Search Results (12)

Guanine deaminase (GDA) catalyzes the first step in purine catabolism by converting guanine to xanthine. Despite its significant role in the development of low-purine food, studies on GDA remain limited compared to other metabolic deaminases. To identify a GDA with high enzyme activity and appropriate optimum parameters, GDAs from Kluyveromyces lactis, Kluyveromyces marxianus, Lentilactobacillus kefiri, and Lactobacillus buchneri were heterologously expressed in Escherichia coli. The GDA from Kluyveromyces marxianus (KM-GD) showed the most potent enzyme activity (2.21 IU/mL) at 30 °C and pH 6.5, which is close to the pH of saccharified wort. Furthermore, analyzing the crystal structures of GDAs from different sources revealed that hydrogen bonds could enhance substrate affinity and strengthen enzyme activity. In addition, active pockets with an appropriate size may contribute to high enzyme activity. Finally, KM-GD helped reduce guanine by 80.33% in beer wort and by 80.00% in matured beer, thus suggesting its promise for industrial application in low-purine food production. Full article

Lactic acid bacteria (LAB) fermentation has been claimed as an effective way of modifying the sensory properties of plant-based foods. However, not much has been published on the influence of different LAB strains on the flavour of the volatile organic compounds (VOCs) produced. Using a defined medium (DM) and proton-transfer-reaction time-of-flight mass spectrometry (PTR-ToF-MS), we assessed the VOCs produced by seven LAB strains, Levilactobacillus brevis WLP672 (LB672), Lactobacillus delbrueckii WLP677 (LD677), Pediococcus damnosus WLP661 (PD661), Lactiplantibacillus plantarum LP100 (LP100), Pediococcus pentosaceus PP100 (PP100), Pediococcus damnosus 5733 (PD5733), and Lentilactobacillus buchneri 5335 (LU5335), at three time points during fermentation (0, 7, and 14 days) at either 25 or 35 °C. Significant variations in VOC production were observed among LAB strains, growing in the same DM composition at either 25 °C or 35 °C. Specifically, the concentration of m/z 87.043 (t.i. diacetyl) was significantly (p < 0.05) higher at 7 days of fermentation at 35 °C by LP100, followed by PP100 at 35 °C and PD661 at 25 °C compared to the other strains at either 25 or 35 °C. The concentration of m/z 115.112 (t.i. 2-heptanone) was significantly (p < 0.05) higher at 7 days of fermentation at either 25 or 35 °C by LP100 compared to the other strains at all temperature and time points. The concentration of m/z 49.011 (t.i. methanethiol) was significantly (p < 0.05) higher after 7 days of fermentation at 35 °C by LB672 compared to the other strains at either 25 or 35 °C. The concentration of m/z 71.085 (t.i. 3-methyl butanol) was significantly (p < 0.05) higher after 7 days of fermentation at either 25 or 35 °C by PD661, LU5335, or PD5733 compared to the other strains studied. A notable increase in specific VOC concentrations was observed at 35 °C compared to 25 °C. This research demonstrates that LAB strains generate distinct VOC profiles in a DM based on strains and fermentation conditions. Therefore, this knowledge provides a basis for controlling and enhancing flavour in plant-based fermentations. Full article

Italian ryegrass is a high-quality forage grass, and a full understanding of the changes in its microbiome and metabolome during aerobic exposure can prolong its aerobic stability and improve its utilization value. Italian ryegrass silage was prepared with deionized water (CK), Lactobacillus rhamnosus BDy3-10 (LR), Lactobacillus buchneri TSy1-3 (LB), and a mixture of these two lactic acid bacteria (M). The silage was maintained at ambient temperature for 60 days followed by aerobic exposure. The results show that the Italian ryegrass silage in the LB and M groups exhibited aerobic stability for up to 19 days. A total of 1881 chemicals were identified in Italian ryegrass silage. These metabolites are associated with bacterial communities, especially Lactobacillus. The addition of lactic acid bacteria resulted in a common differential metabolic pathway compared to CK: “phenylpropanoid biosynthesis”. “Flavone and flavonol biosynthesis” was the significant differential metabolic pathway between LB and LR. Inoculation with LB significantly increased the concentrations of lactic acid, acetic acid, vitexin, and luteolin. In conclusion, lactic acid bacteria (LAB) additives affect the microbial community and metabolites of silage. The application of LB inoculants is a feasible way to obtain well-fermented Italian ryegrass silage and improve aerobic stability, even at higher moisture content levels. Full article

