaf-flower-seed hemp silage, made from an industrial hemp variety, demonstrated detrimental effects on cow health parameters and a significant transfer of several cannabinoids, including the psychoactive tetrahydrocannabinol (∆9-THC), into cow's milk, posing a potential risk to the safety of consumers. Based on those observations, the present study tested the hypothesis that anaerobic fermentation, as during ensiling, increases the content of ∆9-THC in hemp. Therefore, silages of whole plants from the industrial hemp Cannabis sativa L. var. Ivory were prepared in a multifactorial design, with the four treatments 1) untreated control (CON), 2) addition of 10 mL per kg fresh weight homofermentative lactobacilli at 105 cfu/mL (LBAC), 3) addition of 10 mL per kg fresh weight homofermentative lactobacilli at 105 cfu/mL plus 30 g molasses (LBACmol) and 4) addition of propionic acid (10 mL/kg fresh weight) (PRO). Ultra high performance liquid chromatography coupled with tandem mass spectrometry with electrospray ionisation (UHPLC-MS/MS) was performed for analysis of cannabinoids in fresh hemp material and after 10 and 90 days of ensiling. The study revealed that ensiling decreased all acid forms of analysed cannabinoids in hemp at about 40-65% of the initial values after 90 days of storage, with the exception of cannabinolic acid (CBNA), and CBGA, the acidic form of cannabigerol (CBG). This decrease in most acidic forms was accompanied by an increase of the corresponding non-acidic forms of all cannabinoids, including the psychoactive ∆9-THC. Thus, although ensiling decreases the total cannabinoid content, psychoactive compounds like ∆9-THC can increase, enhancing the risk for animal health and a transfer of these substances into animal derived products.

Effects of exogenous lactic acid bacteria and maize meal on fermentation quality and microbial community of Orychophragmus violaceus silage.

Orychophragmus violaceus is a local Brassicaceae in China, while most of it is directly mowed and discarded after the ornamental period. In order to develop forage resources, this study firstly evaluated the potential preservation of O. violaceus silage. O. violaceus was harvested at full-bloom stage, and ensiled without (CK) or with maize meal (Y5), lactic acid bacteria inoculant (Z) and compound additive (Y5Z) for 60 d. Results of chemical and microbiological analysis showed that a large amount of lactic acid was produced and the final pH value was below 4.1 in silages regardless of additive application. CK silage was well preserved as indicated by the low levels of dry matter loss and butyric acid content, and the predominant genus were identified as Enterococcus and Pediococcus. Y5 silage had potential health risks for humans and animals as seen by frequent occurrence of pathogenic bacteria Clostridium and Achromobacter. Z and Y5Z silages were poorly preserved, resulting in great dry matter loss and butyric acid content. Considering the abundant acetic acid production, the dominant Lactobacillus might possess a heterofermentative pathway in Z and Y5Z silages. In conclusion, O. violaceus has the potential to be long stored as silage because of its sufficient water-soluble carbohydrates, while exogenous lactic acid bacteria and maize meal generally provided little positive effect. In future research, efficient homofermentative Lactobacillus strains were suggested to be screened to further enhance the ensiling process of O. violaceus silage.

Metabolic profiling of probiotic strain Lactobacillus delbrueckii subsp. bulgaricus L14 cultivated in presence of prebiotic oligosaccharides and polysaccharides in simulating in vitro gastrointestinal tract system

