Fabiana Regina Xavier Batista

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.

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.

Evaluation of Culture Medium for Human Keratinocytes

Human keratinocytes are needed for tissue engineering of skin applied in tissue repair and regeneration aimed at clinical application. The need to have high cell concentrations within a short time when performing cell proliferation is vital. The growth and maintenance of these cells commonly involve the use of MCDB 153 medium, which is supplemented with animal-derived components, such as growth factors and fetal bovine serum (FBS). The aim of this work was to evaluate different formulations based on MCDB 153 medium for keratinocyte proliferation. For that, several experiments were realized to define which supplements are important for skin cell culture using 24 factorial design. Skin samples were obtained from four consenting patients submitted to dermolipectomy, the plastic surgery operation. These fragments were treated with 0.25% trypsin-EDTA for four hours, at 37oC. Furthermore, the epidermis was separated from the dermis, providing skin cells. Batch cultures were performed in 6 and 96-well plates, in addition to 25 cm2 flasks. Results concerning cell growth and metabolism showed that keratinocytes were full grown up in MCDB 153 medium containing insulin (7.5 µg.mL-1), bovine pituitary extract-BPE (80 µg.mL-1), epidermal growth factor-EGF (0.08 µg.mL-1), hydrocortisone (0.63 µg.mL-1) and glutamine (1 g.L-1). On the other hand, culture media proposed in the experimental design did not resulted in satisfactory cell growth. In addition, although, the initial glucose concentration was low in the most of cases, the lactate was strongly produced by cells reaching 1 g.L-1.