Adalberto Pessoa

Inulin-type fructans: a review on different aspects of biochemical and pharmaceutical technology.

Inulin is a natural storage polysaccharide with a large variety of food and pharmaceutical applications. It is widely distributed in plants, being present as storage carbohydrate in more than 30,000 vegetable products. Due to their wide distribution in nature and significant role in industry, the extraction, isolation and characterization of inulin-type fructans are gaining attention in recent years. Inulin sources have recently received increasing interest as they are a renewable raw material for the production of bioethanol, fructose syrup, single-cell protein and single cell oil, obtainment of fructooligosaccharides and other useful products. This review focuses on the state-of-the-art of biochemical and pharmaceutical technology of inulin-type fructans.

Cellular and molecular mechanisms in the hypoxic tissue: role of HIF-1 and ROS

Reactive oxygen species such as superoxide anion radicals (O2−) and hydrogen peroxide (H2O2) have for long time been recognized as undesirable by‐products of the oxidative mitochondrial generation of adenosine triphosphate (ATP). Recently, these highly reactive species have been associated to important signaling pathways in diverse physiological conditions such as those activated in hypoxic microenvironments. The molecular response to hypoxia requires fast‐acting mechanisms acting within a wide range of partial pressures of oxygen (O2). Intracellular O2 sensing is an evolutionary preserved feature, and the best characterized molecular responses to hypoxia are mediated through transcriptional activation. The transcription factor, hypoxia‐inducible factor 1 (HIF‐1), is a critical mediator of these adaptive responses, and its activation by hypoxia involves O2‐dependent posttranslational modifications and nuclear translocation. Through the induction of the expression of its target genes, HIF‐1 coordinately regulates tissue O2 supply and energetic metabolism. Other transcription factors such as nuclear factor κB are also redox sensitive and are activated in pro‐oxidant and hypoxic conditions. The purpose of this review is to summarize new developments in HIF‐mediated O2 sensing mechanisms and their interactions with reactive oxygen species–generating pathways in normal and abnormal physiology. Copyright

Recovery of inulinase using BDBAC reversed micelles

Inulinase from Candida kefyr was extracted into a reversed micelle phase of the cationic surfactant BDBAC in organic solvents (isooctane/hexanol). Factors affecting the efficiency of the reversed micellar forward-extraction including pH, concentration and type of salts, solvent/co-solvent volume ratio, surfactant concentration, buffer concentration and temperature were investigated. A high micelle size (wo ∼ 120 or RM ∼ 18 nm) was necessary to achieve almost complete inulinase solubilization in the micellar phase, which could be generated by raising the temperature to 37°C. Some parameters for optimization of the back-extraction to a fresh aqueous phase were also investigated. Under optimum conditions of forward and backward-extraction, about 90% of the total enzyme was recovered and the specific activity of the inulinase increased some 3-fold.

Perspectives on Bioenergy and Biotechnology in Brazil

Brazil is one of the world’s largest producers of alcohol from biomass at low cost and is responsible for more than 1 million direct jobs. In 1973, the Brazilian Program of Alcohol (Proalcool) stimulated the creation of a bioethanol industry that has led to large economic, social, and scientific improvements. In the year 1984, 94.5% of Brazil’s cars used bioethanol as fuel. In 2003/2004, 350.3 million of sugarcane produced 24.2 million t of sugar and 14.4 billion L of ethanol for an average 4.3 million cars using ethanol. Since its inception, cumulative investment in Proalcool totals US

Liquid-liquid extraction of commercial and biosynthesized nisin by aqueous two-phase micellar systems.

11 billion, and Brazil has saved US

Marine-derived fungi: diversity of enzymes and biotechnological applications

27 billion in oil imports. The ethanol production industry from sugarcane generates 152 times more jobs than would have been the case if the same amount of fuel was produced from petroleum, and the use of ethanol as a fuel is advantageous for environmental reasons. In 2003, one of the biggest Brazilian ethanol industries started consuming 50% of the residual sugarcane bagasse to produce electrical energy (60 MW), a new alternative use of bioenergy for the Brazilian market. Other technologies for commercial uses of bagasse are in development, such as in the production of natural fibers, sweeteners (glucose and xylitol), single-cell proteins, lactic acid, microbial enzymes, and many other products based on fermentations (submerged and semisolid). Furthermore, studies aimed at the increase in the biosynthesis of sucrose and, consequently, ethanol productivity are being conducted to understand the genetics of sugarcane. Although, at present, there remain technical obstacles to the economic use of some ethanol industry residues, several research projects have been carried out and useful data generated. Efficient utilization of ethanol industry residues has created new opportunities for new value-added products, especially in Brazil, where they are produced in high quantities.

