Juliana de Souza Ferreira

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.

Creamatocrit as a rapid method to estimate the contents of total milk lipids

The Gerber test has been extensively used as an extremely accurate standard method for determining the content of milk lipids. However, it is risky to laboratory workers and hazardous to the environment due to the need for use of reagents. The research and development of alternative methods is of great importance especially for industrial application. In this work, the Creamatocrit method is evaluated to estimate the content of milk fatty material from mammals. Capillary tubes were filled with milk samples and centrifuged at 15 000 rpm for 5 min using an adequate micro centrifuge. The total content of lipids was determined by taking the ratio between the cream phase and the total sample length within the capillary tube. The results obtained show a satisfactory correlation (0.968) between the Creamatocrit and Gerber methods. Thus, we propose the use of the Creamatocrit method as an advantageous alternative to the Gerber method for industrial purposes.

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.