A stable and flexible Au@Ag NPs/PVA SERS platform for thiram residue detection on rough surface.

Flexible and transparent surface-enhanced Raman scattering (SERS) substrates have gained great attention in analysis field as they offer a fast, non-destructive, and highly sensitive platform for in-situ detection. In this work, we present a facile one-pot strategy for synthesizing gold-cored silver shell nanoparticles (Au@Ag NPs) in the polyvinyl alcohol (PVA) colloid. With no other reducing agents, PVA can serve as both reducing and stabilizing agents for forming Au@Ag NPs. Besides, PVA acts as a scaffold to maintain SERS "hot-spots" by preventing nanoparticle aggregation. By using this flexible Au@Ag NPs/PVA colloid, the analytes can be extracted from rough surfaces for SERS measurements with excellent sensitivity, repeatability and stability. The SERS activity of the Au@Ag NPs/PVA remained at 89.8% even after 120 days of storage at room temperature in sealed air atmosphere. The selective detection of thiram residues on the surface of fruits and vegetables was successfully achieved. The limits of detection for thiram residues on apple and tomato surfaces were measured to be 0.58 and 0.56 ng cm-2, respectively, with recovery rate ranging from 91% to 107%. This work demonstrates the immense application potential of SERS colloid platform in the fields of food safety and environmental analysis.

Improving Charge Storage of Biaxially-Oriented Polypropylene under Extreme Electric Fields by Excimer UV Irradiation.

Biaxially-oriented polypropylene (BOPP) is one of the most commonly used materials for film-based capacitors for power electronics and pulsed power systems. To address the pressing issue of performance-limiting loss under extreme electric-fields, here a one-step, high-throughput, and environment-friendly process based on very low-dose ultra-violet irradiation from KrCl (222 nm) and Xe2 (172 nm) excimer is demonstrated. The performance of commercial BOPP is boosted in terms of withstanding electric-field extremes (Weibull breakdown strength 694 to 811 V µm-1 by 17% at 25 °C and 428 to 651 V µm-1 by 52% at 120 °C), discharged energy density, and conduction losses. Importantly, the depth profile of space charge is precisely measured in situ with a high resolution of 500 nm by laser induced pressure pulse. Consequently, the space charge effect and electric-field distortion are reduced and related to the improved polymer films. It is demonstrated that energetic UV photons act as scissors for BOPP chains and dissociate oxygen molecules leading to the more thermally stable oxygen-containing structures, as deep traps to impede charge migration. This work provides a promising approach to produce polymers with customized microscopic characteristics that is compatible with the assembly lines of polymer-based capacitors.

Current trends and prospects of surgical techniques for hepatoblastoma.

Hepatoblastoma, a common extracranial malignant solid tumor in childhood, is often detected at an advanced stage and is difficult to treat surgically. Despite the availability of multiple comprehensive treatments that can be combined with surgery, hepatoblastoma treatment outcomes remain poor. Surgery is the main treatment strategy for hepatoblastoma, but it faces many challenges, including tumor attachment to surrounding tissues, tumor wrapping or invading of vital organs and tissues, the presence of giant or multiple tumors, distant metastasis, the formation of a tumor thrombus, and significant surgical trauma. In this review, we discuss recent research advances and propose potential strategies for overcoming these challenges. Such strategies may improve the rate of hepatoblastoma resection and local control in children, as well as reduce complications and trauma.

Comparison of robotic versus thoracoscopic repair for congenital esophageal atresia: a propensity score matching analysis.