This study examined the effect of lactulose, galactooligosaccharide, fructooligosaccharide, inulin, and β-glucan on the probiotic strain Lactobacillus delbrueckii subsp. bulgaricus L14, cultivated in an in vitro gastrointestinal system model. We analyzed the degree of hydrolysis of the studied prebiotic oligosaccharides in condition of simulated gastric fluid. The results showed that lactulose had the highest resistance, galactooligosaccharide underwent hydrolysis, and fructooligosaccharide was the most sensitive. Among the polysaccharides, fructose was released from inulin and glucose from β-glucan. Short-chain oligosaccharides and metabolites derived from studied prebiotic oligosaccharides and polysaccharides, supported the growth of probiotic strain L14, which showed the highest growth with fructooligosaccharides and β-glucan as carbohydrate sources. The profile of the activated enzymes secreted by the probiotic strain L14, indicated their inducible character. Beta-galactosidase was activated in the presence of lactulose and GalOS, inulinase was activated in the presence of inulin and fructooligosaccharides, and β-glucosidase was activated in the presence of β-glucan fragments. Analysis of the produced organic and short-chain fatty acids showed that the typical representative of the homofermentative lactobacilli Lb. delbrueckii subsp. bulgaricus L14 changes its metabolism from a homofermentative to a heterofermentative type, best expressed in the presence of lactulose, galactooligosaccharide, and β-glucan.

Genomic, probiotic, and metabolic potentials of Liquorilactobacillus nagelii AGA58, a novel bacteriocinogenic motile strain isolated from lactic acid-fermented shalgam

This study aimed to perform genomic, probiotic, and metabolic characterization of a novel Liquorilactobacillus nagelii AGA58 isolated from a lactic acid-fermented shalgam beverage to understand its metabolic potentials and probiotic features. AGA58 is gram-positive, motile, catalase-negative and appears as short rods under the light-microscope. The AGA58 chromosome comprises a single linear chromosome of 2,294,635 bp that is predicted to carry 2135 coding sequences, including 45 tRNA genes, 3 mRNA, and 3 rRNA operons. The genome has a G+C content of 36.9%, including 55 pseudogenes and a single intact prophage. AGA58 is micro-anaerobic due to achieving a shorter doubling time and faster growth rate than micro-aerophilic conditions. It carries flagellar biosynthesis protein-encoding genes predicting motile behavior, which was confirmed with the in vitro motility test. AGA58 is an obligatory homofermentative lactobacillus that can ferment hexose sugars such as galactose, glucose, fructose, sucrose, mannose, N-acetyl glucosamine, maltose, and trehalose to lactate through glycolysis. No acid production from pentoses implies that five-carbon sugars are being utilized for purine and pyrimidine synthesis. Putative pyruvate metabolism revealed formate, malate, oxaloacetate, acetate, acetaldehyde, acetoin, and lactate forms from pyruvate. AGA58 is predicted to encode the LuxS gene and biosynthesis of class IIa and Blp family class-II bacteriocins suggesting this bacterium's antimicrobial potential, linked to antagonism tests that AGA58 can inhibit Escherichia coli ATCC 43895, Salmonellaenterica serovar Typhimurium ATCC 14028, and Klebsiellapneumonia ATCC 13883. Moreover, AGA58 is tolerant to acid and bile concentrations simulating the human gastrointestinal conditions depicting the probiotic potential of the organism as the first report in literature within the same species.

Effects of ensiling conditions on pyrrolizidine alkaloid degradation in silages mixed with two different Senecio spp.

ABSTRACT Pyrrolizidine alkaloid (PA) producing plants like Senecio jacobaea or Senecio vernalis are undesirable in fields for forage production, since PA are toxic to animals and humans. Previous studies have shown that ensiling can decrease the PA content in forages; however, no direct comparison of diverse PA from different Senecio spp. under various ensiling conditions has been made. Therefore, it was hypothesised that individual PA might react differently to ensiling, and silage inoculation with Lactobacillus will affect PA degradation because of a quick drop in pH, contrastingly to poor silage qualities resulting from contamination with soil. Laboratory scale grass silages were prepared in a multifactorial design with two levels of dry matter contents, four ensiling treatments and two storage durations (10 and 90 d). For each combination, four replicates were prepared individually. Ensiling treatments were (1) 10 ml water per kg fresh matter as control (CON), (2) 10 ml heterofermentative Lactobacillus buchneri strain LN4637 at 3 · 105 cfu/kg fresh matter plus 25 g molasses/kg fresh matter (LBHE), (3) 10 ml homofermentative lactobacilli at 3 · 105 cfu/kg fresh matter plus 25 g molasses/kg fresh matter (LBHO) and (4) 10 g soil/kg fresh matter (SOIL). Treatments affected formation of fermentation acids. Acetic acid was highest with treatment LBHE, and butyric acid was highest with treatment SOIL. All ensiling treatments effectively reduced total PA content by degrading the PA N-oxide (PANO) fraction. In parallel, though, the fraction of the tertiary base forms increased by around one-tenth of the original PANO content. Contents of jaconine and senkirkine were higher after ensiling than before, with regards to the sum of PA and PANO for jaconine, indicating higher stability or new formation through degradation of other PA. Overall, ensiling offers opportunities to decrease the PA-PANO content in feed and therefore lowers the risk of intoxication by Senecio in livestock.

