Alexandre Nunes Ponezi

Potential applications of violacein: a microbial pigment

Violacein is a versatile pigment from a bacterium Chromobacterium violaceum that exhibits several biological activities and, at present, has gained increasing importance in industrial markets, such as in medicine, cosmetics, and textiles. In this mini-review, we aimed to describe violacein production and to explore its various biological properties in a pharmacological context, including its antioxidant, immunomodulatory, antitumoral, and antiparasitic activities. In addition, its use in the fields of cosmetics, textiles, food, toys, and insecticides has emerged as unusual potential areas of application to be discussed here.

Characterization of alkaline xylanases from Bacillus pumilus

Alkaline xylanases produced by four different strains of Bacillus pumilus were characterized. The optimal pH and temperature were pH 9.0 and 60oC for strain 13a, and pH 8.0 and 55oC for strains 52, 514, and 4a. Under these conditions the following activities were found after 10 min in the presence of 1% xylan (birchwood): 328 U.ml-1, 131 U.ml-1, 90 U.ml-1, and 167 U.ml-1, respectively, for the four strains. The enzymes were stable at 40oC, with 40% of the xylanase activity remaining after 2 hours for the enzymes of strain 52 and 60% for the other three strains. Stability at 50oC was improved by addition of glycerol. Taking into account the conditions under which kraft pulps are bleached during the manufacture of paper, xylanases from B. pumilus exhibit favorable potential for application to bleaching in the paper making process.

Xylan-hydrolyzing enzyme system from Bacillus pumilus CBMAI 0008 and its effects on Eucalyptus grandis kraft pulp for pulp bleaching improvement

The extracellular productions of beta-xylanase, beta-xylosidase, beta-glucosidase, beta-mannanase, arabinosidase, alpha-glucuronidase, alpha-galactosidase and Fpase from Bacillus pumilus CBMAI 0008 were investigated with three different xylan sources as substrate. The enzymatic profiles on birchwood, Eucalyptus grandis and oat were studied at alkaline and acidic pH conditions. B. pumilus CBMAI 0008 grown on the three carbon sources produced mainly beta-xylanase. At pH 10, the levels of xylanase were 328, 160 and 136 U/ml, for birch, oat and E. grandis, respectively. beta-Mannanase production was induced on E. grandis (5 U/ml) and arabinofuranosidase on oat (5 U/ml). Although small quantities of alpha-glucuronidase had been produced at pH 10, activity at pH 4.8 was 1.5 U/ml, higher than observed for Aspergillus sp. in literature reports. Preliminary assays carried out on E. grandis kraft pulp from an industrial paper mill (RIPASA S.A. Celulose e Papel, Limeira, SP, Brazil) showed a reduction of 0.3% of chlorine use in the pulp treated with the enzymes, resulting in increased brightness, compared to conventional bleaching. The enzymes were more efficient if applied before the initial bleaching sequence, in a non-pre-oxygenated pulp.

Production and purification of alkaline xylanases

Abstract This work investigated more than 500 colonies with xylanolytic activity which were able to grow in a medium containing corn xylan as the only carbon source. Out of the 500 colonies, 22 microorganisms were also able to grow in birchwood xylan and were cellulase-free producers. The xylanase activity was studied at pH 10.0 and pH 5.0. It was observed that the three best producers of alkaline xylanase yielded enzyme levels in the range of 2.6 to 4.0 U/ml. Enzyme levels of 1.0 to 1.25 U/ml were achieved by four other microorganisms. Conversely, there were three microorganisms that produced a xylanase which was mostly active at pH 5.0. There was just one microorganism able to produce an enzyme active at pH 10.0. The alkaline xylanases from crude fermentation broth were extracted in aqueous two-phase systems (ATPS) composed of 16% polyethyleneglycol (PEG 6000) and 8% phosphate salt. A purification factor of 57 and a 41% yield of enzyme activity were achieved for the system containing 16% PEG 6000, 8% K 2 HPO 4 and 12% NaCl.

Iron-binding properties of sugar cane yeast peptides.

The extract of sugar-cane yeast (Saccharomyces cerevisiae) was enzymatically hydrolysed by Alcalase, Protex or Viscozyme. Hydrolysates were fractionated using a membrane ultrafiltration system and peptides smaller than 5kDa were evaluated for iron chelating ability through measurements of iron solubility, binding capacity and dialyzability. Iron-chelating peptides were isolated using immobilized metal affinity chromatography (IMAC). They showed higher content of His, Lys, and Arg than the original hydrolysates. In spite of poor iron solubility, hydrolysates of Viscozyme provided higher iron dialyzability than those of other enzymes. This means that more chelates of iron or complexes were formed and these kept the iron stable during simulated gastro-intestinal digestion in vitro, improving its dialyzability.

