Production of Escherichia coli as a source of nucleic acids

Abstract

Present-day chemical and physical studies of the niicleic acid system of bacteria frequently call for qtiaiitities of cells which are beyond the capacity of traditional culture methods such as that of the shake flask. The case is therefore argued for an increased use of stirred deep cultures because a greater rate of output, a) a higher cell concentration and with improved control of cultural conditions can be achieved. For the isolation of deoxyribonucleic acid and transfer ribonucleic acid, low growth-rate cells should be the most prolific source; whereas for ribosomes, ribosomal ribonucleic acid and messenger ribonucleic acid, high growth cells should give bigger yields. It is concluded that the information is somewhat obscure on what are the best growth conditions for the production of the related enzymes.A batch method for producing low growth-rate cells of Escherichia roli, in lots of 1 kg dry wt., is then described, followed by a continuous method for producing high growth-rate cells, with an output of 3 kg Of dry cells per day. Both cultures have been designed to give maximum yield of cells by promoting nlaximunl assimilation of the carbon substrate. From the point of view of designing a culture, the section dealing with the continuous process discusses the rationale of medium formulation, the calculation of aeration requirements and briefly reviews earlier work on the kinetics of continuous culture. I ,. .

Mixing in the Fermentation and Cell Culture Industries

“…However, production has been limited to a few well-known overexpression systems such as E. coli, although knowledge of the process engineering variables on performance is still limited. The cultivation of E. coli in fedbatch mode to high cell densities is the preferred industrial method for increasing the volumetric productivity of bacterial-derived products such as nucleic acids (Elsworth et al, 1968), amino acids (Forberg and Haggstrom, 1987), and heterologous recombinant production (Risenberg and Schulz, 1991;Bylund et al, 2000). In such fed-batch E. coli cultivations, the carbon source (usually, glucose) is supplied continuously at a growth-limiting rate.…”

The scale-up of microbial batch and fed-batch fermentation processes

“…The fed-batch, high cell density cultivation of microbial strains is the preferred industrial method for increasing the volumetric productivity of such bacterial products as nucleic acids (Elsworth et al, 1968), amino acids (Forberg and Haggstrom, 1987) and heterologous recombinant proteins (Riesenberg and Schulz, 1991). The salient feature of this type of process is the continuous feed of a concentrated growth limiting substrate, usually the carbon source, characterised by an ever increasing level of energy limitation and an ever decreasing specific growth rate.…”

“…For S. cerevisiae, overflow metabolism is known as the 'Crabtree Effect' and the inhibitory bi-product is ethanol but produced in a similar way to acetate in E. coli. In batch fermentation, overflow metabolism can be avoided by the use of a slowly metabolisable carbon source such as glycerol (Elsworth et al, 1968), but the preferred method is the use of a fed-batch process where growth can easily be controlled by substrate feed rate (see Lee, 1996, for a comprehensive review).…”

The effect of open-air factors on the virulence and viability of airborneFrancisella tularensis

“…E. coli strain MRE 162 was prepared as described for batch culture by Elsworth et al . [17]. Bacillus globigii var.…”

“…It was grown as previously described in liquid glucose-cysteine blood agar (GCBA) medium [13,16]. E. coli strain MRE 162 was prepared as described for batch culture by Elsworth et al [17]. Bacillus globigii var.…”