GB1120249A - A method of two- or multistage continuous biotransformation or biosynthesis - Google Patents

Abstract

In a multi-stage process for continuous cultivation of micro-organisms on assimilable carbon, nitrogen and inorganic salts within a liquid substrate with the production of biochemical products, e.g. glucose oxidase and amino acids, or ribonucleic acid proportionately with the growth of micro-organisms, at any stage between the first and penultimate stages partly fermented substrate containing the micro-organism culture in a phase of retarded growth is transferred to a following fermentation stage in which the culture exists in a phase of exponential growth, and this following stage is then fed with fresh substrate. An additive which will act in the continuous process to yield a product but is toxic to the microorganism, may be introduced at the penultimate fermentation stage. According to Example 2, Aspergillus niger was grown in sugar-beet molasses (pH 6.0) in two stages at dilution rates of 0.04-0.05 (retarded growth) and 0.12-0.14 (exponential growth) respectively, giving optimum production of glucose oxidase. In Example 3, Escherichia coli was cultivated in two stages upon specified media, each containing 6-azauracil, to obtain ribonucleic acid. In the first stage the rate of synthesis of the ribonucleic acid was considerably reduced due to the inhibitory effect of the 6-azauracil, whereby the rate of 6-azauracil riboside synthesis corresponded to the rate of the ribonucleic acid synthesis.ALSO:In a multi-stage process for continuous cultivation of micro-organisms on assimilable carbon, nitrogen and inorganic salts within a liquid substrate with the production of biochemical products (sorbose, glucose oxidase, ribonucleic acid, antibiotics, amino acids and other organic acids) proportionately with the growth of micro-organisms, at any stage between the first and penultimate stages partly fermented substrate containing the micro-organism culture in a phase of retarded growth is transferred to a following fermentation stage in which the culture exists in a phase of exponential growth, and this following stage is then fed with fresh substrate. An additive which will act in the continuous process to yield a product but is toxic to the micro-organism, may be introduced at the penultimate fermentation stage. According to the Examples: (1) a culture of Acetobacter suboxidans was grown in a state of retarded growth upon a sorbitol substrate, containing additionally corn steep liquor, yeast extract, disodium hydrogen phosphate and sodium carbonate, at a dilution rate of 0.1 - 0.11. The fermented medium together with the micro-organism culture was passed into a second fermentation stage for exponential growth of the micro-organism, to which stage fresh substrate was being fed so that the total dilution rate in this stage was 0.45. There followed a third stage with the same dilution rate. The yield of sorbose amounted to 98% of the sorbitol processed. (2) Aspergillus niger was grown on sugar-beet molasses (pH 6.0) in two stages at dilution rates of 0.04 - 0.05 (retarded growth) and 0.12 - 0.14 (exponential growth) respectively, giving optimum production of glucose oxidase. (3) Escherichia coli was cultivated in two stages upon specified media containing 6-azauracil in the second stage, to obtain ribonucleic acid and azauracil riboside. The rate of synthesis of the ribonucleic acid was considerably reduced due to the inhibitory effect of the 6-azauracil, whereby the rate of 6-azauracil riboside synthesis corresponded to the rate of ribonudeic acid synthesis.ALSO:In a multi-stage process for continuous cultivation of micro-organisms on assimilable carbon, nitrogen and inorganic salts within a liquid substrate with the production of biochemical products (sorbose, glucose oxidase, ribonucleic acid, antibiotics, amino acids and other organic acids) proportionately with the growth of micro-organisms, at any stage between the first and penultimate stages partly fermented substrate containing the micro-organism culture in a phase of retarded growth is transferred to a following fermentation stage in which the culture exists in a phase of exponential growth, and this following stage is then fed with fresh substrate. An additive which will act in the continuous process to yield a product but is toxic to the micro-organism, may be introduced at the penultimate fermentation stage. According to the examples: (1) a culture of Acetobacter suboxidans was grown in a state of retarded growth upon a sorbitol substrate, containing additionally corn steep liquor, yeast extract, disodium hydrogen phosphate and sodium carbonate, at a dilution rate of 0.1-0.11. The fermented medium together with the micro-organism culture was passed into a second fermentation stage for exponential growth of the micro-organism, to which stage fresh substrate was being fed so that the total dilution rate in this stage was 0.45. There followed a third stage with the same dilution rate. The yield of sorbose amounted to 98% of the sorbitol processed. (2) Aspergillus niger was grown on sugar-beet molasses (pH 6.0) in two stages at dilution rates of 0.04-0.05 (retarded growth) and 0.12-0.14 (exponential growth) respectively, giving optimum production of glucose oxidase. (3) Escherichia coli was cultivated in two stages upon specified media containing 6-azauracil in the second stage, to obtain ribonucleic acid and azauracil riboside. The rate of synthesis of the ribonucleic acid was considerably reduced due to the inhibitory effect of the 6-azauracil, whereby the rate of 6-azauracil riboside synthesis corresponded to the rate of ribonucleic acid synthesis.