Searching for bacteria able to metabolize polycyclic aromatic sulfur compounds in 12-years periodically fed bioreactor.

Biodesulfurization is a promising alternative for removing sulfur molecules from the polycyclic aromatic sulfur compounds (PASC) found in petroleum. PASC consists of recalcitrant molecules that can degrade fuel quality and cause a range of health and environmental problems. Therefore, identifying bacteria capable of degrading PASC is essential for handling these recalcitrant molecules. Microorganisms in environments exposed to petroleum derivatives have evolved specific enzymatic machinery, such as the 4S pathway associated with the dszABC genes, which are directly linked to sulfur removal and utilization as nutrient sources in the biodesulfurization process. In this study, bacteria were isolated from a bioreactor containing landfarm soil that had been periodically fed with petroleum for 12 years, using a medium containing dibenzothiophene (DBT), 4.6-dimethylbenzothiophene, 4-methylbenzothiophene, or benzothiophene. This study aimed to identify microorganisms capable of degrading PASC in such environments. Among the 20 colonies isolated from an inoculum containing DBT as the sole sulfur source, only four isolates exhibited amplification of the dszA gene in the dszABC operon. The production of 2-hydroxybiphenyl (HPB) and a decrease in DBT were detected during the growth curve and resting cell assays. The isolates were identified using 16S rRNA sequencing belonging to the genera Stutzerimonas and Pseudomonas. These isolates demonstrated significant potential for biodesulfurization and/or degradation of PASC. All isolates possessed the potential to be utilized in the biotechnological processes of biodesulfurization and degradation of recalcitrant PASC molecules.

Immobilization of PR4A3 enzyme in pluronic F127 polymeric micelles against colorectal adenocarcinoma cells and increase of in vitro bioavailability.

Traditional therapy for malignant neoplasms involving surgical procedures, radiotherapy and chemotherapy aims to kill neoplastic cells, but also affects normal cells. Therefore, exogenous proteases are the target of studies in cancer therapy, as they have been shown to be effective in suppressing tumors and reducing metastases. Pluronic F127 (F127) is a copolymer of amphiphilic blocks that has shown significant potential for drug administration, as it is capable of incorporating hydrophobic drugs and self-assembling in micrometers of nanometric size. This study investigated the effects of immobilization of the alkaline protease PR4A3 with pluronic F127 micelles on the enzyme-induced cytotoxicity. Protease immobilization was demonstrated through UV-visible and circular dichroism (CD) spectroscopies, as the enzyme interacts with the polymeric micelle of Pluronic F127 without changing its secondary structure. In addition, the immobilized form of the enzyme showed greater bioavailability after passing through the simulated gastrointestinal transit. Cell viability was assessed using the tetrazoic methylthiazole (MTT) assay. The results open perspectives for new research and development for PR4A3 in the treatment of colorectal carcinoma.

Biotechnological potential of mangrove sediments: Identification and functional attributes of thermostable and salinity-tolerant ß-glucanase.

Microorganisms native to mangroves are expected to contain enzymes capable of hydrolyzing different carbon sources. However, most of these microorganisms aren't cultivable; hence, alternative techniques as metagenomics are tools for studying and obtaining some of the natural genomes, genes and enzymes of biotechnological interest. The ß-glucanase was produced using a metagenomic clone of mangrove sediments and detected by functional screening on carboxymethylcellulose substrate. The enzyme was purified by cation exchange chromatography. The peptides detected by mass spectrometry showed 20% identity with the polypeptide deduced from the genomic fragment sequenced. The ORF identified as BglfosD9 possessed 729 bp and the encoded protein showed predicted MW and pI of 28kD and 6.8, respectively. The enzyme was active in a wide range of pH (5-10) with optimum pH at 8, had relative activity greater than 50% at all temperatures tested (5-90 °C), was stable at temperatures of 5, 50 and 90 °C and showed excellent relative activity at high NaCl concentrations. This ß-glucanase also showed high relative activity in the presence of SDS and it could hydrolyze ß-glucan, CMC and Avicel as substrates. These findings support the idea of a new thermostable and active enzyme at basic pH from metagenomic library of mangrove sediment.

Fermentation in fine cocoa type Scavina: Change in standard quality as the effect of use of starters yeast in fermentation.

In the present work we aimed to demonstrate the influence of inoculum starter in support high quality fermentation. Cocoa fermentations were performed in wooden boxes and eight yeasts strains were used in separated fermentations of fine cocoa, type Scavina, as starter inoculum. Temperature, pH, titirable acidity, reducing sugar and free amino acids were evaluated during or after fermentation. The influence of starters yeasts on the decrease of acidity, sugar concentration and free amino acids was significant. The strains Candida parapsilosis, Torulaspora delbrueckii and Pichia kluyveri showed greater changes in the reducing sugar and free amino acids in fermented cocoa beans. These results indicate the ability of yeast used as inoculum starter to modify the end condition and further enhance the quality of fine cocoa beans.

