Biogas and Volatile Fatty Acid Production During Anaerobic Digestion of Straw, Cellulose, and Hemicellulose with Analysis of Microbial Communities and Functions

Abstract

BackgroundAnaerobic digestion (AD) is a promising method for straw treatment, but the complex composition and structure of straw limit AD e ciency and methane production. The main biodegradable components of straw are cellulose and hemicellulose. Because of the different chemical structures and physicochemical properties, the performance of AD of cellulose and hemicellulose is different, thus it's also different from that of straw. Research on the similarities and differences of AD of straw, cellulose and hemicellulose is helpful to clarify the law of anaerobic digestion of straw and provide theoretical basis for further improving the e ciency of anaerobic digestion. However, there are very few studies on AD using cellulose and hemicellulose as raw materials. ResultsRice straw (RS), cellulose, and hemicellulose were used as raw materials to study biogas production performance and changes in the volatile fatty acids (VFAs). Further, microbial communities and genetic functions were analyzed separately for each material. The biogas production potential of RS, cellulose, and hemicellulose was different, with cumulative biogas production of 620.64, 412.50, and 283.75 mL/g•VS − 1 , respectively. The methane content of the biogas produced from cellulose and hemicellulose was approximately 10% higher than that produced from RS after the methane content stabilized. Biogas production and the methane content of RS stabilized more quickly than that of cellulose and hemicellulose. The accumulation of VFAs occurred in the early stage of anaerobic digestion in all the three materials, and the main volatile fatty acid component of RS was acetic acid, whereas that of cellulose and hemicellulose was propionic acid. The cumulative amount of VFAs in both cellulose and

Effect of Combination of Mangrove (Rhizophora apiculata) Leaves and Mirasolia diversifolia in Rations on Production Performance of Goats

“…Cellulose and hemicellulose digestibility is closely related to NDF and ADF digestibility because hemicellulose is part of the fiber fraction. Liu et al (2022) indicated that the digestibility of NDF and ADF is positively correlated with hemicellulose digestibility; as the digestibility of NDF and ADF increases, so does the digestibility of hemicellulose. Despite the fact that the T4 treatment contains higher lignin levels, this difference is not statistically significant when compared to the T1, T2, or T3 treatments.…”

Microbial Dynamics in Anaerobic Digestion: A Review of Operational and Environmental Factors Affecting Microbiome Composition and Function

“…Acetic acid is known to be the primary carbon source for biomethanation through AD. Most of the other VFAs, such as propionic acid, are also transformed into acetic acid before microbes incorporate them into the methane metabolism [67]. Under standard conditions, the transformation of certain VFAs, like propionate and butyrate, towards acetate, H2, and CO2 requires energy absorption, rendering it challenging to happen without external aid during AD.…”

“…Being a vital component in the methanogenic process by serving as substrates, VFAs are positively linked to methane generation, when their concentration remains within a particular range. However, it is important to note that excessive aggregation of VFAs can have an inhibitory effect on AD, ultimately leading to system failure [67]. There is a number of factors accountable for VFA accumulation, mainly linked to turbulences in the conditions of AD [26].…”

Enhancing biogas production from empty fruit bunch through acetic acid pretreatment: process optimization and synergistic effects

“…The high cellulose and hemicellulose content of EFB makes it a suitable feedstock for biogas production through anaerobic digestion. The energy potential of EFB is estimated to be 2.6-2.8 GJ/ton [4]. If all the EFB generated from palm oil mills in Indonesia, Malaysia, and Thailand were used for biogas production, it could potentially generate 38-41 million m³ of biogas per year, equivalent to 22-24 million GJ of energy (calculated based on a biogas yield of 500 m³/ton EFB and an energy content of 22 MJ/m³).…”