Effect of Narrow Feeding Regimes on Anaerobic Digestion Performance and Microbial Community Structure of Rice Straw in Continuously Stirred Tank Reactors

Abstract

Demand-oriented conversion of biogas is conducive to meeting the needs of biogas supply and reduces extra costs related to gas storage facilities. In this study, the effect of feeding regimes (FRs) on anaerobic digestion performance and microbial community structure of rice straw were investigated using continuously stirred tank reactors. The result showed that compared to the FRs of every day and every 6 days, the FR of every 3 days achieved the best biomethane yield and substrate conversion rate, which improved by 17.3% and 12.4%, respectively. Additionally, the FR of every 3 days had a significant impact on microbial richness and diversity, and also improved the abundance of dominant archaea Methanosaeta. This indicated that the FR of every 3 days was suitable for the growth rate of Methanosaeta, which resulted in better anaerobic digestion performance. A narrow FR is helpful to meet the demand-oriented conversion of biogas.

Enhanced Saccharification and Fermentation of Rice Straw by Reducing the Concentration of Phenolic Compounds Using an Immobilized Enzyme Cocktail

“…The composition of rice straw varies with its source/origin. In this study, we observed cellulose contents in rice straw biomass similar to those reported previously, in the range of 35.5–36.7% . After pretreatment with sulfuric acid with three different concentrations (0.1%, 0.5%, and 1.0%), the cellulose and lignin contents were significantly increased.…”

Biomethane Yield, Physicochemical Structures, and Microbial Community Characteristics of Corn Stover Pretreated by Urea Combined with Mild Temperature Hydrotherm

“…For the archaea at the genus level ( Figure 8 b), Methanobacterium was negatively correlated with ethanol, acetic acid and biomethane yield. This result confirmed that Methanobacterium was hydrotrophic towards methanogens, which relied on H 2 and CO 2 as substrates for methanogenesis rather than acetate [ 56 ]. According to present research, nearly 70% of biomethane is produced via acetic acid-methane pathways [ 56 ].…”

“…This result confirmed that Methanobacterium was hydrotrophic towards methanogens, which relied on H 2 and CO 2 as substrates for methanogenesis rather than acetate [ 56 ]. According to present research, nearly 70% of biomethane is produced via acetic acid-methane pathways [ 56 ]. The high relative abundance of Methanobacterium in the untreated group may reflect the deficiency of hydrolysis-acidification processes, which may lead to a lack of acetic acid for subsequent methanogenesis.…”

“…Euryarchaeota was the most dominant species, which had a relative abundance of 46.4–64.0% and 79.3% in pretreated and untreated groups, respectively. Euryarchaeota is important for AD of CS, as it could play a vital role in converting lignocellulose to biomethane (Xu et al [ 44 ] and Guan et al [ 56 ]). Halobacterota populations are considered cellulo-/chininotrophic archaea, which participate in metabolising recalcitrant organic polymers [ 57 ].…”

Effects of Feeding Regimes on Process Performance and Microbial Community Structure in Anaerobic Semi-continuously Stirred Tank Reactors Treating Corn Stover

“…Continuously stirred tank reactors (CSTRs) are widely applied for the AD treatment of high-solid wastes such as crop straws [5]. In this system, biogas is produced conventionally with continuous feeds in laboratory-scale experiments or industrial projects [6]. While it is an advantage of CSTRs, this continuous feed also makes it difficult for the demand-oriented biogas supply, which requires larger amounts of biogas outputs during high-demand periods but smaller outputs during low-demand periods.…”