Green chemistry production of biopolymeric film-derived biomaterial prepared using natural alginate and vanillin compounds for application as a biocurative.

The present work presents the results obtained in the production of vanillin-doped alginate biopolymeric film using green chemistry methodology. Alginate dressings are already a therapeutic reality, but they act only by maintaining the appropriate environment for healing. In order to improve their properties, the incorporation of vanillin was proposed due to its antioxidant and antimicrobial potential. Different biopolymeric films were produced employing the experiment planning through response surface analysis, which allowed determining the best region for a medium value of solubility and high degree of swelling. This region refers to values above 0.07 g of CaCl2 and concentrations above 0.024 g of vanillin, triggering solubility between 25 and 30% and a degree of swelling above 100% and with fixed values of alginate (0.85 g). Such data are related to experiments (A), (B), and (C) listed in Table 1. Regarding the optimization of the process, the normal boundary intersection (NBI) method allowed the analysis of concave regions, predicting the optimal points and generating the Pareto chart with equidistant limits. The antimicrobial test allowed observing the antimicrobial activity against Escherichia coli and Pseudomonas aeruginosa microorganisms from the biopolymeric films, as well as a solution of vanillin with calcium chloride and glycerol obtaining a halo of inhibition only in the presence of vanillin, and there was no significant difference between the results obtained in the experiments (A) and (B). The thermal analyses showed that the material has thermal stability in the ideal temperature range (~ 25 °C) for application as a biocurative. We preliminarily concluded that the alginate biopolymeric film doped with vanillin prepared using green chemical methodology presents antimicrobial properties and thermal stability that indicate its potential use as biocurative.

Lipase production by microorganisms isolated from the Serra de Ouro Branco State Park.

Lipases are hydrolases used in various sectors such as the food, pharmaceutical and chemical synthesis industries. In this study, epiphytic microorganisms were isolated from the Serra of Ouro Branco State Park (Minas Gerais, Brazil) and were subsequently evaluated for their ability to produce extracellular lipases. Among the 46 isolated strains, 25 presented positive results for lipase production in the agar plate screening assay. Two of these strains that expressed the highest diffusion halos, were genetically identified as Serratia marcescens and Pseudomonas fluorescens and catalogued in the Tropical Cultures Collection from the André Tosello Foundation/Brazil as CCT 7796 and CCT 7797, respectively. The fermentation growth kinetics indicated that the maximum extracellular lipase activities were achieved between 96 and 120h of cultivation. The highest lipolytic activity for both strains was observed at an optimum temperature and pH of 37°C and 7.0, respectively. At these conditions, the lipase activity detected in the crude enzymatic extract of both strains was close to 15.0 U/mL. We consider that these species are promising lipase producers for industrial applications.

Repeated batch cell-immobilized system for the biotechnological production of xylitol as a renewable green sweetener.

The present paper studies the biotechnological production of xylitol using sugarcane bagasse hydrolysate in a repeated batch fermentation system with immobilized cells of Candida guilliermondii FTI20037. Immobilized cell system is considered as an attractive alternative to reuse the well-grown and adapted yeast cells in a new fresh fermentation media, without the need of the inoculum stage. In this work, seven repeated batches were performed in a fluidized bed bioreactor using immobilized cells in calcium alginate beads. According to the obtained results it was observed that the immobilized cells of C. guilliermondii can be reused for six successive batches maintaining an average xylitol yield (Y(p/s)) of 0.7 g/L and a volumetric productivity (Q(p)) of 0.42 g/Lh at the end of 432 h of fermentation. On the other hand, in the seventh batch (504 h), a decrease of 44 % in the final concentration of xylitol was observed. This reduction can be explained by the possible diffusion and accumulation of insoluble substances, found in the hemicellulosic hydrolysate, in the interior of the immobilization support resulting in substrate mass transfer limitations.

Progression of 'OMICS' methodologies for understanding the pathogenicity of Corynebacterium pseudotuberculosis: the Brazilian experience.

Since the first successful attempt at sequencing the Corynebacterium pseudotuberculosis genome, large amounts of genomic, transcriptomic and proteomic data have been generated. C. pseudotuberculosis is an interesting bacterium due to its great zoonotic potential and because it causes considerable economic losses worldwide. Furthermore, different strains of C. pseudotuberculosis are capable of causing various diseases in different hosts. Currently, we seek information about the phylogenetic relationships between different strains of C. pseudotuberculosis isolates from different hosts across the world and to employ these data to develop tools to diagnose and eradicate the diseases these strains cause. In this review, we present the latest findings on C. pseudotuberculosis that have been obtained with the most advanced techniques for sequencing and genomic organization. We also discuss the development of in silico tools for processing these data to prompt a better understanding of this pathogen.

Biotechnological utilization of biodiesel-derived glycerol for the production of ribonucleotides and microbial biomass.

