This article presents a detailed study on the conditions for achieving a stable biocatalyst to be used in the production of ethanol from starch. Different pellets were used depending on which characteristic of the biocatalyst was being studied: (a) Saccharomyces cerevisiae entrapped in pectin or calcium alginate gel particles; (b) silica containing immobilized glucoamylase entrapped in pectin gel particles; or (c) pectin gel particles, with the silica-enzyme derivative and yeast coimmobilized. The influence of several variables on the mechanical resistance of the particle, on the viability of the microorganism, and on the rate of substrate hydrolysis was studied with biocatalyst. The best conditions found were 6% pectin gel, 2-mm particle diameter, and cure in 0.2M CaCl2.2H2O/60 mM acetate buffer, pH 4.2, for gel preparation; and 6.0 g/L of CaCl2.2H2O in the fermentation medium. Biocatalyst (c) was successfully tested for the production of ethanol from liquefied manioc flour syrup.

Retamycin is an anthracyclinic antitumoral complex produced by Streptomyces olindensis ICB20. In this work the influence of different glucose concentrations in the feed medium on the production of retamycin was studied. Chemostat cultures employing glucose concentration varying between 10 g/L and 25 g/L showed that use of high glucose concentration resulted in catabolite repression of the biosynthesis of the antitumoral. The highest specific retamycin production rate, qRTM = 7.8 mg/g.h, was obtained when glucose concentration was 10 g/L. The lowest value of qRTM, 2.5 mg/g.h, was observed when glucose concentration was 20 and 25 g/L. The residual glucose concentration varied from 0 to 13 g/L, as the glucose concentration in the feed was increased from 10 to 25 g/L.

Groundwater contamination is becoming a serious problem in many Brazilian regions. European countries started to deal with this issue in the 1980s, mainly caused by the extensive usage of nitrogenous fertilizers and the absence of domestic wastewater treatment. Due to its high solubility, nitrate readily passes through the soil and reaches the aquifer. Thereafter, this ion moves, following groundwater flow, and can be found several kilometers from the area where the pollution occurred. Concern about nitrate contamination is due to the link found between this contaminant and various human health diseases, such as methemoglobin and cancer. Studies carried out in France enabled the design and implementation of several biological denitrification plants throughout the country, in order to remove nitrate from its contaminated groundwater. Heterotrophic denitrification facilities shown to be adequate to treat high water flows with satisfactory nitrate removal efficiency, especially when static media supports are employed. The objective of this research was to evaluate the existence of denitrifying microorganisms in bamboo (Bambusa tuldóides) and verify the feasibility of their use to inoculate a pilot-scale fixed-bed bioreactor. The support material selected to fill the bioreactor bed was commercial polypropylene Pall rings, since such support has a high porosity associated with a wide superficial area. The bioreactor was able to produce and retain a large amount of cells. Using ethanol as carbon source, nitrate (N-NO3(-)) removal efficiency of the bioreactor stood around 80 % for a maximum nitrogen loading rate of approximately 6.5 mg N-NO3 (-) L(-1) h(-1).

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A study of non-aerated submerged fermetation by Saccharomyces cerevisiae was carried out evaluating the effect of pH on the coefficients: (I) of Pirt equation; and (II) of Garden model. In the tests performed, increasing the pH slowed glucose comsumption, and, cell growth and ethanol production decreased with increasing pH from 4.5 to 9.0. Specifically, with regard to ethanol, the high coefficient values associated with the growth from the non-associated growth factor production associated indicate growth. However, for maximum production of glycerol there was a decrease in the coefficient values associated with growth and an increase in coefficient values not associated with the growth. Glucose consumption for cellular maintenance was significant (0,2gglucose / ((gcell.h)) to pH 7.0 and 7.5, where there was a greater production of glycerol. In conclusion it was possible to observe the existence of a relationship between the saline and osmotic stress in the metabolism of Saccharomyces cerevisiae by increasing the maintaining glucose consumption, and glycerol production disassociation cell growth, indicating the intra and extracellular glycerol accumulation.