BACKGROUND: Despite the rapid advancement of robotic surgery across various surgical domains, only cases of robotic repair (RR) for neonates with esophageal atresia (EA) have been reported. Comprehensive studies comparing RR and thoracoscopic repair (TR) are lacking. The authors aimed to compare the safety and efficacy of RR and TR for EA. METHODS: A retrospective multicenter study was conducted on 155 EA neonates undergoing RR (79 patients) or TR (76 patients) between August 2020 and February 2023 using propensity score matching. Asymmetric port distribution and step-trocar insertion techniques were applied during RR. Demographics and surgical outcomes were compared. RESULTS: After matching, 63 patients (out of 79) in RR group and 63 patients (out of 76) in TR group were included. There were no significant differences in short-term outcomes between two groups, except for longer total operative time (173.81 vs. 160.54 min; P <0.001) and shorter anastomotic time (29.52 vs. 40.21 min; P <0.001) in RR group. Compared with TR group, the RR group had older age at surgery (8.00 vs. 3.00 days; P <0.001), but a comparable pneumonia rate. More importantly, the incidence of anastomotic leakage (4.76 vs. 19.05%, P =0.013), anastomotic stricture (15.87 vs. 31.74%, P =0.036) within 1 year postoperatively, and unplanned readmission (32.26 vs. 60.00%, P =0.030) within 2 years postoperatively were lower in RR group than in TR group. CONCLUSIONS: RR is a technically safe and effective option for EA patients. This approach delays the age of surgery without increasing respiratory complication rates while reducing the incidence of postoperative anastomotic complications and unplanned readmission.

PPM Ir-f-phamidol-Catalyzed Asymmetric Hydrogenation of γ-Amino Ketones Followed by Stereoselective Cyclization for Construction of Chiral 2-Aryl-pyrrolidine Pharmacophores.

Transition metal catalysts with a million turnovers and excellent selectivity are rarely reported but are crucial for the industrial manufacture of optical pure pharmaceuticals, natural products, and fine chemicals. In this paper, we report an unprecedented aninoic Ir-f-phamidol catalyst for asymmetric hydrogenation of γ-amino ketones followed by stereoselective cyclization for construction of valuable chiral 2-aryl-pyrrolidine pharmacophores. The Ir-f-phamidol catalyst showed up to 1,000,000 TON and >99% ee, as well as excellent tolerance of substrates and protecting groups, providing various chiral amino alcohol intermediates. Upon optimization of the conditions, the stereoselective cyclization reaction was highly smooth and efficient (quantitative conversions, 92 to >99% ee). Finally, this solution was applied in the preparation of high-value chiral entities containing such chiral 2-aryl-pyrrolidine pharmacophores.

Robotic-Assisted Proctosigmoidectomy vs. Laparoscopic-Assisted Soave Pull-Through for Hirschsprung's Disease: Medium-Term Outcomes From a Prospective Multicenter Study.

OBJECTIVE: To compare the surgical outcomes of robotic-assisted proctosigmoidectomy (RAP) and laparoscopic-assisted Soave pull-through (LAP) for children with Hirschsprung's disease (HD). SUMMARY BACKGROUND DATA: LAP and RAP have been developed for minimally invasive pull-through of HD, but the clinical benefits of robotic-assisted versus laparoscopic-assisted approaches have yet to be proven in a multicenter prospective study. METHODS: This study was a prospective multicenter clinical trial conducted on children with rectosigmoid/descending HD from July 2015 to June 2022, with registration in the Chinese Clinical Trial Registry (ChiCTR2000035220). The primary outcome was the medium-term functional outcomes in children aged ≥4 years based on bowel functional scores, which were assessed and compared between LAP and RAP. RESULTS: A total of 328 consecutive patients (RAP=165, LAP=163) were approached who were considered eligible for elective minimally invasive endorectal pull-through, and 219 patients aged ≥4 years of age completed follow-up (RAP=109, LAP=110). The transanal dissection length and anal traction time were significantly shorter in RAP than those in LAP (0.30 cm vs. 3.70 cm, P <0.001; 45 min vs. 62 min, P <0.001). The RAP group had significantly lower urinary retention rate (0% vs. 5.52%, P=0.006), while other short-term results between two groups were not significantly different. The medium-term overall BFS scores were comparable between two groups; however, among the subgroup of children aged ≤ 3 months at surgery, the RAP group had better anal canal resting pressure at one year postoperatively and amounted to better annual POFC scores at 4-7 years old postoperatively (all P <0.05). CONCLUSIONS: RAP and LAP should have similar medium-term bowel functional outcomes in HD children, but RAP may be associated with a slight functional benefit in infants operated on below age 3 months, requiring further investigation in larger case cohorts.

Enhancement of the phase sensitivity with two-mode squeezed coherent state based on a Mach-Zehnder interferometer.

