Industrial scale bio-detoxification of raw olive mill wastewaters by the use of selected microbial yeast and bacterial strains to obtain a new source for fertigation

Liquid submerged fermentation by selected microbial strains for onion skins valorization and its effects on polyphenols

Onion skins, actually recycled as organic fertilizers, could be used as a substrate in environmental-friendly bioprocesses to recover high-value bioactive compounds and food ingredients.In this work, a bioprospecting method was carried out including 94 bacterial and 45 yeast strains from several agri-food and environmental niches to verify their ability to grow on onion skins as unique nutrients source.Red and yellow onion skins were assessed by newly selected starter-driven liquid submerged fermentation assays mainly aimed at the release and modification of polyphenols through microbial activities. Fermented onion skins were also investigated as a inexpensive favourable source of microbial enzymes (amylases, proteases, lipases, esterases, cellulases, xylanases).In red onion skins, the treatment with Lactiplantibacillus plantarum TB 11-32 produced a slight increase of bioactive compounds in terms of total phenolics, whereas with the yeast strain Zygosaccharomyces mrakii CL 30 - 29 the quercetin aglycone content increased of about 25% of the initial raw material.In yellow onion skins inoculated, the highest content of phenolic compounds was detected with the yeast strain Saccharomyces cerevisiae En SC, while quercetin aglycone increased of about 60% of the initial raw material in presence of the bacterial strain L. plantarum C 180 - 34.In conclusion, the proposed microbial pre-treatment method can be a potential strategy to re-use onion skins as a fermentation substrate, and as a first step in the development of a biorefinery process to produce value-added products from onion by-products.

Combination of Solid State and Submerged Fermentation Strategies to Produce a New Jellyfish-Based Food

This study describes the set-up and optimization of a fermentation strategy applied to a composite raw material containing jellyfish biomass as the principal ingredient. New fermented food was developed by combining fresh jellyfish Rhizostoma pulmo and the sequential solid-state submerged liquid fermentation method used in Asian countries for processing a high-salt-containing raw material. Aspergillus oryzae was used to drive the first fermentation, conducted in solid-state conditions, of a jellyfish-based product, here named Jelly paste. The second fermentation was performed by inoculating the Jelly paste with different selected bacteria and yeasts, leading to a final product named fermented Jellyfish paste. For the first time, a set of safety parameters necessary for monitoring and describing a jellyfish-based fermented food was established. The new fermented products obtained by the use of Debaryomyces hansenii BC T3-23 yeast strain and the Bacillus amyloliquefaciens MS3 bacterial strain revealed desirable nutritional traits in terms of protein, lipids and total phenolic content, as well as valuable total antioxidant activity. The obtained final products also showed a complex enzyme profile rich in amylase, protease and lipase activities, thus making them characterized by unique composite sensory odor descriptors (umami, smoked, dried fruit, spices).

The Controlled Semi-Solid Fermentation of Seaweeds as a Strategy for Their Stabilization and New Food Applications

For centuries, macroalgae, or seaweeds, have been a significant part of East Asian diets. In Europe, seaweeds are not considered traditional foods, even though they are increasingly popular in Western diets in human food applications. In this study, a biological processing method based on semi-solid fermentation was optimized for the treatment of the seaweed Gracilaria gracilis. For the first time, selected lactic acid bacteria and non-conventional coagulase-negative staphylococci were used as starter preparations for driving a bio-processing and bio-stabilization of raw macroalga material to obtain new seaweed-based food prototypes for human consumption. Definite food safety and process hygiene criteria were identified and successfully applied. The obtained fermented products did not show any presence of pathogenic or spoilage microorganisms, thereby indicating safety and good shelf life. Lactobacillus acidophilus-treated seaweeds revealed higher α-amylase, protease, lipase, endo-cellulase, and endo-xylanase activity than in the untreated sample. This fermented sample showed a balanced n-6/n-3 fatty acid ratio. SBM-11 (Lactobacillus sakei, Staphylococcus carnosus and Staphylococcus xylosus) and PROMIX 1 (Staphylococcus xylosus) treated samples showed fatty acid compositions that were considered of good nutritional quality and contained relevant amounts of isoprenoids (vitamin E and A). All the starters improved the nutritional value of the seaweeds by significantly reducing the insoluble indigestible fractions. Preliminary data were obtained on the cytocompatibility of G. gracilis fermented products by in vitro tests. This approach served as a valid strategy for the easy bio-stabilization of this valuable but perishable food resource and could boost its employment for newly designed seaweed-based food products.

