Effects of Temperature Shifts on Microbial Communities and Biogas Production: An In-Depth Comparison

Abstract

Temperature plays a significant role in anaerobic digestion (AD) as it affects the microbial communities and ultimately controls the efficiency of the process. Few studies have looked at temperature-adjusted AD, but it is unclear how the temperature shifts affect biogas production and the dynamics of microorganisms involved in methanogenesis. This study tested two temperature shift scenarios in fed-batch mode using anaerobically digested sewage sludge and glucose-based substrate. The first scenario was acclimatized to upshifting temperatures from 42 °C to 48 °C while the second was acclimatized to downshifting temperatures from 55 °C to 45 °C. Both temperature shift scenarios resulted in a decrease in biogas production, especially at 45 °C. The upshifted scenario experienced a maximum decrease of 83%, and the downshifted scenario experienced a 16–33% decrease in methane production. Next-generation 16S rRNA sequencing revealed the domination of Methanoculleus in the upshifted scenario. However, a low correlation between the number of Methanoculleus and the other hydrogenotrophic methanogens to biogas production indicates inhibition in the hydrogenotrophic pathway. The downshifted scenario showed better biogas production due to the substantial domination of acetoclastic Methanosaeta and the low abundance of sulfate-reducing bacteria. Hence, the temperature shift affects the microbial communities, significantly affecting biogas production performance.

Indigenous Bacteria Diversity of Fermetodege Based on Molecular Analysis The Next Generation Sequencing (NGS)

“…As the variety of thermophilic species grows, the nutrient content in the fermented material begins to become depleted so that most of the various bacterial species die, resulting in a decrease in diversity in the thermophilic phase II. A decreasing number of species means a decrease in overall metabolic activity which results in reducing heat release into the system, so that the system temperature will move to a moderate temperature [23][24].…”

Thermotolerance and Hydrogen Production Potential of Salt-tolerant Microflora from Salt Fields

“…Their adaptation to such environments is anchored in specialized cellular mechanisms: production of compatible solutes, ion balance maintenance, and lipid membrane modification. Beyond mere survival, these adaptive strategies enable halophiles to engage in processes of industrial significance, notably within biotechnological applications such as biofuel generation, waste remediation, and enzyme extraction [27,28,[30][31][32][33].…”

Maximizing Biogas Yield Using an Optimized Stacking Ensemble Machine Learning Approach

“…The common feedstocks include animal manure, agricultural residues, food waste, and wastewater sludge [5,6]. Further, environmental parameters such as temperature, humidity, pH, and moisture level play a vital role during the biogas production process where the optimal temperature range is typically between 35 • C and 55 • C [7,8]. Higher temperatures can accelerate digestion, but extreme temperatures can inhibit microbial activity [8].…”