Assessment of the microbiological origin of blowing defects in Grana Padano Protected Designation of Origin cheese

Recognized worldwide for its history, flavor, and high nutritional quality, Grana Padano (GP) is one of the most traditional Italian raw-milk, hard-cooked, long-ripened cheese. Throughout GP manufacturing, some well-known and undesired bacterial species, such as clostridia, can proliferate and lead to spoilage defects that mischaracterize the final product; however, little is known about the development of late-blowing defects in hard cheese samples without clostridia. Therefore, in this study we aimed to use metataxonomic analysis to identify bacterial taxa associated with the development of late-blowing defect in GP samples. Furthermore, the presence of several heterofermentative lactobacilli species in defective zones were verified by primer-specific PCR assay. Considering α- and β-diversity analyses, no statistically significant differences were detected between cheese samples with and without blowing defect. Following taxonomic assignment, Lactobacillus and Streptococcus were the dominant genera, whereas clostridia-related taxa were not detected in any of the 20 analyzed samples. Using EdgeR, the genera Propionibacterium and Acinetobacter were found to be prevalently more abundant in samples categorized as having "big regular holes." In samples with "small regular holes," multiplex PCR amplification revealed differences in terms of Lactobacillus population composition, mainly obligate homofermentative lactobacilli, between defective and non-defective zones of the same cheese wheel. This study demonstrated that GP samples with blowing defects not caused by clostridial development share similar biodiversity indices with GP collected from control zones, but an imbalance of obligate homofermentative lactobacilli was noticed between samples, which requires further analysis to better comprehend the exact mechanism involved in this process.

Antimicrobial Susceptibility of Lactobacillus delbrueckii subsp. lactis from Milk Products and Other Habitats.

As components of many cheese starter cultures, strains of Lactobacillus delbrueckii subsp. lactis (LDL) must be tested for their antimicrobial susceptibility to avoid the potential horizontal transfer of antibiotic resistance (ABR) determinants in the human body or in the environment. To this end, a phenotypic test, as well as a screening for antibiotic resistance genes (ARGs) in genome sequences, is commonly performed. Historically, microbiological cutoffs (MCs), which are used to classify strains as either ‘sensitive’ or ‘resistant’ based on the minimal inhibitory concentrations (MICs) of a range of clinically-relevant antibiotics, have been defined for the whole group of the obligate homofermentative lactobacilli, which includes LDL among many other species. This often leads to inaccuracies in the appreciation of the ABR status of tested LDL strains and to false positive results. To define more accurate MCs for LDL, we analyzed the MIC profiles of strains originating from various habitats by using the broth microdilution method. These strains’ genomes were sequenced and used to complement our analysis involving a search for ARGs, as well as to assess the phylogenetic proximity between strains. Of LDL strains, 52.1% displayed MICs that were higher than the defined MCs for kanamycin, 9.9% for chloramphenicol, and 5.6% for tetracycline, but no ARG was conclusively detected. On the other hand, all strains displayed MICs below the defined MCs for ampicillin, gentamycin, erythromycin, and clindamycin. Considering our results, we propose the adaptation of the MCs for six of the tested clinically-relevant antibiotics to improve the accuracy of phenotypic antibiotic testing.

