Citric acid: how it is made and used in industry
What it found
Citric acid is made mainly by fermenting sugars with the fungus Aspergillus niger, and around 2.8 million tons are produced worldwide each year.
It is used in food, medicines, cosmetics and many other industries.
What they found
Where it comes from
Citric acid is found naturally in plant and animal tissues, including blood, bone and muscle. It is also present in citrus fruits, with lemons containing 4 to 8% of their dry weight.
How it is made
Over 90% of the world's citric acid is made by three fermentation methods. Around 80% is made by submerged fermentation, mostly using the fungus Aspergillus niger.
Raw materials used
High-purity sugars like sucrose and glucose can be used, but they are expensive. Cheaper options include molasses, starch materials, fruit and vegetable waste, and glycerol.
Food industry uses
In food, citric acid controls acidity, preserves, acts as an antioxidant, helps mix ingredients, boosts flavour and aroma, buffers, and fights bacteria. It also stops fruits and vegetables from browning.
New uses being explored
Citric acid is being tested as a cross-linking agent and plasticizer for starch films, and as a component of deep eutectic solvents for extracting compounds from plants and animals.
What the authors conclude
- They emphasize that there is still much to explore, both in terms of production process techniques and emerging new applications of citric acid.
- They note that new and innovative applications of citric acid in the food industry and beyond are expected to lead to increased production.
How it was done
The authors wanted to gather and update information on how citric acid is produced by microorganisms, the fermentation methods used, and its industrial uses, because the market for it is growing quickly.
They reviewed published research on citric acid's properties, the microorganisms and raw materials used to make it, different fermentation techniques, and its applications in industry.
What it can’t tell you
- This is a review of published research, not a new experiment. It cannot show what would happen if a person consumed citric acid in any particular amount.
- The paper does not report health outcomes in people from eating citric acid.
Who paid
- Funding
- Funded by Wroclaw University of Economics and Business (from the PubMed record).
- Conflicts
- The author declares no conflict of interest. The author alone is responsible for the content and writing of this article.
- Authors work at
- Wroclaw University of Economics and Business, Poland
The paper
- Title
- Citric Acid: Properties, Microbial Production, and Applications in Industries
- Type
- ReviewThe authors read earlier studies and describe what they found. It isn’t a new study.
- Summarised from
- Full text
- Cite
- Książek E (2023). Citric Acid: Properties, Microbial Production, and Applications in Industries. Molecules (Basel, Switzerland). doi:10.3390/molecules29010022Free full textPubMed 38202605DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error