Maria Inês Rezende

Optimization of laccase production by Botryosphaeria sp. in the presence of veratryl alcohol by the response-surface method.

Abstract Botryosphaeria sp. produced two laccases (PPO-I and PPO-II) constitutively, whose titers were enhanced by veratryl alcohol. The effect of veratryl alcohol and yeast extract concentration, time of cultivation and agitation speed were evaluated by factorial analysis to select variables for optimizing the production of laccases. Maximal laccase production was determined using a second-order central-composite design and analyzed by the response-surface method. Veratryl alcohol concentration and time of cultivation were the main factors increasing laccase production, while yeast extract had no influence within the range 0.2–2.0% w/v. Response-surface analysis showed that 30.4 mM veratryl alcohol, for 4.5 days at 28°C and 180 rpm, were the optimal conditions to maximize PPO-I production, while conditions for maximal PPO-II production occurred within a range of 28–35 mM veratryl alcohol over a growth period of 4–5.5 days. The model predicted 5.6 U ml −1 for PPO-I, and 0.6–1.0 U ml −1 for PPO-II, which agreed with the experimentally observed results.

Valores de referência para plumbemia em uma população urbana do Sul do Brasil

Objetivo. Descrever os valores de referencia para chumbo em sangue em uma populacao urbana do Municipio de Londrina, Estado do Parana, Brasil. Metodos. A populacao de referencia foi constituida por 520 voluntarios adultos avaliados de novembro de 1994 a dezembro de 1996. Os criterios de exclusao foram: exposicao ocupacional ao chumbo, exposicao atraves de habitos, fumar mais de 10 cigarros por dia e morar perto de industrias ou de locais que utilizam o chumbo em seus processos produtivos. Tambem foram excluidos individuos com valores de exames clinicos e laboratoriais fora da normalidade, doencas cronicas e disturbios cardiovasculares. Os teores de chumbo em sangue foram determinados por espectrofotometria de absorcao atomica com chama de ar-acetileno. O limite de deteccao obtido foi 1,23 mig/dL. Apos as analises de chumbo em sangue, foram determinados valor minimo, primeiro quartil, mediana, terceiro quartil e valor maximo; media geometrica; intervalo de confianca de 95%; intervalo experimental; e valor de referencia. Resultados. Os valores de referencia para plumbemia variaram de 1,20 a 13,72 mig/dL. A media geometrica foi igual a 5,5 mig/dL. Conclusoes. Em geral, os valores obtidos no presente estudo sao mais baixos do que aqueles obtidos em outros paises. Estudos adicionais deveriam enfocar a obtencao de valores de referencia em outras populacoes brasileiras que vivem em regioes mais industrializadas.

Antimicrobial activity of essential oils from Pimenta pseudocaryophyllus and Tynanthus micranthus

The present study describes the chemical composition and antimicrobial activity of essential oils obtained by hydrodistillation from the leaves of Pimenta pseudocaryophyllus (1.0% w/w) and Tynanthus micranthus (1.1% w/w). GC and GC/MS analysis demonstrated that eugenol was the only component in the T. micranthus essential oil (99.9%) and the major component in the P. pseudocaryophyllus essential oil (92.59%), which also presented methyleugenol, terpinen-4-ol, o-cymene and (E)-caryophyllene, among others. Both the oils presented antimicrobial activity against bacteria, yeast and filamentous fungi tested.The Bioautography test revealed that eugenol was the bioactive component in both the oils against Cladosporium herbarum. This is the first report about the T. micranthus essential oil, and the antifungal activity of P. pseudocaryophyllus. The results confirmed the potential of eugenol-rich essential oils not only as a source of flavor compounds, but also of use as antimicrobial agent in agriculture and in pharmaceutical and food products.

