Production of biosurfactant by Bacillus subtilis LB5a on a pilot scale using cassava wastewater as substrate

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)The main characteristic of biosurfactants is their property of reducing the superficial and interfacial tension between two immiscible liquids of different polarities. The main obstacle to the application of biosurfactants is the high production costs, the use of alternative substrates being indicated to solve this problem. This work report the production of biosurfactant by Bacillus subtilis LB5a on a pilot scale using cassava wastewater as the substrate, and the study of the parameters related to its production. The cassava wastewater was heated, centrifuged and poured into a 40-liter batch pilot bioreactor adapted for simultaneous foam collection during the fermentative process. The temperature was maintained at 35 degrees C, agitation at 150 rpm and aeration 0.38 vvm during the first 12 h, and 0.63 vvm for the rest of the process. Samples of liquid fermentate were collected at regular intervals for the analysis of total carbohydrates, reducing sugars, pH, CFU/mL count and superficial tension. The foam was centrifuged and the biosurfactant purified. The kinetic data of the process showed that both the microbial population, which reached a maximum after about 24 h, and the foam production of 10.6 L, peaked between 24 and 36 h, coinciding with the greatest production of biosurfactant. The yield of semi-purified surfactant in the foam was 2.4 g/L. The superficial tension of the medium was reduced from 51 to 27 mN/m and the critical micellar concentration was 11 mg/L, which, in principle, characterizes it as a good tensoactive agent. As a function of its composition and productivity, cassava wastewater was identified as a good substrate for the production of the biosurfactant.35910711078Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

USE OF BACILLUS PUMILUS CBMAI 0008 AND PAENIBACILLUS SP CBMAI 868 FOR COLOUR REMOVAL FROM PAPER MILL EFFLUENT

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)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.402354357Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Production and purification of alkaline xylanases

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% K2HPO4 and 12% NaCl. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.681495

Effect of lecithin and soy oil on the fermentative performance of Saccharomyces uvarum I Z 1904

The proposal of this work was to study the effects of lecithin and soy oil on the fermentative performance of Saccharomyces tn,arum I Z 1904, a yeast used in the industrial production of ethanol. High Test Molasses (HTM) was chosen as the fermentation media because it is a substratum that is poor in nutrients, and because it permits one to distinguish the action of lipids from other nutritional factors. The study of the optimization of the concentration of lipids by surface response analysis showed that the lipids favor the performance of the yeast principally when applied separately. Maximum concentrations of the two sources of lipids in the media stimulated the budding rate but did not constitute a protection against cell death. Considering the action of lipids on the cellular parameters studied, the supplementation of the media with 3.0 g/l of soy oil permitted the obtention of maximum responses of cellular viability, budding rate and viability of the buds after 6 successive cycles. In relation to the fermentative parameters, the use of 1.5 g/l of soy oil provided high yields and an equilibrium between the mass of ethanol produced (EM) and the alcoholic yield (Y-p/s), whereas the cellular viability after 6 cycles did not differ statistically from that observed with 3g/l of oil.27425526

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. (C) 2002 Elsevier Science Ltd. All rights reserved.88191