Search

The challenge of feeding over 9 billion humans by 2050 requires a ‘rethink’ of the current linear food production system. In the view of a circular economy, insects can provide a possible solution to valorise waste to produce new foods and materials, as well as the opportunity to solve some environmental problems. Tenebrio molitor (TM) is the first insect approved by the European Commission as a novel food and widely explored by the research world. Although mass production of TM is still not competitive compared to traditional protein sources, studies and companies in the sector are improving the entire production process to meet the growing need for alternative and sustainable protein foods. The use of food loss and waste to replace commercial feed in TM rearing can improve the economic and environmental sustainability of the production process. Furthermore, the exploitation of the variety of TM-based products can lead to the creation of new value chains and employment opportunities. In this review, we focus on the ability of TM to convert low-value substrates into novel foods and materials, as well as the possibility of using the TM rearing waste to obtain fertilisers and bioproducts, such as chitin and chitosan. TM capacity to degrade plastic waste such as polyethylene and polystyrene, thanks to its highly differentiated gut microbiota, is mentioned. Critical aspects related to sustainability and scaling-up of TM rearing are analysed. Hints on food safety of TM-based products are provided. Therefore, this study is a comprehensive review of TM multifunctionality and, at the same time, identifies possible ways to improve the economic and environmental impact of this insect with a circular economy perspective.

The increase in the world population leads to rising demand and consumption of plastic raw materials; only a small percentage of plastics is recovered and recycled, increasing the quantity of waste released into the environment and losing its economic value. The plastics represent a great opportunity in the circular perspective of their reuse and recycling. Research is moving, on the one hand, to implement sustainable systems for plastic waste management and on the other to find new non-fossil-based plastics such as polyhydroxyalkanoates (PHAs). In this review, we focus our attention on Tenebrio molitor (TM) as a valuable solution for plastic biodegradation and biological recovery of new biopolymers (e.g. PHA) from plastic-producing microorganisms, exploiting its highly diversified gut microbiota. TM’s use for plastic pollution management is controversial. However, TM microbiota is recognised as a source of plastic-degrading microorganisms. TM-based plastic degradation is improved by co-feeding with food loss and waste as a dietary energy source, thus valorising these low-value substrates in a circular economy perspective. TM as a bioreactor is a valid alternative to traditional PHA recovery systems with the advantage of obtaining, in addition to highly pure PHA, protein biomass and rearing waste from which to produce fertilisers, chitin/chitosan, biochar and biodiesel. Finally, we describe the critical aspects of these TM-based approaches, mainly related to TM mass production, eventual food safety problems, possible release of microplastics and lack of dedicated legislation.

The increase in the world population leads to rising demand and consumption of plastic raw materials; only a small percentage of plastics is recovered and recycled, increasing the quantity of waste released into the environment and losing its economic value. The plastics represent a great opportunity in the circular perspective of their reuse and recycling. Research is moving, on the one hand, to implement sustainable systems for plastic waste management and on the other to find new non-fossil-based plastics such as polyhydroxyalkanoates (PHAs). In this review, we focus our attention on Tenebrio molitor (TM) as a valuable solution for plastic biodegradation and biological recovery of new biopolymers (e.g. PHA) from plastic-producing microorganisms, exploiting its highly diversified gut microbiota. TM's use for plastic pollution management is controversial. However, TM microbiota is recognised as a source of plastic-degrading microorganisms. TM-based plastic degradation is improved by co-feeding with food loss and waste as a dietary energy source, thus valorising these low-value substrates in a circular economy perspective. TM as a bioreactor is a valid alternative to traditional PHA recovery systems with the advantage of obtaining, in addition to highly pure PHA, protein biomass and rearing waste from which to produce fertilisers, chitin/chitosan, biochar and biodiesel. Finally, we describe the critical aspects of these TM-based approaches, mainly related to TM mass production, eventual food safety problems, possible release of microplastics and lack of dedicated legislation.

Nowadays, it is urgent to produce in larger quantities and more sustainably to reduce the gap between food supply and demand. In a circular bioeconomy vision, insects receive great attention as a sustainable alternative to satisfy food and nutritional needs. Among all insects, Tenebrio molitor (TM) is the first insect approved by the European Food Safety Authority as a novel food in specific conditions and uses, testifying its growing relevance and potential. This review holistically presents the possible role of TM in the sustainable and circular solution to the growing needs for food and nutrients. We analyze all high value-added products obtained from TM (powders and extracts, oils and fatty acids, proteins and peptides, and chitin and chitosan), their recovery processes (evaluating the best ones in technical and environmental terms), their nutritional and economical values, and their biological effects. Safety aspects are also mentioned. TM potential is undoubted, but some aspects still need to be discussed, including the health effects of substances and microorganisms in its body, the optimal production conditions (that affect product quality and safety), and TM capacity to convert by-products into new products. Environmental, economic, social, and market feasibility studies are also required to analyze the new value chains. Finally, to unlock the enormous potential of edible insects as a source of nutritious and sustainable food, it will be necessary to overcome the cultural, psychological, and regulatory barriers still present in Western countries.

