Higher Lactic Acid Content Research Articles

English

This study reports on the effectiveness of silage additive based on consortium Lacticaseibacillus paracasei L1a and Bacillus licheniformis WJ53A in comparison with three homofermentative lactic acid bacteria (LAB) (Pediococcus acidilactici 12c, L. Lacticaseibacillus paracasei L1a, and L. plantarum S1aR). For this purpose, the antagonistic activity of these isolated LAB was tested. The impact of the isolated LAB on silage acidity, organic acid content, and dry matter of silage was also determined. The fungal and bacterial DNA load in the conserved silages was estimated using quantitative PCR and their effects on the quality category of silage were evaluated. The obtained results showed all inoculants being effective in ensiling of maize with the consortium (L1a + WJ53A), showing a high lactic acid content (94.51%, P<0.0001) in comparison to control (88.28%, P<0.0001). The consortium also showed a lower acetic acid (5.49% to 10%, P=0.0002) and absolutely no butyric acid in respect to control silage (0% to 1.64%, P<0.0001). The qPCR results presented an increase in the final LAB DNA concentration of silage conserved with consortium (0.002487 ng, P=0.0002) when compared to control (0.001127 ng, P=0.0002) but did differ from the inoculant of L1a (0.001790 ng, P=0.0219). Also, the final fungal DNA concentration showed the effectiveness of the consortium by the reduction of fungal DNA in comparison to control (0.00027 ng against 0.00106 ng, P=0.0007). The most interesting result is the inhibition of clostridia growth based on the qPCR analysis which showed a lower clostridial DNA in silage inoculated with the consortium (P<0.001) against all the inoculants used in this study. This research shows the advantage of ensilaging with a consortium of a homofermentative LAB and a Bacillus strain B. licheniformis WJ53A which reduces the risk of clostridial infections in livestock farming

Effects of Different Types of LAB on Dynamic Fermentation Quality and Microbial Community of Native Grass Silage during Anaerobic Fermentation and Aerobic Exposure

Silage of native grasses can alleviate seasonal forage supply imbalance in pastures and provide additional sources to meet forage demand. The study aimed to investigate the effects of Lactobacillus plantarum (LP), Lactobacillus buchneri (LB), and Lactobacillus plantarum in combination with Lactobacillus buchneri (PB) on the nutritional quality, fermentation quality, and microbial community of native grass silage at 2, 7, 15, and 60 days after ensiling and at 4 and 8 days after aerobic exposure. The results showed that dry matter content, crude protein content, the number of lactic acid bacteria, and lactic acid and acetic acid content increased and pH and ammonia nitrogen content decreased after lactic acid bacteria (LAB) inoculation compared with the control group (CK). LP had the lowest pH and highest lactic acid content but did not have greater aerobic stability. LB maintained a lower pH level and acetic acid remained at a higher level after aerobic exposure; aerobic bacteria, coliform bacteria, yeast, and molds all decreased in number, which effectively improved aerobic stability. The effect of the compound addition of LAB was in between the two other treatments, having higher crude protein content, lactic acid and acetic acid content, lower pH, and ammonia nitrogen content. At the phylum level, the dominant phylum changed from Proteobacteria to Firmicutes after ensiling, and at the genus level, Lactiplantibacillus and Lentilactobacillus were the dominant genera in both LAB added groups, while Limosilactobacillus was the dominant genus in the CK treatment. In conclusion, the addition of LAB can improve native grass silage quality by changing bacterial community structure. LP is beneficial to improve the fermentation quality in the ensiling stage, LB is beneficial to inhibit silage deterioration in the aerobic exposure stage, and compound LAB addition is more beneficial to be applied in native grass silage.

Effects of growth stage on the fermentation quality, microbial community, and metabolomic properties of Italian ryegrass (Lolium multiflorum Lam.) silage.

