From Grape By-Products to Enriched Yogurt Containing Pomace Extract Loaded in Nanotechnological Nutriosomes Tailored for Promoting Gastro-Intestinal Wellness.

Grape pomace is the main by-product generated during the winemaking process; since it is still rich in bioactive molecules, especially phenolic compounds with high antioxidant power, its transformation in beneficial and health-promoting foods is an innovative challenge to extend the grape life cycle. Hence, in this work, the phytochemicals still contained in the grape pomace were recovered by an enhanced ultrasound assisted extraction. The extract was incorporated in liposomes prepared with soy lecithin and in nutriosomes obtained combining soy lecithin and Nutriose FM06®, which were further enriched with gelatin (gelatin-liposomes and gelatin-nutriosomes) to increase the samples' stability in modulated pH values, as they were designed for yogurt fortification. The vesicles were sized ~100 nm, homogeneously dispersed (polydispersity index < 0.2) and maintained their characteristics when dispersed in fluids at different pH values (6.75, 1.20 and 7.00), simulating salivary, gastric and intestinal environments. The extract loaded vesicles were biocompatible and effectively protected Caco-2 cells against oxidative stress caused by hydrogen peroxide, to a better extent than the free extract in dispersion. The structural integrity of gelatin-nutriosomes, after dilution with milk whey was confirmed, and the addition of vesicles to the yogurt did not modify its appearance. The results pointed out the promising suitability of vesicles loading the phytocomplex obtained from the grape by-product to enrich the yogurt, offering a new and easy strategy for healthy and nutritional food development.

Bridging biotechnology and nanomedicine to produce biogreen whey-nanovesicles for intestinal health promotion.

New intestinal health-promoting biotechnological nanovesicles were manufactured by combining the main environmental pollutant generated from the cheese-making process, whey, with phospholipid, sodium hyaluronate and dextrin, thus overcoming environmental and medical challenges. An efficient, consolidated and eco-friendly preparation method was employed to manufacture the vesicles and the bioactive whey was obtained by mesophilic dark fermentation without external inoculum through a homolactic pathway, which was operated in such a way as to maximize the production of lactic acid. The biotechnological nutriosomes and hyalonutriosomes were relatively small (∼100 nm) and characterized by the net negative surface charge (>-30 mV). The addition of maltodextrin to the liposomes and especially to the hyalurosomes significantly stabilized the vesicles under acidic conditions, simulating the gastric environment, as their size and polydispersity index were significantly lower (p < 0.05) than those of the other formulations. The vesicles were effectively internalized by Caco-2 cells and protected them against oxidative stress. Nutriosomes promoted the proliferation of Streptococcus salivarius, a human commensal bacterium, to a better extent (p < 0.05) than liposomes and hyalurosomes, as a function of the concentration tested. These findings could open a new horizon in intestinal protection and health promotion by integrating biotechnology, nanomedicine, sustainability principles and bio-circular economy.

Dark fermentative volatile fatty acids production from food waste: A review of the potential central role in waste biorefineries.

Volatile fatty acids (VFAs) are high-value chemicals that are increasingly demanded worldwide. Biological production via food waste (FW) dark fermentation (DF) is a promising option to achieve the sustainability and environmental benefits typical of biobased chemicals and concurrently manage large amounts of residues. DF has a great potential to play a central role in waste biorefineries due to its ability to hydrolyze and convert complex organic substrates into VFAs that can be used as building blocks for bioproducts, chemicals and fuels. Several challenges must be faced for full-scale implementation, including process optimization to achieve high and stable yields, the development of efficient techniques for selective recovery and the cost-effectiveness of the whole process. This review aims to critically discuss and statistically analyze the existing relationships between process performance and the main variables of concern. Moreover, opportunities, current challenges and perspectives of a FW-based and fermentation-centred biorefinery layout are discussed.

A cascade biorefinery for grape marc: Recovery of materials and energy through thermochemical and biochemical processes.

The agro-industrial sector makes a high contribution to greenhouse gas emissions; therefore, proper waste management is crucial to reduce the carbon footprint of the food chain. Hydrothermal carbonization (HTC) is a promising and flexible thermochemical process for converting organic materials into energy and added-value products that can be used in different applications. In this work, grape marc residues before and after an extraction process for recovering polyphenols were hydrothermally treated at 220 °C for 1 h. The resulting hydrochar and process water were investigated to test an innovative cascade approach aimed at a multiple product and energy recovery based on the integration of HTC with anaerobic digestion. The results show that this biorefinery approach applied to grape marc could allow to diversify and integrate its potential valorisation options. The produced hydrochars possess an increased fixed carbon content compared to the feedstock (up to +70 %) and, therefore, can be used in soil, immobilizing carbon in a stable form and partially replacing peat in growing media (up to 5 % in case of hydrochar from grape marc after extraction), saving the consumption of this natural substrate. In addition, energy can be recovered from both hydrochar by combustion and from process water through anaerobic digestion to produce biogas. Hydrochars show good properties as solid fuel similar to lignite, with an energy content of around 27 MJ kg-1 (+30 % compared to the feedstock). The anaerobic digestion of the process water allowed obtaining up to 137 mL of biomethane per gram of fed COD. Finally, while HTC process waters are suitable for biological treatment, attention must be paid to the presence of inhibiting compounds that induce acute toxic effects in aerobic conditions. The proposed approach is consistent with the principles of circular economy and could increase the overall sustainability and resilience of the agro-industrial sector.