Ten yeast strains were evaluated concerning their capabilities to assimilate biodiesel-derived glycerol in batch cultivation. The influence of glycerol concentration, temperature, pH and yeast extract concentration on biomass production was studied for the yeast selected. Further, the effect of agitation on glycerol utilization by the yeast Hansenula anomala was also studied. The yeast H. anomala CCT 2648 showed the highest biomass yield (0.30 g g(-1)) and productivity (0.19 g L(-1) h(-1)). Citric acid, succinic acid, acetic acid and ethanol were found as the main metabolites produced. The increase of yeast extract concentration from 1 to 3 g L(-1) resulted in high biomass production. The highest biomass concentration (21 g L(-1)), yield (0.45 g g(-1)) and productivity (0.31 g L(-1) h(-1)), as well as ribonucleotide production (13.13 mg g(-1)), were observed at 700 rpm and 0.5 vvm. These results demonstrated that glycerol from biodiesel production process showed to be a feasible substrate for producing biomass and ribonucleotides by yeast species.

Biotechnological production of xylitol: enhancement of monosaccharide production by post-hydrolysis of dilute acid sugarcane hydrolysate.

Dilute-acid hydrolysis pretreatment of sugarcane bagasse resulted in release of 48% (18.4 g/L) of the xylan in the hemicellulose fraction into the hydrolysate as monomeric xylose. In order to enhance the recuperation of this monomer, a post-hydrolysis stage consisted of thermal treatment was carried out. This treatment resulted in an increase in xylose release of 62% (23.5 g/L) of the hemicellulose fraction. Original and post-hydrolysates were concentrated to the same levels of monomeric xylose in the fermentor feed. During the fermentation process, cellular growth was observed to be higher in the post-hydrolysate (3.5 g/L, Y(x/s) = 0.075 g cells/g xylose) than in the original hydrolysate (2.9 g/L, Y(x/s) = 0.068 g cells/g xylose). The post-treated hydrolysate required less concentration of sugars resulting in a lower concentration of fermentation inhibitors, which were formed primarily in the dilute acid hydrolysis step. Post-hydrolysis step led to a high xylose-xylitol conversion efficiency of 76% (0.7 g xylitol/g xylose) and volumetric productivity of 0.68 g xylitol/L h when compared to 71% (0.65 g xylitol/g xylose and productivity of 0.61 g xylitol/L h) for the original hemicellulosic hydrolysate.

Novel isolates for biological detoxification of lignocellulosic hydrolysate.

In this paper, two new strians, Issatchenkia occidentalis (Lj-3, CCTCC M 2006097) and Issatchenkia orienalis (S-7, CCTCC M 2006098), isolated from different environments on solid media, were used in the detoxification process of the hemicellulosic hydrolysate of sugarcane bagasse. High-pressure liquid chromatography elution curve of UV-absorption compounds represented by acetic acid, furfural, and guaiacol (toxic compounds found in the hemicellulosic hydrolysate) showed that several chromatographic peaks were evidently diminished for the case of detoxified hydrolysate with isolate strains compared to the high peaks resulted for no detoxified hydrolysate. It was clear that these inhibitors were degraded by the two new isolates during their cultivation process. Fermentation results for the biodetoxified hydrolysate showed an increase in xylitol productivity (Q (p)) by 1.97 and 1.95 times (2.03 and 2.01 g l(-1) h(-1)) and in xylitol yield (Y (p)) by 1.72 and 1.65 times (0.93 and 0.89 g xylitol per gram xylose) for hydrolysate treated with S-7 and Lj-3, respectively, in comparison with no detoxified hydrolysate (1.03 g l(-1) h(-1) and 0.54 g xylitol per gram xylose). This present work demonstrated the importance of Issatchenkia yeast in providing an effective biological detoxification approach to remove inhibitors and improve hydrolysate fermentability, leading to a high xylitol productivity and yield.

Biotechnological production of xylitol in a three-phase fluidized bed bioreactor with immobilized yeast cells in Ca-alginate beads.

Cells of Candida guilliermondii entrapped in Ca-alginate beads were used for xylitol production, from concentrated hemicellulose hydrolyzate of sugarcane bagasse, in a fluidized bed bioreactor (FBR). The maximum xylitol concentration 28.9 g xylitol/L was obtained at a high aeration rate of 600 mL/min after 70 h of fermentation, indicating that the use of high aeration rate in this system is favored for better oxygen transfer into the immobilized cells. The specific xylitol productivity and the xylitol yield were of 0.4 g xylitol/L.h and 0.58 g xylitol/g xylose respectively. The immobilization efficiency at the end of the fermentation was of 65 %. After 90 h of fermentation xylitol productivity and yield decreased to 0.25 g xylitol/L.h and 0.47 g xylitol/g xylose respectively, indicating the beginning of xylitol consumption by the yeast. The use of FBR system with immobilized cells presented high xylitol yield and productivity.