This study aimed to investigate the effects of different growth stages (booting period-SYK; initial flowering-SCK; full flowering-SSK) on the fermentation quality, microbial community, metabolic pathways and metabolomic characteristics of Italian ryegrass silage. Single molecule real-time (SMRT) sequencing and ultra-high performance liquid chromatography-mass spectrometry (UHPLC-MS/MS) were used to analyze bacterial communities and metabolites, respectively. After 60 d of fermentation, SYK had the lowest pH and the highest lactic acid content, which were significantly different from the other groups. The bacteria with the highest abundance in SYK, SCK and SSK groups were Lactiplantibacillus plantarum (63.98%), Weissella minor (28.82%) and Levilactobacillus brevis (64.81%), respectively. In addition, among the main differential metabolites in different growth stages, the number of amino acids was the most, and the corresponding metabolic pathways were mainly amino acid metabolic pathways. The biosynthesis of phenylalanine, tyrosine and tryptophan was significantly enriched (p<0.01) at booting stage and full flowering stage. Purine metabolism and ABC transporter pathway were significantly enriched at the initial flowering (p<0.001). Lactiplantibacillus plantarum had a negative correlation with xanthine and ganoderic acid F. Weissella minor had a positive correlation with D-Mannose and ganoderic acid F. Levilactobacillus brevis had a positive correlation with xanthine, and Latilactobacillus sakei had a positive correlation with cinnamic acid, D-Mannose, 2-Hydroxycinnamic acid and uridine. In conclusion, this study reveals the interaction mechanisms between ryegrass raw materials at different growth stages and epiphytic microorganisms during ensiling fermentation, providing new ideas for screening functional lactic acid bacteria, and laying a theoretical foundation for the production of safe and high-quality silage.

Effects of cellulase and Lactiplantibacillus plantarum on the fermentation quality, microbial diversity, gene function prediction, and in vitro rumen fermentation parameters of Caragana korshinskii silage

In the present study, we investigated the effects of cellulase and Lactiplantibacillus plantarum (L. plantarum) on the fermentation quality, microbial diversity, gene function prediction, and in vitro rumen fermentation parameters of the Caragana korshinskii (C. korshinskii) silage. The experimental treatment groups included control (CK), cellulase (C), L. plantarum (L), and cellulase + L. plantarum (CL). Triplicate silos were sampled after 14 and 56 days of ensiling. The microbial diversity of C. korshinskii silage at 56 days was analyzed using Illumina MiSeq sequencing technology, and the effects of C. korshinskii silage on rumen fermentation were evaluated by the in vitro artificial rumen gas production method. The results showed that the addition of cellulose and L. plantarum treatments reduced ammonia-nitrogen (NH3-N), dry matter (DM), neutral detergent fiber (NDF), and acid detergent fiber content during ensiling. Compared with the CK group, higher lactic acid content was observed in the silage of the C and L groups, but the CL group had a higher acetic acid (AA) content. Compared with the CK group, the relative abundance of Lactiplantibacillus significantly increased, but that of Enterococcus, Weissella, Enterobacter, and Pediococcus significantly decreased in all other groups except the C group (p &amp;lt; 0.05). The results of gene function prediction were as follows: pyruvate kinase, 1-phosphofructokinase, and fructokinase were lactate production enzymes, which suggested the association of the high AA content in the CL group to the high abundance of 6-phosphate glucose dehydrogenase. The abundance of H + -transporting ATPase and ATP-binding cassette (ABC) transporters in the L and CL groups was higher than that in the CK groups. Metabolism of terpenoids and polyketides, mismatch repair, DNA replication, nucleotide excision repair, and homologous recombination increased in the CL group compared with those in the CK group. Compared with the CK group, NH3-N and microbial protein content and the degradation rates of DM and NDF increased in the L and CL groups. To conclude, the L and CL groups had increased Lactiplantibacillus abundance, improved fermentation quality, and high DM degradation rates compared with the CK group.

