The Origin of a Psychobiotic
The story of plantarum PS128 begins in a kitchen, not a laboratory. This specific and now widely researched probiotic strain was originally isolated from a traditional Taiwanese fermented food called fu-tsai. While the broader species Lactobacillus plantarum is common in many fermented foods worldwide, PS128 is a unique isolate with documented psychobiotic properties, meaning it can influence the gut-brain axis. The discovery was made by a research team led by Professor Ying-Chieh Tsai at National Yang-Ming University in Taiwan, who were screening various bacteria for psychotropic potential. Their work involved testing hundreds of lactic acid bacteria strains, and PS128 was identified as having the highest potential for beneficial effects on mood and behavior. This isolation from a common, traditional food source has cemented its place in the world of modern nutraceuticals, bridging the gap between ancient dietary practices and contemporary scientific research.
The Traditional Fermentation Process of Fu-tsai
To truly understand the source of plantarum PS128, one must appreciate the artisanal process of creating fu-tsai. This Hakka ethnic food product is made by naturally fermenting mustard greens. The steps are deliberate and contribute to the rich bacterial diversity from which PS128 was eventually isolated.
- Harvesting and Wilting: Freshly harvested mustard greens are first left in the sun to wilt slightly.
- Salting and Compression: The wilted greens are layered with salt and compressed firmly in a vessel, often by stepping on them. This process draws out the plant's sap.
- First Fermentation: The greens undergo an initial anaerobic fermentation for at least a week at ambient temperature.
- Sun-Drying and Repacking: The fermented mustard is then cleaned, sun-dried, and repacked tightly into jars with additional salt. The jars are typically sealed and turned upside down.
- Maturation: The sealed jars are left to mature for several months, sometimes up to a year, which allows the microbial ecosystem to develop fully.
It is during this spontaneous fermentation process that the lactic acid bacteria, including L. plantarum strains, naturally proliferate. The researchers carefully sampled these fermented mixtures to find and isolate the specific PS128 strain.
From Isolation to Commercial Production
After its isolation in 2007, the PS128 strain underwent significant research and development. It was deposited with the Leibniz Institute DSMZ, a German Collection of Microorganisms and Cell Cultures, with accession number DSM 28632, to ensure its preservation and identification. The commercialization of the PS128 strain is managed by Bened Biomedical Co., Ltd., a company spun out from National Yang-Ming University, where the strain was first identified. Modern production methods ensure a consistent, potent, and safe product for consumer use. This represents a crucial transition from a naturally occurring microorganism in a food item to a precisely manufactured probiotic supplement, with controlled colony-forming unit (CFU) counts and standardized quality.
Comparison: Traditional Fermentation vs. Modern Production
| Aspect | Traditional Fu-tsai Production | Modern PS128 Production |
|---|---|---|
| Source | Naturally occurring microbes present in mustard greens and the environment | PS128 strain is isolated, purified, and cultivated in a controlled lab setting |
| Consistency | Variable microbial makeup and potency depending on environmental factors | Standardized CFU count and verified strain identity in every batch |
| Safety | Relies on traditional fermentation knowledge; potential for variation | Tested for genotoxicity, stability, and absence of biogenic amines to ensure safety |
| Application | Consumed as a fermented vegetable food ingredient | Used as a targeted psychobiotic dietary supplement in capsule or powder form |
| Scale | Small-scale, often artisanal, family or local production | Large-scale, industrial manufacturing by a biomedical company |
Conclusion: The Journey of PS128
The story of plantarum PS128 is a testament to the potential hidden within traditional food sources. It illustrates how meticulous scientific research can take a microorganism from a humble, fermented vegetable and transform it into a well-defined, standardized nutraceutical with targeted health benefits. While it may have started in a jar of Taiwanese fu-tsai, its journey as a documented psychobiotic continues in clinical trials and commercial products worldwide. The origin of plantarum PS128 is a powerful example of how ancient dietary practices can inform and enrich modern scientific innovation.
For more detailed information on the isolation and genomic sequencing of plantarum PS128, you can read the scientific study published in Gut Pathogens.
