Paula Rúbia Ferreira Rosa

Hydrogen production from cheese whey with ethanol-type fermentation: Effect of hydraulic retention time on the microbial community composition

The effects of different hydraulic retention times (HRTs) of 4, 2, and 1h and varying sources of inoculum (sludge from swine and sludge from poultry) on the hydrogen production in two anaerobic fluidized bed reactors (AFBRs) were evaluated. Cheese whey was used as a substrate, and 5000mgCODL(-1) was applied. The highest hydrogen yield (HY) of 1.33molmol(-1) lactose and highest ethanol yield (EtOHY) of 1.22molEtOHmol(-1) lactose were obtained at the highest HRT (4h). When the reactors were operated at an HRT of 1h, methane (0.68LCH4h(-1)L(-1)) was produced concurrently with hydrogen (0.51LH2h(-1)L(-1)). The major metabolites observed were soluble ethanol, methanol, acetic acid, and butyric acid. Cloning of the 16S rRNA gene sequences indicated that the microbial community were affiliated with the genera Selenomonas sp. (69% of the sequences), and Methanobacterium sp. (98% of the sequences).

Organic loading rate impact on biohydrogen production and microbial communities at anaerobic fluidized thermophilic bed reactors treating sugarcane stillage.

This study aimed to evaluate the effect of high organic loading rates (OLR) (60.0-480.00 kg COD m(-3)d(-1)) on biohydrogen production at 55°C, from sugarcane stillage for 15,000 and 20,000 mg CODL(-1), in two anaerobic fluidized bed reactors (AFBR1 and AFBR2). It was obtained, for H2 yield and content, a decreasing trend by increasing the OLR. The maximum H2 yield was observed in AFBR1 (2.23 mmol g COD added(-1)). The volumetric H2 production was proportionally related to the applied hydraulic retention time (HRT) of 6, 4, 2 and 1h and verified in AFBR1 the highest value (1.49 L H2 h(-1)L(-1)). Among the organic acids obtained, there was a predominance of lactic acid (7.5-22.5%) and butyric acid (9.4-23.8%). The microbial population was set with hydrogen-producing fermenters (Megasphaera sp.) and other organisms (Lactobacillus sp.).

Chemometric tools in chemical fractionation data of soil samples from five antarctic research stations

Este estudo foi centrado na avaliacao quimica de amostras de solos provenientes de diversas estacoes de pesquisa na Antartica. Amostras de solos de referencia foram coletadas em locais com minimo impacto antropico, distantes das estacoes de pesquisa. Locais selecionados nas vizinhancas das estacoes Frei Montalva e Escudero (Chile), Grande Muralha (China), Bellingshausen (Russia) e Artigas (Uruguai) foram os pontos a priori supostamente antropizados deste estudo. O procedimento de extracao sequencial (SEP) baseado no protocolo proposto pelo BCR (Community Bureau of Reference) foi aplicado para a determinacao de Cu, Mn e Zn. Com o auxilio dos metodos PCA (analise de componentes principais) e PARAFAC (analise de fatores paralelos) foram extraidas informacoes significativas a partir dos dados brutos obtidos com SEP. As amostras de solos afetadas pelas estacoes de pesquisa estao associadas com elevadas concentracoes de metais pesados (especialmente Cu e Zn, dentre os elementos investigados, nas fracoes mais labeis de SEP aplicado). Este indicio de contaminacao esta relacionado com o uso de oleo diesel para geracao de energia pelas estacoes antarticas. The aim of this study was to carry out a broad chemical investigation of selected soil samples from Antarctica, near different Antarctic scientific stations. Soil samples collected in background reference sites, with minimal human impact, far away from the stations were used as control samples. Anthropogenic places at the vicinity of the following stations Frei Montalva and Escudero (Chile), Great Wall (China), Bellingshausen (Russia) and Artigas (Uruguay) were studied as a priori human impacted sites. The sequential extraction procedure (SEP) based on the BCR (Community Bureau of Reference) protocol was applied for Cu, Mn and Zn determination. With the help of PCA (principal component analysis) and PARAFAC (parallel factor analysis) methods, meaningful information was extracted from the raw data obtained from SEP procedure. Soil samples affected by the scientific stations are associated with higher heavy metal contents (especially Cu and Zn, between the investigated metals, in the most labile fractions of the SEP applied). This pollution signal is associated with diesel use for the energy generation by the Antarctic stations.

Review of Continuous Fermentative Hydrogen-Producing Bioreactors from Complex Wastewater

In recent years, the production of hydrogen through dark fermentation has become increasingly popular because it is a sustainable approach to produce clean energy. Thus, an evaluation of studies reported on hydrogen production from different complex wastewaters will be of immense importance in economizing production technologies. This work presents a review of the advances in the bioreactor and bioprocess design for biohydrogen production from different complex wastewaters. The biohydrogen production is discussed emphasizing the production metabolic pathways, bioreactor configuration and operation, organic loading rate (OLR), pretreatment of wastewater, as well as microbial diversity. Also, in this review, various bioreactor configurations and performance parameters including H 2 yield (HY) and hydrogen production rate (HPR) are evaluated and presented. The work concludes with challenges and prospects of biohydrogen production and claims for more systematic and comprehensive studies on the subject.