Phytochemical and antifungal activity of anthraquinones and root and leaf extracts of Coccoloba mollis on phytopathogens

The aim of this work was to study the phytochemical and antifungal activity of anthraquinones and root and leaf extracts of Coccoloba mollis on phytopathogens. The chemical analysis of ethanolic extracts showed a mixture of long-chain hydrocarbons, carboxyl esters and 3-taraxerone in the leaf extract. Two anthraquinones (emodin and physcion) were isolated and identified from the root extract. Phytochemical screening using the pharmacognostic methods revealed the presence of flavonoids and tannins in the leaves and roots. Anthraquinones were only found in the root extract, no alkaloids, coumarins, saponins and simple phenolics were present. The antifungal activity of C. mollis extracts and anthraquinones isolated from the root of this plant against Botryospheria ribis, B. rhodina, Lasiodiplodia theobromae and Fusarium sp showed promising results for their use as fungicides, where emodin was the most active compound, which inhibited the microorganisms tested up to 44%.

Culturable bacterial pool from aged petroleum-contaminated soil: identification of oil-eating Bacillus strains

Information gleaned from soil microbiota may provide access to new economically important species. Here, we describe the isolation, identification, and genetic diversity of high-density bacterial populations isolated from aged oil-contaminated soil. Twenty different morphotypes were identified in populations present at densities of up to 107 cells g−1 soil, encompassing seven bacterial genera based on 16S rRNA sequencing. Six isolates of the genus Bacillus were identified, three of which appear to consume oil. The genetic clusters defined by the DNA fingerprinting analysis suggest that there is a close relationship between these oil-eating Bacillus species. Isolates able to grow using crude oil as a carbon source were biochemically characterized and found to exhibit high lipolytic activity in liquid medium and to produce alkaline-stable biosurfactants. Fluorescence spectroscopy analysis of the cell-free extract from the oil-eating Bacillus sp. strain MO.04b showed an increase in the relative fluorescence intensity of low-molecular-mass aromatics concomitantly with an increase in the protein content, suggesting the transformation of aromatic hydrocarbons to the liquid phase in response to biodegradation. The approach adopted in this study suggests a low diversity of the high-density bacterial population colonizing an aged oil-contaminated soil and may prove useful in selecting bacterial isolates for bioremediation studies and biotechnological applications such as biosurfactant production.

Production of biossurfactants using soybean meal andrice husk with Bacillus amyloliquefaciens mo-04b bysolid state fermentation (ssf)

The biosurfactants are produced by various microorganisms and comprise a diversity of molecules characterized by low toxicity, high biodegradability and potential substitutes for synthetic surfactants that cause environmental impact. The southern region of Brazil has an agricultural based economy that produces large volumes of solid-waste per year. These solid-wastes must be properly treated and/or disposed. Alternatively, biotechnological strategies of use or re-use these solid-wastes have been applied aiming the production of metabolites with economic value. Given that, the production of biosurfactants by solid-state fermentation using agricultural-waste as substrates seems to be a promising option to decrease biosurfactant production costs. The goal of this study was to avaluate the capacity of production biosurfactants by Bacillus amyloliquefaciens MO-04B in solid state fermentation (FES), isolated from soil contaminated by oil collected near to the Getulio Vargas Refinery-PR (PR-REPAR) and characterized as a producer of surfactin by submerged fermentation. The cultures were developed in 250 mL Erlenmeyer flasks containing soybean mean and rice husk 3:1g (w/w), dampened with a solution of salts (3 g/L KH2PO4, 7 g/L K2HPO4, 0.2 g/L MgSO4.7H2O; 1 g/L (NH4)2SO4, giving 80 % moisture; inoculated with 1 mL of cell suspension (4.108 CFU/mL) and incubated at 30 ± 2 °C for 30 h. The disruption was by adding 50 mL of distilled water content homogenised at 180 rpm for 30 min, and centrifuged at 10,000 rpm, 20 min., 4 ± 2 °C. In the supernatant were recovered by precipitation biosurfactants (6M HCl, pH 2) 4 ± 2 °C (overnigth) and extracted with dichloromethane. The sample was resuspended in water, neutralized (0.5 M NaOH, pH 7) and lyophilized. The performance of biosurfactants was 33 mg/GDS were solubilized in determining the emulsification index (IE24) equal to 62.5 % and the lowering of surface tension (ST) which was 39.6 mN/m. Thus Bacillus amyloliquefaciens MO-04b produced biosurfactants (lipopeptides/surfactin) by solid state fermentation substrates using soybean meal and rice husk as substrates. Futher studies will be developed to optimize the production of biosurfactants using factorial design and analysis by response surface methodology.