The cultivation and investigation of strictly anaerobic microorganisms belong to the fields of anaerobic microbial physiology, microbiology, and biotechnology. Anaerobic cultivation methods differ from classic microbiological techniques in several aspects. The requirement for special instruments, which are designed to prevent the contact of the specimen with air/molecular oxygen by different means of manipulation, makes this field more challenging for general research compared to working with aerobic microorganisms. Anaerobic microbiological methods are required for many purposes, such as for the isolation and characterization of new species and their physiological examination, as well as for anaerobic biotechnological applications or medical indications. This review presents the historical development of methods for the cultivation of strictly anaerobic microorganisms focusing on methanogenic archaea, anaerobic cultivation methods that are still widely used today, novel methods for anaerobic cultivation, and almost forgotten, but still relevant, techniques.

Securing new sources of renewable energy and achieving national self-sufficiency in natural gas have become increasingly important in recent times. The study described in this paper focuses on three geologically diverse underground gas reservoirs (UGS) that are the natural habitat of methane-producing archaea, as well as other microorganisms with which methanogens have various ecological relationships. The objective of this research was to describe the microbial metabolism of methane in these specific anoxic environments during the year. DNA sequencing analyses revealed the presence of different methanogenic communities and their metabolic potential in all sites studied. Hydrogenotrophic Methanobacterium sp. prevailed in Lobodice UGS, members of the hydrogenotrophic order Methanomicrobiales predominated in Dolní Dunajovice UGS and thermophilic hydrogenotrophic members of the Methanothermobacter sp. were prevalent in Tvrdonice UGS. Gas composition and isotope analyses were performed simultaneously. The results suggest that the biotechnological potential of UGS for biomethane production cannot be neglected.

As a renewable energy carrier, dark fermentative biohydrogen (H₂) represents a promising future alternative to fossil fuels. Recently, the limited H₂ yield of 4 moles of H₂ per mole glucose, the so-called “Thauer limit”, was surpassed by a defined artificial consortium. In this article, we demonstrate the upscaling of this drawing board design, from serum bottles to laboratory scale bioreactors. Our results illustrate that this designed microbial co-culture can be successfully implemented in batch mode, with maximum H₂ yields of 6.18 and 4.45 mol mol⁻¹ substrate. Furthermore, we report volumetric H₂ productivities of 105.6 and 80.8 mmol H₂ L⁻¹ h⁻¹_. These rates are higher than for any other dark fermentative H₂ production system using a synthetic microbial co-culture applied in batch mode on a defined medium. Our study is an important step forward for the application of artificial microbial consortia in future biotechnology and energy production systems.

Molasses stillage, with its high organic content and nutrient-rich composition, represents a promising feedstock for biogas production. This study systematically evaluated its biochemical methane potential (BMP) using two inocula (wastewater treatment plant vs agricultural biogas plant) across three temperatures (40, 50, 60 °C) and initial substrate load (ISL: 2, 5, 10 g·L_incolum ^-1). The wastewater inoculum achieved superior methane yields (0.262-0.477 N m³·kg_vs ^-1), peaking at 50 °C with a 22% increase over agricultural systems (0.192-0.378 N m³·kg_vs ^-1). 16S rRNA sequencing revealed the wastewater treatment plant inoculum's superior functional diversity, dominated by syntrophic Chloroflexota and Acidobacteriota alongside methanogenic Methanobacterium (52-61% relative abundance) and acetoclastic Methanothrix (18-23%). In contrast, agricultural biogas plant inocula showed specialized thermophilic communities dominated by Bacillota (68-72%) and hydrogenotrophic Methanoculleus (29-34%). Both systems exhibited inhibition at 60 °C/ISL10 (yields reduced by 34-42%), correlating with declining diversity and Methanofastidiosum proliferation. These findings provide two key operational insights: wastewater inocula offer greater process stability due to microbial diversity, and 50 °C represents the thermal optimum for stillage codigestion, balancing yield and community resilience.

The phenomenon of microbiologically induced corrosion (MIC) has been known for more than 100 years, but its role as a cause of accidents in the process industry is still somewhat underestimated. Microbiologically induced corrosion is often associated with anaerobic environments, where microorganisms such as sulfate-reducing bacteria or methanogenic archaea are significantly involved in accelerating corrosion of metallic materials. This study aims to assess the significance of microbiologically induced corrosion in industrial accidents, identify facilities and conditions most at risk, and propose effective prevention strategies. Analysis of publicly available accident databases, together with expert assessment of operating conditions, suggests that MIC might be associated with roughly 10–20% of corrosion-related incidents; however, this range should be interpreted cautiously due to substantial limitations in reporting and confirmation practices. The presence of anaerobic microorganisms and biofilms substantially increases the likelihood of MIC, underscoring the need for systematic monitoring of microbial communities and environmental conditions to improve preventive measures and enhance plant safety. However, the analysis is limited by the incomplete and heterogeneous reporting of corrosion mechanisms in publicly accessible accident databases. Consequently, the estimated contribution of MIC should be interpreted with caution, as many events lack sufficient microbiological or environmental detail to allow definitive classification.