DD295190A5 - PROCESS FOR MICROBIAL PRODUCTION OF GLUCONIC ACID - Google Patents

Abstract

The invention relates to a process for the microbial production of gluconic acid by oxidation of glucose by means of Acetobacter methanolicus IMET 11402 (DSM 8167) {substrate dosage; Glucose concentration; Glucose acid; Acetobacter methanolicus; Induction phase; Yield; Productivity}

Description

example 1 7h 10-30% The "catalyst" Acetobacter methanolicus IMET11402 is placed in a 12 L stirred fermentor under the following conditions 32 ⁰ C cultivated non-sterile continuously: 4, <M, 2 dwell time: Methanol, C-labeled pO ₂ : Temperature: PH value: Carbon source:

The required biomass suspension is added to the 12 l stirred fermentor used for gluconic acid production. At 3I initial charge the biomass concentration is 3g / l.

The actual gluconic acid formation process is preceded by a growth phase or induction phase of the acidophilic methylotrophic gluconic acid producer. For this purpose ammonium sulfate, nutrient and trace salts for a biomass increase of 3 g BTS / I are presented in the production fermentor. At the same time 5 g / l glucose are added. During the growth or induction phase, the following conditions are met:

Temperature: 32 ^° C

pH value: 4.0

pO ₂ : 10-30%

Glucose is added discontinuously after wasting. This growth or induction phase is completed after 5 hours. The biomass concentration reaches a value of 6g / l, and the nitrogen concentration at the end of this phase is close to Omg / l.

With the glucose addition of 10 g / l, the gluconic acid formation process is initiated, at the same time the glucose dosage is started according to the glucose consumption rate; to keep the glucose concentration almost constant. After reaching a gluconic acid concentration of 215 g / l is continued until a glucose degradation less than 2 g / l. The average productivity is 16g / l h. A yield of 0.92 g of gluconic acid per g of glucose is achieved.

Example 2

The cultivation of Acetobacter methanolicus and the induction phase are carried out analogously to Example 1. Following the induction phase, the glucose concentration is increased to 25 g / l and thus initiated the gluconic acid formation process. Again, glucose glucose consumption rate is started simultaneously with glucose dosage to glucose concentration at 25 g / L. After that, the glucose concentration is kept to less than 2g / l. The glucose dosage is degraded up to a gluconic acid concentration of 205g / l. The average productivity is 25 g / l h, the gluconic acid yield 1.04 g / g.

Example 3

Biomass cultivation and induction phase are carried out analogously to Example 1. The glucose concentration in the fermentor is raised to 80 g / l to initiate the gluconic acid production. The glucose concentration of 80 g / l is kept almost constant by glucose dosage up to a gluconic acid concentration of 150 g / l. Thereafter, the glucose dosage is stopped and the glucose concentration is reduced again to less than 2 g / l. The average productivity is 26g / l h, the yield 0.935g gluconic acid of glucose.

Claims (1)

Process for the preparation of gluconic acid by means of bacteria of the species Acetobacter methanolicus IMET 11402, characterized in that the product formation process is started with a glucose concentration between 15 and 50 g / l, preferably 20 to 25 g / l, and that this concentration is maintained over the duration of the process by continuous replenishment is kept constant by glucose. Field of application of the invention The invention relates to a process for the microwave gluconic acid production by oxidation of glucose by means of Acetobacter methanolicus IMET11402. Characteristic of the known state of the art The technical production of gluconic acid by oxidation of glucose is carried out with the help of molds, eg. Aspergillus niger, or bacteria, preferably with species of the genus Acetobacter / Gluconobacter. In general, these are two-stage processes. The "catalyst" (biomass) can be produced according to the batch principle, but also in the continuous process according to the chemostat principle, as is done, for example, in the process according to DD-WP 236754. For product formation, the batch operation or fedbatch operation in the technical dipstick, although proposals for continuous processes are also known (DD-WP 253836) Most processes do not work according to the chemostat principle, but the substrate is offered in portions, the process usually with A high concentration is started and periodically glucose is tracked in the course of the process, so that considerable substrate gradients occur (see DE-AS1817907). This procedure has the disadvantage that the theoretically possible yield and the organism-specific productivity can not be achieved. Object of the invention The object of the invention is to increase the yield and the productivity of processes for the bacterial production of gluconic acid by oxidation of glucose. Essence of the invention The object of the invention is to fully exploit the organism-specific performance in terms of efficiency, speed and product concentration. According to the invention, the object is achieved in that the process is started with a glucose concentration in the range of 20 to 50 g / l and it is ensured that during the oxidation process, the glucose concentration remains constant in this range. The substrate may be added in solid or liquid form. The replenishment of Gk jose is stopped, depending on the desired final concentration of gluconic acid. In the interest of residual concentrations of glucose less than 2 g / l this has to be done as long as cell damage is not yet significant. The current glucose concentration in the fermentor is monitored by measurement. In question come off-line and on-line principles, based on colorimetric and / or enzymatic methods. Ausführungsbelsplele