Method for producing citric acid by citric acid wastewater reflux fermentation

A citric acid wastewater and citric acid technology, applied in the field of fermentation engineering, can solve problems such as unsatisfactory effect, long cycle, incomplete wastewater treatment, etc., and achieve the effects of saving process water and steam consumption, stable fermentation, and saving sewage treatment costs

Active Publication Date: 2014-10-22
JIANGNAN UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Judging from the current status of wastewater treatment in the citric acid industry, the effect is not ideal. These methods generally require pretreatment in the early stage, the cycle is long, and the wastewater treatment is not thorough. Further advanced treatment is required to meet the discharge standard, and the treatment cost is relatively high.

Method used

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  • Method for producing citric acid by citric acid wastewater reflux fermentation

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] 200kg of corn flour and 600kg of citric acid waste sugar water were mixed evenly in a batching tank at 50°C, and calcium hydroxide was added to adjust the pH to 5.8, and 250g of high-temperature-resistant α-amylase with an enzyme activity unit of 20,000U / g was added. After the second injection liquefaction, the temperature of the first injection is 97°C, the temperature of the second injection is 130°C, keep in the tank for 0.5~1h, the iodine test is light brown and it is qualified, and the liquefaction mixture is obtained, and then 70% of the liquefaction mixture is put into Plate and frame filter press to obtain liquefied supernatant.

[0024] Prepare seed medium and fermentation nutrient solution, wherein the seed medium is to mix the liquefied clear liquid and the liquefied mixed solution at a ratio of 1:1.5, and add citric acid waste water to replenish water; the fermented nutrient solution is to mix the liquefied clear liquid and the liquefied mixed solution at a r...

Embodiment 2

[0028] 100kg of cassava flour and 150kg of citric acid waste sugar water were mixed evenly in a batching tank at 60°C, and calcium hydroxide was added to adjust the pH to 5.9, and 125g of high-temperature-resistant α-amylase with an enzyme activity unit of 20,000U / g was added. After the second injection liquefaction, the temperature of the first injection is 99°C, the temperature of the second injection is 125°C, maintain in the maintenance tank for 0.5~1h, the iodine test is light brown, and the liquefaction mixture is obtained, and then 60% of the liquefaction mixture is put into Plate and frame filter press to obtain liquefied supernatant.

[0029] Prepare seed medium and fermentation nutrient solution, wherein the seed medium is to mix the liquefied clear liquid and the liquefied mixed solution at a ratio of 1:1.5, and add citric acid waste water to replenish water; the fermented nutrient solution is to mix the liquefied clear liquid and the liquefied mixed solution at a ra...

Embodiment 3

[0033] 300kg of corn flour, 200kg of cassava flour raw materials, 2000kg of citric acid waste sugar water, mixed evenly in a batching tank at 55°C, adding calcium hydroxide to adjust the pH to 5.9, adding 800g of high temperature resistant α-amylase with an enzyme activity unit of 20000U / g. Liquefied by two injections, the temperature of the first injection is 101°C, the temperature of the second injection is 120°C, maintain in the maintenance tank for 0.5~1h, and pass the iodine test to light brown to obtain a liquefied mixed liquid, and then 80% of the liquefied mixed liquid Enter the plate and frame filter to obtain the liquefied supernatant.

[0034] Prepare seed medium and fermentation nutrient solution, wherein the seed medium is to mix the liquefied clear liquid and the liquefied mixed solution at a ratio of 1:2, and add citric acid waste water to replenish water; the fermented nutrient solution is to mix the liquefied clear liquid and the liquefied mixed solution at a r...

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Abstract

The invention relates to a method for producing citric acid by citric acid wastewater reflux fermentation. The method comprises the following steps: uniformly mixing a starchy raw material with citric acid wastewater, and adding high-temperature alpha-amylase (2) carrying out injection on the mixed solution twice, and carrying iodine test to obtain a qualified liquefied mixed solution; carrying out plate-frame pressure filtration on the liquefied mixed solution to obtain a liquefied clear solution; (3) mixing the liquefied clear solution with the liquefied mixed solution, adding the citric acid wastewater for water replenishing to obtain a seed culture medium, and carrying out strain seed culture; (4) mixing the liquefied clear solution with the liquefied mixed solution, adding citric acid wastewater for water replenishing to obtain a fermentation nutrient solution, and carrying out fermentation culture; and (5) after the fermentation is finished, carrying out solid-liquid separation to remove the thallus, and extracting by a hydrogen calcium process or chromatography to obtain the citric acid, wherein the generated wastewater returns to the steps (1), (3) and (4), and the cycle repeats. The method has the advantages high fermentation stability and equivalent level with the original technique, saves the consumption of process water and vapor, saves the sewage treatment cost, and has important environmental benefit and economic benefit.

Description

technical field [0001] The invention relates to the technical field of fermentation engineering, in particular to a method for producing citric acid by direct reflux fermentation of citric acid wastewater without any treatment. Background technique [0002] Citric acid is widely used in the fields of food, medicine and chemical industry because of its pleasant sour taste, refreshing taste, no aftertaste, safety and non-toxicity, and has become the edible organic food with the largest production and consumption in the world. acid. China is the world's largest exporter of citric acid. In 2012, the production capacity has exceeded 1.1 million tons. About 90% of citric acid is exported abroad, accounting for about 70% of the world's total output. The production of citric acid mainly adopts liquid submerged fermentation, and a large amount of wastewater will be generated during the extraction process, which contains some organic acids, sugars, protein colloids, minerals and othe...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C12P7/48C12R1/685
Inventor 石贵阳胡志杰蒋小东孙福新金赛王宝石张杰李赢
Owner JIANGNAN UNIV
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