We theoretically study the phase estimation based on a Mach-Zehnder interferometer (MZI) with a two-mode squeezed coherent state. By maximizing the quantum Fisher information, we find that the quantum Cramér-Rao bounds (QCRB) can reach sub-Heisenberg limit under the phase-matched condition. The optimal phase sensitivity can reach the sub-shot noise limit (SNL) and approach the QCRB by employing the intensity difference detection. Meanwhile, compared with the MZI fed with a coherent plus a single-mode squeezed vacuum state, this scheme can have better performance by adjusting the squeezing parameter and the mean photon number. With the same parameter, our scheme shows more sensitive phase measurement than the SU(1,1) interferometer with a coherent plus a vacuum state. We also show that the phase sensitivity of our proposal can still reach the SNL when the loss of the photon is 36%. This scheme can provide potential applications in optical sensors.

Alfalfa as a vegetable source of ß-carotene: The change mechanism of ß-carotene during fermentation.

The objectives of this study were to explore the ß-carotene-producing bacteria and ascertain the main factors affecting ß-carotene content via investigating the effects of various additives on ß-carotene content, bacterial community succession, and quality of fermented alfalfa, using single-molecule real-time (SMRT) sequencing technology. Fresh alfalfa was fermented without (CON) or with squalene (SQ), the combination of Lactobacillus plantarum and cellulase (LPEN), and the combination of SQ and LPEN (SQLPEN) for 3, 45, and 90 d. The results showed that relative to the fresh alfalfa, extensive ß-carotene loss in all groups occurred in the early fermentation phase (3 d) since epiphytic Pantoea agglomerans with the ability to produce ß-carotene disappeared and ß-carotene was oxidized by lipoxygenase and peroxidase. With the prolonged fermentation days, ß-carotene content in all groups increased due to bacterial community succession in the middle and late phases of fermentation (45 and 90 d). The species L. parabuchneri, L. kunkeei, and L. kullabergensis (r = 0.591, 0.366, 0.341, orderly) had positive correlations with ß-carotene content (P < 0.05). Bacterial functional potential prediction showed that species L. kunkeei, L. helsingborgensis, and L. kullabergensis had positive (r = 0.478, 0.765, 0.601) correlations with C10-C20 isoprenoid biosynthesis (P < 0.01), and L. helsingborgensis and L. kullabergensis had positive (r = 0.805, 0.522) correlations with ß-carotene biosynthesis (P < 0.01). Additionally, the pH and propionic acid (r = -0.567, -0.504) had negative correlations with ß-carotene content (P < 0.01). The CON group was preserved well after 90 d, LPEN and SQLPEN further improved fermentation quality. In conclusion, certain Lactobacillus had the potential for ß-carotene biosynthesis, and high pH and propionic acid content were the unbenefited factors for ß-carotene retention in fermented alfalfa.

Dynamics associated with fermentation and aerobic deterioration of high-moisture Italian ryegrass silage made using Lactobacillus plantarum and caproic acid.

AIMS: To determine the fermentation quality, aerobic stability, and chemical composition of Italian ryegrass silage prepared with Lactobacillus plantarum (LP), caproic acid (CA), and their combination during ensiling and feed-out phase. METHODS AND RESULTS: Six treatments: control (CON), LP, 0.15% caproic acid (LCA), 0.2% caproic acid (HCA), LCA + LP, and HCA + LP were employed for 30 days ensiling and an 8-days aerobic stability test. LP had similar pH value and lactic acid content with LCA + LP, while the contents of NH3-N and total VFAs in LCA + LP were significantly lower than those in LP and CON, and the fermentation quality of LCA + LP performed best among all silages. As air-exposure extended, contents of water-soluble carbohydrates (WSC), lactic, and acetic acids decreased, while pH, and NH3-N content increased significantly. The population of lactic acid bacteria gradually decreased in contrast to increased counts of aerobic bacteria and yeasts. Compared with LCA, 0.2% CA delayed the aerobic deterioration as judged by a slower increase in pH and high residual of WSC and lactic acid, and negligible ethanol content and anaerobe spores counts remained in HCA at the end of air exposure. Compared with CON (73 h), LP showed less aerobic stability (38 h), whereas HCA and HCA + LP prolonged aerobic stability for 210 and 152 h, better than LCA (109 h) and LCA + LP (146 h). CONCLUSIONS: Lactobacillus plantarum apparently improved the fermentation quality, and combined with CA exhibited greater efficiency in inhibiting undesirable microorganism during ensiling. CA at 0.2% optimally extended the aerobic stability.