Immunomodulation of the Vaginal Ecosystem by Ligilactobacillus salivarius CECT 30632 Improves Pregnancy Rates among Women with Infertility of Unknown Origin or Habitual Abortions

In this study, the probiotic potential of Ligilactobacillus salivarius CECT 30632 was assessed, including properties specifically related with gynecological targets. This strain displayed co-aggregative and antimicrobial activity against a wide spectrum of vaginal pathogens while being respectful with the growth of vaginal lactobacilli. The strain produced a high concentration of lactic acid and displayed α-amylase activity when assayed in vitro. It showed a noticeable survival rate after exposition to conditions similar to those present in the human digestive tract and was adhesive to both vaginal and intestinal cells. Subsequently, their capacity to increase pregnancy rates among women with habitual abortion or infertility of unknown origin was studied. Administration of L. salivarius CECT 30632 (~9 log10 CFU) daily for a maximum of six months to these women was safe and led to a successful pregnancy rate of 67.5% (80% and 55% for women with repetitive abortion and infertile women, respectively). Significant differences in Nugent score, vaginal pH, and vaginal concentrations of lactobacilli, TGF-β, and VEFG were observed when the samples collected before the intervention were compared with those collected after the treatment among those women who got pregnant. Therefore, this strain can modulate the vaginal ecosystem and lead to better fertility outcomes.

Characteristics of lactic acid bacteria, microbial community and fermentation dynamics of native grass silage prepared in Inner Mongolian Plateau.

To prepare high-quality silage, we studied the chemical composition, silage fermentation, characterization, and identification of lactic acid bacteria (LAB) associated with the silage fermentation of native grass on the Inner Mongolian Plateau. LAB were isolated from fresh native grass and their silage, and silages were prepared using a small-scale fermentation system with 2-3 cm length in plastic bags. The dominant species of native grasses used were Stipa baicalensis, Leymus chinensis, Cleistogenes squarrosa, Melissilus ruthenicus and Pulsatilla turczaninovii, which contained 47.83-59.43 % moisture, 55.12-67.74 % neutral detergent fiber (NDF), and 8.72-14.55 crude protein (CP), and these nutrients did not change greatly during ensiling. Good preservation with a relatively low pH (below 4.44) and high (p < 0.05) lactic acid content (>0.58) was obtained after ensiling. Based on the morphological and biochemical characteristics, these isolates were divided into 12 groups (A-L). All isolate strains were gram-positive and catalase-negative bacteria that produce lactic acid from glucose. Group A-K were cocci, while group L was rod-shaped. Group A-E formed D-lactic acid, but group H-K formed L-lactic acid, and other groups formed DL-lactic acid. Group A-E were heterofermentative, and Group F-L were homofermentative types of LAB. According to the 16S rRNA gene sequences analysis, strains were identified as genus Leuconostoc (A, B, and C), Weissellla (D, E), Pediococcus (F, G), Enterococcus (H, I, J and K), and Lactiplantibacillus (L). Enterococcus (E.) faecium (29.17%, percentage of total isolates) and Pediococcus (P.) acidilactici (18.75%) were the most frequently occurring dominant species. This study suggests that the native grasses contained abundant LAB species, and they can be used as good-quality silages in animal husbandry. In addition, the strains P. acidilactici and E. faecium were the most frequently isolated from native grass silages as dominant species which can be a potentially excellent inoculant for native grass silage.

Synthesis of Lactic Acid from Molasses by Lactobacillus acidophilus Using a Batch Fermentation Process

Lactic acid is a chemical with widespread applications, mainly in pharmaceutical, cosmetic, chemical as well as food industries. One of the major uses of lactic acid is the polylactic acid (PLA) feedstock which is biodegradable and biocompatible as an alternative to plastic derived from fossil fuels. Efforts continue to be made to reduce the cost of producing PLA in order to compete with the conventional petrochemical-based plastics. This include the use of molasses as a raw material because it is cheap and contains high glucose. The purpose of this study was to obtain cell concentrations through the addition of starter volume that produces high concentrations of lactic acid and to obtain the growth kinetics of Lactobacillus acidophilus during the fermentation process. This study was conducted in several stages; the design of bioreactors, inoculation of Lactobacillus acidophilus, and fermentation of molasses. In a batch system, molasses substrate was directly inserted as much as 500 ml in the fermentor and the addition of starter volume of Lactobacillus acidophilus was 1; 3; 5 dan 10% v/v. The fermentation of molasses for 72 hours and the product was analysed every 8 hours. The highest concentration of lactic acid produced in batch fermented molasses was added to 5% (v/v) starter volume with 72 hours of fermentation time, which was 23.1 mg/L, with value the carrying-capacity coefficient (k) and the maximum net specific growth rate (µnet) were 0.2379 h-1 and 0.0160 h-1 respectively.

