José Daniel Gonçalves Vieira

Principles, techniques, and applications of biocatalyst immobilization for industrial application

Immobilization is one of the most effective and powerful tools used in industry, which has been studied and improved since the last century. Various immobilization techniques and support materials have been used on both laboratory and industrial scale. Each immobilization technique is applicable for a specific production mostly depending on the cost and sensibility of process. Compared to free biocatalyst systems, immobilization techniques often offer better stability, increased activity and selectivity, higher resistance, improved separation and purification, reuse of enzymes, and consequently more efficient process. Recently, many reviews have been published about immobilization systems; however, most of them have focused on a specific application or not emphasized in details. This review focuses on most commonly used techniques in industry with many recent applications including using bioreactor systems for industrial production. It is also aimed to emphasize the advantages and disadvantages of the immobilization techniques and how these systems improve process productivity compared to non-immobilized systems.

Enzymatic activity of endophytic bacterial isolates of Jacaranda decurrens Cham. (Carobinha-do-campo)

The objectives of this work was to isolate endophytic bacteria from Jacaranda decurrens Cham. and screening of some enzymes of biotechnological interest. Ten (10) bacterial species were isolated and identified from the leaves and steams. All the isolates presented enzymatic activity, which was ranked as follows: proteolytic (60%) and amilolytic activity (60%), lipolytic (40%), esterasic (40%). However, cellulolytic and pectinolytic activities were not detected. This is the first report on the isolation and identification of endophytic bacteria from Jacaranda decurrens Cham.

Detection of metallo-beta-lactamase in Pseudomonas aeruginosa isolated from hospitalized patients in Goiânia, State of Goiás

Pseudomonas aeruginosa is a bacterium frequently isolated from hospital environments. This study had the aims of evaluating the susceptibility profile of Pseudomonas aeruginosa previously isolated from patients in a hospital in Goiânia (Goiás, Brazil), performing phenotypic screening for metallo-beta-lactamase production and detecting its genes using the polymerase chain reaction technique. Seventy-five 75 Pseudomonas aeruginosa isolates were evaluated between January 2005 and January 2007. Biochemical identification was performed using the API 20E system and an antibiogram was produced using the Kirby-Bauer method. Among the 62 isolates that were resistant to imipenem and ceftazidime, 35 (56.4%) produced metallo-beta-lactamase, while 26 (74.3%) showed the bla(SPM-1) gene. The frequency of Pseudomonas aeruginosa that produces metallo-beta-lactamase suggests that greater control over the dissemination of resistance in hospital environments is needed.

Candida albicans isoladas da cavidade bucal de crianças com síndrome de Down: ocorrência e inibição do crescimento por Streptomyces sp

Comparison of the presence of Candida yeasts in the buccal cavity of children without and with Downs syndrome showed a statistically significant difference in the case of children that were affected by this chromosomopathy, rendering them more predisposed to buccal candidiasis, probably due to anatomicophysiologic alterations of the mouth resulting from trisomy of chromosome 21. Constant recurrence of buccal candidiasis in children with this chromosomal alteration lead to the search for a possible therapeutic alternative. Seeking to determine the antifungal activity of Streptomyces sp isolated from various Brazilian soils, 5 strains have been tested for Candida albicans isolated from the buccal cavity of children with Downs syndrome. It was observed that the isolate presented a diversity in the size of the halos (9-31 mm in diameter) of growth inhibition of the yeasts, suggesting a possible use as a therapeutic antifungal.

Determinação da resistência antimicrobiana associada em isolados clínicos de Staphylococcus aureus e Pseudomonas aeruginosa em um hospital público de Goiânia, Estado de Goiás

This study evaluated the associated antimicrobial resistance of Pseudomonas aeruginosa and Staphylococcus aureus in relation to an antimicrobial agent with other drugs. The associated antimicrobial resistance was calculated by means of the relative risk. There was an obvious relationship between oxacillin resistance and resistance to other antimicrobial agents among isolates of oxacillin-resistant Staphylococcus aureus (68.5%), greater than 32%, except for linezolid (6.7%). Pronounced associated resistance among drugs was observed for Pseudomonas aeruginosa isolates, particularly for ciprofloxacin and carbapenems (59.6% to 60.7%) and for aminoglycosides and carbapenems (66.3 % to 67.7 %) and other beta-lactam antibiotics (52.3% to 85.8%). The present study emphasizes the importance of diagnostic cultures and susceptibility testing for selecting the correct antimicrobial agent, with regard to the clinical impact of increased multiresistance and selection of associated antimicrobial resistance.

Resistência antimicrobiana associada em isolados clínicos de Enterococcus spp

INTRODUCTION The increasing prevalence of enterococci strains in hospitals, particularly among isolates of vancomycin-resistant enterococci (VRE), poses important problems because of the limited effect of antimicrobial therapy for enterococcal infections. METHODS This work presents a retrospective investigation of quantitative in vitro susceptibility data for the range of antimicrobials against Enterococcus spp. isolates and evaluation of the association of resistance between antimicrobial agents recommended as the treatment of choice for infections caused by VRE through calculation of the relative risk. RESULTS Of the 156 enterococci isolates, 40 (25.6%) were resistant to 3 or more antimicrobials, including 7.7% (n = 12/156) vancomycin resistant. The association of elevated resistance was more pronounced among VRE isolates against alternative and primary antimicrobials for the treatment of infections caused by these pathogens, including ampicillin (100%, RR = 7.2), streptomycin (90.9%, RR = 4.9), rifampin (91.7%, RR = 3.1) and linezolid (50%, RR = 11.5), despite high susceptibility to this drug (94.9%). CONCLUSIONS The significant associated resistance to alternative and first choice antimicrobials used in the treatment of serious infections of strains with the VRE phenotype and that require a combined therapeutic regime, revealed even more limited therapeutic alternatives in the institution analyzed.

