Full recycling of citric acid wastewater through anaerobic digestion, air-stripping and pH control

Abstract Anaerobic digestion effluent (ADE) from the anaerobic digestion treatment of citric acid wastewater can be reused as a potential substitute for process water in the citric acid fermentation. However, excessive sodium contained in ADE significantly decreases citric acid production. In this paper, the inhibition mechanism of sodium on citric acid fermentation was investigated. We demonstrated that excessive sodium did not increase oxidative stress for Aspergillus niger, but reduced the pH of the medium significantly over the period 4–24 h, which led to lower activities of glucoamylase and isomaltase secreted by A. niger, with a decrease of available sugar concentration and citric acid production. ADE was pretreated by air-stripping prior to recycle and 18 g/L calcium carbonate was added at the start of fermentation to control the pH of the medium. The inhibition caused by ADE was completely alleviated and citric acid production substantially increased from 118.6 g/L to 141.4 g/L, comparable to the fermentation with deionized water (141.2 g/L). This novel process could decrease wastewater discharges and fresh water consumption in the citric acid industry, with benefit to the environment.

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Improving Citric acid Production of an Industrial Aspergillus Niger CGMCC 10142: Identification and Overexpression of a High-affinity Glucose Transporter with Different Promoters

10.21203/rs.3.rs-105405/v1 ◽

2020 ◽

Author(s):

Xianli Xue ◽

Futi Bi ◽

Boya Liu ◽

Jie Li ◽

Lan Zhang ◽

...

Keyword(s):

Citric Acid ◽

Aspergillus Niger ◽

Acid Production ◽

Glucose Transporter ◽

Citrate Synthase ◽

Sugar Content ◽

Citric Acid Production ◽

Acid Fermentation ◽

Total Sugar Content ◽

High Affinity

Abstract Background: The transporter of glucose plays an important role in the fermentation of citric acid. In this research, a high-affinity glucose transporter (HGT1) was identified and overexpressed in industrial strain A. niger CGMCC 10142. The overexpressed-HGT1 strains were obtained to verify the glucose transporter functions with different promoters PglaA and Paox1.Result: The sugar contents and citric acid production during fermentation were tracked. As speculated, the HGT1-overexpressed strains showed higher citric acid production and lower residual sugar contents. The best-performing strain on the fermentation is A. niger 20-15 transformant of which the total sugar content and residual reducing sugar both were reduced by 31% and 44.9% comparing to A. niger CGMCC 10142, and the final citric acid production was correspondingly increased to 174.1 g/L comparing to A. niger CGMCC 10142 with 162.3 g/L. Besides HGT1, the transcription levels of related genes as citrate synthase and glucokinase in transformants were also significantly higher than A. niger CGMCC 10142.Conclusion: The results indicate that HGT1 understandably alleviates the metabolic restriction caused by insufficient sugar transporters and finally improves the utilization of sugar. This study confirms the important role of glucose transporter HGT1 in the citric acid fermentation process of Aspergillus niger.

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Citric acid production by recycling its wastewater treated with anaerobic digestion and nanofiltration

Process Biochemistry ◽

10.1016/j.procbio.2017.04.022 ◽

2017 ◽

Vol 58 ◽

pp. 245-251 ◽

Cited By ~ 8

Author(s):

Hongjian Zhang ◽

Jian Xu ◽

Xianfeng Su ◽

Jiawei Bao ◽

Ke Wang ◽

...

Keyword(s):

Anaerobic Digestion ◽

Citric Acid ◽

Acid Production ◽

Citric Acid Production

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Review on production of citric acid by fermentation technology

GSC Biological and Pharmaceutical Sciences ◽

10.30574/gscbps.2021.17.3.0313 ◽

2021 ◽

Vol 17 (3) ◽

pp. 085-093

Author(s):

Sweta V. Lende ◽

Heera Karemore ◽

Milind J. Umekar

Keyword(s):

Citric Acid ◽

Submerged Fermentation ◽

Acid Production ◽

Citric Acid Production ◽

Acid Fermentation ◽

Waste Products ◽

Factors Affecting ◽

Candida Sp ◽

Pharmaceutical Industries ◽

Fermentation Technology

Citric acid is the most important organic acid produced in tonnage and is extensively used in food and pharmaceutical industries. It is produced mainly by submerged fermentation using Aspergillus niger or Candida sp. from different sources of carbohydrates, such as molasses and starch-based media. In view of surges in demand and growing markets, there is always a need for the discovery and development of better production techniques and solutions to improve production yields and the efficiency of product recovery. To support the enormous scale of production, it is necessary and important for the production process to be environmentally friendly by utilizing readily available and inexpensive agro-industrial waste products, while maintaining high production yields. This review article for fermentation of citric acid and Microbial production of citric acid, Substrates and strategies of citric acid production for Surface fermentation, Submerged fermentation, Solid-state fermentation and also the effects of various Factors affecting of citric acid fermentation conditions are Carbon source, Nitrogen limitation, Phosphorus source, Lower Alcohols, pH of culture medium, Trace elements, Aeration and Other factors. citric acid recovery options and the numerous applications of citric acid, based on the literature review information of citric acid production by fermentation technology.

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