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This study aimed to examine the bacterial, methanogenic archaeal, and eukaryotic community structure in both the midgut and hindgut of Pachnoda marginata larvae using an amplicon sequencing approach. The goal was to investigate how various diets and the soil affect the composition of these three‐domain microbial communities within the gut of insect larvae. The results indicated a notable variation in the microbial community composition among the gut compartments. The majority of the bacterial community in the hindgut was composed of Ruminococcaceae and Christensenellaceae. Nocardiaceae, Microbacteriaceae, and Lachnospiraceae were detected in midgut samples from larvae feeding on the leaf diet, whereas Sphingomonadaceae, Rhodobacteraceae, and Promicromonasporaceae dominated the bacterial community of midgut of larvae feeding on the straw diet. The diet was a significant factor that influenced the methanogenic archaeal and eukaryotic community patterns. The methanogenic communities in the two gut compartments significantly differed from each other, with the midgut communities being more similar to those in the soil. A higher diversity of methanogens was observed in the midgut samples of both diets compared to the hindgut. Overall, the microbiota of the hindgut was more host‐specific, while the assembly of the midgut was more influenced by the environmental microorganisms. [ABSTRACT FROM AUTHOR]

The development of innovative technologies in wastewater treatment create the concept of biorefinery in wastewater treatment plants (WWTPs), placing anaerobic processes in the highlight. Starting from the conventional anaerobic treatment processes to 'closing the loop' scheme, next generation WWTPs are ready to serve for water, energy and materials mining. While bioenergy is still dominating the resource recovery, recovery of value-added materials (i.e. struvite, biopolymers, cellulose) are receiving significant attention in recent years. So, what are the state-of-the-art approaches for energy-efficient resource recovery and re-use from municipal wastewater? This paper follows a critical review on the validated technologies in operational environment available and further suggests possible market routes for the recovered materials in WWTPs. Considering the development and verification of a novel technology together with the valorization of the obtained products, biorefinery and resource recovery approaches were gathered in this review paper from a circular economy point of view. General currently-faced barriers were briefly addressed to pave the way to create to-the-point establishments of resource recovery facilities in the future. [ABSTRACT FROM AUTHOR]

Cattle manure is frequently used as an inoculum for the start-up of agricultural biogas plants or as a co-substrate in the anaerobic digestion of lignocellulosic feedstock. Ruminal microbiota are considered to be effective plant fiber degraders, but the microbes contained in manure do not necessarily reflect the rumen microbiome. The aim of this study was to compare the microbial community composition of cow rumen and manure with respect to plant fiber-digesting microbes. Bacterial and methanogenic communities of rumen and manure samples were examined by 454 amplicon sequencing of bacterial 16S rRNA genes and mcrA genes, respectively. Rumen fluid samples were dominated by Prevotellaceae (29%), whereas Ruminococcaceae was the most abundant family in the manure samples (31%). Fibrobacteraceae (12%) and Bacteroidaceae (13%) were the second most abundant families in rumen fluid and manure, respectively. The high abundances of fiber-degrading bacteria belonging to Prevotellaceae and Fibrobacteraceae might explain the better performance of anaerobic digesters inoculated with rumen fluid. Members of the genus Methanobrevibacter were the predominant methanogens in the rumen fluid, whereas methanogenic communities of the manure samples were dominated by the candidate genus Methanoplasma. Our results suggest that inoculation or bioaugmentation with fiber-digesting rumen microbiota can enhance the anaerobic digestion of lignocellulosic biomass. [ABSTRACT FROM AUTHOR]

The aim of this study was to develop an effective bioaugmentation concept for anaerobic digesters treating lignocellulosic biomass such as straw. For that purpose, lignocellulose-degrading methanogenic communities were enriched on wheat straw from cow and goat rumen fluid as well as from a biogas reactor acclimated to lignocellulosic biomass (sorghum as mono-substrate). The bacterial communities of the enriched cultures and the different inocula were examined by 454 amplicon sequencing of 16S rRNA genes while the methanogenic archaeal communities were analyzed by terminal restriction fragment length polymorphism (T-RFLP) fingerprinting of the mcrA gene. Bacteroidetes was the most abundant phylum in all samples. Within the Bacteroidetes phylum, Bacteroidaceae was the most abundant family in the rumen-derived enrichment cultures, whereas Porphyromonadaceae was the predominant one in the reactor-derived culture. Additionally, the enrichment procedure increased the relative abundance of Ruminococcaceae (phylum: Firmicutes) in all cultures. T-RFLP profiles of the mcrA gene amplicons highlighted that the ruminal methanogenic communities were composed of hydrogenotrophic methanogens dominated by the order Methanobacteriales regardless of the host species. The methanogenic communities changed significantly during the enrichment procedure, but still the strict hydrogenotrophic Methanobacteriales and Methanomicrobiales were the predominant orders in the enrichment cultures. The bioaugmentation potential of the enriched methanogenic cultures will be evaluated in further studies. [ABSTRACT FROM AUTHOR]

Anaerobic co-digestion of cow manure (CM) and barley (Hordeum vulgare, HV) was evaluated in terms of biochemical methane potentials with respect to five different CM to HV mixing ratios of 1:0, 2:1, 1:1, 1:2, and 0:1 based on volatile solids (VS) contents. Bacterial community composition of the seed sludge was examined using 454 pyrosequencing of 16S rRNA gene sequences. Based on the taxonomic classification, major bacterial phyla belonged to the Firmicutes (42%) and Bacteroidetes (22%). Co-digestion of CM and barley was superior at all mixing ratios when compared with the digestion of CM alone. The digestion systems failed at the ratio of 0:1, and there was no methane production. The presence of barley caused high acidification, but there was no volatile fatty acids accumulation at the end of the digestion. Highest specific methane productions were obtained at CM to HV mixing ratios of 2:1 and 1:1 as 216 CH4/g VS and 230 CH4/g VS, respectively. Because of the highest specific methane production, the optimal CM to HV mixing ratio was found to be 1:1 in this study. © 2015 American Institute of Chemical Engineers Environ Prog, 35: 589-595, 2016 [ABSTRACT FROM AUTHOR]