Robotic-assisted proctosigmoidectomy for Hirschsprung's disease: A multicenter prospective study.

BACKGROUND: Robotic surgery is a cutting-edge minimally invasive technique that overcomes many shortcomings of laparoscopic techniques, yet few studies have evaluated the use of robotic surgery to treat Hirschsprung's disease (HSCR). AIM: To analyze the feasibility and medium-term outcomes of robotic-assisted proctosigmoidectomy (RAPS) with sphincter- and nerve-sparing surgery in HSCR patients. METHODS: From July 2015 to January 2022, 156 rectosigmoid HSCR patients were enrolled in this multicenter prospective study. Their sphincters and nerves were spared by dissecting the rectum completely from the pelvic cavity outside the longitudinal muscle of the rectum and then performing transanal Soave pull-through procedures. Surgical outcomes and continence function were analyzed. RESULTS: No conversions or intraoperative complications occurred. The median age at surgery was 9.50 months, and the length of the removed bowel was 15.50 ± 5.23 cm. The total operation time, console time, and anal traction time were 155.22 ± 16.77, 58.01 ± 7.71, and 45.28 ± 8.15 min. There were 25 complications within 30 d and 48 post-30-d complications. For children aged ≥ 4 years, the bowel function score (BFS) was 17.32 ± 2.63, and 90.91% of patients showed moderate-to-good bowel function. The postoperative fecal continence (POFC) score was 10.95 ± 1.04 at 4 years of age, 11.48 ± 0.72 at 5 years of age, and 11.94 ± 0.81 at 6 years of age, showing a promising annual trend. There were no significant differences in postoperative complications, BFS, and POFC scores related to age at surgery being ≤ 3 mo or > 3 mo. CONCLUSION: RAPS is a safe and effective alternative for treating HSCR in children of all ages; it offers the advantage of further minimizing damage to sphincters and perirectal nerves and thus providing better continence function.

Ru-Catalyzed Asymmetric Reductive Amination of Aryl-Trifluoromethyl Ketones for Synthesis of Primary α-(Trifluoromethyl)arylmethylamines.

The ruthenium-catalyzed asymmetric reductive amination of aryl-trifluoromethyl ketones affording high value primary α-(trifluoromethyl)arylmethylamines using cheap NH4OAc as the nitrogen source and H2 as the reductant is reported. This user-friendly and simple catalytic method tolerates various aromatic functions with electron-withdrawing or -donating substituents at the para- or meta-positions and as well challenging heteroaromatic functions, yielding primary α-(trifluoromethyl)arylmethylamines with excellent chemoselectivities, enantioselectivities, and useful yields (80-97% ee, 51-92% isolated yields). Finally, scalable and concise synthesis of key drug intermediates using this methodology is presented.

Deep-Growing Neural Network With Manifold Constraints for Hyperspectral Image Classification.

In the absence of sufficient labels, deep neural networks (DNNs) are prone to overfitting, resulting in poor performance and difficulty in training. Thus, many semisupervised methods aim to use unlabeled sample information to compensate for the lack of label quantity. However, as the available pseudolabels increase, the fixed structure of traditional models has difficulty in matching them, limiting their effectiveness. Therefore, a deep-growing neural network with manifold constraints (DGNN-MC) is proposed. It can deepen the corresponding network structure with the expansion of a high-quality pseudolabel pool and preserve the local structure between the original and high-dimensional data in semisupervised learning. First, the framework filters the output of the shallow network to obtain pseudolabeled samples with high confidence and adds them to the original training set to form a new pseudolabeled training set. Second, according to the size of the new training set, it increases the depth of the layers to obtain a deeper network and conducts the training. Finally, it obtains new pseudolabeled samples and deepens the layers again until the network growth is completed. The growing model proposed in this article can be applied to other multilayer networks, as their depth can be transformed. Taking HSI classification as an example, a natural semisupervised problem, the experimental results demonstrate the superiority and effectiveness of our method, which can mine more reliable information for better utilization and fully balance the growing amount of labeled data and network learning ability.

