Metataxonomic characterization of the microbial community involved in the production of biogas with microcrystalline cellulose in pilot and laboratory scale.

Biogas, produced in anaerobic digestion, is a sustainable alternative for generating energy from agro-industrial and municipal waste. Information from the microbiota active in the process expands the possibilities for technological innovation. In this study, taxonomic annotations, and functional prediction of the microbial community of the inoculum of two processes were carried out: an industrial unit (pilot-scale urban solid waste plant-IU) and a laboratory-scale reactor fed with swine and cattle waste (LS). The biochemical potential of biogas was obtained using tested inoculum with microcrystalline cellulose, obtaining 682 LN/kgVS (LSC-laboratory scale inoculum and microcrystalline cellulose), and 583 LN/kgVS (IUC-industrial unit inoculum and microcrystalline cellulose), which is equivalent to a recovery of 91.5% of total biogas to LSC. The phyla Synergistota and Firmicutes were more abundant in LS/LSC. In the IU/IUC (treatment of restaurant waste and customs seizures), there was a greater microbiological variety and a predominance of the Bacteroidota, Cloacimonadota, Firmicutes and Caldatribacteriota. The genus Methanosaeta predominated in the process, and it was possible to infer the genes (K01895, K00193 and K00625) related to acetoclastic pathway, as well as endoglucanases that are involved in the metabolism of cellulose (LSC). Terpenoids, polyketides, cofactors, and vitamin metabolism were higher in reactors that received different substrates (IU; IUC). The taxonomic and functional differences revealed the importance of determining the microbiota in the analysis of the potential of an inoculum, combined with the use of microcrystalline cellulose, which can provide optimization information in the production of clean energy.

Seasonal characterization of the prokaryotic microbiota of full-scale anaerobic UASB reactors treating domestic sewage in southern Brazil.

Upflow Anaerobic Sludge Blanket (UASB) reactors are alternatives in the anaerobic treatment of sanitary sewage in different parts of the world; however, in temperate environments, they are subject to strong seasonal influence. Understanding the dynamics of the microbial community in these systems is essential to propose operational alternatives, improve projects and increase the quality of treated effluents. In this study, for one year, high-performance sequencing, associated with bioinformatics tools for taxonomic annotation and functional prediction was used to characterize the microbial community present in the sludge of biodigesters on full-scale, treating domestic sewage at ambient temperature. Among the most representative phyla stood out Desulfobacterota (20.21-28.64%), Proteobacteria (7.48-24.90%), Bacteroidota (10.05-18.37%), Caldisericota (9.49-17.20%), and Halobacterota (3.23-6.55%). By performing a Canonical Correspondence Analysis (CCA), Methanolinea was correlated to the efficiency in removing Chemical Oxygen Demand (COD), Bacteroidetes_VadinHA17 to the production of volatile fatty acids (VFAs), and CI75cm.2.12 at temperature. On the other hand, Desulfovibrio, Spirochaetaceae_uncultured, Methanosaeta, Lentimicrobiaceae_unclassified, and ADurb.Bin063-1 were relevant in shaping the microbial community in a co-occurrence network. Diversity analyses showed greater richness and evenness for the colder seasons, possibly, due to the lesser influence of dominant taxa. Among the principal metabolic functions associated with the community, the metabolism of proteins and amino acids stood out (7.74-8.00%), and the genes related to the synthesis of VFAs presented higher relative abundance for the autumn and winter. Despite the differences in diversity and taxonomic composition, no significant changes were observed in the efficiency of the biodigesters.

Viability of Cabralea canjerana extracts to control the South American fruit fly, Anastrepha fraterculus.

Several representatives of Meliaceae contain biologically active compounds that are toxic to insects with few negative effects on the environment and humans. Our study evaluated the activity of ethyl acetate and ethanol extracts from the fruit and seeds of Cabralea canjerana (Vellozo) Mart (Sapindales: Meliaceae) on Anastrepha fraterculus (Wiedemann) (Diptera: Tephritidae). Limonoids and triterpenes were detected in fruit and seed extracts. Each extract was added to an artificial diet at three concentrations and tested after 24, 48, and 72 hr of extract application. Ethyl acetate extracts were the most active ones and showed the effect of both dose and time elapses after application on the insects. The highest toxic effect on A. fraterculus adults was from ethyl acetate extracts from fruit, followed by extracts from seeds. These extracts showed antifeedant activities. Extract solutions sprinkled on fruits of Carica papaya (L.) (Brassicales: Caricaceae) caused oviposition repellency and negatively affected the biological development of A. fraterculus. Ethyl acetate extracts highly hampered oviposition, but seed extracts showed lesser oviposition deterrence. The fruit and seed extracts diminished pupal viability. Particularly, the ethyl acetate fruit extract caused malformed adults. The sex ratio was also affected, resulting in female predominance for the fruit extract, while the seed extract showed a dose-dependent effect. Low doses caused male abundance, but at higher concentrations the effect was reversed. These encouraging results showed that the C. canjerana extracts have great potential as new tools to be used in integrated pest management programs to protect fruits against A. fraterculus.