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Journal ArticleDOI: 10.1016/J.BIORTECH.2021.124915

Altering bacterial community: A possible way of lactic acid bacteria inoculants reducing CO2 production and nutrient loss during fermentation

02 Mar 2021-Bioresource Technology (Elsevier)-Vol. 329, pp 124915-124915
Abstract: CO2 production during ensiling is a source of greenhouse gases emissions and a cause of nutrient loss of silage. To investigate the influence of additives on CO2 production and relevant bacterial communities, stylo and rice straw were ensiled with sucrose and Lactobacillus plantarum (LP). After 30 days fermentation, LP reduced CO2 production (from 66.2 to 0 mL/100 g fresh matter in stylo, from 83.7 to 16.6 mL/100 g fresh matter in rice straw) and weight loss (from 2.71 to 1.72% in stylo, from 2.75 to 2.40% in rice straw). CO2 production was positively correlated (P

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Topics: Silage (55%), Fermentation (54%), Lactobacillus plantarum (54%) ... show more
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Open accessJournal ArticleDOI: 10.1186/S12866-021-02213-2
Duo Wen Sa1, Lu Qiang1, Zhen Wang, Gentu Ge1  +2 moreInstitutions (1)
19 May 2021-BMC Microbiology
Abstract: The objective of this study was to evaluate the chemical compositions and microbial communities of salt-tolerant alfalfa silage. Salt-tolerant alfalfa was ensiled with no additive control, and cellulase for 30 and 60 to 90 days. In this study, the dry matter (DM) content of the raw material was 29.9% DM, and the crude protein (CP) content of the alfalfa was 21.9% CP. After 30 days of fermentation, the DM content with the cellulase treatment was reduced by 3.6%, and the CP content was reduced by 12.7%. After 60 days of fermentation, compared with alfalfa raw material, the DM content in the control group (CK) was reduced by 1%, the CP content was reduced by 9.5%, and the WSC (water-soluble carbohydrates) content was reduced by 22.6%. With the cellulase, the lactic acid content of the 30- and 60-day silages was 2.66% DM and 3.48% DM. The content of Firmicutes in salinized alfalfa raw material was less than 0.1% of the total bacterial content. Before and after ensiling, the microbes had similar composition at the phylum level, and were composed of Firmicutes, Actinobacteria, Bacteroidetes, and Proteobacteria. The abundance of Pantoea was dominant in fresh alfalfa. In the absence of additives, after 30 days and 60 days of silage, the dominant lactic acid bacteria species became Lactococcus and Enterococcus. The results showed that LAB (Lactobacillus, Lactococcus, Enterococcus, and Pediococcus) played a major role in the fermentation of saline alfalfa silage. It also can better preserve the nutrients of saline alfalfa silage. The use of cellulase enhances the reproduction of Lactobacillus. The fermentation time would also change the microbial community of silage fermentation.

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Topics: Silage (57%), Fermentation (54%), Cellulase (52%) ... show more

3 Citations


Journal ArticleDOI: 10.1016/J.ANIFEEDSCI.2021.115082
Jie Zhao1, Xuejing Yin1, Siran Wang1, Junfeng Li1  +1 moreInstitutions (1)
Abstract: This study aimed to separate the effects of chemical composition and epiphytic microflora on the fermentation quality and bacterial community of Napier grass silage. Napier grass was harvested in two vegetative stages (Early, EG; Late, LG) with 24 or 28% dry matter, cut into theoretical lengths of 2–3 cm, and ensiled in bag-type silos containing 450 g fresh matter for 30 d. A 2 × 2 factorial arrangement of treatments (2 chemical composition × 2 epiphytic microbiota) in a completely randomized design were as follows: EG epiphytic microbiota + gamma-ray irradiated EG (EMEG), LG epiphytic microbiota + gamma-ray irradiated EG (LMEG), EG epiphytic microbiota + gamma-ray irradiated LG (EMLG), and LG epiphytic microbiota + gamma-ray irradiated LG (LMLG). Triplicates per treatment were sampled after 30 d of ensiling for fermentation quality and bacterial community analyses. The maturity of Napier grass had a great impact on its chemical composition and epiphytic microflora at harvest. Silages made from irradiated EG (EMEG and LMEG) had higher lactic acid concentration and lactic:acetic acid ratio, and lower pH value and ammonia nitrogen (NH3-N) concentration than the silages made from irradiated LG (EMLG and LMLG). Species differential analyses showed that the chemical composition variation significantly affected the relative abundance of Lactobacillus, Lactococcus, Enterobacter, Serratia, unclassified Lactobacillales, Leuconostoc and Pediococcus in EMEG and EMLG silages. While there was no effect of epiphytic microbial variation on the relative abundance of bacterial genera in EMLG and LMLG silages. These results manifested that, in this study, chemical composition rather than epiphytic microflora affected the succession of bacterial community in Napier grass silages, thereby affecting the final fermentation quality.

