Influence of Temperature on Biogas Production Efficiency and Microbial Community in a Two-Phase Anaerobic Digestion System

Shiwei Wang,Xiaofei Lu,Fang Ma,Guang Zhao,Ping Wang,Weiwei Ma

doi:10.3390/w11010133

Abstract

In this study, the influence of temperature on biogas production efficiency and the microbial community structure was investigated in a two-phase anaerobic digestion reactor for co-digestion of cow manure and corn straw. The results illustrated that the contents of solluted chemical oxygen demand (SCOD) and volatile fatty acid (VFA) in the acidogenic phase and biogas production in the methanogenic phase maintained relatively higher levels at temperatures ranging from 35–25 °C. The methane content of biogas production could be maintained higher than 50% at temperatures above 25 °C. The microbial community structure analysis indicated that the dominant functional bacteria were Acinetobacter, Acetitomaculum, and Bacillus in the acidogenic phase and Cenarchaeum in the methanogenic phase at 35–25 °C. However, the performances of the acidogenic phase and the methanogenic phase could be significantly decreased at a lower temperature of 20 °C, and microbial activity was inhibited obviously. Accordingly, a low temperature was adverse for the performance of the acidogenic and methanogenic phases, while moderate temperatures above 25 °C were more conducive to high biogas production efficiency.

Highlights

Global energy consumption and environmental pollution have become global issues.Oil, as one of the most important economic energy developments, has been excessively exploited and consumed
When the temperature dropped from 25 ◦ C to 20 ◦ C, the methane content decreased obviously with a methane content of only 25.2%. These results indicated that the activity of methanogenic bacteria was more sensitive to low temperature disturbance
Methanogen diversity significantly decreased, and the relative abundances of Methanobrevibacter, Methanoculleus, and Methanospirillum were less than 3%. These results indicated that low temperatures had a negative effect on the methanogenic bacteria community structure in the methanogenic phase

Summary

Introduction

Global energy consumption and environmental pollution have become global issues.Oil, as one of the most important economic energy developments, has been excessively exploited and consumed. The development and utilization of primary energy and the exploration of alternative renewable clean energy have become a focus of global concern [1,2]. As a large agricultural country, China produced large amounts of agricultural organic waste such as straw and livestock manure every year, which was an important source of biomass energy [3]. Straw and livestock manure can be converted into clean energy such as methane, thereby realizing the reuse of agricultural organic waste [4]. The technology for the treatment of straw and livestock manure is not sufficiently advanced. The utilization rate of straw waste in China is insufficient and a large amount of straw is incinerated, resulting in large amounts of soot and bad weather. Innovative and effective processes for the resourceful utilization of agricultural organic waste were urgently developed

Methods

Results

Conclusion