Environmental life cycle assessment of polyhydroxyalkanoates production from cheese whey.

Cheese whey (CW) is the main by-product of the dairy industry and is often considered one of the main agro-industrial biowaste streams to handle, especially within the European Union, where the diary activities play an essential role in the agrarian economy. In the paper, Life Cycle Assessment (LCA) is used to analyse the feasibility of producing polyhydroxyalkanoates (PHA) as the main output of an innovative CW valorisation route which is benchmarked against a conventional anaerobic digestion (AD) process. To this aim, the LCA inventory data are derived from lab-scale PHA accumulation tests performed on real CW, while data from the literature of concern are used for modelling both the PHA extraction from the accumulating biomass and for the alternative CW valorisation through AD. The comparison shows that AD would have better environmental performances than the baseline PHA production scenario. For example, the climate change indicator values result 44.8 and -35.7 kg CO2 eq./t CW for the baseline PHA recovery and AD, respectively. LCA proved to be a useful tool to highlight the weak points of innovative processes and suggest proper improvements. Once improved and again analysed through the LCA, the PHA production process from CW shows that environmental performance comparable to AD may be achieved. With reference, again, to the climate change indicator the value can be reduced to -50.3 kg CO2 eq./t CW for the improved PHA production process.

The dairy biorefinery: Integrating treatment processes for cheese whey valorisation.

With an estimated worldwide production of 190 billion kg per year, and due to its high organic load, cheese whey represents a huge opportunity for bioenergy and biochemicals production. Several physical, chemical and biological processes have been proposed to valorise cheese whey by producing biofuels (methane, hydrogen, and ethanol), electric energy, and/or chemical commodities (carboxylic acids, proteins, and biopolymers). A biorefinery concept, in which several value-added products are obtained from cheese whey through a cascade of biotechnological processes, is an opportunity for increasing the product spectrum of dairy industries while allowing for sustainable management of the residual streams and reducing disposal costs for the final residues. This review critically analyses the different treatment options available for energy and materials recovery from cheese whey, their combinations and perspectives for implementation. Thus, instead of focusing on a specific valorisation platform, in the present review the most relevant aspects of each strategy are analysed to support the integration of different routes, in order to identify the most appropriate treatment train.

Organic waste biorefineries: Looking towards implementation.

The concept of biorefinery expands the possibilities to extract value from organic matter in form of either bespoke crops or organic waste. The viability of biorefinery schemes depends on the recovery of higher-value chemicals with potential for a wide distribution and an untapped marketability. The feasibility of biorefining organic waste is enhanced by the fact that the biorefinery will typically receive a waste management fee for accepting organic waste. The development and implementation of waste biorefinery concepts can open up a wide array of possibilities to shift waste management towards higher sustainability. However, barriers encompassing environmental, technical, economic, logistic, social and legislative aspects need to be overcome. For instance, waste biorefineries are likely to be complex systems due to the variability, heterogeneity and low purity of waste materials as opposed to dedicated biomasses. This article discusses the drivers that can make the biorefinery concept applicable to waste management and the possibilities for its development to full scale. Technological, strategic and market constraints affect the successful implementations of these systems. Fluctuations in waste characteristics, the level of contamination in the organic waste fraction, the proximity of the organic waste resource, the markets for the biorefinery products, the potential for integration with other industrial processes and disposal of final residues are all critical aspects requiring detailed analysis. Furthermore, interventions from policy makers are necessary to foster sustainable bio-based solutions for waste management.

Propionate Production by Bioelectrochemically-Assisted Lactate Fermentation and Simultaneous CO2 Recycling.

Production of volatile fatty acids (VFAs), fundamental building blocks for the chemical industry, depends on fossil fuels but organic waste is an emerging alternative substrate. Lactate produced from sugar-containing waste streams can be further processed to VFAs. In this study, electrofermentation (EF) in a two-chamber cell is proposed to enhance propionate production via lactate fermentation. At an initial pH of 5, an applied potential of -1 V vs. Ag/AgCl favored propionate production over butyrate from 20 mM lactate (with respect to non-electrochemical control incubations), due to the pH buffering effect of the cathode electrode, with production rates up to 5.9 mM d-1 (0.44 g L-1 d-1). Microbial community analysis confirmed the enrichment of propionate-producing microorganisms, such as Tyzzerella sp. and Propionibacterium sp. Organisms commonly found in microbial electrosynthesis reactors, such as Desulfovibrio sp. and Acetobacterium sp., were also abundant at the cathode, indicating their involvement in recycling CO2 produced by lactate fermentation into acetate, as confirmed by stoichiometric calculations. Propionate was the main product of lactate fermentation at substrate concentrations up to 150 mM, with a highest production rate of 12.9 mM d-1 (0.96 g L-1 d-1) and a yield of 0.48 mol mol-1 lactate consumed. Furthermore, as high as 81% of the lactate consumed (in terms of carbon) was recovered as soluble product, highlighting the potential for EF application with high-carbon waste streams, such as cheese whey or other food wastes. In summary, EF can be applied to control lactate fermentation toward propionate production and to recycle the resulting CO2 into acetate, increasing the VFA yield and avoiding carbon emissions and addition of chemicals for pH control.