Linking Landscape, Environment, Agriculture and Food

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Publications

Wine Microbial Consortium: Seasonal Sources and Vectors Linking Vineyard and Winery Environments

Publication . Camilo, Sofia; Chandra, Mahesh; Branco, Patricia; Malfeito-Ferreira, Manuel

ABSTRACT: Winemaking involves a wide diversity of microorganisms with different roles in the process. The wine microbial consortium (WMC) includes yeasts, lactic acid bacteria and acetic acid bacteria with different implications regarding wine quality. Despite this technological importance, their origin, prevalence, and routes of dissemination from the environment into the winery have not yet been fully unraveled. Therefore, this study aimed to evaluate the WMC diversity and incidence associated with vineyard environments to understand how wine microorganisms overwinter and enter the winery during harvest. Soils, tree and vine barks, insects, vine leaves, grapes, grape musts, and winery equipment were sampled along four seasons. The isolation protocol included: (a) culture-dependent microbial recovery; (b) phenotypical screening to select fermenting yeasts, lactic acid, and acetic acid bacteria; and (c) molecular identification. The results showed that during all seasons, only 11.4% of the 1424 isolates presumably belonged to the WMC. The increase in WMC recovery along the year was mostly due to an increase in the number of sampled sources. Acetic acid bacteria (Acetobacter spp., Gluconobacter spp., Gluconoacetobacter spp.) were mostly recovered from soils during winter while spoilage lactic acid bacteria (Leuconostoc mesenteroides and Lactobacillus kunkeii) were only recovered from insects during veraison and harvest. The fermenting yeast Saccharomyces cerevisiae was only isolated from fermented juice and winery equipment. The spoilage yeast Zygosaccharomyces bailii was only recovered from fermented juice. The single species bridging both vineyard and winery environments was the yeast Hanseniaspora uvarum, isolated from insects, rot grapes and grape juice during harvest. Therefore, this species appears to be the best surrogate to study the dissemination of the WMC from vineyard into the winery. Moreover, the obtained results do not evidence the hypothesis of a perennial terroir-dependent WMC given the scarcity of their constituents in the vineyard environment along the year and the importance of insect dissemination.

2022-07Journal article

Open access

The Role of Mild Alkaline Pretreatment in the Biorefinery Upgrade of Spent Coffee Grounds

Publication . Ribeiro, Gabriel Mota; Martins, Pedro L.; Oliveira, Ana Cristina; Carvalheiro, Florbela; Fragoso, Rita; Duarte, Luís C.

ABSTRACT: This work proposes a valorization route for spent coffee grounds (SCG), a widespread lignocellulosic residue, encompassing the production of: biomethane, lignin, and oligosaccharides as value-added products obtained simultaneously during a mild alkaline (NaOH) pretreatment. The studied operational variables were the reaction time (60-240 min), temperature (25-75 degrees C), and the NaOH concentration (0-2.5 M). The severity factor suitably describes the global process kinetics, with higher severities (log Mo = 5.5) yielding high product yields, 18.02% and 13.25% (on dry SCG basis) for lignin and oligosaccharides (XGMOS), respectively. Solid yield is negatively impacted by all studied variables (at the 95% confidence level). Conversely, XGMOS yield is positively influenced both by time and catalyst concentration, whereas lignin yield is only (positively) influenced by catalyst concentration. Optimal balance between product formation and potential operational costs is putatively achieved when using 0.625 M NaOH, at 50 degrees C for 60 min. The mild alkaline pretreated biomass (MAP-SCG) was compared to untreated SCG for biomethane production by anaerobic co-digestion with pig slurry (PS), using a ratio of biomass/PS = 1/3 (volatile solids (VS) basis). The proposed valorization route enabled the sequential production of 6.25 kg lignin, 6.36 kg oligosaccharides, and 138.05 kg biomethane per 100 kg of non-extracted SCG (and 287.60 kg pig slurry), in an integrated process that is technically feasible and promotes the circular bioeconomy.

2023-05Journal article

Open access

Exploring the Multifaceted Potential of a Peptide Fraction Derived from Saccharomyces cerevisiae Metabolism: Antimicrobial, Antioxidant, Antidiabetic, and Anti-Inflammatory Properties

Publication . Branco, Patricia; Mauricio, Elisabete; Costa, Ana; Ventura, Diogo; Roma-Rodrigues, Catarina; Duarte, Maria Paula; Fernandes, Alexandra

ABSTRACT: The rising demand for minimally processed, natural, and healthier food products has led to the search for alternative and multifunctional bioactive food components. Therefore, the present study focuses on the functional proprieties of a peptide fraction derived from Saccharomyces cerevisiae metabolism. The antimicrobial activity of the peptide fraction is evaluated against various foodborne pathogens, including Candida albicans, Candida krusei, Escherichia coli, Listeria monocytogenes, and Salmonella sp. The peptide fraction antioxidant properties are assessed using FRAP and DPPH scavenging capacity assays. Furthermore, the peptide fraction's cytotoxicity is evaluated in colorectal carcinoma and normal colon epithelial cells while its potential as an antidiabetic agent is investigated through alpha-amylase and ff-glucosidase inhibitory assays. The results demonstrate that the 2-10 kDa peptide fraction exhibits antimicrobial effects against all tested microorganisms, except C. krusei. The minimal inhibitory concentration for E. coli, L. monocytogenes, and Salmonella sp. remains consistently low, at 0.25 mg/mL, while C. albicans requires a higher concentration of 1.0 mg/mL. Furthermore, the peptide fraction displays antioxidant activity, as evidenced by DPPH radical scavenging activity of 81.03%, and FRAP values of 1042.50 +/- 32.5 mu M TE/mL at 1.0 mg/mL. The peptide fraction exhibits no cytotoxicity in both tumor and non-tumoral human cells at a concentration up to 0.3 mg/mL. Moreover, the peptide fraction presents anti-inflammatory activity, significantly reducing the expression of the TNF ff gene by more than 29.7% in non-stimulated colon cells and by 50% in lipopolysaccharide-stimulated colon cells. It also inhibits the activity of the carbohydrate digestive enzymes alpha-amylase (IC50 of 199.3 +/- 0.9 mu g/mL) and alpha-glucosidase (IC20 of 270.6 +/- 6.0 mu g/mL). Overall, the findings showed that the peptide fraction exhibits antibacterial, antioxidant, anti-inflammatory, and antidiabetic activity. This study represents a step forward in the evaluation of the functional biological properties of S. cerevisiae bioactive peptides.

2023-08Journal article

Open access