Use of Bacillus pumilus CBMAI 0008 and Paenibacillus sp. CBMAI 868 for colour removal from paper mill effluent

Bacillus pumilus and Paenibacillus sp. were applied on the paper mill effluent to investigate the colour remotion. Inocula were individually applied in effluent at pH 7.0, 9.0 and 11.0. The real colour and COD remotion after 48h at pH 9.0 were, respectively, 41.87% and 22.08% for B. pumilus treatment and 42.30% and 22.89% for Paenibacillus sp. Gel permeation chromatography was used to verify the molar masses of compounds in the non-treated and treated effluent, showing a decrease in the compounds responsible for the paper mill effluent colour.

Identification of Microbiota for Activated Sludge Acclimated By Paper Mill Effluent Kraft E1 Bioremediation

Conventional systems treating paper effluents and cellulose are quite efficient in the reduction of Chemical Oxygen Demand (COD) and Biochemical Oxygen Demand (BOD). In general, there is primary stage clarification followed by secondary treatment, usually with a biological system (activated sludge). However, for the efficient degradation of some organic compounds in this effluent, adapted microorganism accomplish the treatment which are necessary resulting in effluents with low concentrations of recalcitrant compounds. There are two methods for microorganism acclimation: genes cloning or natural. In this work, the original biomass collected from a domestic sewage treatment plant was adapted for application in the bioremediation of paper mill effluent, Kraft E 1 . So, the aim of this work was verifying the correlation of protozoa organisms and physical-chemical parameters during the acclimation period. The acclimation of the biomass was verified mainly through the reduction of COD. The monitoring of biomass growth was followed by measurement of suspended solids and volatile suspended solids. Parameters such as pH, Dissolved Oxygen (DO) and temperature were also monitored daily. The biological study was accomplished microscopically through the identification of protozoa that are considered bioindicators of the activated sludge system. The biomass acclimation period was 39 days. The stabilization of the system was observed through constant rates of total COD (56%). The suspended solids at the beginning of the acclimation phase were from 1580 mg L ¹ to 3580 mg L ¹, indicating biomass growth. A small acclimation period was necessary to observe the diversity of protozoa, mainly free ciliates, but nematodes were also present, indicating poor sludge sediment. At the end of the acclimation phase predominantly rotifers, but some free ciliates, ciliated communities and fixed ciliated were observed, indicating a good purification capacity of the system. Within the organisms amoeba was observed and this indicates good quality to the final effluent. Then, it is possible to correlate the biota presence with the high capacity of COD removal from the activated sludge system.

Análise da biodegradação dos componentes do óleo cítrico por CG/EM e análise da população microbiana de um reator de lodo ativado no tratamento de água residuária de uma indústria cítrica

Wastewater from citric industry was used to biodegradation study through an activated sludge system. The analyses accomplished by CG/MSD showed that compounds of the orange oil as the limoneno, was resistant to biodegradation. The microbiological evaluation developed during the biodegradation period showed that the number and type of bacteria present in the system varied according to the time, and a succession of microorganisms can be observed. The microrganism identified as LAB-9 (Pseudomonas struzieri) and LAB-7 (not identified) prevailed during whole the process, suggesting that they were the main responsible for the removal of the organic matter or the better adapted to the type of wastewater. The system of activated sludge was efficient in the reduction of DBO and DQO, reaching values of 79 and 78%, respectively, in a period of 15 h, with a relationship F/M 4:2.

Cupuaçu (Theobroma grandiflorum) residue and its potential application in the bioremediation of 17-Α-ethinylestradiol as a Pycnoporus sanguineus laccase inducer

Abstract Bioremediation is a strategy to mitigate environmental impacts of hazardous pollutants from anthropogenic sources. Natural byproducts, including agroindustrial wastes (AW) can be used to induce enzyme biosynthesis, leading up to enhancement of pollutants degradation process. Therefore, this study aimed to evaluate the use of cupuaçu, Theobroma grandiflorum AW as Pycnoporus sanguineus Laccase (Lac) inducer in order to promote 17-α-ethinylestradiol (EE2) bioremediation. The macro and micro-nutrients levels of cupuaçu AWs were evaluated in order to establish further correlations with enzymatic biosynthesis induction. The fungus was cultivated for 7 days in temperature of 28 ± 2 °C and agitation of 150 rpm. For bioremediation, Lac enzymatic extract was added to EE2 solution (10 µg mL−1) and the percentage of removal was evaluated by HPLC after 1–24 hr of reaction. At optimized conditions, the enzyme extract production was remarkably enhanced by adding only 1% (w/v) of cupuaçu AW. Lac activity reached 1642 U mL−1 on the 6th day of culture, which was higher than positive control (511 U mL−1). 86% of EE2 removal was reached after 4 hr, and after 8 hr of reaction, 96.5% was removed. Analysis by direct infusion in MS-ESI-TOF exhibited intermediary compounds formed by radical hydroxilation.