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Competition with well-established, fine-tuned chemical processes is a major challenge for the industrial implementation of the enzymatic synthesis of beta-lactam antibiotics. Enzyme-based routes are acknowledged as an environmental-friendly approach, avoiding organochloride solvents and working at room temperatures. Among different alternatives, the(More)
Brazil is the largest producer of bioethanol, and sugarcane is the main raw material. Bioethanol is produced by both batch and continuous processes, and in some cases, flocculating yeast is used. This article analyzes the Brazilian Ethanol Program. For the 1996-1997 harvest, Brazil produced 14.16 billion L of ethanol and 13.8 million metric t of sugar, from(More)
BACKGROUND Sugarcane is the most efficient crop for production of (1G) ethanol. Additionally, sugarcane bagasse can be used to produce (2G) ethanol. However, the manufacture of 2G ethanol in large scale is not a consolidated process yet. Thus, a detailed economic analysis, based on consistent simulations of the process, is worthwhile. Moreover, both ethanol(More)
Trypsin was immobilized on chitosan gels coagulated with 0.1 or 1 M NaOH and activated with glutaraldehyde or glycidol. The derivatives were characterized by their recovered activity, thermal (40, 55 and 70 degrees C) and alkaline (pH 11) stabilities, amount of enzyme immobilized on gels for several enzyme loads (8-14 mg(protein)/g(Gel)) and compared to(More)
This paper presents stable carboxypeptidase A (CPA)-glyoxyl derivatives, to be used in the controlled hydrolysis of proteins. They were produced after immobilizing-stabilizing CPA on cross-linked 6% agarose beads, activated with low and high concentrations of aldehyde groups, and different immobilization times. The CPA-glyoxyl derivatives were compared to(More)
In spite of the large number of reports on fed-batch cultivation of E. coli, alternative cultivation/induction strategies remain to be more deeply exploited. Among these strategies, it could be mentioned the use of complex media with combination of different carbon sources, novel induction procedures and feed flow rate control matching the actual cell(More)
The influence of medium composition and culture conditions on Streptococcus pneumoniae serotype 23F cultivation was investigated in order to develop an industrial method for polysaccharide (PS) production. Acid-hydrolyzed casein (AHC) and dialyzed enzymatically hydrolyzed soybean meal (EHS) were investigated as nitrogen sources, and the vitamin solution of(More)
Mass transfer effects were investigated for the synthesis of ampicillin and amoxicillin, at pH 6.5 and 25 degrees C, catalyzed by penicillin G acylase immobilized on agarose. The influence of external mass transfer was analysed using different stirring rates, ranging form 200 to 800 rpm. Above 400 rpm, the film resistance may be neglected. Intra-particle(More)
Cephalosporin C production process with Cephalosporium acremonium ATCC 48272 in synthetic medium was investigated and the experimental results allowed the development of a mathematical model describing the process behavior. The model was able to explain fairly well the diauxic phenomenon, higher growth rate during the glucose-consumption phase, and the(More)
The use of the hemicellulose fraction of biomass may be important for the feasibility of the production of second generation bioethanol. Wild strains of Saccharomyces cerevisiae are widely used in industry for production of 1st generation ethanol, and the robustness of this yeast is an important advantage in large scale applications. Isomerization of xylose(More)