Characterization of γ-glutamyl cysteine ligases from Limosilactobacillus reuteri producing kokumi-active γ-glutamyl dipeptides.

γ-Glutamyl cysteine ligases (Gcls) catalyze the first step of glutathione synthesis in prokaryotes and many eukaryotes. This study aimed to determine the biochemical properties of three different Gcls from strains of Limosilactobacillus reuteri that accumulate γ-glutamyl dipeptides. Gcl1, Gcl2, and Gcl3 were heterologously expressed in Escherichia coli and purified by affinity chromatography. Gcl1, Gcl2, and Gcl2 exhibited biochemical with respect to the requirement for metal ions, the optimum pH and temperature of activity, and the kinetic constants for the substrates cysteine and glutamate. The substrate specificities of the three Gcls to 14 amino acids were assessed by liquid chromatography-mass spectrometry. All three Gcls converted ala, met, glu, and gln into the corresponding γ-glutamyl dipeptides. None of the three were active with val, asp, and his. Gcl1 and Gcl3 but not Gcl2 formed γ-glu-leu, γ-glu-ile, and γ-glu-phe; Gcl3 exhibited stronger activity with gly, pro, and asp when compared to Gcl2. Phylogenetic analysis of Gcl and the Gcl-domain of GshAB in lactobacilli demonstrated that most of Gcls were present in heterofermentative lactobacilli, while GshAB was identified predominantly in homofermentative lactobacilli. This distribution suggests a different ecological role of the enzyme in homofermentative and heterofermentative lactobacilli. In conclusion, three Gcls exhibited similar biochemical properties but differed with respect to their substrate specificity and thus the synthesis of kokumi-active γ-glutamyl dipeptides. KEY POINTS: • Strains of Limosilactobacillus reuteri encode for up to 3 glutamyl cysteine ligases. • Gcl1, Gcl2, and Gcl3 of Lm. reuteri differ in their substrate specificity. • Gcl1 and Gcl3 produce kokumi-active dipeptides.

Lactic acid production ability of Lactobacillus sp. from four tropical fruits using their by-products as carbon source

The present work was aimed at studying the technological properties of lactobacilli isolated from four tropical fruits (banana, papaya, pineapple, and orange) sold in Dschang (a city of the Menoua Division, West-Cameroon), as well as their ability to produce lactic acid (LA) from by-products of these fruits. After isolation and preliminary identification, homofermentative isolates were investigated for acidifying, amylolytic, cellulolytic activities as well as exopolysaccharides production. The chemical composition of the by-products was determined prior to fermentation assays and the most promising isolates were identified by 16S rRNA gene sequencing. From the 54 homofermentative lactobacilli obtained, 9 isolates were pre-selected based on their higher acidifying activity in MRS-Glucose medium. They all showed amylolytic activity, with the most important activity (54.26 ± 0.10 μg of reducing sugar/ml/min) recorded by isolate O31. Relatively to their cellulolytic activity, isolate 1B9 showed the best activity, displaying a production rate of 7.98 ± 0.40 μg glucose/ml/min, while none of them produced exopolysaccharides. The proximate analysis showed that the fruit-derived by-products contained proteins (0.40 ± 0.06% DM to 1.54 ± 0.06% DM), carbohydrates (61.75 ± 0.75% DM to 71.94 ± 2.02% DM) that are main nutrient needs for bacterial growth. Banana-derived and pineapple-derived by-products showed the highest LA production rates with values, 26.37 ± 0.05 g/l (isolate 3A5) and 26.29 ± 0.38 g/l (isolate 1B9) respectively after 16 h of fermentation. Based on the principal component analysis, isolates O31, 1B9, 3A5, 3A9 and 4O8 were selected as the most promising isolates and were identified as Lactobacillus plantarum strains. According to the obtained results, lactobacilli from tropical fruits displayed properties of commerical interest and can be promising candidates in the valorisation of by-products from tropical fruits through LA production.

