Performance of Methane Production and Microbial Structure Distribution for Vinasse Anaerobic Digestion

Vinasse is a by-product in the process of wine production. Vinasse were used as the research object. The effects of different substrate total solids (TS) concentrations (0.5%, 1%, 1.5%, and 2% ), inoculation and vinasse ratios ( 0. 25, 0. 5, 0. 75, 1, and 1.5), and temperatures ( 25 Tl, 37 °C, and 50 t ) on performance of methane production for vinasse AD were investigated. The results showed that methane production was increased gradually with the increase of TS concentration, and the maximum cumulative biogas production ( 532. 8 mL/g ) and methane production ( 294. 7 mL/g ) were obtained at 2% TS. The inoculation ratio was an important factor affecting the anaerobic digestion system, with the increase of inoculation ratio, the cumulative biogas and methane production of the system showed an increasing and then decreasing trend, the system collapsed and did not produce methane at inoculation ratios of 0. 25 and 0. 5, and the maximum cumulative biogas and methane production were obtained when the inoculation ratio was 1. When TS was 2%, and inoculation ratio was 1.5, the cumulative biogas production obtained at a fermentation temperature of 50°C was 559.4 mL/g, which was 10.2% higher than that at 37°C, and the cumulative methane production obtained was 284.0 mL/g, which was not significantly higher than that at 37 °C (P > 0.05). After gas production kinetic analysis by using the modified Gompertz model, it was found that the higher the TS was, the higher the inoculum ratio and the temperature were, and the shorter the methane production latency period was. The microbial communities in the AD system at different temperatures were also analyzed, and it was found that Bacteroidetes and Firmicutes were the dominant phyla, and the methanogenic bacteria were gradually replaced by hydrogenotrophic instead of acetoclastic methanogens with the increase of temperature. Therefore, TS concentration, inoculation ratio and temperature were important factors for AD, and it was initially determined that the methanogenic performance of vinasse mesophilic AD with 2% TS and an inoculation ratio of 1 was relatively good, and the research result can provide data support for the application of vinasse AD technology. © 2023 Chinese Society of Agricultural Machinery. All rights reserved.