Исследование особенностей культивирования молочнокислых бактерий в подсырной сыворотке и уфпермеате для получения β-галактозидаз

Lactic acid microorganisms are potential sources of the β-galactosidase enzyme, which can be used for the hydrolysis of lactose in the production of low- and lactose-free food products, as well as a catalyst in the biosynthesis of lactulose, galactooligosaccharides, and other valuable food additives. The need of lactic acid bacteria for the presence in the cultivation medium of additional sources of carbon, nitrogen, and other components significantly increases the cost of bacterial β-galactosidases. Lactose-containing raw materials, in particular whey and its UV permeate, are a promising and fairly cheap analogue of expensive complex media for the cultivation of lactic acid microorganisms. In this work, the features of cultivation of various types of lactic acid bacteria (Lactobacillus acidophilus, Streptococcus thermophilus, Lactobacillus plantarum, Lactobacillus rhamnosus LGG, Lactococcus lactis ssp.) in different types of secondary milk raw materials (whey and UV permeate) were studied.. It has been shown that cheese whey is a more favorable medium for their growth than UV permeates. The highest concentration of lactic acid was obtained in experiments with L. acidophilus. To accelerate the growth of lactic acid bacteria in the permeate; it was proposed to use the addition of 2% peptone.

WPŁYW DODATKU GLUKONIANU I CYTRYNIANU MAGNEZU NA JAKOŚĆ KOZIEGO I KROWIEGO MLEKA FERMENTOWANEGO PRZEZ LACTOBACILLUS ACIDOPHILUS

Background. The aim of the study was to determine the effect of the addition of magnesium glu conate and citrate on the physicochemical properties, the number of bacterial cells and the organoleptic properties of cow’s and goat’s milk fermented by Lactobacillus acidophilus. Results and conclusions. The fortification of milk with magnesium gluconate and citrate had a signif icant effect on the active acidity of milk before fermentation. After the addition of magnesium compounds and repasteurization of processed milk, the pH value of the milk decreased. The addition of magnesium compounds (gluconate and citrate) did not differentiate active acidity in the goat’s milk fermented by Lactobacillus acidophillus LA-5 on the 7th day of cold storage. The opposite relationship was shown for the fermented cow's milk. The content of lactic acid, apart from the magnesium compound used, was also affected by the type of milk used. The fermented goat’s milk was characterized by a higher content of lactic acid compared to the fermented cow’s milk. The addition of gluconate and magnesium citrate in creased the syneresis level of probiotic fermented milk. The highest syneresis was shown in the goat’s milk with magnesium citrate. Enriching milk with magnesium gluconate significantly shaped the color parameters of the resulting fermented milk, which was characterized by a darker color. In all groups, the milk was characterized by the share of yellow and green colors. However, the level of their intensity was significantly different, depending on the type of milk and the magnesium compound used. In the ferment ed goat’s and cow’s milk, the number of Lactobacillus acidophillus LA-5 cells above 8 log CFU∙g-1 was found, which means that the resulting fermented milk meets the criterion for classifying it as a probiotic product.

Using PICRUSt2 to explore the functional potential of bacterial community in alfalfa silage harvested at different growth stages

