Department of Hydraulics and Sanitation, School of Engineering of São Carlos, University of São Paulo, Av. João Dagnone, 1100, Jd. Santa Angelina, CEP 13563-120 São Carlos, SP, Brazil.
Department of Chemical Engineering, Federal University of São Carlos, Rod. Washington Luis, km 235, CEP 13565-905 São Carlos, SP, Brazil.
Sci Total Environ. 2023 Dec 15;904:166294. doi: 10.1016/j.scitotenv.2023.166294. Epub 2023 Aug 14.
Sugarcane vinasse exits the distillation process at high temperatures, which may differ from the optimal temperatures for dark fermentation and anaerobic digestion. A 15 °C temperature increase, for example, stops sugarcane vinasse methane generation, making distillery vinasse digestion complicated. Conversely, in other aspects, co-digesting vinasse and glycerol has been proven to stabilize methane production from vinasse because of sulfate dilution. However, glycerol has not been tested to stabilize vinasse digestion under temperature changes. Thus, this study compared the effects of different temperature settings on the co-digestion of 10 g COD L of vinasse and glycerol (50 %:50 % on a COD basis) in anaerobic fluidized bed reactors (AFBR), i.e., an acidogenic and a methanogenic one-stage AFBRs operated at 55, 60, and 65 °C, and two methanogenic AFBRs fed both with acidogenic effluent (one operated at room temperature (25 °C) and the other at 55, 60, and 65 °C). The co-digestion provided steady methane generation at all AFBRs, with methane production rates ranging from 2.27 to 2.93 L CH d L, whether in one or two stages. A feature of this research was to unravel the black box of the role of sulfate in the digestion of sugarcane vinasse, which was rarely studied. Desulfovibrio was the primary genus degrading 1,3-propanediol into 3-hydroxypropanoate after genome sequencing. Phosphate acetyltransferase (EC: 2.3.1.8, K00625) and acetate kinase (EC: 2.7.2.1, K00925) genes were also found, suggesting propionate was metabolized. In practical aspects, regarding the two-stage systems, the thermophilic-mesophilic (acidogenic-methanogenic) configuration is best for extracting additional value-added products because 1,3-propanediol may be recovered at high yields with steady methane production at reduced energy expenditure in a reactor operated at room temperature. However, the one-stage design is best for methane generation per system volume since it remained stable with rising temperatures, and all systems presented similar methane production rates.
甘蔗糖蜜在高温下离开蒸馏过程，这可能不同于黑暗发酵和厌氧消化的最佳温度。例如，温度升高 15°C 会停止甘蔗糖蜜的甲烷生成，使酿酒厂糖蜜消化变得复杂。相反，在其他方面，已经证明共消化糖蜜和甘油可以通过硫酸盐稀释来稳定糖蜜的甲烷生成。然而，甘油尚未经过测试以在温度变化下稳定糖蜜消化。因此，本研究比较了不同温度设置对 10 g COD L 甘蔗糖蜜和甘油（基于 COD 的 50%：50%）在厌氧流化床反应器（AFBR）中的共消化的影响，即一个产酸和一个产甲烷的一级 AFBR，分别在 55、60 和 65°C 下运行，以及两个进料均为产酸液的产甲烷 AFBR（一个在室温（25°C）下运行，另一个在 55、60 和 65°C 下运行）。共消化在所有 AFBR 中均提供了稳定的甲烷生成，甲烷生成速率范围为 2.27 至 2.93 L CH d L，无论是在一级还是两级中。本研究的一个特点是揭示硫酸盐在糖蜜消化中的作用这一黑箱，这一作用很少被研究。脱硫弧菌是在基因组测序后将 1,3-丙二醇降解为 3-羟基丙酸盐的主要属。还发现了磷酸乙酰转移酶（EC：2.3.1.8，K00625）和乙酸激酶（EC：2.7.2.1，K00925）基因，表明丙酸被代谢。在实际方面，对于两级系统，嗜热-中温（产酸-产甲烷）配置最适合提取额外的增值产品，因为在室温下运行的反应器中，1,3-丙二醇可以以高收率回收，同时保持稳定的甲烷生成，从而降低能量消耗。然而，对于每个系统体积的甲烷生成而言，一级设计是最佳的，因为随着温度的升高它保持稳定，并且所有系统的甲烷生成率相似。