Selecting fermentation products for food waste valorisation with HRT and OLR as the key operational parameters

Acidogenic fermentation is attractive for food waste valorisation. A better understanding is required on how operation affects product selectivity. This study demonstrated that the hydraulic retention time (HRT) and organic loading rate (OLR) selected fermentation pathways in a single-stage, semi-continuous stirred tank reactor. Three combinations of HRT and OLR were tested to distinguish the effect of each parameter. Three fermentation profiles with distinct microbial communities were obtained. Predominantly n-butyric acid (13 ± 2 gCOD L−1, 55 ± 14% of carboxylates) was produced at an HRT of 8.5 days and OLR around 12 gCOD L−1d−1. Operating at an HRT two days longer, yet with similar OLR, stimulated chain elongation (up to 13.6 gCOD L−1 of n-caproic acid). This was reflected by a microbial community twice as diverse at longer HRT as indicated by first and second order Hill number (1D = 24 ± 4, 2D = 12 ± 3) and by a higher relative abundance of genera related to secondary fermentation, such as the VFA-elongating Caproiciproducens spp., and secondary lactic acid fermenter Secundilactobacillus spp.. Operating at a higher OLR (20 gCOD L−1d−1) but HRT of 8.5 days, resulted in typical lactic acid fermentation (34 ± 5 gCOD L−1) harbouring a less diverse community (1D = 8.0 ± 0.7, 2D = 5.7 ± 0.9) rich in acid-resistant homofermentative Lactobacillus spp. These findings demonstrate that a flexible product portfolio can be achieved by small adjustments in two key operating conditions. This improves the economic potential of acidogenic fermentation for food waste valorisation.

Additives affect the distribution of metabolic profile, microbial communities and antibiotic resistance genes in high-moisture sweet corn kernel silage

This work investigated the effects of chemical additive vanillin (V), homofermentative Lactobacillus plantarum (LP), and heterofermentative Lactobacillus brevis (LB) on the distribution of the metabolome, microbial communities, viruses, and antibiotic-resistance genes in high-moisture corn kernel silage. LP and LB improved lactic acid production, whereas V and LB inhibited protein degradation. A significant difference was observed between the metabolite profiles of silage treated with additives and a control. In silage, the Proteobacteria and Ascomycota were the main hosts of antibiotic-resistance genes, primarily antibiotic efflux. The additives significantly affected the virus content in silage, and LB-treated silage featured the lowest virus content. Overall, these findings suggest that the application of the additive LB to high-moisture corn kernel silage impacts antibiotic-resistance gene reduction and virus distribution within the silage.

The bacterial community and metabolome dynamics and their interactions modulate fermentation process of whole crop corn silage prepared with or without inoculants.

SummaryMulti‐omics approach was adopted to investigate the modulation of bacterial microbiota and metabolome as well as their interactions in whole crop corn ensiling systems by inoculating homofermentative Lactobacillus plantarum or heterofermentative Lactobacillus buchneri. Inoculations of the two different inoculants resulted in substantial differences in microbial community and metabolic composition as well as their dynamics in ensiled corn. Inoculants also altered the correlations of microbiota in different manners, and various keystone species were identified in corn silages with different treatments. Many metabolites with biofunctional activities like bacteriostatic, antioxidant, central nervous system inhibitory and anti‐inflammatory were found in the present silage. A constitutive difference in microbiota dynamics was found for several pathways, which were upregulated by specific taxa in middle stage of fermentation, and widespread associations between metabolites with biofunctions and the species of lactic acid bacteria dominated in silage were observed. Multiple microbial and metabolic structures and dynamics were correlated and affected the fermentation process of the corn ensiling systems. Results of the current study improve our understanding of the complicated biological process underlying silage fermentation and provide a framework to re‐evaluate silages with biofunctions, which may contribute to target‐based regulation methods to produce functional silage for animal production.