Intercropping systems and exogenous microorganism additives are recognized for their potential to influence silage fermentation and quality. This study aims to evaluate the impacts of maize–lablab bean intercropping and lactic acid bacteria (LAB) additives on silage yield, nutritional quality, and economic profitability. A randomized block design was employed with two cropping patterns—maize monocrop (M) and maize–lablab intercrop (ML)—and five additive treatments: No additives (CK), and varying ratios of Lactobacillus Plantarum (LP) and Lactobacillus Buchneri (LB), T1 (100% LP), T2 (9LP:LB), T3 (8LP:2LB), and T4 (100% LB). The silage was analyzed and evaluated for its nutritional quality, fermentation quality, and fermentation effect after 90 days of fermentation. ML intercropping significantly enhanced the fresh matter yields by 8.59% and crude protein content by 8.73% compared to M. From the point of view of inoculation with different lactobacilli, the pH, AA, and NH₃-N/TN were lower in the T2 and T3 treatments than in the other treatments, while LA was significantly higher. The V-score, which reflects the overall fermentation quality, was excellent across all treatments, with scores exceeding 80 points; the T2 treatment in ML silage achieved the highest score of 99.58. In addition, intercropping can increase the net income of farmers by 21.67%. In conclusion, maize–lablab intercropping combined with LAB inoculation, particularly with the T2 and T3 treatments, significantly enhances the silage quality and economic returns by reducing pH, increasing the LA content, and improving the CP levels. This study is the first to comprehensively analyze the synergistic effects of altering cropping systems and adding functional microorganisms on forage yield and fermentation quality, offering strategic insights for farms, especially mixed farms, to produce high-quality feed. We recommend adopting these methods to improve feed quality and maximize the profitability of silage production systems. Full article

In the enhancement of Novel Sorghum bicolor × S. propinquum Hybrid utilization, optimal planting densities and silage methods remain elusive. This study assesses the effects of planting densities, cellulase (CE), Lactobacillus buchneri (LAB), and their combination (LC) on fermentation quality and bacterial diversity of the hybrid silage. The experiment was carried out in a completely random block design with four additives and five planting densities (M1, M2, M3, M4, M5) as follows (4 additives × 5 planting densities): a control group without additives (CK), a group treated with Lactobacillus buchneri (LAB), a group with cellulase (CE), and a group treated with a combination of LAB and CE (LC), maintaining triplicates per treatment. In this study, the additive treatment improved the fermentation quality of silage compared with the control. In the M2-LC group, the contents of crude protein (CP; 7.88%), ether extract (EE; 1.91%), and ash (7.76%) were the highest, while the pH (3.30) was the lowest. The water-soluble carbohydrate (WSC; 11.28%) content was the highest in the M3-CE group, the lactic acid (LA; 6.79%) content was the highest in the M4-CE group, and the acetic acid (AA; 7.71%) content was the highest in the M2-LAB group. Meanwhile, the neutral washing fiber (NDF; 53.17%) content was the lowest in the M5-CE group, the acid detergent fiber (ADF; 41.01%) content was the lowest in the M2-CE group, and the propionic acid (PA; 0.26%) content was the lowest in the M1-LAB group. Adding LC notably reduced bacterial diversity, boosted Lentilactobacillus, and curbed Proteobacteria. LAB and LC markedly improved amino acid metabolism over CE and CK. Conversely, beta-lactam resistance, flagellar assembly, and ascorbate/aldarate metabolism pathways were suppressed. In the future, we will explore a variety of additives and adjust the cutting height to improve its comprehensive quality, create an innovative path for silage production, promote the efficient use of agricultural resources, and provide high-quality feed for animal husbandry. Full article

A long-term use of chemical drugs cannot cure type II diabetes mellitus (T2DM) and their numerous toxic side effects can be harmful to human health. In recent years, probiotics have emerged as a natural resource to replace chemical drugs in alleviating many human ailments. Healthy children’s intestines have a lot of colonized Lactobacilli and Bifidobacterium, and these beneficial bacteria can help promote overall health. The objective of this study was to isolate potential antidiabetic probiotic strains from healthy children and evaluate their application prospects. Firstly, Lactobacillus and Bifidobacterium strains were isolated from healthy children’s feces and identified by the pheS or clpC genes with their respective 16S rRNA genes. Then, hydrophobicity, artificial gastrointestinal fluid tolerance, α-Glucosidase and Dipeptidyl peptidase IV (DPP-IV) inhibitory activities of isolated strains were determined, and antioxidant activities and promoting secretion of GLP-1 in STC-1 cells of candidate strains were tested. Results showed that 6 strains of Lactobacillus and Bifidobacterium were obtained from the feces of healthy children aged 3 years, respectively, including Lacticaseibacillus paracasei L-21 and L-25, Levilactobacillus brevis L-16, Lentilactobacillus buchneri L-9, Lactiplantibacillus plantarum L-8 and L-3, Bifidobacterium bifidum 11-1 and B-84, Bifidobacterium longum subsp. longum 6-1, 6-2, B42 and B53. The hydrophobicity and auto-aggregation levels of all these strains were higher than 30% and 50%, respectively, and the decrease in the number of colonies of all strains in the artificial gastrointestinal fluid was less than 2 log CFU/mL. Strains L-3, L-8, L-9, L-21, 6-1, 11-1, B53 and B84 were selected based on their high α-glucosidase inhibitory activity and DPP-IV inhibitory activity, and results of the antioxidant capacity assay showed that the remaining strains all had intense comprehensive antioxidant activity. Additionally, Lacticaseibacillus paracasei L-21 and Bifidobacterium longum subsp. longum B-53 had the most substantial prompting effect on GLP-1 secretion in the STC-1 cell line. These results indicated that Lacticaseibacillus paracasei L-21 and Bifidobacterium longum subsp. longum B-53 could be used as a potential antidiabetic strain; thus, its application as a food supplement and drug ingredient could be recommended after in vivo mitigation of type II diabetes test. Full article

