Dark fermentation effluent as substrate for hydrogen production from Rhodobacter capsulatus highlighting the performance of different fermentation systems.

Hydrogen production by biological route is a potentially sustainable alternative. Nowadays, energy production from sustainable sources has become urgent for several countries as well as for international policies. In this perspective, hydrogen has gained substantial global attention as clean, sustainable, and versatile energy carrier. In the current work, the resulting effluent from dark fermentation, rich in organic acids, was used as substrate for the purple non-sulfur bacteria (PNS) Rhodobacter capsulatus. In the first stage, experiments were carried out in bioreactors of 50 mL to check the influence of the composition of the effluent dark fermentation. The results proved that the provision of a sugar source improved bio-H2 production. The lactose and lactic acid concentrations exceeding 4.4 and 12 g/L, respectively, resulted in a productivity of up to 37.14 mmol H2/L days. Based on initial conditions obtained on the previous assays, in the second stage, a photo-fermentation in enlarged scale (1.5 L) was performed with the purpose to monitor the production of hydrogen and metabolites, sugar consumption and growth cells during the process. It was observed that the maximum productivity obtained was 98.23 mmol H2/L days in 26 h of process.

Alternative techniques to improve hydrogen production by dark fermentation.

The production of biofuels as an alternative to the fossil fuels has been mandatory for a cleaner and sustainable process. Hydrogen is seen as the fuel of the future because it has a very high energy density and its use produces only water instead of greenhouse gases and other exhaust pollutants. The biological synthesis of hydrogen by dark fermentation complies with these criteria. In the current work, the use of cheese whey permeate was evaluated aiming hydrogen production by dark fermentation using a microbial consortium in the semi-continuous process, with a reaction volume of 700 mL. The volume of the medium renewal and the frequency of replacements of fresh medium were evaluated to extend the production of H2. It is important to note decreases in the hydrogen production after 84 h. The target-product content became higher particularly when 466 mL of medium were withdrawn, in every 24 h in the first two replacements and, subsequently, in every 12 h. Besides, it was observed lower lactic acid concentration under this condition, suggesting that the shorter removal time of the medium could inhibit lactic acid bacteria, which may secrete bacteriocins that inhibit the hydrogen-producing microorganisms.

Evaluation of the temperature effect on vegetable oils by chemical analysis and ultraviolet­visible spectroscopy / Avaliação do efeito da temperature em óleos vegetais por analyses químicas e espectroscopia ultravioleta visível

Several methodologies could be used to characterize vegetable oil besides estimating thermal modification provided by high temperatures. These techniques are used as a proper tool to determine compositional and functional analysis of food ingredients and finished products. In general, vegetable oils are extracted from seeds like the rapeseed (canola oil) soybean (soybean oil), among others. In the present study vegetable oils such as canola and soybean were heated at a temperature of 100°C from 1h up to 28 h and the degraded products were measured to assess the oil stability at temperature. The determination of acid number, peroxide value and iodine number by chemical analysis was carried out for the estimation of the oxidative heat stability of these oils. Ultraviolet­visible spectroscopy strategy was also used to better comprehend this phenomenon, since it greatly improve the performance of measurements, in order to step up sensitivity. The findings demonstrated that vegetable oils thermal deteriorated as seen in the batocromic displacement of the samples heated and increasing the specific absorption in 350 nm. These data were capable to highlight the differences observed in the degree of unsaturation of oils.

Inúmeras metodologias podem ser utilizadas para caracterizar óleos vegetais, além de estimar modificações térmicas ocasionadas por altas temperaturas. Estas técnicas são usadas como ferramentas específicas para determinar a composição e função de ingredientes em alimentos e em produtos finais processados. Em geral, óleos vegetais são extraídos de sementes como a colza ou soja, entre outros. No presente trabalho, óleos vegetais como canola e soja foram aquecidos a temperatura de 100 °C entre 1 e 28 horas e os produtos de degradação foram medidos para avaliar a estabilidade do óleo na temperatura. As determinações da acidez, índice de peróxido e índice de iodo por análises químicas foram realizadas para estimar a estabilidade e a oxidação térmica dos óleos. A espectroscopia ultravioleta visível foi uma estratégia também utilizada para melhor compreender este fenômeno, uma vez que esta técnica aumenta o desempenho nas quantificações e quando se objetiva o incremento na sensibilidade. Os resultados demonstraram a deterioração térmica dos óleos vegetais através do deslocamento batocrômico das amostras aquecidas e o aumento da absorção a 350 nm. Estes dados ressaltam as diferenças observadas no grau de insaturação dos óleos.