BackgroundThis study evaluated the effects of growth stage and storage time on fermentation characteristics, bacterial communities and their functionality in alfalfa (Medicago sativa L.) silage. Alfalfa was harvested at initial flowering (10–20% bloom, AL1) and full flowering (> 80% bloom, AL2) stages, respectively. The harvested alfalfa was ensiled in 15 L plastic silos. Triplicate silos were sampled after 1, 3, 7, 15, 30 and 60 days of ensiling, respectively. Fermentation products were analyzed on each sampling day. The bacterial communities and their functional potential after 3 and 60 days were analyzed by high-throughput sequencing technique and PICRUSt2 method.ResultsAL2 had better fermentation quality than AL1 with lower pH, ammonia nitrogen and butyric acid concentrations and higher lactic acid concentrations on day 60. AL2 had higher abundances of Weissella and Lactobacillus after 3 days, and lower abundances of Enterobacter and Enterobacteriaceae on day 60 compared to AL1. In metabolic pathway analysis, ensiling promoted the carbohydrate and amino acid metabolism, and inhibited the signal transduction and membrane transport. In enzyme analysis, AL2 had lower abundances of nitrite reductase (NADH) and ornithine decarboxylase than AL1 on day 60. In phenotype analysis, AL2 had higher proportions of facultatively anaerobic and lower proportions of anaerobic, potentially pathogenic and gram negative than AL1 on day 60.ConclusionsHigh throughput sequencing technique combined with PICRUSt2 can be successfully used to describe the changes of bacterial communities and their functionality in silage. This approach can improve our understanding of the silage microbiology to further regulate the fermentation products.Graphical

Dynamics in fermentation quality, bacterial community, and metabolic profile during silage fermentation of late-harvested elephant grass.

The present study aimed to evaluate the effects of delayed harvest and storage length on fermentation products, bacterial community, and metabolic shifts of elephant grass silage. The late-harvested elephant grass (LG) was naturally fermented (NLG) for 1, 3, 7, 15, 30, and 60 days, respectively. After 60-day ensiling, NLG displayed homolactic fermentation with low pH value, butyric acid, and ammonia nitrogen concentrations, and high lactic acid concentration, and ratio of lactic acid to acetic acid. Pseudomonas, Sphingomonas, and Pantoea dominated the bacterial community in LG, but Lactobacillus, Lactococcus, and Pediococcus were the advantageous genera in a 3-day and 60-day NLG. The correlation heatmap revealed that Acetobacter was positively related to acetic acid, ethanol, ammonia nitrogen, and butyric acid concentrations. There were distinct differences in the KEGG (Kyoto Encyclopedia of Genes and Genomes) metabolic profiles of fresh and ensiled LG. Ensiling suppressed the metabolism of amino acid, vitamins, and energy, while promoted the metabolism of carbohydrate. The LG can be well-fermented without additives, but its low crude protein content should not be ignored when applied in agricultural practice. The ensiling process remarkably affected the fermentation quality, bacterial community, and metabolic profiles of NLG.

Effect of lactobacilli inoculation on protein and carbohydrate fractions, ensiling characteristics and bacterial community of alfalfa silage.

Alfalfa (Medicago sativa L.) silage is one of the major forages with high protein for ruminants. The objective of this study was to investigate the effects of lactobacilli inoculants on protein and carbohydrate fractions, ensiling characteristics and bacterial community of alfalfa silage. Wilted alfalfa (35% dry matter) was inoculated without (control) or with Lactobacillus coryniformis, Lactobacillus casei, Lactobacillus plantarum, and Lactobacillus pentosus and ensiled for 7, 15, and 60 days. Silage inoculated with L. pentosus was superior to L. coryniformis, L. casei, L. plantarum in improving the fermentation quality of alfalfa silage, as indicated by the lowest ammonia nitrogen content and silage pH during ensiling. There was minor difference in water soluble carbohydrates content among all silages, but L. pentosus inoculants was more efficient at using xylose to produce lactic acid, with lower xylose content and higher lactic acid content than the other inoculants. Compared with the control, L. pentosus inoculants did not affect true protein content of silage, but increased the proportions of buffer soluble protein and acid detergent soluble protein. The L. pentosus inoculants reduced the bacterial diversity In alfalfa silage with lower Shannon, Chao1, and Ace indices, and promoted relative abundance of lactobacillus and decreased the relative abundance of Pediococcus compared with the control. As well as L. pentosus inoculants up-regulated amino acid, carbohydrate, energy, terpenoids, and polypeptides metabolism, and promoted lactic acid fermentation process. In summary, the fermentation quality and nutrient preservation of alfalfa silage were efficiently improved by inoculated with L. pentosus.

Dynamics of the fermentation quality and microbiotsa in Ephedra sinica treated native grass silage.