Myriophyllum aquaticum (M. aquaticum) is a commonly used aquatic macrophyte for water purification and could be utilized as animal food. However, the high water content of M. aquaticum makes it difficult for long-term preservation, which leads to challenges as an ideal animal feed ingredient. The storage of Silage for long periods may be a proper method to solve the problem. In the present paper, we assess the effects of lactic acid bacteria Lactobacillus buchneri (LB), Lactobacillus plantarum (LP), or their combination on fermentation and microbial communities during the ensiling of M. aquaticum silage. The results show that the LP-treated silage displays a higher lactic acid concentration than that in the control silage. Both LB and LP increased the abundance of Lactobacillus, but decreased the abundance of Serratia and Prevotella_9 in M. aquaticum silage after 60 days of ensiling. Both LB and LP increased the diversity and richness of fungi. Therefore, the inoculation of LP improved silage fermentation during ensiling. These results show that the inoculation of lactic acid bacteria improves the fermentation quality of M. aquaticum silage, which makes it possible for the application of M. aquaticum to animal forage in the future. Full article

This study was conducted to evaluate the effect of lactic acid bacteria (LAB) on fermentation quality, mycotoxin concentrations, and microbial communities of whole-crop corn silages infested with mycotoxigenic fungi. Cultured spores (10⁶ cfu/mL) of mycotoxigenic Aspergillus flavus and Fusarium graminearum were sprayed (5 mL) on corn forage on 27 July and 10 August 2018. On 21 August 2018, sprayed (FI; 3 plots) and unsprayed (NFI; 3 plots) corn forage were harvested at the 1/2 kernel milk line stage, followed by chopping and ensiling without inoculants (CON), or with Lactobacillus buchneri (LB, 1 × 10⁶ cfu/g FW), Lactobacillus plantarum (LT, 1 × 10⁶ cfu/g FW), or L. buchneri + L. plantarum (BT: both L. buchneri and L. plantarum applied at 0.5 × 10⁶ cfu/g FW). After 90 d of ensiling, FI silages had a higher (p < 0.05) pH value and higher acetic acid (ACA), ethanol, and ammonia nitrogen (ammonia N) concentrations, but lower (p < 0.05) lactic acid (LA) concentrations than NFI silage. The inoculants decreased pH and increased LA concentration and LA/ACA compared with CON. The aflatoxin B₁ (AFB₁) was only detected in FI fresh corn and silages; ensiling decreased (p < 0.05) AFB₁ concentration compared with fresh corn, and LB and BT decreased AFB₁ concentration compared with CON. The zearalenone (ZEN), deoxynivalenol (DON), and fumonisin B₁ (FB₁) concentrations were similar (p < 0.05) for NFI silages, while ZEN concentration in BT was the lowest (p < 0.05) among all FI silages; DON and FB₁ concentrations in LB, LT, and BT silages were significantly lower (p < 0.05) than those of CON in FI silages. The fungal infestation increased the bacterial and fungal diversity of silages compared with NFI silages. The FI silages had a higher relative abundance (RA) of Lactobacillus, Weissella, Wickerhamomyces, Pichia, and Epicoccum than the corresponding NFI silages. The RA of Aspergillus and Fusarium markedly decreased after 90 d of ensiling, and the inoculation expanded this trend irrespective of fungal infestation. The Penicillium in FI silages survived after 90 d of ensiling, while the inoculants decreased the RA of Penicillium. Inoculants mitigate the adverse effects of fungal infestation on corn silage quality by changing the bacterial and fungal communities. Full article