Production of xylitol and bio-detoxification of cocoa pod husk hemicellulose hydrolysate by Candida boidinii XM02G.

The use of cocoa pod husk hemicellulose hydrolysate (CPHHH) was evaluated for the production of xylitol by Candida boidinii XM02G yeast isolated from soil of cocoa-growing areas and decaying bark, as an alternative means of reusing this type of waste. Xylitol was obtained in concentrations of 11.34 g.L-1, corresponding to a yield (Yp/s) of 0.52 g.g-1 with a fermentation efficiency (ε) of 56.6%. The yeast was tolerant to inhibitor compounds present in CPHHH without detoxification in different concentration factors, and was able to tolerate phenolic compounds at approximately 6 g.L-1. The yeast was also able to metabolize more than 99% (p/v) of furfural and hydroxymethylfurfural present in the non-detoxified CPHHH without extension of the cell-growth lag phase, showing the potential of this microorganism for the production of xylitol. The fermentation of cocoa pod husk hydrolysates appears to provide an alternative use which may reduce the impact generated by incorrect disposal of this waste.

Use of Metagenomics and Isolation of Actinobacteria in Brazil's Atlantic Rainforest Soil for Antimicrobial Prospecting.

Modern techniques involving molecular biology, such as metagenomics, have the advantage of exploiting a higher number of microorganisms; however, classic isolation and culture methods used to obtain antimicrobials continue to be promising, especially in the isolation of Actinobacteria, which are responsible for the production of many of these compounds. In this work, two methodologies were used to search for antimicrobial substances-isolation of Actinobacteria and metagenomics of the Atlantic Rainforest soil and of the cultivation of cocoa intercropped with acai berry in the Atlantic Rainforest. The metagenomic libraries were constructed with the CopyControl Fosmid Library kit EPICENTRE, resulting in a total of 2688 clones, 1344 of each soil sample. None of the clones presented antimicrobial activity against the microorganisms tested: S. aureus, Bacillus subtilis, and Salmonella choleraesuis. A total of 46 isolates were obtained from the isolation of soil Actinobacteria: 24 isolates from Atlantic Rainforest soil and 22 isolates from the intercrop cultivation soil. Of these, two Atlantic Rainforest soil isolates inhibited the growth of S. aureus including a clinical isolate of S. aureus MRSA-a promising result, since it is an important multidrug-resistant human pathogen.

Microbial surfactant activities from a petrochemical landfarm in a humid tropical region of Brazil.

The goal of this study was to assess the presence and surfactant potential of naturally occurring microbes from a tropical soil with petrochemical contamination. Microorganisms in a soil sample from a Brazilian landfarm were isolated and grown on petroleum as the sole carbon source. Of 60 isolates screened for petroleum-based growth, 7 demonstrated surfactant activities by the drop-collapse methodology over various types of oils. From their growth profiles in liquid culture during 132 h, all had their first detection of surfactant activity after 96 h. Little is currently known about biosurfactant-producing microorganisms in tropical environments contaminated by hydrophobic compounds, and the search for them is essential for bioremediation and for oil recovery enhanced by microbes. Our results indicate that different petroleum-grown microorganisms showing surfactant activity can be recovered from landfarm soil in a tropical environment.

Effects of immobilization in Ba-alginate on nitrile-dependent oxygen uptake rates of Candida guilliermondi

Yeast cells immobilized by entrapment in Ba-alginate gel were investigated for growth pattern and respiratory activity. The oxygen uptake rates (OUR) of cells entrapped in gels with 4 per cent alginate were 5.2 and 23 per cent lower than the OUR of 2 per cent alginate and free cells, respectively. The mass-transfer resistance offered by the matrix and growth of the entrapped cells determine a gradient of nutrients throughout the gel which is responsible for both a lower specific growth rate of immobilized cells with respect to that of free ones, and a heterogeneous biomass distribution, with progressively increasing cellular density from the inside to the outside of the matrix. Gel-matrix polymer concentration affected the maximum oxygen uptake of immobilized growing yeast cells.

The use of acetonitrile as the sole nitrogen and carbon source by Geotrichum sp. JR1

Uma linhagem de levedura identificada como Geotrichum sp. JR1 foi capaz de utilizar acetonitrila, em concentrações de 0,5 a 2M, como única fonte de carbono e de nitrogênio. A geração de amônia durante o crescimento do microrganismo indica a presença de sistema enzimático capaz de degradar acetonitrila. Durante os ensaios enzimáticos, com células cultivadas em acetonitrila, foram detectados ácido acético e acetamida como produtos indicando a presença de sistema enzimático capaz de degradar acetonitrila e acetamida. Este trabalho é o primeiro a descrever a utilização de acetonitrila como única fonte de carbono e de nitrogênio por uma levedura.