ABSTRACT
The fundamental knowledge available about the microorganism, substrates, and process represent the basis on which a rational approach for the design and formulation of media for microbial processes can be attempted. In this respect, it is necessary to analyze critically the main objective to be optimized (yield, productivity, quality of final product, etc.). The first step of medium development is concerned with the decision to be taken about the adequate components to be used, followed by the calculation of their concentrations. After medium preparation and experimentation, the application of the most appropriate statistical optimization methodology will make it possible to attain the optimal medium. Medium design and formulation for plant cell processes are still carried out on an empirical basis owing to the lack of fundamental knowledge. However, some general guidelines can be given for growth and production media considering the experimental evidence available about the functions and influence of the medium components for promoting growth and product formation. Adequate manipulation of the carbon, nitrogen, and phosphorus sources and phytohormones and the inclusion of precursors and elicitors in the medium represent the best strategy for improving medium development for plant cell processes. The development of cost-effective medium supplies for mammalian cell culture production of proteins is a key element for a commercially successful process. Medium development is a task that requires experience, time, and resources in its solutions, which may be several. An optimal formulation is elusive because there will always be room for improvement, but through systematic, comprehensive work, practical combinations of nutrients, factors, and feeding schedules can be developed in a reasonable time. A properly developed formulation can bring the burden of the medium below 10% of the total cost of a mammalian cell process.
Subject(s)
Biotechnology/methods , Culture Media , Culture Techniques/methods , Animals , Cell Division , Cell Line , Escherichia coli/growth & development , Humans , Hybridomas/cytology , Mammals , Plant Cells , Pseudomonas/growth & developmentABSTRACT
The influence of different organic and inorganic nitrogen source combinations and Câ¶N ratios was studied in connection with growth and protein production ofBacillus thuringiensis var.israelensis. Protein production was assumed to be proportional to delta-endotoxin production. Delta-endotoxin concentration increased when media were supplemented with (NH4)2SO4, but the delta-endotoxin: biomass dry weight ratio was unaffected by different Câ¶N ratios. Organic nitrogen source, yeast extract, could be partially replaced by (NH4)2SO4 with a significant increase in delta-endotoxin production.
ABSTRACT
The effects of media composition on growth parameters, total protein production (including delta-endotoxin) and its relation to the biological properties ofBacillus thuringiensis var.israelensis was investigated. The replacement of glucose by glycerol as the carbon source yielded higher concentrations of delta-endotoxin. This increase in toxicity was associated with increased amounts of the 130 kDa polypeptide fraction. The biocide activity was not related to haemolytic activity. specific growth rate nor spore count.
ABSTRACT
This work was undertaken to study the use of molasses and cheese whey in culture media for growth and toxigenic activities of C. perfringens type D. Three media were used namely: 1) A modified Gordon medium 2) a molasses medium and 3) a whey medium which composition are shown in Table 1. The experiments were carried out in a 400 ml microfermentor by using 300 ml of media with automatic pH control (7,0 +/- 0,1) at 37 degrees C. Samples were taken for determination of microbial count and toxigenic activity. Fig. 1, 2, and 3 show the results obtained. The toxigenic activities obtained with the molasses and the Gordon media are similar, while it was not detected any activity in the cheese whey medium. It can be concluded that molasses could be a suitable and inexpensive basic component of culture media for toxin production by C. perfringens type D.
Subject(s)
Bacterial Toxins/metabolism , Clostridium perfringens/growth & development , Culture Media , Lactose , Molasses , Bacteriological Techniques , Clostridium perfringens/metabolismABSTRACT
Se ensayo el empleo de melaza y suero de queso en la formulacion de medios para el desarrollo y produccion de toxina de una cepa de Clostridium perfringens tipo D y se comparan los resultados con el medio de Gordon modificado mencionado en la bibliografia. Las experiencias realizadas demuestram que empleando medio de melaza se alcanzan rendimientos de toxina similares a los obtenidos con el medio de Gordon modificado, con lo cual se concluye que la melaza puede ser un componente basico economico para la produccion de toxina del microorganismo citado. Con respecto al suero de queso como componente de medios puede concluir-se que debe descartarse su empleo en procesos de tipo discontinuo como el empleado en el presente trabajo, para la produccion de toxina de Clostridium perfringens tipo D
Subject(s)
Bacterial Toxins , Clostridium perfringens , Culture MediaABSTRACT
This work was undertaken to study the use of molasses and cheese whey in culture media for growth and toxigenic activities of C. perfringens type D. Three media were used namely: 1) A modified Gordon medium 2) a molasses medium and 3) a whey medium which composition are shown in Table 1. The experiments were carried out in a 400 ml microfermentor by using 300 ml of media with automatic pH control (7,0 +/- 0,1) at 37 degrees C. Samples were taken for determination of microbial count and toxigenic activity. Fig. 1, 2, and 3 show the results obtained. The toxigenic activities obtained with the molasses and the Gordon media are similar, while it was not detected any activity in the cheese whey medium. It can be concluded that molasses could be a suitable and inexpensive basic component of culture media for toxin production by C. perfringens type D.
ABSTRACT
Se ensayo el empleo de melaza y suero de queso en la formulacion de medios para el desarrollo y produccion de toxina de una cepa de Clostridium perfringens tipo D y se comparan los resultados con el medio de Gordon modificado mencionado en la bibliografia. Las experiencias realizadas demuestram que empleando medio de melaza se alcanzan rendimientos de toxina similares a los obtenidos con el medio de Gordon modificado, con lo cual se concluye que la melaza puede ser un componente basico economico para la produccion de toxina del microorganismo citado. Con respecto al suero de queso como componente de medios puede concluir-se que debe descartarse su empleo en procesos de tipo discontinuo como el empleado en el presente trabajo, para la produccion de toxina de Clostridium perfringens tipo D
Subject(s)
Clostridium perfringens , Culture Media , Bacterial ToxinsABSTRACT
Amylase production by a Bacillus subtilis strain can occur without aeration after reaching the stationary phase of growth, provided the pH is controlled.
