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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]

A single-nucleotide primer extension (SNuPE) assay in combination with taxon-specific 16S rRNA gene PCR analysis is developed for detecting and typing of 'Dehalococcoides' species. The studies have shown SNuPE as a novel approach for rapid parallel detection of microorganisms and typing of different nucleic acid signature sequences from environmental samples.

An enrichment culture dominated by one type of Dehalococcoides sp. (83% of clones) was characterised. This culture, originally derived from contaminated groundwater from the area of Bitterfeld- Wolfen ( Saxony- Anhalt, Germany), dehalogenates chlorinated ethenes to ethene. Further, the culture also dehalogenated vinyl bromide ( VB) and 1,2-dichloroethane ( DCA) to ethene, 1,2,3,4- and 1,2,3,5-tetrachlorobenzene ( Te CB), penta- and hexachlorobenzene ( Pe CB and HCB) to trichlorobenzenes ( TCB), lindane to monochlorobenzene ( MCB) and pentachlorophenol ( PCP) to 2,3,4,6-tetrachlorophenol ( Te CP). Growth was proven by quantitative PCR for all active cultures, except for those with Te CB, lindane and PCP. The growth yields obtained ranged from (2.9 ± 0.7) × 107 cells μmol−1 Br− released on VB to (34.8 ± 5.4) × 107 cells μmol−1 Cl− released on VC. Genes coding for nine putative reductive dehalogenases, the enzymes that mediate the respiratory process of dehalogenation, were identified. Phylogenetic analysis revealed eight reductive dehalogenases with similar sequences in other Dehalococcoides strains and one unique sequence. [ABSTRACT FROM AUTHOR]

A Dehalococcoides-dominated culture coupling reductive dechlorination of tetrachloroethene (PCE) to ethene to growth was enriched from a European field site for the first time. Microcosms were set up using groundwater from a chlorinated ethene-contaminated anaerobic aquifer in Bitterfeld (Germany). Active, lactate-amended microcosms capable of PCE dechlorination to ethene without the accumulation of intermediates were used for further enrichment. After three transfers on lactate as an electron donor and PCE as an electron acceptor, the enrichment was transferred to parallel cultures with one of the chlorinated ethenes as an electron acceptor and acetate and hydrogen as the carbon and energy source, respectively. After three more transfers, a highly purified culture was derived that was capable of dechlorinating PCE with hydrogen and acetate as the electron donor and carbon source, respectively. PCR, followed by denaturing gradient gel electrophoresis, cloning and sequencing revealed that this culture was dominated by a Dehalococcoides sp. belonging to the Pinellas group. Investigation of substrate specificity in the parallel cultures suggested the presence of a novel Dehalococcoides that can couple all dechlorination steps, from PCE to ethene, to energy conservation. Quantitative real-time PCR confirmed growth with PCE, cis-dichloroethene, 1,1-dichloroethene or vinyl chloride as electron acceptors. The culture was designated BTF08 due to its origin in Bitterfeld. [ABSTRACT FROM AUTHOR]

Agricultural wastes are considered as the most important biomass for anaerobic digesters due to the high energy content, high abundance, and low costs. However, complex lignocellulosic structure limits the hydrolysis of these materials. Thus, effective lignocellulose degradation strategies are developing to enhance the hydrolysis rate. The aim of this study is to enrich microbial consortia that degrade lignocellulosic biomass from the hindgut of Pachnoda marginata larvae. Within this scope, Pachnoda marginata larvae kept on a lignocellulose rich diet for 3 weeks and then dissected. The hindgut compartment was transferred to culture bottles. Bacterial community compositions were examined by amplicon sequencing of the 16S rRNA gene on the Illumina MiSeq platform, methanogenic archaeal communities were determined by the T-RFLP method. Biogas production was increased over time and methane production was observed in all bottles. The bacterial community profile of the enrichment culture was shifted as a result of the enrichment procedure with particularly the abundance of Porphyromonadaceae (phylum: Bacteroidetes) increasing during prolonged subcultivation. The methanogenic community was dominated by Methanobrevibacter. Our results show the successful establishment of an enrichment culture from the gut system of Pachnoda marginata larvae that effectively degrades complex lignocellulose rich biomass. [ABSTRACT FROM AUTHOR]

Flexible biogas production that adapts biogas output to energy demand can be regulated by changing feeding regimes. In this study, the effect of changes in feeding intervals on process performance, microbial community structure, and the methanogenesis pathway was investigated. Three different feeding regimes (once daily, every second day, and every 2 h) at the same organic loading rate were studied in continuously stirred tank reactors treating distiller's dried grains with solubles. A larger amount of biogas was produced after feeding in the reactors fed less frequently (once per day and every second day), whereas the amount remained constant in the reactor fed more frequently (every 2 h), indicating the suitability of the former for the flexible production of biogas. Compared to the conventional more frequent feeding regimes, a methane yield that was up to 14% higher and an improved stability of the process against organic overloading were achieved by employing less frequent feeding regimes. The community structures of bacteria and methanogenic archaea were monitored by terminal restriction fragment length polymorphism (T-RFLP) analysis of 16S rRNA and mcrA genes, respectively. The results showed that the composition of the bacterial community varied under the different feeding regimes, and the observed T-RFLP patterns were best explained by the differences in the total ammonia nitrogen concentrations, H2 levels, and pH values. However, the methanogenic community remained stable under all feeding regimes, with the dominance of the Methanosarcina genus followed by that of the Methanobacterium genus. Stable isotope analysis showed that the average amount of methane produced during each feeding event by acetoclastic and hydrogenotrophic methanogenesis was not influenced by the three different feeding regimes., (Copyright © 2016, American Society for Microbiology. All Rights Reserved.)