In this study, the influence of two lactic acid bacteria (LAB) strains [Lactobacillus rhamnosusBDy (LR-BDy) andLactobacillus buchneriTSy (LB-TSy)] selected from Southwest China on the fermentation characteristics and in vitro gas production ofBroussonetia papyrifera(paper mulberry) silage were experimentally explored. The experimental groups were a control group (C), an LB-TSy treatment (LB), an LR-BDy treatment (LR), and an LR-BDy + LB-TSy hybrid group (LR × LB). After the LAB were added, the pH value of paper mulberry silage significantly declined (p< 0.05), and the crude protein content was effectively preserved (p< 0.05). However, no significant changes were found in the levels of neutral detergent fiber, acid detergent fiber, and crude ash (p> 0.05). The lactic acid content in paper mulberry silage was evidently increased (p< 0.05). The in vitro gas production in the LR at 36, 48, and 72 h were markedly higher than that in the other treatments (p< 0.05). Owing to the addition of LAB, the microbial diversity in paper mulberry silage was reduced, while the relative bacterial abundance ofLactobacilluswas enhanced. Hence, the addition of LAB selected from the warm and humid region in Southwest China can improve the quality of paper mulberry silage and elevate its feeding value in this region.Keywords:paper mulberry;silage;in vitro gas production;microbial community;lactic acid bacteria
Excessive water production impacted marine natural gas hydrate production. Cationic polyacrylamide (CPAM), one kind of chemical reagent, was used for the first time to selectively reduce water production while having less impact on gas production. After quartz sands with an absolute permeability of 100–1000 mD were treated with CPAM, the water phase permeability was reduced to 1/15, while the gas phase permeability almost had no change. Furthermore, CPAM was effective in controlling water flow in quartz sands with an absolute permeability range of 100–1000 mD. The water phase permeability initially decreased and then stabilized as the concentration of CPAM increased from 500 to 20,000 ppm. Additionally, the formation of methane hydrate in pretreated quartz sands with CPAM led to a greater reduction in quartz sands’ permeability than the sum of the respective reduction for CPAM treatment and methane hydrate formation. In addition, compared to quartz sands treated only with CPAM, the dissociation of 5% methane hydrate significantly increased the permeability of CPAM-treated quartz sands, but the permeability was smaller than that before CPAM treatment.
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