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Topics: Silage (52%)

Journal ArticleDOI: 10.1016/J.ANIFEEDSCI.2021.114998
Qing Zhang1, Xiang Guo1, Mingyang Zheng1, Dekui Chen1  +1 moreInstitutions (1)
Abstract: Silage is traditionally and globally used as an important feed source for ruminants. The smell of silage affects not only feed intake of animals but also the milk flavor and quality. Stylo and rice straw were ensiled with or without a Lactobacillus plantarum strain (LP) for 30 days. Microbial communities were detected by Illumina HiSeq sequencing method and volatile chemicals for the smell features were also analyzed using a metabolomics approach. The addition of LP decreased (P

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Topics: Lactobacillus plantarum (57%), Silage (56%), Microbial inoculant (54%)

Journal ArticleDOI: 10.1016/J.JHAZMAT.2021.127627
Cheng Zong1, Qifeng Wu1, Zhihao Dong1, Aili Wu1  +3 moreInstitutions (1)
Abstract: Silage, an important forage feed, contains hazardous mycotoxins due to spoilage caused by unreasonable management. Deteriorated silage becomes a mycotoxin source and threatens human health and the eco-environment. Recycling deteriorated silage and exploiting beneficial substances would be profitable and environmentally friendly. Squalene [60.3–73.9 mg/kg fresh matter (FM)] and 6 types of mycotoxins (4.56–10,080 ug/kg FM) were found in deteriorated silages. To clarify the source and synthesis mechanism of squalene, alfalfa was ensiled at low temperature (LT, 3–20 ℃), 25 ℃ (T25), 30 ℃ (T30) or 35 ℃ (T35) for 10, 40 and 70 d. The highest squalene was detected when alfalfa ensiled for 40 d (P = 0.033) or ensiled at LT and T30 (P

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Topics: Silage (52%), Forage (51%)

Journal ArticleDOI: 10.1016/J.BIORTECH.2021.125928
Hui Sun1, Xian Cui1, Xian Cui2, Rangling Li1  +2 moreInstitutions (2)
Abstract: Ensiling has been developed as mainstream technologies to preserve lignocellulose biomass for biogas production. However, the lack of general evaluation methods and process mechanism research hinders the understanding of its effectiveness. In this context, we reviewed existing studies and proposed some key considerations: (1) For assessing the ensiling process, determined dry matter contents should be corrected according to the volatilization loss in oven-drying method to obtain accurate storage loss and methane yield; (2) For comprehensive assessments, the trade-off between storage loss and enhanced biomethane yield should be evaluated from the entire-chain process; (3) The mechanism to enhance methane yield is primarily attributed to increased lignocellulosic biodigestibility through acid-based hydrolysis and biological degradation during ensiling; (4) Measures including co-storage, increasing buffering capacity, adjusting carbon/nitrogen ratio, and additives can be adopted to increase biogas production. The proposed methods, mechanisms, and measures (3Ms) could help initiate the specific quality criteria of biogas-oriented silages.

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Topics: Biogas (53%), Biomass (51%)

References
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38 results found


Open accessBook
01 Jan 1981-
Abstract: When THE BIOCHEMISTRY OF SILAGE was first published in 1981, it was immediately recognised as an outstanding guide to the subject. Now, a decade later, silage is even more important as a feed for cattle and sheep. It is therefore timely that the book has been completely updated by Dr McDonald and his former colleagues at the Edinburgh School of Agriculture, Dr Henderson and Dr Heron.The emphasis on the microbiology of silage has been strengthened in this second edition, and rightly so. Silage research has developed from understanding the basic biochemical processes and is now focused on the interactions between the different microorganisms and their influence on the pattern of fermentation in the silo.THE BIOCHEMISTRY OF SILAGE, SECOND EDITION is an important contribution to our understanding of the ensiling process and of silage as an animal feed, and thus is an invaluable and comprehensive source of information for students, teachers, research workers and advisers.

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Topics: Silage (51%)

2,034 Citations


Open accessJournal ArticleDOI: 10.1111/J.1574-6976.1996.TB00253.X
Z. G. Weinberg, Richard E. Muck1Institutions (1)
Abstract: Inoculants are used as silage additives to improve preservation efficiency and to enhance animal performance. In most commercially available inoculants, homofermentative lactic acid bacteria (LAB) have been used because they are fast and efficient producers of lactic acid, improving natural silage fermentation. Specific LAB inuculants may also have beneficial effects on animal performance even if there is no effect on fermentation. However, these types of inoculants are not always advantageous. They do not necessarily prevent sermentation by clostridia in moist silages, and they sometimes impair the aerobic stability of grass and small grain silages. Therefore, new criteria for silage inoculants should be established which consider the specific needs of the crop being ensiled. New approaches which are being taken to develop improved inoculants for silage include the following: (1) using LAB isolates which are more specific to the target crops; (2) inclusion of heterofermentative LAB to produce volatile fatty acids to inhibit yeasts and moulds upon aerobic exposure; (3) inclusion of organisms other than LAB in inoculants to inhibit detrimental microorganisms; (4) selection or engineering of LAB strains to inhibit specific microorganisms; and (5) cloning and expression of genes which would enable selected LAB strains to utilize polysaccharides in crops which are low in soluble carbohydrates. Many of these new strategies for formulating inoculants are being tested, but further research is needed to determine the most successful approaches.

