Dynamic changes in carbohydrate components and the bacterial community during the ensiling of wilted and unwilted sweet sorghum.

Sweet sorghum can be used to produce a substantial quantity of biofuel due to its high biological yield and high carbohydrate content. In this study, we investigated the dynamic changes in fermentation characteristics, carbohydrate components, and the bacterial community during the ensiling of wilted and unwilted sweet sorghum. The results revealed a rapid fermentation pattern and high-quality fermentation quality in wilted and unwilted sweet sorghum, wherein lactic acid, and acetic acid accumulated and stabilized during the initial 9 days of ensiling, with the pH values less than 4.2, until 60 days of ensiling. We found that the ensiling of sweet sorghum involved the degradation (5% ~ 10%) of neutral detergent fiber (NDF) and hemicellulose and that the degradation of NDF fit a first-order exponential decay model. A shift in dominance from Lactococcus to Lactobacillus occurred before the first 9 days of ensiling, and the abundance of Lactobacillus (r = -0.68, p < 0.001) was negatively correlated with the NDF content. The relative abundances of Lactobacillus in wilted and unwilted sweet sorghum after ensiling for 60 days were 76.30 and 93.49%, respectively, and relatively high fermentation quality was obtained. In summary, ensiling is proposed as a biological pretreatment for sweet sorghum for subsequent biofuel production, and unlike other materials, sweet sorghum quickly achieves good fermentation quality and has great potential for bioresource production.

Strong metal support interaction (SMSI) and MoO3 synergistic effect of Pt-based catalysts on the promotion of CO activity and sulfur resistance.

In industrial applications, Pt-based catalysts for CO oxidation have the dual challenges of CO self-poisoning and SO2 toxicity. This study used synthetic Keggin-type H3PMo12O40 (PMA) as the site of Pt, and the Pt-MoO3 produced by decomposition of PMA was anchored to TiO2 to construct the dual-interface structure of Pt-MoO3 and Pt-TiO2, abbreviated as Pt-P&M/TiO2. Pt-0.125P&M/TiO2 with a molar ratio of Pt to PMA of 8:1 showed both good CO oxidation activity and SO2 tolerance. In the CO activity test, the CO complete conversion temperature T100 of Pt-0.125P&M/TiO2 was 113 ℃ (compared with 135 ℃ for Pt/TiO2). In the SO2 resistance test, the conversion efficiency of Pt-0.125P&M/TiO2 at 170 ℃ remained at 60% after 72 h, while that of Pt/TiO2 was only 13%. H2-TPR and XPS tests revealed that lattice oxygen provided by TiO2 and hydroxyl produced by MoO3 increased the CO reaction rate on Pt. According to the DFT theoretical calculation, the electronegative MoO3 attracted the d-orbital electrons of Pt, which reduced the adsorption energy of CO and SO2 from - 4.15 eV and - 2.54 eV to - 3.56 eV and - 1.52 eV, respectively, and further weakened the influence of strong CO adsorption and SO2 poisoning on the catalyst. This work explored the relationship between catalyst structure and catalyst performance and provided a feasible technical idea for the design of high-performance CO catalysts in industrial applications.