This study aimed to evaluate the effects of Ephedra sinica on physicochemical characteristics and bacterial community of ensiled native grass by multiple physicochemical analyses combined with high-throughput sequencing. Treatments were a control treatment with no additive (CON), E. sinica was added at 1% (CEa1), 3% (CEa2), and 5% of the fresh materials (CEa3). Compared to the CON group, the dry matter and water-soluble carbohydrate contents were significantly (p < 0.05) decreased in the CEa1 group. Compared to the CON group, the pH was significantly (p < 0.05) decreased in E. sinica treated silages, and a higher lactic acid content was observed in E. sinica treated silages. At the genus level, the abundance of Enterococcus, Lactobacillus, Pediococcus, and Weissella were the predominant member in the CON, CEa1, CEa2, and CEa3 groups, respectively. The abundance of Lactobacillus was significantly (p < 0.05) increased in the CEa1 group and Pediococcus was significantly (p < 0.05) increased in the CEa2 group. According to the 16S rRNA gene-predicted functional profiles, the inoculation of E. sinica accelerated the carbohydrate metabolism. In summary, the addition of E. sinica could improve the silage quality of native grass by regulating the bacterial community, and the addition of a 1% percentage of fresh materials exhibited the potential possibility of responding to get high-quality native grass silages. The utilization of herbal additives on fermentation quality combined with 16S rRNA gene-predicted functional analyses will contribute to the direction of future research in improving silage quality.

Statistical optimization of the fermentation factors for increased biorefinery of corn-steep water effluent to lactic acid by Enterococcus faecium strain WH51-1

Organic waste bioprocessing for production of useful products are increasing due to fossil fuel depletion, problems with waste management, and the requirement for biodegradable plastics. Lactic acid (LA) is important in foods, polymer beverages, cosmetics, and medicine applications. However, the main challenge in the large-scale processing of LA is the enhanced production and productivity using low-cost resources. In this study, Enterococcus faecium WH51-1, a newly obtained thermo-alkali tolerant LA bacterium, was used for LA production from corn-steep water (CSW) as raw material. The optimal culture conditions and medium components were established. Different concentrations of yeast extract (YE) and pH values were investigated with highest LA production of 48.2 ± 2.7 g/L at a yield of 0.89 ± 0.04 g/g-consumed sugars and a productivity of 0.50 ± 0.03 g/L.h at pH 8.5 without YE supplementation. A central composite design (CCD) was utilized to determine the high LA concentrations at optimal values for the process variables (sugar concentrations, temperature, inocula sizes, pH value, and YE concentration). The model was realized with an acceptable fit. The optimization of the factors was carried out by normal probability plots, interaction-plots, incorporating effect plots, analysis of variance (ANOVA), surface plots, Pareto charts, and contour plots. All the parameters were influenced at a 5% significance level. Additionally, some of the possible interactions between these parameters also influenced the production process. A regression model was suggested and fitted the experimental data very well. The results of this work investigated that LA synthesized of the optimized-fermentation conditions was 10% greater than classical optimization methods. This study presented a green “free nutrient” and cost-effective utilization of corn steep effluent as a cheap alternative substrate for biorefinery to lactic acid.Graphical

Clean recovery and recycling of seasonal surplus forage grass by microbial driven anaerobic fermentation: a case study of napiergrass