Detection of sulfur mustard simulants using the microwave atmospheric pressure plasma optical emission spectroscopy method.

Sulfur mustard (SM) is one kind of highly toxic chemical warfare agent and easy to spread, while existing detection methods cannot fulfill the requirement of rapid response, good portability, and cost competitiveness at the same time. In this work, the microwave atmospheric pressure plasma optical emission spectroscopy (MW-APP-OES) method, taking the advantage of non-thermal equilibrium, high reactivity, and high purity of MW plasma, is developed to detect three kinds of SM simulants, i.e., 2-chloroethyl ethyl sulfide, dipropyl disulfide, and ethanethiol. Characteristic OES from both atom lines (C I and Cl I) and radical bands (CS, CH, and C2) is identified, confirming MW-APP-OES can preserve more information about target agents without full atomization. Gas flow rate and MW power are optimized to achieve the best analytical results. Good linearity is obtained from the calibration curve for the CS band (linear coefficients R 2 > 0.995) over a wide range of concentrations, and a limit of detection down to sub-ppm is achieved with response time on the order of second. With SM simulants as examples, the analytical results in this work indicate that MW-APP-OES is a promising method for real-time and in-site detection of chemical warfare agents.

Acceptor Engineering Produces Ultrafast Nonradiative Decay in NIR-II Aza-BODIPY Nanoparticles for Efficient Osteosarcoma Photothermal Therapy via Concurrent Apoptosis and Pyroptosis.

Small-molecule photothermal agents (PTAs) with intense second near-infrared (NIR-II, 1,000 to 1,700 nm) absorption and high photothermal conversion efficiencies (PCEs) are promising candidates for treating deep-seated tumors such as osteosarcoma. To date, the development of small-molecule NIR-II PTAs has largely relied on fabricating donor-acceptor-donor (D-A-D/D') structures and limited success has been achieved. Herein, through acceptor engineering, a donor-acceptor-acceptor (D-A-A')-structured NIR-II aza-boron-dipyrromethene (aza-BODIPY) PTA (SW8) was readily developed for the 1,064-nm laser-mediated phototheranostic treatment of osteosarcoma. Changing the donor groups to acceptor groups produced remarkable red-shifts of absorption maximums from first near-infrared (NIR-I) regions (~808 nm) to NIR-II ones (~1,064 nm) for aza-BODIPYs (SW1 to SW8). Furthermore, SW8 self-assembled into nanoparticles (SW8@NPs) with intense NIR-II absorption and an ultrahigh PCE (75%, 1,064 nm). This ultrahigh PCE primarily originated from an additional nonradiative decay pathway, which showed a 100-fold enhanced decay rate compared to that shown by conventional pathways such as internal conversion and vibrational relaxation. Eventually, SW8@NPs performed highly efficient 1,064-nm laser-mediated NIR-II photothermal therapy of osteosarcoma via concurrent apoptosis and pyroptosis. This work not only illustrates a remote approach for treating deep-seated tumors with high spatiotemporal control but also provides a new strategy for building high-performance small-molecule NIR-II PTAs.

A 13-million turnover-number anionic Ir-catalyst for a selective industrial route to chiral nicotine.

Developing catalysts with both useful enantioselectivities and million turnover numbers (TONs) for asymmetric hydrogenation of ketones is attractive for industrial production of high-value bioactive chiral entities but remains a challenging. Herein, we report an ultra-efficient anionic Ir-catalyst integrated with the concept of multidentate ligation for asymmetric hydrogenation of ketones. Biocatalysis-like efficacy of up to 99% ee (enantiomeric excess), 13,425,000 TON (turnover number) and 224 s-1 TOF (turnover frequency) were documented for benchmark acetophenone. Up to 1,000,000 TON and 99% ee were achieved for challenging pyridyl alkyl ketone where at most 10,000 TONs are previously reported. The anionic Ir-catalyst showed a novel preferred ONa/MH instead of NNa/MH bifunctional mechanism. A selective industrial route to enantiopure nicotine has been established using this anionic Ir-catalyst for the key asymmetric hydrogenation step at 500 kg batch scale, providing 40 tons scale of product.