The present study aimed to investigate effects of dual-purpose inoculants (antifungal and carboxylesterase activities) not only on corn silage quality, but also its shelf life against mold contamination at feed-out phase. Corn forage was ensiled for 252 d with different inoculants of the following: control (CON), Lactobacillus brevis 5M2 (5M), Lactobacillus buchneri 6M1 (6M), and mixture of 5M and 6M at 1:1 ratio (MIX). After ensiling, corn silage was contaminated with Fusarium graminearum. Silages applied inoculants had positive effects by increased organic acid and lactic acid bacteria, and decreased undesirable microbes. At feed-out phase, contamination of F. graminearum into corn silage had a negative effect on aerobic stability caused by increased growth of undesirable microbes. However, silages applied inoculants had positive effects by decreased undesirable microbes and extended lactic acid bacteria and aerobic stability. Generally, MIX silage presented better effects on organic acid production, rumen degradation, inhibition of undesirable microbes, and aerobic stability than 5M silage and 6M silage. The present study concluded that application of inoculants into corn silage had positive effects on fermentation characteristics and extended shelf life against mold contamination at feed-out phase. A mixed inoculant appeared to have better effects of antifungal and carboxylesterase than a single inoculant. Full article

This study was conducted to screen dual-purpose lactic acid bacteria (LAB) from uncontrolled farm-scale silage, and then we confirmed their effects on corn silage. The LAB were isolated from eight farm-scale corn silages, and then we screened the antifungal activity against Fusarium graminearum and the carboxylesterase activity using spectrophotometer with p-nitrophenyl octanoate as substrate and McIlvane solution as buffer. From a total of 25 isolates, 5M2 and 6M1 isolates were selected as silage inoculants because presented both activities of antifungal and carboxylesterase. According 16S rRNA gene sequencing method, 5M2 isolate had 100.0% similarity with Lactobacillus brevis, and 6M1 isolate had 99.7% similarity with L. buchneri. Corn forage was ensiled in bale silo (500 kg) for 72 d without inoculant (CON) or with mixture of selected isolates at 1:1 ratio (INO). The INO silage had higher nutrient digestibility in the rumen than CON silage. Acetate was higher and yeasts were lower in INO silage than in CON silage on the day of silo opening. In all days of aerobic exposure, yeasts were lower in INO silage than CON silage. The present study concluded that Lactobacillus brevis 5M2 and L. buchneri 6M1 confirmed antifungal and carboxylesterase activities on farm-scale corn silage. Full article

The purpose of this study was to evaluate the probiotic characteristics and neuroprotective effects of bacteria isolated from Korean fermented foods. Three bacterial strains (Lactobacillus fermentum KU200060, Lactobacillus delbrueckii KU200171, and Lactobacillus buchneri KU200793) showed potential probiotic properties, such as high tolerance against artificial gastric juice and bile salts, sensitivity to antibiotics, nonproduction of carcinogenic enzymes, and high adhesion to intestinal cells. Heat-killed L. fermentum KU200060 and L. buchneri KU200793 showed higher antioxidant activity than heat-killed L. delbrueckii KU200171. The conditioned medium (CM) was used to evaluate the reaction between HT-29 cells and each heat-killed strain. All CMs protected SH-SY5Y cells from 1-methyl-4-phenylpyridinium (MPP⁺)-induced toxicity. The expression of brain-derived neurotropic factor (BDNF) mRNA in HT-29 cells treated with CM containing heat-killed L. buchneri KU200793 was the highest. The CM significantly reduced the Bax/Bcl-2 ratio and increased BDNF mRNA expression in SH-SY5Y cells treated with MPP⁺. These results indicate that L. buchneri KU200793 can be used as a prophylactic functional food, having probiotic potential and neuroprotective effects. Full article

Ultraviolet (UV) exposure triggers the abnormal production of reactive oxygen (ROS) species and the expression of matrix metalloproteinases (MMPs) that are responsible for photoaging. Probiotics are widely used in healthcare and for immune enhancement. One probiotic, Lactobacillus buchneri is found in Kimchi. This study was aimed at assessing the anti-photoaging effect of plant extracts fermented with L. buchneri (PELB) to develop functional cosmetics. We investigated the anti-photoaging effect of PELB in a UVB-induced photoaging in vitro model and selected effective extracts using the elastase inhibition assay, ELISA for Type I procollagen and collagenase-1, and quantitative real time PCR. Normal human dermal fibroblasts and epidermal keratinocytes were pre-treated with PELB and exposed to UVB. We found that PELB decreased elastase activity and increased type I collagen expression in a UVB-induced photoaging in vitro model. In addition, PELB greatly reduced collagenase activity and MMP mRNA levels in a UVB-induced photoaging in vitro model. Furthermore, PELB promoted the expression of moisture factor and anti-oxidant enzymes in a UVB-induced photoaging in vitro model. These results indicated that the PELB could be potential candidates for the protective effects against UVB-induced photoaging. Overall, these results suggest that PELB might be useful natural components of cosmetic products. Full article