In this study, the anaerobic fermentation technique was conducted to accomplish the clean recycling of surplus napiergrass. The surplus napiergrass harvested at two harvest dates (early vegetative stage, NI; late vegetative stage, NII) was treated as follows: (i) natural fermentation of NI (NNI); (ii) natural fermentation of NII (NNII) and stored for 1, 3, 7, 15, 30 and 60 days. After 60 days of anaerobic fermentation, NNI had higher lactic acid concentration and ratio of lactic to acetic acid, but lower pH value and ammonia–nitrogen concentration than NNII. Lactobacillus and Enterobacter were, respectively, dominant in both 7-day NNI and NNII, while Lactobacillus was the most abundant genus in 30-day NNI and NNII. Both harvest date and store time altered the bacterial co-occurrence networks of fresh and fermented napiergrass. The complexity of the bacterial networks decreased from NII, NI, NNII to NNI. The correlations were primarily positive in the bacterial networks of NI, NII, NNII-7 and NNII-30 with positive correlative proportion of 53.0%, 64.3%, 53.1% and 55.6%, but negative in those of NNI-7 (47.4%) and NNI-30 (46.2%) with positive correlative proportion of 47.4% and 46.2%, respectively. Overall, the fermentation quality and microbial community structure of napiergrass during anaerobic fermentation were highly influenced by harvest date and store time. Based on the principle of stable fermentation and high quality, anaerobic fermentation of NI for at least 15 days is recommended. The in-depth understanding of microbial community dynamics and co-occurrence networks during anaerobic fermentation of napiergrass is important for revealing the fermentation mechanism and can contribute to resource recycling without increasing cost.Graphical

Synergetic Effect of Metschnikowia pulcherrima and Lachancea thermotolerans in Acidification and Aroma Compounds in Airén Wines.

On the one hand, the species Lachancea thermotolerans is known for its high genetic diversity, allowing for the existence of strains that produce high concentrations of lactic acid. In contrast, the species Metschnikowia pulcherrima is renowned for its high enzymatic activity capable of producing aromatic esters during fermentation. By enhancing acidity and boosting the concentration of aromatic compounds, both species are currently used to enhance the organoleptic profile of wines. In this regard, ternary fermentations with M. pulcherrima and L.&amp;nbsp;thermotolerans were carried out and the wines produced were further analysed with GC-FID, FTIR, and UV-Vis spectrophotometry. The outcomes showed that the species M. pulcherrima favored an increase in ethyl lactate (between 37 and 41 mg/L) along with an increased concentration of 2-phenylethyl alcohol (between 30 and 35 mg/L), whereas the species L. thermotolerans was able to produce 1 g/L of lactic acid in ternary fermentations. Additionally, pH levels were slightly lower in these fermentations and the color of the white wines produced showed less chemical oxidation as hue values were lower than the control. Finally, the ternary fermentations of L. thermotolerans and M. pulcherrima had higher overall rating in the tasting. In conclusion, ternary fermentations involving these two non-Saccharomyces species are suggested as a substitute for spontaneous fermentations in the production of wines from neutral varieties to express freshness more vividly. This biotechnology may be further favored by the possibility of applying emerging technologies for the removal of microorganisms in grapes and musts.

High‐intensity ultrasound reduces fermentation time and improves textural properties, antioxidant activity and probiotic survival in fermented probiotic strawberry drink

SummaryThis study aimed to evaluate the effect of high‐intensity ultrasound (HIUS) application with different processing times (2.5, 5, 7.5 and 10 min) on the physicochemical, rheological and textural properties, antioxidant activity (AA) and probiotic survival in strawberry‐flavoured fermented probiotic strawberry drink during storage (7°C for 28 days). The application of HIUS resulted in products with lower fermentation times, higher organic acid stability during storage and improved texture (higher firmness and consistency) and functional properties (higher phenolic compounds content and/or AA). Using 2.5 min of processing time would be advisable due to the better probiotic survival to simulated gastrointestinal conditions (probiotic counts higher than 106 CFU mL−1), reduced fermentation times (reduction in 3 h), higher lactic acid content during storage and enhanced AA. The products showed a viable probiotic counts higher than 106 CFU mL−1 during the entire shelf life. HIUS may be considered as an adequate pre‐treatment in the development of probiotic fermented probiotic strawberry drink.

Microbial community and fermentation characteristic of whole-crop wheat silage treated by lactic acid bacteria and Artemisia argyi during ensiling and aerobic exposure.