Conventional and volatile salts as precipitating agents for recombinant antiviral protein / Sais convencionais e voláteis como agentes de precipitação para proteína recombinante com ação antiviral

Recombinant proteins expressed in cell culture have been shown to be relevant in the biopharmaceutical production focusing human health. The current work investigated the precipitation process of recAVLOEc protein, synthesized by E. coli BL21 (DE3) pLysS cells. The system is used for the AVLO expression that shown antiviral activity and it was found in the hemolymph of Lonomia obliqua caterpillar. The precipitation was conducted by the use of conventional salts (ammonium sulfate and sodium sulfate) and the volatile ammonium carbamate salt. Initially, the precipitated protein obtained from bacterial lysate was added to L929 cells to evaluate the cytotoxic effect; and besides Vero cells were infected with measles virus to verify the antiviral action of the precipitated recombinant protein. Toxic effect on the culture of L929 cells was observed for the precipitate obtained by the use of ammonium sulfate and sodium sulfate. In addition, tests in L929 cell cultures infected with EMC virus showed that samples of precipitated protein by salts did not show antiviral action. In Vero cell cultures, the precipitated protein by sodium sulfate showed antiviral action for measles virus.

Proteínas recombinantes expressas em culturas celulares têm se mostrado importantes na produção de fármacos de interesse para a saúde humana. Este estudo investigou a precipitação da proteína recAVLOEc, sintetizada por células de E. coli BL21 (DE3) pLysS, utilizadas como sistema de expressão da AVLO, proteína com atividade antiviral, originalmente encontrada na hemolinfa da lagarta Lonomia obliqua. A precipitação foi conduzida por meio do uso de sais convencionais (sulfato de amônio e de sódio) e do sal volátil carbamato de amônio. Inicialmente o precipitado proteico obtido do lisado bacteriano foi administrado em culturas de células L929 para avaliar o efeito citotóxico e posteriormente em células Vero infectadas com o vírus do sarampo, para a verificação da ação antiviral. Um efeito tóxico em culturas de L929 foi observado para os precipitados obtidos pelo uso de sulfato de amônio e de sódio. Testes em culturas de L929 infectadas com o vírus EMC foram também efetuados e as amostras de proteínas precipitadas com os sais convencionais e o sal volátil não resultaram em ação antiviral. Em culturas de células Vero, o uso do sulfato de sódio como agente de precipitação das proteínas contidas no lisado bacteriano resultou em ação antiviral para o sarampo.

Replacement of sugars to hydrogen production by Rhodobacter capsulatus using dark fermentation effluent as substrate.

Hydrogen is a promising alternative for the increased global energy demand since it has high energy density and is a clean fuel. The aim of this work was to evaluate the photo-fermentation by Rhodobacter capsulatus, using the dark fermentation effluent as substrate. Different systems were tested by changing the type of sugar in the dark fermentation, investigating the influence of supplementing DFE with sugar and adding alternate and periodically lactose and glucose throughout the process. The supplementation of the DFE with sugar resulted in higher H2 productivity and the replacement of the sugars repeatedly during the photo-fermentation process was important to maintain the cell culture active. By controlling the residual amount of sugar, bacteria inhibition was avoided; lactic acid, that was toxic to the biomass, was consumed and the metabolic route of butyric acid production was predominant. Under optimum conditions, the H2 productivity reached 208.40mmolH2/Ld in 52h.

Prospective technology on bioethanol production from photofermentation.

The most important global demand is the energy supply from alternative source. Ethanol may be considered an environmental friendly fuel that has been produced by feedstock. The production of ethanol by microalgae represent a process with reduced environmental impact with efficient CO2 fixation and requiring less arable land. This work studied the production of ethanol from green alga Chlamydomonas reinhardtii through the cellular metabolism in a light/dark cycle at 25 °C in a TAP medium with sulfur depletion. The parameters evaluated were inoculum concentration and the medium supplementation with mixotrophic carbon sources. The combination of C.reinhardtii and Rhodobacter capsulatus through a hybrid or co-culture systems was also investigated as well. C.reinhardtii maintained in TAP-S produced 19.25±4.16 g/L (ethanol). In addition, in a hybrid system, with medium initially supplemented with milk whey permeated and the algal effluent used by R. capsulatus, the ethanol production achieved 19.94±2.67 g/L.