Microbiology and Molecular Biology Tools for Biogas Process Analysis, Diagnosis and Control

Abstract

Many biotechnological processes such as biogas production or defined biotransformations are carried out by microorganisms or tightly cooperating microbial communities. Process breakdown is the maximum credible accident for the operator. Any time savings that can be provided by suitable early-warning systems and allow for specific countermeasures are of great value. Process disturbance, frequently due to nutritional shortcomings, malfunction or operational deficits, is evidenced conventionally by process chemistry parameters. However, knowledge on systems microbiology and its function has essentially increased in the last two decades, and molecular biology tools, most of which are directed against nucleic acids, have been developed to analyze and diagnose the process. Some of these systems have been shown to indicate changes of the process status considerably earlier than the conventionally applied process chemistry parameters. This is reasonable because the triggering catalyst is determined, activity changes of the microbes that perform the reaction. These molecular biology tools have thus the potential to add to and improve the established process diagnosis system. This chapter is dealing with the actual state of the art of biogas process analysis in practice, and introduces molecular biology tools that have been shown to be of particular value in complementing the current systems of process monitoring and diagnosis, with emphasis on nucleic acid targeted molecular biology systems.

Diversity and Abundance of Microbial Communities in UASB Reactors during Methane Production from Hydrolyzed Wheat Straw and Lucerne

“…The aim of the present study was to obtain information on microbial communities in the above mentioned UASB reactors and to reveal knowledge on the response to substrate composition and increasing organic load as well as acidification events. Knowledge on the microbial community and its responses can provide valuable information on process performance, explain observed variations, and aid in long-term process management [38,39]. Many studies have investigated the microbial community composition in CSTR processes with the aim to understand its response to various operating parameters and performance variables (as reviewed in [19]).…”

Detection of novel syntrophic acetate‐oxidizing bacteria from biogas processes by continuous acetate enrichment approaches

“…The mesophilic S. schinkii oxidizes acetate in association with the hydrogenotrophic M. bourgensis, tolerates high ammonium levels and has a growth temperature ranging from 25 to 40°C (Westerholm et al, 2010). Despite the narrow temperature range for growth of this type strain, relatives to this species have been found in mesophilic biogas digesters (37-40°C; Westerholm et al, 2011aWesterholm et al, ,b, 2012aWesterholm et al, ,b, 2015Karlsson et al, 2012;Moestedt et al, 2014;Sun et al, 2014;M€ uller et al, 2016) and in digesters operating at moderate (42-45°C; Moestedt et al, 2014;Westerholm et al, 2015) and thermophilic (49-60°C; Weiss et al, 2008;Sun et al, 2014;Lebuhn et al, 2015;M€ uller et al, 2016) temperatures. Together, these findings indicate that, apart from the wide-ranging temperature span, relatives to S. schinkii are able to remain active under varying operating conditions in terms of ammonia concentration, HRT, substrate feed and digester configuration.…”

DNA and RNA Extraction and Quantitative Real-Time PCR-Based Assays for Biogas Biocenoses in an Interlaboratory Comparison

“…However, reliable quantitative assessment of RNA species is a challenge in its current state, and results must remain uncertain because solid data on the (m)RNA recovery rate (see below) and RT efficiency are difficult to obtain [ 42 , 43 ]. However, RT efficiency data are an integral part in the assessment of the RT-qPCR efficiency and both data are essential to determine the method detection limit.…”