Method for producing citric acid by continuous fermentation of Aspergillus niger

A technology of citric acid and Aspergillus niger, applied in the field of fermentation engineering, can solve the problems of restricting the popularization and application of yeast, difficult production process of citric acid, difficult separation and purification of citric acid, etc. The effect of reducing raw material cost and operating cost

Active Publication Date: 2017-08-08
JIANGNAN UNIV +1
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Problems solved by technology

[0004] However, the production process of continuous fermentation of citric acid is difficult, because the synthesis of citric acid is partly growth-coupled, and the special mycelium structure of Aspergillus niger is not conducive to the formation of continuous process
Domestic and foreign literature on continuous or semi-continuous fermentation of citric acid focuses on yeast, but the fermentation process will produce a large amount of isocitric acid (5%~10%), which makes it difficult to separate and purify citric acid. Promoted application of

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  • Method for producing citric acid by continuous fermentation of Aspergillus niger

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Effect test

Embodiment 1

[0037] Example 1: Glucose and soybean meal powder were used to prepare seed medium (total nitrogen 8%, total nitrogen 0.15%) and fermentation medium (F1: total sugar 15.2%, total nitrogen 0.08%; F2~F10: total sugar 15.2%, total nitrogen 0.25%); cultivate mature Aspergillus niger spores to inoculate the seed medium, and the concentration of the spore liquid after transplanting is 300,000 / ml; cultivate for 20h to obtain a mature seed liquid, and then transfer the fermentation medium with 20% inoculum After 48 hours of fermentation and cultivation, 1 / 3 of the fermented liquid was divided, and the remaining fermented liquid continued to be fermented in F1 after the division. When the concentration of reducing sugar in the fermentation medium was lower than 0.5%, the fermentation ended and citric acid was obtained. The separated fermented liquid is dispersed and processed by a disperser. After the treatment, the average diameter of the bacteria ball is 90um, and it is transferred to...

Embodiment 2

[0039] Example 2: Corn flour and deionized water are mixed uniformly in a batching tank at about 60°C at a ratio of 1:3, and calcium hydroxide is added to adjust the pH to 6.0, and high-temperature α-amylase is added at 25U / g corn flour, and after The second injection liquefaction, the iodine test is qualified (light brown), and the corn liquefaction mixture is obtained; 70% of the mixture is filtered through the plate frame to obtain the corn liquefaction clear liquid. The corn liquefaction mixed liquid and the clear liquid were mixed in a certain proportion to prepare seed medium (12% total sugar, add a certain amount of ammonium sulfate to adjust total nitrogen 0.25%) and fermentation medium (F1: 16% total sugar, 0.05% total nitrogen; F2~F10: total sugar 16%, total nitrogen 0.15%). Cultivate mature Aspergillus niger spores to inoculate the seed medium, and the concentration of the spore liquid after transplanting is 450,000 / ml; cultivate for 28 hours to obtain mature seed l...

Embodiment 3

[0041]Embodiment 3: Same as Embodiment 2, corn flour and water are mixed evenly according to a certain ratio, and the liquefied mixed liquid is obtained through secondary jet liquefaction, the liquefied liquid is mixed with water according to a certain ratio, and a certain proportion of ammonium sulfate is added to prepare the seed culture medium ( Total sugar 9.5%, 0.26%). Mix cassava flour and water at a ratio of 1:4 in a batching tank at about 60°C, add calcium hydroxide to adjust the pH to 5.8, add high-temperature α-amylase at 30 U / g cassava flour, and undergo secondary jet liquefaction to obtain Cassava liquefaction liquid; cassava liquefaction mixed liquid is all filtered through plate and frame to obtain cassava liquefaction clear liquid. Mix cassava liquefaction clear liquid with water according to a certain ratio, add a certain amount of corn flour liquefaction liquid, and prepare fermentation medium (F1: total sugar 14%, total nitrogen 0.15%; F2~F10: total sugar 14%...

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Abstract

The invention relates to a method for producing citric acid by continuous fermentation of Aspergillus niger, which comprises the following steps: (1) carrying out progressive amplification culture on Aspergillus niger to obtain mature spores; (2) inoculating the spore solution to a seed culture medium, and culturing to obtain a mature seed solution; (3) transferring the mature seed solution to a fermentation culture medium F1; (4) after the fermentation and culture, dividing the fermentation solution into two parts, and continuing fermenting one part of the fermentation solution to obtain the citric acid; (5) and dispersing the other part of the fermentation solution to obtain a dispersed hypha fermentation solution; (6) inoculating the dispersed hypha fermentation solution into a fermentation culture medium F2; and after the fermentation and culture, returning to the step (4), and repeating like this, thereby implementing continuous fermentation. The method obviously lowers the production cost and operating cost, obviously shortens the production cycle and enhances the production efficiency; and the method enhances the equipment utilization rate, lowers the labor intensity, is easier to operate, and can be widely used in citric acid production.

Description

technical field [0001] The invention relates to the technical field of fermentation engineering, in particular to a process for producing citric acid by continuous fermentation using Aspergillus niger. Background technique [0002] Citric acid has the characteristics of non-toxic, odorless, high solubility and strong chelating ability, and is widely used in food, medicine, chemical industry and other fields. With the development of the world economy and the improvement of people's living standards, the market demand for citric acid is also growing rapidly, with an annual growth rate of 3-5%. [0003] 80% of the world's citric acid production is obtained by Aspergillus niger through submerged fermentation, and batch fermentation is generally used. However, the batch fermentation method has the disadvantages of long non-production cycle, low utilization rate of equipment, and low production efficiency, which has become a technical bottleneck for the development of citric acid...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C12P7/48C12R1/685
Inventor 石贵阳陈坚王宝石张杰胡志杰蒋小东孙福新李赢张梁李由然丁重阳顾正华
Owner JIANGNAN UNIV
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