Removal of phosphorus from wastewater by Diutina rugosa BL3: Efficiency and pathway

A novel phosphorus removal yeast BL3 was isolated from an alternating anaerobic/aerobic biofilter and identified as Diutina rugosa by 26S rDNA gene sequence analysis. Yeast BL3 could effectively remove phosphorus from synthetic wastewater containing 2-20 mg/L phosphorus under optimal environmental conditions. The highest phosphorus removal efficiency was above 70% under the conditions of DO 6.86 mg/L, C/P ratios of 60, N/P ratios of 3.3, pH 6.0-9.0, and at 25.0-35.0 °C. The phosphorus distribution in the aqueous solution and different components of yeast BL3 analysis indicated that around 55%-70% and 20%-40% of removed phosphorus were transferred into extracellular polymeric substances (EPS) and yeast cells, respectively. The plausible phosphorus transfer pathway was proposed based on the phosphorus distribution and species analysis, suggesting the important role of EPS as a phosphorus reservoir. These results indicate that yeast BL3 can efficiently remove phosphorus under aerobic conditions without alternating anaerobic/aerobic cycling, and thus has significant potential for practical application in wastewater phosphorus removal.

Available Pathways for Operationalizing Circular Economy into the Olive Oil Supply Chain: Mapping Evidence from a Scoping Literature Review

Circular economy (CE) is increasingly seen as a promising paradigm for transitioning agri-food systems towards more sustainable models of production and consumption, enabling virtuous and regenerative biological metabolisms based on strategies of eco-efficiency and eco-effectiveness. This contribution seeks to provide a theoretical and empirical framework for operationalizing the CE principles into the olive oil supply chain, that plays a central role in the agroecological systems of the Mediterranean region. A scoping literature review has been conducted in order to identify the available pathways so far explored by scholars for reshaping the olive oil supply chain from a circular perspective. The analyzed literature has been charted on the base of the circular pathway examined, and according to the supply chain subsystem(s) to which it refers. Results are discussed highlighting the main issues, the technology readiness level of the available pathways, the prevailing approaches and knowledge gaps. A synthetic evidence map is provided, framing visually the scrutinized pathways into the Ellen MacArthur Foundation’s CE ‘butterfly’ graph. The work is intended to be a valuable baseline for inquiring how circularity can be advanced in the specific supply chain of olive oil, and which are the strategic opportunities, as well as the barriers to overcome, in order to foster the transition.

Agri-Food Contexts in Mediterranean Regions: Contributions to Better Resources Management

The agri-food frameworks have specific characteristics (production units with small dimensions and in great number with implications in the respective markets) that call for adjusted approaches, even more so when they are considered in Mediterranean contexts (where global warming will have relevant impacts). In fact, the Mediterranean regions and countries have particular specificities (due to their climate conditions) that distinguish them from their neighbours. This is particularly true in Europe, for example, where the southern countries present socioeconomic dynamics (associated with the respective public debt) that are different from those identified in the northern regions. From this perspective, it seems pertinent to analyse the several dimensions of the agri-food systems in the Mediterranean area. To achieve these objectives, a search was carried out on 26 December 2020 on the scientific databases Web of Science Core Collection (WoS) and Scopus for the topics “agr*-food” and “Mediterranean”. These keywords were selected after a previous literature survey and to capture the agri-food contexts in Mediterranean regions. The keyword “agr*-food” was considered in this way to allow for a wider search (including “agri-food”, “agro-food”, etc.). Considering only articles (excluding proceeding papers, book chapters, and books, because in some cases it is difficult to access the entire content of the document), 100 and 117 documents were obtained from the WoS and Scopus, respectively. After removing the duplicated studies and taking into account the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) approach, 137 documents were surveyed through a literature review. As main insights, several dimensions embedded in the concept of agri-food were highlighted, from those related to heritage subjects to natural assets. On the other hand, the following subtopics were identified: agri-food dynamics and sustainability, agriculture and agri-food systems, agri-chains and food consumption, and food production and composition impact on agri-chains. Stressing the gaps in the scientific literature, related to the topics here addressed, there are possibilities to better explore the several dimensions and solutions offered by the new developments associated with smart agriculture and agriculture 4.0, specifically for the Mediterranean contexts and their challenges. Finally, to complement the PRISMA methodologies, an MB2MBA2 (Methodology Based on Benchmarking of Metadata, from scientific databases, and Bibliometric Assessment and Analysis) approach is suggested to carry out systematic literature reviews, based on bibliometric analysis.