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Topics: Microbial inoculant (60%), Silage (51%), Lactobacillus buchneri (51%)

416 Citations


Book ChapterDOI: 10.2134/AGRONMONOGR42.C2
01 Jan 2003-

415 Citations


Open accessJournal ArticleDOI: 10.3168/JDS.2017-13839
Abstract: Additives have been available for enhancing silage preservation for decades. This review covers research studies published since 2000 that have investigated the efficacy of silage additives. The review has been divided into 6 categories of additives: homofermentative lactic acid bacteria (LAB), obligate heterofermentative LAB, combination inoculants containing obligate heterofermentative LAB plus homofermentative LAB, other inoculants, chemicals, and enzymes. The homofermentative LAB rapidly decrease pH and increase lactic acid relative to other fermentation products, although a meta-analysis indicated no reduction in pH in corn, sorghum, and sugarcane silages relative to untreated silages. These additives resulted in higher milk production according to the meta-analysis by mechanisms that are still unclear. Lactobacillus buchneri is the dominant species used in obligate heterofermentative LAB silage additives. It slowly converts lactic acid to acetic acid and 1,2-propanediol during silo storage, improving aerobic stability while having no effect on animal productivity. Current research is focused on finding other species in the Lb. buchneri group capable of producing more rapid improvements in aerobic stability. Combination inoculants aim to provide the aerobic stability benefits of Lb. buchneri with the silage fermentation efficiency and animal productivity benefits of homofermentative LAB. Research indicates that these products are improving aerobic stability, but feeding studies are not yet sufficient to make conclusions about effects on animal performance. Novel non-LAB species have been studied as potential silage inoculants. Streptococcus bovis is a potential starter species within a homofermentative LAB inoculant. Propionibacterium and Bacillus species offer improved aerobic stability in some cases. Some yeast research has focused on inhibiting molds and other detrimental silage microorganisms, whereas other yeast research suggests that it may be possible to apply a direct-fed microbial strain at ensiling, have it survive ensiling, and multiply during feed out. Chemical additives traditionally have fallen in 2 groups. Formic acid causes direct acidification, suppressing clostridia and other undesired bacteria and improving protein preservation during ensiling. On the other hand, sorbic, benzoic, propionic, and acetic acids improve silage aerobic stability at feed out through direct inhibition of yeasts and molds. Current research has focused on various combinations of these chemicals to improve both aerobic stability and animal productivity. Enzyme additives have been added to forage primarily to breakdown plant cell walls at ensiling to improve silage fermentation by providing sugars for the LAB and to enhance the nutritive value of silage by increasing the digestibility of cell walls. Cellulase or hemicellulase mixtures have been more successful at the former than the latter. A new approach focused on Lb. buchneri producing ferulic acid esterase has also had mixed success in improving the efficiency of silage digestion. Another new enzyme approach is the application of proteases to corn silage to improve starch digestibility, but more research is needed to determine the feasibility. Future silage additives are expected to directly inhibit clostridia and other detrimental microorganisms, mitigate high mycotoxin levels on harvested forages during ensiling, enhance aerobic stability, improve cell wall digestibility, increase the efficiency of utilization of silage nitrogen by cattle, and increase the availability of starch to cattle.

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Topics: Lactobacillus buchneri (65%), Silage (59%), Fermentation (52%) ... show more

222 Citations


Journal ArticleDOI: 10.1016/S0360-3199(03)00024-7
Abstract: A newly isolated Citrobacter sp. Y19 for CO-dependent H 2 production was studied for its capability of fermentative H 2 production in batch cultivation. When glucose was used as carbon source, the pH of the culture medium significantly decreased as fermentation proceeded and H 2 production was seriously inhibited. The use of fortified phosphate at 60– 180 mM alleviated this inhibition. By increasing culture temperatures (25–36°C), faster cell growth and higher initial H 2 production rates were observed but final H 2 production and yield were almost constant irrespective of temperature. Optimal specific H 2 production activity was observed at 36°C and pH 6–7. The increase of glucose concentration (1– 20 g/l ) in the culture medium resulted in higher H 2 production, but the yield of H 2 production (mol H 2 /mol glucose) gradually decreased with increasing glucose concentration. Carbon mass balance showed that, in addition to cell mass, ethanol, acetate and CO 2 were the major fermentation products and comprised more than 70% of the carbon consumed. The maximal H 2 yield and H 2 production rate were estimated to be 2.49 mol H 2 / mol glucose and 32.3 mmol H 2 / g cell h , respectively. The overall performance of Y19 in fermentative H 2 production is quite similar to that of most H 2 -producing bacteria previously studied, especially to that of Rhodopseudomonas palustris P4, and this indicates that the attempt to find an outstanding bacterial strain for fermentative H 2 production might be very difficult if not impossible.

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Topics: Fermentation (52%)

220 Citations