Effects of Lactobacillus hilgardii 60TS-2, with or without homofermentative Lactobacillus plantarum B90, on the aerobic stability, fermentation quality and microbial community dynamics in sugarcane top silage

This study investigated the effects of Lactobacillus hilgardii (LH), alone or in combination with Lactobacillus plantarum (LP), on the aerobic stability, fermentation quality and dynamics of the bacterial and fungal communities of sugarcane top silage. Results demonstrated that LH and LHLP (LH combined with LP) improved the aerobic stability of sugarcane top silages. As the exposure time increased, the pH values and the contents of lactic acid, acetic acid, as well as propionic acid remained stable in silage treated with LH and LHLP. The abundance of L. hilgardii was enriched and the undesirable microorganisms, such as Acetobacter pasteurianus, Paenibacillus amylolyticus and yeasts like Kazachstania humilis, were suppressed in silages treated with LH and LHLP. In conclusion, LH-treated silage, whether with LP or not, positively impacted the fungal and bacterial microbes. This improved the quality of fermentation, the aerobic stability, and reduced aerobic spoilage in sugarcane top silage.

Health-promoting effects of Lactobacillus-fermented barley in weaned pigs challenged with Escherichia coli K88 +

Fermented feeds are being considered as practical alternatives to antimicrobial growth promoters (AGP) supplemented in nursery pig diets. This study aimed to investigate health-promoting effects of fermented barley in weaned pigs challenged with Escherichia coli K88 +. A total of 37 piglets were weaned at 21 ± 1 day of age (6.41 ± 0.47 kg of BW) and assigned to either of the following five treatment groups: (1) unchallenged control (UCC; n = 7), (2) challenged control (CC; n = 7), (3) AGP (CC + 0.1% AGP; n = 7), (4) Ferm1 (challenged and fed homofermentative Lactobacillus plantarum (Homo)-fermented barley; n = 8) and (5) Ferm2 (challenged and fed heterofermentative L. buchneri (Hetero)-fermented barley; n = 8). The control diet included unfermented barley. Barley was fermented with either Homo or Hetero for 90 days under anaerobic conditions. On day 10, all pigs except those in UCC group were orally inoculated with E. coli K88 + (6 × 109 colony forming units/ml). The pre-planned orthogonal test was performed to compare (1) UCC and CC, (2) CC and AGP, (3) CC and Ferm1 + Ferm2, as well as (4) Ferm1 and Ferm2. Challenged control pigs showed shorter (P < 0.05) villus height (VH) in the duodenum and deeper (P < 0.05) crypt depth (CD) in the jejunum than UCC pigs. The AGP group had higher (P < 0.05) VH and lower (P < 0.05) IL-6 gene expression in the jejunum compared with CC group. Compared to CC, Ferm1 and Ferm2 had decreased (P < 0.05) CD in the duodenum, IL-6 gene expression in the jejunum and rectal temperature at 24 h post-challenge. Pigs fed fermented barley diets showed greater (P < 0.05) faecal abundance of Clostridium Cluster IV and Lactobacilli than those fed UCC diet. Ferm2-fed pigs showed lower (P < 0.05) concentrations of band cells, eosinophils and lymphocytes at 6, 24 and 48 h after challenge, respectively, and lower (P < 0.05) faecal abundance of Enterobacteriaceae 24 h after challenge than the Ferm1-fed pigs. In conclusion, the substitution of unfermented barley with fermented barley in a nursery diet showed similar results as those shown by AGP supplementation in terms of enhancing the intestinal morphology and modulating faecal microbiota composition, as well as down-regulating the pro-inflammatory cytokines; therefore, fermented barley can be a possible nutritional strategy for managing nursery pigs fed diets without in-feed AGP.