Detoxifying mycotoxins and antifungal properties of two rumen-derived Enterococcus species in artificially contaminated corn silages.

BACKGROUND: Mycotoxins contamination in food and feed has emerged as an issue of serious concern because they pose serious health risks to both humans and livestock. The study aimed to evaluate the effects of two rumen-derived Enterococcus spp. on fermentation and hygienic quality of artificially contaminated corn silages. The toxigenic fungal-infested (FI) and non-fungal infested (NFI) corn was harvested at 1/2 milk line stage and ensiled without additives (CON) or with Enterococcus faecalis (E) or Enterococcus faecium (M). RESULTS: The pH of FI silages was higher than that of NFI silages, the pH in NFI-M was lower than in NFI-CON. Inoculating E. faecium markedly increased lactic acid concentration compared to CON and E silages. Both E. faecium and E. faecalis decreased the deoxynivalenol (DON) and zearalenone (ZEN) concentrations compared with the CON for FI silages, while E. faecium was more effective in eliminating aflatoxin B1 (AFB1 ). The FI silage had higher bacterial and fungal Shannon indexes than NFI silages. The relative abundance (RA) of Aspergillus and Fusarium marked a decline from day 5 to day 90. Inoculating E. faecium and E. faecalis reduced the RA of Penicillium compared to CON. In vitro mycotoxins removal assay indicated that E. faecium was more effective in AFB1 detoxification while having lower detoxifying ZEN capacity than E. faecalis. CONCLUSION: Inoculating rumen-derived Enterococcus spp. isolates alleviated the negative effects of fungal infestation on the fermentation and hygienic quality of corn silages by changing the microbial communities and detoxifying mycotoxins. © 2023 Society of Chemical Industry.

Recent advances in plasma-enabled ammonia synthesis: state-of-the-art, challenges, and outlook.

With the increase in the greenhouse effect and reduction of fossil fuel resources, it is urgent to find a feasible solution to directly convert power to chemicals using renewable energy and achieving zero carbon emissions targets. It is necessary to convert renewable energy (i.e., solar, wind, water, etc.) into electrical power replacing fossil-fuel-fired power. Therefore, the power-to-chemicals approach is gaining more and more attention. In the past two decades, non-thermal plasma, electro-catalysis, photo-catalysis, and their hybrid approaches have shown great potential for the power-to-chemicals solution. This paper introduces the application of plasma technology in energy conversion, focusing on three main routes for plasma-enabled ammonia synthesis, and analyses the state-of-the-art. Research results of ammonia synthesis based on plasma technology are discussed. The application of advanced in situ diagnostics evidences the importance of specific intermediate species and reaction pathways. Electrons, vibrationally-excited species, free radicals, and surface-adsorbed species play important roles in plasma-catalytic ammonia synthesis. Combined with experiments and simulations, the mechanisms of plasma-catalytic ammonia synthesis are examined. Vibrationally-excited species can effectively reduce the catalytic surface energy barrier. The techno-economics of the plasma-enabled ammonia synthesis technology is discussed in view of its competitive advantages. It is emphasized that the power-to-chemicals approach can be adapted for most chemical manufacturers, and these methods would play crucial roles in reducing carbon emissions and environmental pollution. Finally, suggestions are provided for the sustainable development of the power-to-chemicals industry in the future.

Concise Synthesis of Chiral Tricyclic Lactams by Tandem Dynamic Kinetic Asymmetric Reductive Amination/Lactamization Using Ammonium Salts.

The atom- and step-efficient synthesis of chiral fused tricyclic lactams from readily available ketoesters using cheap ammonium salts as the nitrogen source is reported. This ruthenium-catalyzed system operates through an efficient tandem dynamic kinetic asymmetric reductive amination (ARA)/lactamization and produces chiral fused tricyclic lactams in high yields with excellent diastereo- and enantioselectivity (up to >99 % ee, >20 : 1 dr and 98 % yield). The robust method was also applied to the concise synthesis of key intermediates in the synthesis of rivastigmine analogues and chiral N-heterocyclic carbene catalysts.

