COCONUT

The growing demand for sustainable and nutritious plant-based foods has created new opportunities for the development of fermented alternatives with improved safety, nutritional value and sensory quality. However, successful fermentation of plant matrices requires microbial cultures specifically adapted to these substrates and able to establish stable and functional microbial communities.

The COCONUT project (MiCrObial COnsortia for New plant-based fermented prodUcTs) aimed to exploit the microbial biodiversity preserved in collections derived from traditional and spontaneous fermented foods to design tailored microbial consortia for innovative plant-based fermentations. Rather than relying on single starter cultures, the project focused on selecting complementary lactic acid bacteria (LAB) and coagulase-negative staphylococci displaying desirable safety, metabolic and technological characteristics, capable of efficiently colonising plant matrices and driving controlled fermentations.

An integrated workflow combining microbial ecology, molecular characterization, safety assessment, phenotypic screening and laboratory-scale food production was adopted. More than 300 bacterial isolates originating from traditional fermented foods, including cheeses, fermented vegetables, fermented meats and silages, were initially screened for their phylogenetic diversity. Representative strains were subsequently characterised for antibiotic resistance, biogenic amine production, antimicrobial and metabolic properties before being assembled into tailored microbial consortia. Selected combinations were progressively validated in model fermentations of nuts and legumes and finally applied to the development of innovative fermented plant-based prototypes.

Results achieved

The project successfully achieved all its scientific objectives, establishing a comprehensive microbial platform for the development of fermented plant-based foods. Phylogenetic characterization of more than 300 bacterial isolates highlighted the remarkable biodiversity associated with traditional fermented foods, leading to the selection of representative lactic acid bacteria and coagulase-negative staphylococci belonging to 21 bacterial species. These strains were deposited in the University of Parma Culture Collection (UPCC), creating a publicly accessible microbial resource that will support future research and industrial applications.

Comprehensive safety and technological characterization enabled the selection of strains suitable for food fermentation. The selected microorganisms exhibited a favourable safety profile, with limited antibiotic resistance, absence of histamine production and only a limited number of tyramine-producing isolates. Their antimicrobial, metabolic and technological properties were subsequently investigated to identify complementary traits and assemble

tailored microbial consortia combining rapid acidification, microbial stability and desirable aroma-forming potential.

The designed microbial consortia were evaluated through model fermentations using two representative plant substrates, cashew nuts and cannellini beans. These studies demonstrated that carefully assembled multi-strain consortia significantly improved fermentation performance compared with single strains, enhancing acidification kinetics, substrate colonisation and technological robustness. The experimental activities also allowed optimisation of the production process, including substrate pre-treatment and fermentation conditions, to ensure effective control of the native microbiota while preserving the performance of the selected starter cultures.

Building upon these results, laboratory-scale production protocols were developed for innovative fermented plant-based prototypes. In particular, an optimised fermented cashew-based cream was obtained using a tailored microbial consortium composed of Leuconostoc mesenteroides, Lacticaseibacillus paracasei and Staphylococcus xylosus. The optimised process combined thermal pre-treatment with controlled fermentation, allowing rapid acidification below the critical safety threshold (pH < 4.4), effective control of Enterobacteriaceae, excellent persistence of the selected LAB throughout refrigerated storage and the development of a balanced volatile profile. The dynamics of the designed consortium were further investigated using both culture-dependent and molecular approaches, confirming the stability and functionality of the selected microorganisms during fermentation and storage.

Overall, COCONUT demonstrated that the microbial biodiversity associated with traditional fermented foods represents a valuable reservoir for the rational design of tailored microbial consortia able to support safe, stable and high-quality fermentation of plant-based substrates. Beyond the development of innovative fermented prototypes, the project generated publicly available microbial resources, technological knowledge and fermentation protocols that provide a scientific basis for future industrial exploitation and contribute to expanding the availability of sustainable fermented plant-based foods.

D.D. del MUR n. 1409 del 14/09/2022

CUP: J53D23018570001

Coordinator: Università degli Studi di Parma

Ruolo UNIBO: PI/R

Sostegno finanziario UE: € 102.820,00

Ambiti di ricerca: Microbiologia agroambientale e degli alimenti

Scientific Officer: Giulia Tabanelli

Duration: 30/11/2023 - 29/11/2025

Research group: Giulia Tabanelli, Fausto Gardini.

Funding

Funded by the European Union - NextGenerationEU under the National Recovery and Resilience Plan (PNRR) - Mission 4 Education and research - Component 2 From research to business - Investment 1.1 Notice PRIN 2022 PNRR (DD N. 1409 del 14/09/2022), entitled "miCrObial COnsortia for New plant-based fermented prodUcTs", proposal code P2022SPCRW- CUP J53D23018570001.