This article was inspired by a client of mine who purchased chitosan oligosaccharides for use in microbial fermentation. This led me to discover a new aspect: chitosan oligosaccharides can not only be used as an additive in combination with microorganisms to enhance their activity, but also play an important role in the microbial fermentation stage. Next, I will explain this role in detail:
Chitosan oligosaccharide (COS), derived from the natural polymer chitosan, is renowned for its excellent biocompatibility and biodegradability. It is a valuable additive in microbial fermentation media, particularly during anaerobic fermentation, where it can effectively enhance carbon sequestration, shorten the lag phase, increase product yield, and optimize microbial community structure.
Functions:
Induced enzyme production: Used in fermentation to produce chitosanase, chitinase, and other enzymes.
Antimicrobial/probiotic research: Utilizing its antimicrobial properties to screen for resistant strains or promote the growth of probiotics (such as lactic acid bacteria).
Plant growth-promoting bacterial fermentation: Chitosan oligosaccharides can enhance the activity of rhizobia and nitrogen-fixing bacteria.
Advantages:
Chitosan oligosaccharides are composed of glucosamine and N-acetylglucosamine, providing carbon and nitrogen sources for microorganisms capable of secreting chitosanase or chitinase (such as certain fungi and bacteria).
They are biologically active and can stimulate secondary metabolism (such as antibiotic and enzyme production) in some microorganisms.
Limitations:
Nutritional limitation: They lack essential components such as inorganic salts and vitamins and require supplementation (such as yeast extract or inorganic salts).
Microbial specificity: They are only suitable for strains capable of degrading chitooligosaccharides (such as Trichoderma, Aspergillus, and Bacillus). They may not be effective against common industrial strains (such as Escherichia coli and Saccharomyces cerevisiae).
Which microorganisms are suitable?
| Microorganism type | Representative strains | Application Scenarios |
| Fungi | Trichoderma | Chitosanase production, biocontrol agent fermentation |
| Aspergillus | Organic acid or enzyme production | |
| Bacteria | Bacillus | Antimicrobial peptide, biofertilizer fermentation |
| Pseudomonas | Pollutant degradation or biosurfactant synthesis | |
| Actinomycetes | Streptomyces | Antibiotic production |