When you talk about fermented foods, kimchi stands out not only as a culinary delight but also as a treasure trove of microbial wonders. One might typically view viral resistance in bacteria as a cause for concern, as it may halt therapy. In the context of kimchi, this resistance shines brightly, enhancing the culinary experience with its remarkable flavors. These bacteria play a crucial role in fermenting kimchi, making them essential for its production. If these bacteria were to be attacked by bacteriophages, the entire process of kimchi production could come to a standstill or reduce production, depriving us of the delightful flavors that make kimchi a culinary delight.
Produced through low-temperature fermentation without pre-sterilization, kimchi hosts a diverse microbial community, shaping its unique flavors and textures. Researchers at the World Institute of Kimchi have delved into this microbial universe, uncovering fascinating insights into the dominant lactic acid bacteria (LAB) species that safeguard kimchi against viral invasions.
In a pioneering study published in the journal Food Microbiology, scientists explored long-term fermented kimchi stored at low temperatures, collecting samples from various regions in South Korea. Their meticulous analysis revealed a specific LAB strain, Pediococcus inopinatus, as the stalwart defender in over 88% of the studied kimchi samples. What sets P. inopinatus apart is its well-developed clustered regularly interspaced short palindromic repeats (CRISPR) system, a sophisticated prokaryotic adaptive immune system that combats phages, and viruses that infect and replicate within bacteria.
Through whole-genome sequencing analysis, the researchers unearthed the unique genetic traits of P. inopinatus. This exceptional LAB strain boasts an abundance of the csa3 gene, responsible for the transcription factors that activate cas genes. Consequently, P. inopinatus stores a wealth of genetic information about phages, enabling it to fend off viral invasions effectively. After the initial phage infection, P. inopinatus becomes adept at preventing subsequent infections, ensuring the stability of the kimchi fermentation process.
This research not only sheds light on the intricate microbial dynamics within kimchi but also paves the way for future studies exploring the broader implications of these findings. As the world continues to grapple with viral challenges, the humble kimchi emerges as a source of inspiration, offering valuable lessons in microbial resilience and antiviral defense mechanisms. The microbial guardians of kimchi, particularly P. inopinatus, stand as a testament to nature’s ingenuity, reminding us of the boundless wonders that the microbial world has to offer.
To read more please visit Mun, S. Y., Lee, W., Lee, S. Y., Chang, J. Y., & Chang, H. C. (2024). Pediococcus inopinatus with a well-developed CRISPR-Cas system dominates in long-term fermented kimchi, Mukeunji. Food Microbiology, 117, 104385.