Dynamics of Phyllosphere Microbiota and Chemical Parameters at Various Growth Stages and Their Contribution to Anaerobic Fermentation of Pennisetum giganteum.

This work evaluated the dynamic changes of phyllosphere microbiota and chemical parameters at various growth stages of Pennisetum giganteum and their effects on the bacterial community, cooccurrence networks, and functional properties during anaerobic fermentation. P. giganteum was collected at two growth stages (early vegetative stage [PA] and late vegetative stage [PB]) and was naturally fermented (NPA and NPB) for 1, 3, 7, 15, 30, and 60 days, respectively. At each time point, NPA or NPB was randomly sampled for the analysis of chemical composition, fermentation parameter, and microbial number. In addition, the fresh, 3-day, and 60-day NPA and NPB were subjected to high-throughput sequencing and Kyoto Encyclopedia of Genes and Genomes (KEGG) functional prediction analyses. Growth stage obviously affected the phyllosphere microbiota and chemical parameters of P. giganteum. After 60 days of fermentation, NPB had a higher lactic acid concentration and ratio of lactic acid to acetic acid but a lower pH value and ammonia nitrogen concentration than NPA. Weissella and Enterobacter were dominant in 3-day NPA and Weissella was dominant in 3-day NPB, while Lactobacillus was the most abundant genus in both 60-day NPA and NPB. The complexity of bacterial cooccurrence networks in the phyllosphere decreased with P. giganteum growth. The ensiling process further decreased the complexity of bacterial networks, with the simplest bacterial correlation structures in NPB. There were great differences in the KEGG functional profiles of PA and PB. Ensiling promoted the metabolism of lipid, cofactors, vitamins, energy, and amino acids but suppressed the metabolism of carbohydrates and nucleotides. Storage time had a greater influence than growth stage on bacterial community diversity, cooccurrence networks, and functional profiles of P. giganteum silage. Differences in bacterial diversity and functionality of P. giganteum silage caused by growth stage appear to be offset by long-term storage. IMPORTANCE The phyllosphere microbiota consists of various and complex microbes, including bacteria with crucial relevance to the quality and safety of fermented food and feed. It initially derives from soil and becomes specific to its host after interaction with plants and climate. Bacteria associated with the phyllosphere are highly abundant and diverse, but we know little about their succession. Here, the phyllospheric microbiota structure was analyzed within the growth of P. giganteum. We also evaluated the effects of phyllosphere microbiota and chemical parameter changes on the anaerobic fermentation of P. giganteum. We observed remarkable differences in bacterial diversity, cooccurrence, and functionality of P. giganteum at various growth stages and storage times. The obtained results are important for understanding the fermentation mechanism and may contribute to high-efficient production without additional cost.

Sustainable utilization of residual grass: effect of anaerobic storage days on chemical composition, fermentation performance, microbial community, and functional profiles of Pennisetum giganteum.

The seasonal surplus and putrefactive property of moist forages inevitably increase the pressure on environmental protection and residual grass disposal. In the current work, the anaerobic fermentation approach was adopted to assist the sustainable recycling of leftover Pennisetum giganteum (LP), and its chemical composition, fermentation performance, bacterial community and functional profiles during anaerobic fermentation were studied. Fresh LP was spontaneously fermented for up to 60 d. At the end of anaerobic fermentation, fermented LP (FLP) displayed homolactic fermentation with low pH value, ethanol, and ammonia nitrogen concentrations but high lactic acid concentration. Weissella was dominant in 3-day FLP, yet Lactobacillus was the overwhelming genus (92.6%) in 60-day FLP. The anaerobic fermentation process promoted (P < 0.05) the metabolism of carbohydrate and nucleotide while suppressing (P < 0.05) that of lipid, cofactors, vitamins, energy, and amino acid. The results showed that the residual grass with LP as an example could be successfully fermented even if no additives were added, without signs of clostridial and fungal contamination.