Waste Reduction at the Source and Waste Recycle through Briquetting of the Reduction Charge in the black- ash process

Physical losses of material as flue dust in the oil fired rotary furnaces of black ash process for barite reduction have been arrested using briquetted charge. Similarly fine particles of barium sulphate obtained in the purification of barite could be recycled as a resource by exploiting advantages of catalysis and briquetting techniques

Diffusion-adsorption problems in macromolecular systems: new techniques for parameter estimation

It has been shown that the techniques used for estimation of diffusion-adsorption parameters in the past have certain basic flaws. New and efficient techniques for parameter estimation have been proposed. These have many advantages such as using the full concentration-time profile (rather than part of it), time saving, etc. The validity of these techniques has been demonstrated by the analysis of the data generated in our laboratory on adsorption of polyacrylamide and also the data on adsorption of dyes on chitin reported in the literature

Large Scale Processing of Tetanus Toxin from Fermentation Broth

773-778Separation of bacterial cells, concentration and sterile filtration are some of the major unit operations in the processing of large volumes of fermentation broth in the production of bacterial vaccines. Separation of cells is traditionally achieved by centrifugation or by dead-ended depth filtration. These solid-liquid separation methods are time consuming, toxin recoveries are not satisfactory and it is difficult to validate a depth filtration system. Tetanus toxoid is prepared by detoxifying the culture filtrates of Clostridium tetani and further purifying it by ultrafiltration and salt fractionation. This article describes comparison of performance of deadend filtration and Tangential Flow Filtration (TFF) system for clarification of tetanus fermentation broth and further use of a similar system for concentration and purification of tetanus toxoid

The amino acid requirements of Corynebacterium diphtheriae PW 8 substrain CN 2000

Aims: To determine the amino acid requirement and utilization pattern of Corynebacterium diphtheriae during growth and toxin production. Methods and Results: Comparing across different batches of beef-based media, the growth and toxin yield were correlated significantly with nine of the amino acids. The amino acid utilization pattern during growth of C. diphtheriae further showed that only four of the nine amino acids, namely cystine, histidine, aspartate and methionine, were critical for growth of the vaccine strain. Further investigations using synthetic media with combinations of amino acid supplements demonstrated that among the four, cystine was the most growth limiting. Conclusions: Only certain amino acids are critical for growth and toxin production by C. diphtheriae, cystine being the single most important. Significance and Impact of the Study: Owing to the potential threat from Bovine Spongiform Encephalopathy (BSE), a need is recognized by vaccine manufacturers to substitute beef-based production media. An understanding of the specific amino acid requirements would help to develop and optimize alternative production media

Consider genetic algorithms to optimize batch distillation

This article does not have an abstract

Optimization of continuous distillation columns using stochastic optimization approaches

The present work describes the use of two stochastic optimization formalisms, namely, genetic algorithms (GAs) and simultaneous perturbation stochastic approximation (SPSA), for the optimization of continuous distillation columns. Both the simple and azeotropic systems are considered in the analysis. In particular, for a specified degree of separation the problem of finding the optimal values of: (i) the number of stages, (ii) reflux ratio (entrainer quantity in the case of azeotropic distillation), (iii) feed location(s), have been addressed. The GA-based optimization has several attractive features such as: (i) convergence to the global rather than to a local minimum, (ii) the objective function need not satisfy smoothness, differentiability, and continuity criteria, (iii) robustness of the algorithm. The other optimization technique used in the study i.e., SPSA, is a rapid gradient-descent related method for multivariate optimization and is especially well-suited in situations where direct computation of the objective function gradient is not feasible, or the objective function measurements could be noisy. The feasibility of utilizing the GA and SPSA techniques has been demonstrated by considering the separation of three binary and two azeotropic systems of industrial relevance

An effective, simple and low-cost pretreatment for culture clarification in tetanus toxoid production

Chemically inactivated tetanus toxin (tetanus toxoid, TT), purified from cultures of a virulent Clostridium tetani strain, is the active pharmaceutical ingredient of anti-tetanus vaccines. Culture clarification for TT production and is usually performed by filtration-based techniques. Final clarification of the culture supernatant is achieved by passage through 0.2 µm pore size filtering membranes. Large particles removal (primary clarification) before final filtration (secondary clarification) reduces costs of the overall clarification process. With this aim, chitosan-induced particle aggregation was assessed as an alternative for primary clarification. Three chitosan variants were tested with similar results. Optimal clarification of culture supernatant was achieved by the addition of 8 mg chitosan per l of culture. Extrapolation analysis of filter sizing results indicate that 100 l of chitosan-treated supernatant can be finally filtered with a 0.6 m2 normal filtration cartridge of 0.45 + 0.2 µm pore size. The clarified material is compatible with current standard downstream processing techniques for TT purification. Thus, chitosan-induced particle aggregation is a suitable operation for primary clarification.Fil: Ávila, Lucía. Ministerio de Salud de la Nación. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorios e Institutos de Salud "Doctor Carlos G. Malbrán". Instituto Nacional de Producción de Biológicos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Cascone, Osvaldo. Ministerio de Salud de la Nación. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorios e Institutos de Salud "Doctor Carlos G. Malbrán". Instituto Nacional de Producción de Biológicos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Nanobiotecnología. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Nanobiotecnología; ArgentinaFil: Biscoglio, Mirtha Josefa. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Ministerio de Salud de la Nación. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorios e Institutos de Salud "Doctor Carlos G. Malbrán". Instituto Nacional de Producción de Biológicos; ArgentinaFil: Fingermann, Matias. Ministerio de Salud de la Nación. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorios e Institutos de Salud "Doctor Carlos G. Malbrán". Instituto Nacional de Producción de Biológicos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

The Potential of Physicochemical and Immunochemical Assays to Replace Animal Tests in the Quality Control of Toxoid Vaccines - The Report and Recommendations of ECVAM Workshop 61a

The workshop on the potential of physicochemical and immunochemical assays to replace animal tests in the quality control of toxoid vaccines was held at ECVAM on 14-15 April 2005, under the co-chairmanship of Coenraad Hendriksen and Gideon Kersten. The objectives of the workshop were: a) to review the state-of-the-art of physico-chemical, biochemical and immunochemical tests for the quality control of diphtheria and tetanus toxoid vaccines and b) to identify possibilities and limitations for their use in the regulatory framework, i.e. replacing the use of in vivo tests. The outcome of the discussions and the recommendations given by the workshop participants are summarised in this report.JRC.I.2-Validation of biomedical testing method

The Consistency Approach for the Quality Control of Vaccines

Current lot release testing of conventional vaccines emphasizes quality control of the final product and is characterized by its extensive use of laboratory animals. This report, which is based on the outcome of an ECVAM workshop, discusses the concept of consistency testing as an alternative approach for lot release testing. The consistency approach for the routine release of vaccines is based upon the principle that the quality of vaccines is a consequence of a quality system and of consistent production of lots with similar characteristics to those lots that have been shown to be safe and effective in humans or the target species. The Report indicates why and under which circumstances this approach can be applied, the role of the different stakeholders, and the need for international harmonization. It also gives recommendations for its implementation.JRC.I.2-Validation of biomedical testing method