High-density cultivation of Lactobacillus and Bifidobacterium using an automatic feedback feeding method

A new automatic feeding system has been developed, to allow the high-density cultivation of homofermentative Lactobacillus and Bifidobacterium species. The system allowed the automatic supplementation of glucose, and neutralization of acidity based on the consumption of glucose and the production of acids in the growth medium through a sophisticated computerized program. During the pH-controlled culturing, the quantity of NaOH was directly related to the quantity of acids produced. The system supplying the glucose was linked to alkali supplementation to achieve the automatic addition of k mL glucose after 1 mL NaOH solution was automatically added. The glucose consumption and acid production patterns of each strain were carefully studied before the application of the automatic feeding system. All strains (Lactobacillus and Bifidobacterium species) used approximately 90% of the glucose for the production of acids. The NaOH concentration in the alkali bottle and the glucose concentration in the feed bottle were based on the following formulae: Calkali40×2×90%=Cglucose180·k (homofermentative Lactobacillus); Calkali40×5×90%=Cglucose180×2·k (Bifidobacterium). After using this system, the glucose concentration in the fermentation broth remained stable during the culturing of the strains, and the density of the strains was significantly increased, demonstrating the effectiveness of the method.

Modulation of Metabolome and Bacterial Community in Whole Crop Corn Silage by Inoculating Homofermentative Lactobacillus plantarum and Heterofermentative Lactobacillus buchneri.

The present study investigated the species level based microbial community and metabolome in corn silage inoculated with or without homofermentative Lactobacillus plantarum and heterofermentative Lactobacillus buchneri using the PacBio SMRT Sequencing and time-of-flight mass spectrometry (GC-TOF/MS). Chopped whole crop corn was treated with (1) deionized water (control), (2) Lactobacillus plantarum, or (3) Lactobacillus buchneri. The chopped whole crop corn was ensiled in vacuum-sealed polyethylene bags containing 300 g of fresh forge for 90 days, with three replicates for each treatment. The results showed that a total of 979 substances were detected, and 316 different metabolites were identified. Some metabolites with antimicrobial activity were detected in whole crop corn silage, such as catechol, 3-phenyllactic acid, 4-hydroxybenzoic acid, azelaic acid, 3,4-dihydroxybenzoic acid and 4-hydroxycinnamic acid. Catechol, pyrogallol and ferulic acid with antioxidant property, 4-hydroxybutyrate with nervine activity, and linoleic acid with cholesterol lowering effects, were detected in present study. In addition, a flavoring agent of myristic acid and a depression mitigation substance of phenylethylamine were also found in this study. Samples treated with inoculants presented more biofunctional metabolites of organic acids, amino acids and phenolic acids than untreated samples. The Lactobacillus species covered over 98% after ensiling, and were mainly comprised by the L. acetotolerans, L. silagei, L. parafarraginis, L. buchneri and L. odoratitofui. As compared to the control silage, inoculation of L. plantarum increased the relative abundances of L. acetotolerans, L. buchneri and L. parafarraginis, and a considerable decline in the proportion of L. silagei was observed; whereas an obvious decrease in L. acetotolerans and increases in L. odoratitofui and L. farciminis were observed in the L. buchneri inoculated silage. Therefore, inoculation of L. plantarum and L. buchneri regulated the microbial composition and metabolome of the corn silage with different behaviors. The present results indicated that profiling of silage microbiome and metabolome might improve our current understanding of the biological process underlying silage formation.

Effect of Lactobacillus plantarum and Lactobacillus buchneri addition on fermentation, bacterial community and aerobic stability in lucerne silage

Changes in the microbial community are closely related to the fermentation of silage. However, how host genetic variation shapes the community structure of the silage microbiota and its metabolic phenotype is poorly understood. The objective of present study was to evaluate the effects of the application of the homo-fermentative Lactobacillus plantarum and hetero-fermentative Lactobacillus buchneri strains to lucerne silage on the fermentation characteristics, aerobic stability, and microbial community and their correlations. The three silages treated with L. plantarum or L. buchneri were well preserved and had significantly lower pH values, butyric acid, propionic acid, and ammonia-N concentrations, and significantly higher residual water-soluble carbohydrate, dry matter and lactic acid contents than the controls. The treated groups had more lactic acid bacteria and lower quantities of other bacteria in their microbial communities. Inoculation of lactic acid bacteria influenced the abundances of other bacteria and controlled the silage fermentation characteristics. L. buchneri inhibited the abundance of Enterobacter_ludwigii to increase the crude protein content, L. plantarum improve the neutral detergent fibre content by affecting the abundance of Arthrobacter_sp._Ens13. In conclusion, the application of L. plantarum and L. buchneri improved the quality of lucerne silage fermentation, and L. buchneri resulted in greater improvements after aerobic exposure.

