Microbial community adaptability to altered temperature conditions determines the potential for process optimisation in biogas production

Air‐side ammonia stripping coupled to anaerobic digestion indirectly impacts anaerobic microbiome

“…High‐pH conditions inhibit methanogenic archaea (Yuan et al ., ; Chen et al ., ), and high oxygen concentrations modify microbial composition by removing Clostridium senso stricto 1, which negatively impacts the capacity for hydrogen production (Yang and Wang, ). Finally, high temperature correlates with lower microbial community diversity and complexity (Karakashev et al ., ; Westerholm et al ., ). But, to the best of our knowledge, the combination of high temperature, pH and oxygen levels on AD microbiome has not been assessed previously.…”

“…Overloading events are also associated with an increase in free ammonia nitrogen (FAN) concentrations in the digesters when the substrate used is rich in nitrogen compounds such as manure (De Francisci et al, 2015;Regueiro et al, 2016;Sun et al, 2016) and some types of food waste (Gao et al, 2015;Yun et al, 2016). High levels of ammonia can inhibit microbial activities (Liu and Sung, 2002;Zhang et al, 2012;Westerholm et al, 2018) although it has been demonstrated that acclimatization of microbial communities can alleviate this inhibition (Yan et al, 2019). It is well known that acetoclastic methanogens are less tolerant to ammonium than hydrogenotrophic archaea (Angelidaki and Ahring, 1993;Vrieze et al, 2012;Westerholm et al, 2012Westerholm et al, , 2018Yan et al, 2019), and consequently, increasing ammonium concentration shifts methanogenesis from acetoclastic to hydrogenotrophic pathway (L€ u et al, 2013;Werner et al, 2014;Regueiro et al, 2016).…”

“…High levels of ammonia can inhibit microbial activities (Liu and Sung, 2002;Zhang et al, 2012;Westerholm et al, 2018) although it has been demonstrated that acclimatization of microbial communities can alleviate this inhibition (Yan et al, 2019). It is well known that acetoclastic methanogens are less tolerant to ammonium than hydrogenotrophic archaea (Angelidaki and Ahring, 1993;Vrieze et al, 2012;Westerholm et al, 2012Westerholm et al, , 2018Yan et al, 2019), and consequently, increasing ammonium concentration shifts methanogenesis from acetoclastic to hydrogenotrophic pathway (L€ u et al, 2013;Werner et al, 2014;Regueiro et al, 2016). In contrast, less is known about the effects of high ammonium concentrations on bacterial organisms.…”

“…In contrast, less is known about the effects of high ammonium concentrations on bacterial organisms. Recent studies have reported the dominance of Bacteroidetes group under low-ammonium conditions, while under high concentrations the phylum Cloacimonetes disappears and the Firmicutes phylum, in particular Clostridiales and Lactobacillales orders, dominates the community (Werner et al, 2014;Vrieze et al, 2015;Regueiro et al, 2016;Westerholm et al, 2018). When high ammonia levels inhibit obligate acetoclastic methanogens, the microbial community shifts towards syntrophic acetate oxidation pathway (Westerholm et al, 2016) although the keystone taxa responsible for the function are unclear (Werner et al, 2014;Theuerl et al, 2019).…”

Different response of bacteria, archaea and fungi to process parameters in nine full‐scale anaerobic digesters

“…In contrast to fungal communities, bacterial and archaeal communities present in anaerobic digesters have been extensively analysed under various conditions by different molecular approaches based on 16S rDNA sequences and metagenome studies (Sundberg et al, 2013;Abendroth et al, 2015;De Vrieze et al, 2015;Klang et al, 2015;Langer et al, 2015;Westerholm et al, 2018). Nevertheless, the presence and microbial abundances based on DNA extracts do not necessarily reflect metabolic activity of these microbes .…”