Scale-up of diluted sulfuric acid hydrolysis for producing sugarcane bagasse hemicellulosic hydrolysate (SBHH)

Nisin is a natural additive for conservation of food, and can also be used as a therapeutic agent. Nisin inhibits the outgrowth of spores, the growth of a variety of Gram-positive and Gram-negative bacteria. In this paper we present a potentially scalable and cost-effective way to purify commercial and biosynthesized in bioreactor nisin, including simultaneously removal of impurities and contaminants, increasing nisin activity. Aqueous two-phase micellar systems (ATPMS) are considered promising for bioseparation and purification purposes. Triton X-114 was chosen as the as phase-forming surfactant because it is relatively mild to proteins and it also forms two coexisting phases within a convenient temperature range. Nisin activity was determined by the agar diffusion assay utilizing Lactobacillus sake as a sensitive indicator microorganism. Results indicated that nisin partitions preferentially to the micelle rich-phase, despite the surfactant concentration tested, and its antimicrobial activity increases. The successful implementation of this peptide partitioning, from a suspension containing other compounds, represents an important step towards developing a separation method for nisin, and more generally, for other biomolecules of interest.

Separation of inulinase from Kluyveromyces marxianus using reversed micellar extraction

The ocean is considered to be a great reservoir of biodiversity. Microbial communities in marine environments are ecologically relevant as intermediaries of energy, and play an important role in nutrient regeneration cycles as decomposers of dead and decaying organic matter. In this sense, marine-derived fungi can be considered as a source of enzymes of industrial and/or environmental interest. Fungal strains isolated from different substrates, such as invertebrates, decaying wood, seawater, sediments, and mangrove detritus, have been reported to be producers of hydrolytic and/or oxidative enzymes, with alginate lyase, amylase, cellulase, chitinase, glucosidase, inulinase, keratinase, ligninase, lipase, nuclease, phytase, protease, and xylanase being among the enzymes produced by fungi of marine origin. These enzymes present temperature and pH optima ranging from 35 to 70∘C, and 3.0 to 11.0, respectively. High-level production in bioreactors is mainly performed using submerged-state fermentation. Certain marine-derived fungal strains present enzymes with alkaline and cold-activity characteristics, and salinity is considered an important condition in screening and production processes. The adaptability of marine-derived fungi to oceanic conditions can be considered an attractive point in the field of fungal marine biotechnology. In this review, we focus on the advances in discovering enzymes from marine-derived fungi and their biotechnological relevance.

Enhanced Xylitol Production by Precultivation of Candida guilliermondii Cells in Sugarcane Bagasse Hemicellulosic Hydrolysate

Sugarcane bagasse was pretreated with diluted sulfuric acid to obtain sugarcane bagasse hemicellulosic hydrolysate (SBHH). Experiments were conducted in laboratory and semi-pilot reactors to optimize the xylose recovery and to reduce the generation of sugar degradation products, as furfural and 5-hydroxymethylfurfural (HMF). The hydrolysis scale-up procedure was based on the H-Factor, that combines temperature and residence time and employs the Arrhenius equation to model the sulfuric acid concentration (100 mg(acid)/g(dm)) and activation energy (109 kJ/mol). This procedure allowed the mathematical estimation of the results through simulation of the conditions prevailing in the reactors with different designs. The SBHH obtained from different reactors but under the same H-Factor of 5.45+/-0.15 reached similar xylose yield (approximately 74%) and low concentration of sugar degradation products, as furfural (0.082 g/L) and HMF (0.0071 g/L). Also, the highest lignin degradation products (phenolic compounds) were rho-coumarilic acid (0.15 g/L) followed by ferulic acid (0.12 g/L) and gallic acid (0.035 g/L). The highest concentration of ions referred to S (3433.6 mg/L), Fe (554.4 mg/L), K (103.9 mg/L). The H-Factor could be used without dramatically altering the xylose and HMF/furfural levels. Therefore, we could assume that H-Factor was directly useful in the scale-up of the hemicellulosic hydrolysate production.

LPS removal from an E. coli fermentation broth using aqueous two-phase micellar system

Inulinase from K. marxianus was extracted into a reversed micelle phase of the cationic surfactant BDBAC (n-benzyl-n-dodecyl-n-bis(2-hydroxyethyl)ammonium chloride) in isooctane/hexanol. The extractions carried out with cells (5.9 g/l) presented a recovery yield of 87% and a purification factor 2.8. Similar values were found for inulinase recovered from the clarified medium (91% recovery yield and 2.8 purification factor). For scaled-up (400-fold) extractions, the recovery of the initial activity reached 77% and the enrichment factor was 2.8.