Corrigendum to: Effect of Lactobacillus plantarum and Lactobacillus buchneri addition on fermentation, bacterial community and aerobic stability in lucerne silage

Changes in the microbial community are closely related to the fermentation of silage. However, how host genetic variation shapes the community structure of the silage microbiota and its metabolic phenotype is poorly understood. The objective of present study was to evaluate the effects of the application of the homo-fermentative Lactobacillus plantarum and hetero-fermentative Lactobacillus buchneri strains to lucerne silage on the fermentation characteristics, aerobic stability, and microbial community and their correlations. The three silages treated with L. plantarum or L. buchneri were well preserved and had significantly lower pH values, butyric acid, propionic acid, and ammonia-N concentrations, and significantly higher residual water-soluble carbohydrate, dry matter and lactic acid contents than the controls. The treated groups had more lactic acid bacteria and lower quantities of other bacteria in their microbial communities. Inoculation of lactic acid bacteria influenced the abundances of other bacteria and controlled the silage fermentation characteristics. L. buchneri inhibited the abundance of Enterobacter_ludwigii to increase the crude protein content, L. plantarum improve the neutral detergent fibre content by affecting the abundance of Arthrobacter_sp._Ens13. In conclusion, the application of L. plantarum and L. buchneri improved the quality of lucerne silage fermentation, and L. buchneri resulted in greater improvements after aerobic exposure.

Эколого-биологическая характеристика Lactobacillus acidophilus

&lt;p&gt;Lactobacillus acidophilus - homofermentative lactobacillus, specializing in living in the gastrointestinal and urogenital tracts of mammals and birds. It accompanies a person from birth and throughout his life, providing a whole range of useful services, the main one of which is active participation in the body's defense system against the harmful action of undesirable microorganisms (preventing the growth of pathogenic bacteria and restraining populations of opportunistic microbes at a safe level) . It is this property of the acidophilus rod that explains its wide practical use in various probiotic products and preparations of dietary, medical and agricultural purposes.&lt;br /&gt;Although the acidophilus rod is known and purposefully used for a long time, it still ha the great potential for the research. The use of gene-molecular approaches has made it possible to clarify the systematic position of L. acidophilus in the family of lactobacilli and to identify a group of closely related species, often indistinguishable by traditional physiological and biochemical identification methods. Today, the efforts of researchers are focused on elucidating the molecular mechanisms by which antagonistically active strains of L. acidophilus carry out a bactericidal and bacteriolytic effect on harmful microbes. Disclosure of these mechanisms will not only allow more efficient selection and use of strains of L. acidophilus, but also create a new class of antibiotics that are more effective and have less side effects than existing ones.&lt;br /&gt;This review is devoted to the description of the probiotic microorganism Lactobacillus acidophilus. In the article the biological and ecological properties of the acidophilus rod are described in detail, examples of practical use of this microorganism in various branches of the national economy are given.&lt;/p&gt;

Draft Genome Sequences of the Aerobic Strains Lactobacillus gasseri AL3 and AL5.

ABSTRACTAdaptation to the aerobic environment has been investigated in heterofermentative lactobacilli, while data on how homofermentative lactobacilli adapt to oxygen are limited. We report here the draft genome sequences of the aerobic strains Lactobacillus gasseri AL3 and AL5 that allow an in-depth investigation of the genes involved in oxidative metabolism and the stress response.