Enterobacteriaceae ISOLATES FROM THE ORAL CAVITY OF WORKERS IN A BRAZILIAN ONCOLOGY HOSPITAL

The evaluation of workers as potential reservoirs and disseminators of pathogenic bacteria has been described as a strategy for the prevention and control of healthcare-associated infections (HAIs). The aim of this study was to evaluate the presence of Enterobacteriaceae in the oral cavity of workers at an oncology hospital in the Midwest region of Brazil, as well as to characterize the phenotypic profile of the isolates. Saliva samples of 294 workers from the hospital’s healthcare and support teams were collected. Microbiological procedures were performed according to standard techniques. Among the participants, 55 (18.7%) were colonized by Enterobacteriaceae in the oral cavity. A total of 64 bacteria were isolated, including potentially pathogenic species. The most prevalent species was Enterobacter gergoviae (17.2%). The highest rates of resistance were observed for β-lactams, and 48.4% of the isolates were considered multiresistant. Regarding the enterobacteria isolated, the production of ESBL and KPC was negative. Nevertheless, among the 43 isolates of the CESP group, 51.2% were considered AmpC β-lactamase producers by induction, and 48.8% were hyper-producing mutants. The significant prevalence of carriers of Enterobacteriaceae and the phenotypic profile of the isolates represents a concern, especially due to the multiresistance and production of AmpC β-lactamases.

Isolation and prospection of diazotrophic rhizobacteria associated with sugarcane under organic management

Microorganisms associated with organic management are essential in nutrient transformation and release for plant use. The present study aimed to isolate, identify and characterize plant growth promoting diazotrophic rhizobacteria associated with sugarcane under organic management. Rhizospheres of organic sugarcane varieties IAC 911099 and CTC4 were sampled and inoculated onto nitrogen free NFb and Burk media. The isolated microorganisms were screened in vitro concerning their ability to produce plant growth promoting factors. Eighty-one bacteria were isolated; 45.6% were positive for the nifH gene and produced at least one of the evaluated plant growth promotion factors. The production of indole-3-acetic acid was observed in 46% of the isolates, while phosphate solubilization was observed in 86.5%. No isolates were hydrogen cyanide producers, while 81% were ammonia producers, 19% produced cellulases and 2.7%, chitinases. Microorganisms belonging to the Burkholderia genus were able to inhibit Fusarium moniliforme growth in vitro. Plant growth promoting microorganisms associated with organic sugarcane, especially belonging to Burkholderia, Sphingobium, Rhizobium and Enterobacter genera, can be environmentally friendly alternatives to improve sugarcane production.

Is there still room to explore cyclodextrin glycosyltransferase-producers in Brazilian biodiversity?

In the present work, different Brazilian biomes aiming to identify and select cyclodextrin glycosyltransferase-producer bacteria are explored. This enzyme is responsible for converting starch to cyclodextrin, which are interesting molecules to carry other substances of economic interest applied by textile, pharmaceutical, food, and other industries. Based on the enzymatic index, 12 bacteria were selected and evaluated, considering their capacity to produce the enzyme in culture media containing different starch sources. It was observed that the highest yields were presented by the bacteria when grown in cornstarch. These bacteria were also characterized by sequencing of the 16S rRNA region and were classified as Bacillus, Paenibacillus, Gracilibacillus and Solibacillus.

PRODUÇÃO DE EXOPOLISSACARÍDEOS A PARTIR DE BASTONETES GRAMPOSITIVOS ISOLADOS DE CONTAMINANTES DE CULTURA DE TECIDO VEGETAL

Contaminants present in the cultures of plant tissue commonly are associated with endophytic microorganisms. These microorganisms usually have a production of some biological compounds which can be used as biotechnological products, among them, the exopolysaccharides (EPSs). A vast number of bacteria known produces significant amount of EPSs, drawing attention in recent decades both in the research and industry, due to its properties and applications. The production of EPSs by microorganisms is an alternative to a new source of production of soluble or insoluble polymers, that have a wide application in environmental areas and medicine, food chemical and pharmaceutical industries. EPSs are products of cellular metabolism of microorganisms that can be connected to the cell surface or when they are excreted to the medium. For this reason, the goal of this work was to verify the production of EPSs by gram-positive rods bacteria. Six strains were used for the production of EPSs in culture medium directed to the formation of the polymer cellulose. All of the used strains have produced significant amount of EPSs, having its higher production during the first 48 hours, being selected two strains with higher yields of EPSs. A positive association of bacterial density was linked to the production of biomass of EPSs. With the scanning electron microscopy (SEM) was able to see the production of EPSs. In conclusion, the results demonstrate the potential of bacterial strains to produce EPSs, being necessary new studies related to their characterization and potential application.