Whole-crop wheat silage (WCWS) is an excellent feed material for ruminants. However, microbial fermentation during silage production consumes valuable nutrients, decreasing the quality of silage. The main objective of this study was to assess how the addition of increasing amounts of Artemisia argyi (AA) affected fermentation quality, microbial composition, and mycotoxin production in whole-crop wheat at dough stage (WCWD) silage during ensiling to aerobic exposure compared with Lactiplantibacillus buchneri (LB). The addition of 20% AA, resulted in a lower pH and higher lactic acid content, was found in silage treated with 20% AA, and an obvious increase in the relative abundance of Lactobacillus was detected in silages treated with LB and 20% AA, respectively. Meanwhile, inoculation with 20% AA decreased the abundance of harmful microorganisms, including Acinetobacter, Enterobacter, and Aspergillus. It also reduced the contents of mycotoxins, Aflatoxin B1 (AFB1), and deoxynivalenol (DON) during ensiling and aerobic exposure. These results confirmed that WCWD treated with 20% AA could improve the fermentation quality and enhance the aerobic stability of silage.

Effects of developmental stage and store time on the microbial community and fermentation quality of sweet sorghum silage

This study investigated the effects of developmental stage and store time on the chemical composition, microbial community, co-occurrence networks and fermentation characteristics of sweet sorghum silage. Sweet sorghum harvested at two developmental stages (heading stage, S1; hard dough stage, S2) was treated as follows: (I) natural fermentation of S1 (NS1); (II) natural fermentation of S2 (NS2) and ensiled for 1, 3, 7, 15, 30 and 60 days. After 60 days of ensiling, NS2 silage had higher lactic acid concentration and the ratio of lactic to acetic acid, and lower pH value and acetic acid concentration than NS1 silage. Meanwhile, NS2 silage also had higher ammonia nitrogen (NH3-N) content than NS1 silage, but the NH3-N content of both treatments was lower than 100 g/kg TN. Leuconostoc and Lactococcus were respectively dominant in both 7-day NS1 and NS2 silages, while Lactobacillus was the most abundant genus in 30-day NS1 and NS2 silages. The developmental stage altered the bacterial co-occurrence networks of fresh and ensiled sweet sorghum. Spearman’s correlation heatmap showed that the higher lactic acid content and ratio of lactic to acetic acid in NS2 silage could be associated with the higher water-soluble carbohydrate content in S2 material, the higher abundance of Lactococcus in the initial phase of ensiling and the higher abundance of Lactobacillus in the late phase of ensiling. These results concluded that the sweet sorghum harvested at the hard dough stage is preferred for silage production over the sweet sorghum harvested at the heading stage. HIGHLIGHTS Microbial succession pattern was studied on fresh and ensiled samples. Growth stage affected the chemical and microbial parameters of sweet sorghum. Epiphytic microbiota was correlated with the chemical composition of forage. Metagenomic sequencing showed Lactobacillus was dominated in all silages. Growth stage accelerated the fermentation of sweet sorghum silage.

The effects of epiphytic microbiota and chemical composition of Italian ryegrass harvested at different growth stages on silage fermentation.

The influence of epiphytic microbiota and chemical composition on fermentation quality and microbial community of Italian ryegrass silage was evaluated. Italian ryegrass harvested at the filling stage (FS) and the dough stage (DS) was sterilized by gamma-ray irradiation and inoculated as follows: (I) FS epiphytic microbiota + irradiated FS (FF); (II) FS epiphytic microbiota + irradiated DS (FD); (III) DS epiphytic microbiota + irradiated DS (DD); (IV) DS epiphytic microbiota + irradiated FS (DF). After 60 days of ensiling, silage made from irradiated FS had a lower pH and ammonia nitrogen (NH3 -N) content and a higher lactic acid (LA) content than that made from irradiated DS. Similarly, silage inoculated with the epiphytic microbiota of DS had a lower pH and NH3 -N content and a higher LA content than that inoculated with the epiphytic microbiota of FS. However, LA-type fermentation (lactic acid:acetic acid > 2:1) was presented at DF and DD. The principal coordinates analysis showed that the distance between FF and DF and FD and DD was closer than other treatments, suggesting that the microbial community of silages made from irradiated FS (or DS) was more similar. The epiphytic microbiota played a more important role in the fermentation type, whereas the chemical composition had a great influence on the contents of fermentation end-products. However, chemical composition had a stronger effect on the microbial community of silage than the epiphytic microbiota. © 2022 Society of Chemical Industry.