Innovative technological potential of Lachancea thermotolerans in the fermentation of table olives

Table olives are one of the most widely consumed fermented vegetables, with strong consumer acceptance. While their global production is widespread, cultivation is mainly concentrated in Mediterranean countries such as Spain, Italy, and Greece. However, the industry faces persistent challenges, particularly the low survival rate of commercial starter cultures during early fermentation. This has prompted a search for novel microorganisms with high biotechnological potential. Among them, Lachancea thermotolerans (Lt) stands out for its acidification capacity and beneficial interactions with lactic acid bacteria (LAB).

In this context, this study evaluated the technological potential of a collection of Lt strains. Initially, their acidification capacity was assessed in different culture media. Additional traits such as salt and low pH tolerance were also measured. The best-performing strains were then selected for co-culture studies with Lactiplantibacillus plantarum (Lp) strains. To evaluate the microbial interactions, biofilm formation was assessed on abiotic surfaces. Several Lt–Lp consortia significantly improved biofilm development compared to monocultures. These enhanced biofilms were further examined using scanning electron microscopy to understand structural interactions.

Selected Lt strains were then used in fermentations of Spanish-style green table olives, followed by inoculation with a reference Lp strain. In all fermenters, Lt successfully dominated the early stages, accelerating acidification and enabling rapid LAB growth. Final packaged olives fermented with two selected Lt strains received the highest sensory scores, confirming their positive impact on product quality.

In summary, Lt shows strong potential as a table olive starter culture, capable of forming stable, efficient microbial consortia and improving the sensory and microbiological quality of table olives.

Acknowledgments:
Project PID2021-125864OA-I00 funded by MICIU/AEI/10.13039/501100011033 and FEDER, EU. P. Gil-Flores also acknowledges her research contract PCI IN000286 funded by MCIN and FEDER.