1. Thermophilic Solid-State Anaerobic Digestion of Corn Straw, Cattle Manure, and Vegetable Waste: Effect of Temperature, Total Solid Content, and C/N Ratio
- Author
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Zhang Longjiang, Guangyin Zhen, Rongting Ji, Liu Chenwei, Su Lianghu, Chen Mei, and Sun Xu
- Subjects
Bacteroidia ,Article Subject ,Nitrogen ,Physiology ,Firmicutes ,020209 energy ,02 engineering and technology ,010501 environmental sciences ,Zea mays ,01 natural sciences ,Microbiology ,Bioreactors ,Biogas ,Vegetables ,0202 electrical engineering, electronic engineering, information engineering ,Animals ,Anaerobiosis ,Food science ,Ecology, Evolution, Behavior and Systematics ,0105 earth and related environmental sciences ,Bacteria ,biology ,Chemistry ,Microbiota ,Temperature ,Bacteroidetes ,Straw ,biology.organism_classification ,Manure ,Carbon ,QR1-502 ,Anaerobic digestion ,Biofuel ,Biofuels ,Cattle ,Research Article - Abstract
Thermophilic solid-state anaerobic digestion (SS-AD) of agricultural wastes, i.e., corn straw, cattle manure, and vegetable waste, was carried out in this study. The effects of temperature (40-60°C), initial solid content (ISC, 17.5-32.5%), and C/N ratio (15-32 : 1) on biogas production were evaluated using a Box-Behnken experimental design (BBD) combined with response surface methodology (RSM). The results showed that optimization of process parameters is important to promote the SS-AD performance. All the factors, including interactive terms (except the ISC), were significant in the quadratic model for biogas production with SS-AD. Among the three operation parameters, the C/N ratio had the largest effect on biogas production, followed by temperature, and a maximum biogas yield of 241.4 mL gVS-1 could be achieved at 47.3°C, ISC = 24.81 % , and C / N = 22.35 . After 20 d of SS-AD, the microbial community structure under different conditions was characterized by high-throughput sequencing, showing that Firmicutes, Bacteroidetes, Chloroflexi, Synergistetes, and Proteobacteria dominated the bacterial community, and that Firmicutes had a competitive advantage over Bacteroidetes at elevated temperatures. The biogas production values and relative abundance of OPB54 and Bacteroidia after 20 d of SS-AD can be fitted well using a quadratic model, implying that OPB54 and Bacteroidia play important roles in the methanogenic metabolism for agricultural waste thermophilic SS-AD.
- Published
- 2020