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Endurance of methanogenic archaea in anaerobic bioreactors treating oleate-base...
Salvador, A. F.; Cavaleiro, A. J.; Sousa, D. Z.; Alves, M. M.; Pereira, M. A.Methanogenic archaea are reported as very sensitive to lipids and long chain fatty acids (LCFA). Therefore, in conventional anaerobic processes, methane recovery during LCFA-rich wastewater treatment is usually low. By applying a start-up strategy, based on a sequence of step feeding and reaction cycles, an oleate-rich wastewater was efficiently treated at an organic loading rate of 21 kg COD m(-3) day(-1) (50 ...
Biomethanation potential of biological and other wastes
Costa, J. C.; Sousa, D. Z.; Pereira, M. A.; Stams, A. J. M.; Alves, M. M.Anaerobic technology has been traditionally applied for the treatment of carbon rich wastewater and organic residues. Anaerobic processes can be fully integrated in the biobased economy concept for resource recovery. After a brief introduction about applications of anaerobic processes to industrial wastewater treatment, agriculture feedstock and organic fraction of municipal solid waste, the position of anaerob...
Atrazine dissipation and its impact on the microbial communities and community ...
Tortella, G.; Mella-Herrera, R.; Sousa, D. Z.; Rubilar, Olga; Acuña, J. J.; Briceño, G.; Diez, M. C.The effects of repeated atrazine application (40mg a.i.kg-1) on its degradation, microbial communities and enzyme activities were studied in a peat based biomixture composed by straw, soil and peat in the volumetric proportions of 2:1:1 that can be used in on-farm biopurification system. Atrazine removal efficiency was high (96%, 78% and 96%) after each atrazine application and did not show a lag phase. Microbi...
Extreme thermophilic biohydrogen production from arabinose and glucose
Abreu, A. A.; Karakashev, Dimitar; Angelidaki, I.; Sousa, D. Z.; Alves, M. M.Continuous hydrogen production rate from arabinose was significantly higher than from glucose, when higher organic loading rate was used. This fact was associated to higher lactate production in the reactor fed with glucose. The higher concentration of lactate was not a consequence of bacterial community shift, and is likely related to changes in the main metabolic pathways of glucose catabolism.
Addition of electron acceptors stimulates methanogenesis from lipids by anaerob...
Guedes, Ana P.; Cavaleiro, A. J.; Silva, Sérgio; Alves, M. M.; Stams, A. J. M.; Sousa, D. Z.Incubation of anaerobic sludge with triolein or oleate in the presence of nitrate or sulphate led to an increased methane production, relatively to incubations without inorganic electron acceptor. Faster methane production was obtained in assays amended with nitrate. Methanogenesis occurred after the reduction of alternative electron acceptors.
ProFuelDB : an open-access database of physiological properties of biofuel-prod...
Lourenço, C. P.; Pereira, M. A.; Lourenço, Anália; Sousa, D. Z.Anaerobic microorganisms are attractive for the synthesis of fuels and chemicals, but information on the physiology of culturable anaerobes is dispersed in scientific literature. Herewith we present the ProFuelDB, a web-based publicly available database prototype compiling information on the physiology of anaerobic prokaryotes with relevance for biofuels production. It is foreseen that this prototype will evolv...
Metaproteomics of anaerobic microbial communities degrading long-chain fatty acids
Salvador, A. F.; Bize, A.; Alves, M. M.; Bouchez, T.; Sousa, D. Z.The anaerobic conversion of long-chain fatty acids (LCFA), and specifically the difference between the degradation of unsaturated- and saturated-LCFA, is not fully understood. In this work, syntrophic degradation of stearate (C18:0) and oleate (C18:1) was studied. A comparative metaproteomics approach, in which proteins were analyzed by LC-MS/MS, was combined with 16S rRNA gene pyrosequencing. Saturated- and un...
Effect of pH and pressure on syngas fermentation by anaerobic mixed cultures
Pereira, F. M.; Alves, M. M.; Sousa, D. Z.Syngas fermentation by mesophilic anaerobic mixed cultures was studied, regarding the effect of initial medium pH (5.8, 6.9 and 7.6) and total initial syngas pressure (1.0, 1.75 and 2.5 atm) in methane production and other alternative products (acids and alcohols). Complete consumption of CO and H2 was achieved in less than 72 h at 1.0 atm syngas, and within 240 h for higher syngas pressures. The highest specif...
Non-syntrophic reactions in anaerobic unsaturated LCFA conversion by methanogen...
Cavaleiro, A. J.; Pereira, M. A.; Stams, A. J. M.; Alves, M. M.; Sousa, D. Z.Lipids are energy-rich compounds. This energy can be conserved as biogas in anaerobic bioreactors but the process is frequently hindered by long-chain fatty acids (LCFA) accumulation. LCFA catabolism is thought to occur via beta-oxidation, performed by anaerobic bacteria that live in obligatory syntrophy with H2 consuming methanogens, but the initial steps of unsaturated LCFA biodegradation are still unclear. I...
Enrichment and microbial characterization of syngas converting anaerobic cultures
Alves, J. I.; Visser, Michael; Stams, A. J. M.; Plugge, Caroline M.; Alves, M. M.; Sousa, D. Z.Bioconversion of recalcitrant biomass/waste into bulk chemicals or biofuels is often not feasible. By gasification of these materials, syngas (mainly composed of CO2, CO and H2) is generated and can be used for the production of high value compounds by thermochemical or biotechnological processes. Here, three thermophilic cultures enriched with syngas mixtures or pure CO (T-Syn, T-Syn-CO and T-CO) were studied....
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