• Energy Research

A new method for CO2 recovery was proposed for cultivation of different microalgae. First, a chemical fixation, where CO2 was injected in alkalinized vinasse to form (bi)carbonate salts, was performed. In addition, biological fixation with CO2-enriched air injection was also accomplished for evaluation of the most promising results. Two bioreactor systems, a stirred-tank reactor and a bubble column reactor, were employed. A higher carbon transfer rate (43.35 g.L-1.h-1) was achieved in the bubble column reactor using NaOH-alkalinized vinasse, along with reductions of the chemical oxygen demand (COD), biological oxygen demand (BOD) and turbidity (TD). This allowed the cultivation of microalgae and cyanobacteria at vinasse concentrations between 70 and 100%, reaching a biomass production of 2.25 g.L-1 in 15 days of culture. The viability of chemical CO2 fixation together with the use of 100% treated vinasse from a bioethanol production unit for microalgae cultivation has been demonstrated in a successfully integrated biorefinery approach.

Photobioreactors (PBRs) are equipment of central importance for the massive cultivation of microalgae, providing controlled conditions for high cell productivity. There are a few popular PBR designs, with contrasting advantages and limitations, such as poor light distribution, mass transfer, or hydrodynamic behavior. Due to the environmental concerns in recent decades and the discovery of new, useful microalgal metabolites, the interest in finding alternatives to solve technological bottlenecks of PBRs has intensified. In this process, new geometries, materials, and modes of light supply were developed, generating a significant scientific and technological output, reported in papers and patents. We present a technological landscape analysis of photobioreactor design, focusing on improvements of the classical geometries and trends in industrial photobioreactors. The analysis of 412 patent documents showed a surge in innovation filing since 2005 and a reduction in the number of new documents along the last decade. The recent efforts in design improvement, the leading countries, institutes and companies that innovate, and the trends in PBR technology are presented and discussed.

The importance of forest ecosystems for ecological balance and as a reservoir of genetic heritage and biodiversity is evident, the need for conservation is further exalted by the great anthropic pressure suffered by these ecosystems due to the increasing demand of the forest sector. The possibility of using biotechnological practices to combine conservation with sustainable economic development emerges as a promising alternative for the recovery and use of forest species, especially those threatened with extinction. The aims of the article is to demonstrate the main aspects of Forest Biotechnology with regard to conservation and the continuity of the supply of the demand of the economic sector. The central role of wood in economic development has led to the intense exploitation of forest ecosystems, which has resulted in the loss of biodiversity and reduced capacity to meet the demands of the sector. The tools of forest biotechnology, when employed in the optimization of conservation, allow a compatibilization with commercial production, acting as instruments of sustainable development. Forestry Biotechnology acts as an instrument to reconcile conservation with economic development, including forests at the heart of a strategy for a sustainable future.

Propionic acid (PA) is widely used as additive in animal feed and also in the manufacturing of cellulose-based plastics, herbicides, and perfumes. Salts of propionic acid are used as preservative in food. PA is mainly produced by chemical synthesis. Nowadays, PA production by fermentation of low-cost industrial wastes or renewable sources has been an interesting alternative. In the present investigation, PA production by Propionibacterium acidipropionici ATCC 4965 was studied using a basal medium with sugarcane molasses (BMSM), glycerol or lactate (BML) in small batch fermentation at 30 and 36 degrees C. Bacterial growth was carried out under low dissolved oxygen concentration and without pH control. Results indicated that P. acidipropionici produced more biomass in BMSM than in other media at 30 degrees C (7.55 g l(-1)) as well as at 36 degrees C (3.71 g l(-1)). PA and biomass production were higher at 30 degrees C than at 36 degrees C in all cases studied. The best productivity was obtained by using BML (0.113 g l(-1) h(-1)), although the yielding of this metabolite was higher when using glycerol as carbon source (0.724 g g(-1)) because there was no detection of acetic acid. By the way, when using the other two carbon sources, acetic acid emerged as an undesirable by-product for further PA purification.

The National Alcohol Program--PróAlcool, created by the government of Brazil in 1975 resulted less dependency on fossil fuels. The addition of 25% ethanol to gasoline reduced the import of 550 million barrels oil and also reduced the emission CO(2) by 110 million tons. Today, 44% of the Brazilian energy matrix is renewable and 13.5% is derived from sugarcane. Brazil has a land area of 851 million hectares, of which 54% are preserved, including the Amazon forest (350 million hectares). From the land available for agriculture (340 million hectares), only 0.9% is occupied by sugarcane as energy crop, showing a great expansion potential. Studies have shown that in the coming years, ethanol yield per hectare of sugarcane, which presently is 6000 L/ha, could reach 10,000 L/ha, if 50% of the produced bagasse would be converted to ethanol. This article describes the efforts of different Brazilian institutions and research groups on second generation bioethanol production, especially from sugarcane bagasse.

Abstract This work deals with the utilization of soybean molasses (a low cost byproduct) to produce ethanol, an important biofuel, using the microorganism Zymomonas mobilis NRRL 806, a gram negative bacterium. At the first part of the work, laboratorial scale tests, using 125 mL flasks were performed to evaluate the effect of three variables on ethanol production: soybean molasses concentration (the sole carbon and nitrogen source), pH and period of previous aerobial phase. The optimal soybean concentration was around 200 g L-1 of soluble solids, pH between 6.0 and 7.0, and the period of previous aerobial phase did not provide significant effect. At the second part, kinetic tests were performed to compare the fermentation yields of Zymomonas mobilis NRRL 806 in flasks and in a bench scale batch reactor (it was obtained respectively 78.3% and 96.0% of the maximum theoretical yields, with productions of 24.2 and 29.3 g L-1 of ethanol). The process with a reactor fermentation using Saccharomyces cerevisiae LPB1 was also tested (it was reached 89.3% of the theoretical maximum value). A detailed kinetic behavior of the molasses sugars metabolism for Z. mobilis was also shown, either in reactor or in flasks. This work is a valuable tool for further works in the subject of ethanol production from agro-industrial by-products.

The aim of this work was to develop an economical bioprocess to produce the bio-ethanol from soybean molasses at laboratory, pilot and industrial scales. A strain of Saccharomyces cerevisiae (LPB-SC) was selected and fermentation conditions were defined at the laboratory scale, which included the medium with soluble solids concentration of 30% (w/v), without pH adjustment or supplementation with the mineral sources. The kinetic parameters - ethanol productivity of 8.08g/Lh, YP/S 45.4%, YX/S 0.815%, m 0.27h(-1) and microX 0.0189h(-1) - were determined in a bench scale bioreactor. Ethanol production yields after the scale-up were satisfactory, with small decreases from 169.8L at the laboratory scale to 163.6 and 162.7L of absolute ethanol per ton of dry molasses, obtained at pilot and industrial scales, respectively.