Citric Acid Production of Yeasts: An Overview

Abstract

Background Citric acid, an intermediate product of the Krebs cycle, has a wide usage area in the food industry since it has some functions such as acidulant, flavouring agent, preservative and antioxidant. Although molds are the most commonly used microorganisms in the citric acid production, it is known that there are significant advantages of using yeasts. Purpose and scope The microbial citric acid production mechanism needs to be well understood to make production more efficient. In this study, the yeasts used in the production, fermentation types and the factors affecting production were reviewed with studies. Methodology Although production of citric acid can be produced by chemical synthesis, the fermentation is preferred because of its low cost and ease of use. More than 90% of citric acid produced in the world is obtained by fermentation. Results Yarrowia lipolytica, Candida zeylanoides and Candida oleophila are evaluated for citric acid production with substrates such as molasses, glucose, sucrose and glycerol. On the other hand, there is great interest in developing processes with new substrates and/ or microorganisms. Conclusion Although the microbial strain is an important factor, the factors such as carbon, phosphorus and nitrogen sources, aeration, the presence of trace elements and pH are also parameters affecting the production.

Citric Acid Recovery and Methanol Production from a Waste Food Fruit Sample by Thermal Decomposition of a Reusable Zinc Citrate Complex

“…Although the zinc citrate complex has potential uses in drug industries, the conversion of value-added chemicals from the zinc citrate complex is an alternative renewable resource to fill the demand in the chemical industries since the zinc citrate complexes are easily obtained from the various food industry sectors. 3 Extraction and Reusability of Zinc Metals from Waste Batteries. In general, commercial zinc oxide is widely used in the material synthesis industries for the production of many valuable products.…”

“…2 Another significant portion is used in the pharmaceutical industry, where it is typically used as an effervescent and flavoring agent. 3 Commonly, CA is commercially delivered through submerged microorganisms by the fermentation process of molasses; 4 the fermentation strategy utilizing Aspergillus niger is the most promising route for the production of CA in the food industries worldwide. 5 Although several techniques were developed to blend CA with various chemicals to produce value-added products in chemical industries, more noteworthy success has been accomplished using microbial fermentation (90% production in the world market), and over time, this framework has become the strategy of choice for commercial generation in chemical synthesis.…”

Extraction of fulvic acid by citric acid–ethanol method and its biochemical activity

“…However, the present study innovatively adopted citric acid, a non‐toxic and non‐hazardous organic acid, as the extracting agent. As a strong organic acid, citric acid can generate three hydrogen ions to replace the metal ions of FA salts, thereby generating free FA 23,24 . Furthermore, citric acid can be complexed and precipitated with metal ions, which is beneficial to remove impurities in FA 24 .…”

“…As a strong organic acid, citric acid can generate three hydrogen ions to replace the metal ions of FA salts, thereby generating free FA. 23,24 Furthermore, citric acid can be complexed and precipitated with metal ions, which is beneficial to remove impurities in FA. 24 It is also rich in oxygen-containing functional groups, 25 which is beneficial to increasing the active groups of the extracted FA.…”

“…23,24 Furthermore, citric acid can be complexed and precipitated with metal ions, which is beneficial to remove impurities in FA. 24 It is also rich in oxygen-containing functional groups, 25 which is beneficial to increasing the active groups of the extracted FA. Additionally, the carboxyl and phenolic hydroxyl groups in FA can form hydrogen bonds with the highly electronegative oxygen atoms of ethanol, thus promoting the dissolution of FA in ethanol and enabling effective extraction.…”