The mitochondrial 2-oxoglutarate carrier (OGC), isolated and purified from rat brain mitochondria, was reconstituted into proteoliposomes to study the interaction with hemin, a porphyrin derivative, which may result from the breakdown of heme-containing proteins and plays a key role in several metabolic pathways. By kinetic approaches, on the basis of the single binding centre gated pore mechanism, we analyzed the effect of hemin on the transport rate of OGC in uptake and efflux experiments in proteoliposomes reconstituted in the presence of the substrate 2-oxoglutarate. Overall, our experimental data fit the hypothesis that hemin operates a competitive inhibition in the 0.5–10 µM concentration range. As a consequence of the OGC inhibition, the malate/aspartate shuttle might be impaired, causing an alteration of mitochondrial function. Hence, considering that the metabolism of porphyrins implies both cytoplasmic and mitochondrial processes, OGC may participate in the regulation of porphyrin derivatives availability and the related metabolic pathways that depend on them (such as oxidative phosphorylation and apoptosis). For the sake of clarity, a simplified model based on induced-fit molecular docking supported the in vitro transport assays findings that hemin was as good as 2-oxoglutarate to bind the carrier by engaging specific ionic hydrogen bond interactions with a number of key residues known for participating in the similarly located mitochondrial carrier substrate binding site.

Background and Objective: Hepatopancreas is an accessory organ associated with the liver in some fish, even including sea bass (Dicentrharcus labrax L.). Hepatopancreas contains an exocrine portion but until now its function has poorly been investigated. Methods: Here, European farmed sea bass have been treated with a feed enriched in polyphenols extracted from seeds of red grape (Nero di Troia cultivar) at two different doses (100 and 200 mg/kg, respectively) from day 273 to day 323. In fish samples, hepatopancreas area sizes have been measured to evaluate the effects of this dietary regimen on its morphology. Results: Quite interestingly, in treated fish area sizes of hepatopancreas were higher than those detected in untreated fish. Two hundred mg dose of polyphenols was more effective than that of 100 mg/kg polyphenols. Finally, hepatic polyphenol concentration was diminished in fish receiving 100 mg dose polyphenols and normalized with 200 mg dose in comparison to untreated fish. This evidence suggests the utilization of polyphenols for liver function, even including hepatopancreas development. Conclusion: Our data suggest an expansion of hepatopancreas induced by polyphenol administration that is also associated with less mortality in farmed fish.

Background: Olive tree leaves have been used in the Mediterranean area as traditional medicine in virtue of their healthy effects. Olive leaf extracts (OLEs) contain higher amounts of polyphenols than those detected in the extra virgin olive oil and fruit. Several lines of evidence support the cardioprotective, anti-oxidant and anti-inflammatory activities exerted by OLEs. Methods: Peripheral blood mononuclear cells from twenty-five healthy donors were cultured in the presence of 3 µg of two OLE extracts, extract A (resuspended in water) and extract B (resuspended in 70% ethanol). After harvesting, cell pellets were used for cytofluorimetric phenotyping, while supernatants were assayed for cytokine release by means of ELISA. Furthermore, in the same supernatants nitric oxide (NO) content was determined. Results: Both extracts, but especially extract A, increased absolute numbers of CD8+ and natural killer (NK) cells. In addition, an increased production of interferon (IFN)-γ by both extracts as an expression of T helper (h)1 activation was observed. Finally, both extracts enhanced NO release. Conclusion: OLEs, and mostly extract A, are able to in vitro modify healthy human immune response by increasing IFN-γ production which seems to be associated to the higher absolute numbers of CD8+ and NK cells and this may suggest a reinforcement of the anti-tumor activity. Furthermore, increased levels of NO may indicate the potential cardioprotective effects exerted by OLEs in virtue of their vasodilation dependent activity. Finally, OLEs are able to maintain the equilibrium between T regulatory cells and Th17 cells as evidenced by unmodified levels of interleukin (IL)-IL-10 and IL-17, respectively. In the light of these results, OLEs are potential therapeutic compounds for the treatment of chronic inflammatory disease, also preventing cardiovascular event outcome.

The in vitro ability of polyphenols, extracted from red grape, to modulate peripheral blood mononuclear cell responses has been evaluated in 20 obese (Ob) people. With regard to cytokine release in response to phorbol myristate acetate (PMA), levels of interleukin-2 (IL-2), interferon-γ(IFN-γ), IL-4, IL-10, and IL-17 were higher in the Ob than in healthy (H) subjects.Vice versa, IL-21 concentrations were detected only in H people but they were undetectable in the Ob counterpart. In general terms, levels of IL-1β, IL-6, IL-8, and tumor necrosis factor-αwere higher in Ob people when compared to H controls. On the other hand, polyphenols did not modify IFN-γ, IL-4, and IL-17 levels. However, an increase in IL-2 was observed in H individuals, whereas its levels were decreased in the Ob counterpart. Polyphenols significantly increased IL-10 release from H donors, whereas a trend to increase was observed in Ob people. In addition, polyphenols were able to significantly increase levels of H IL-21, while this was not the case in Ob people. Since IL-21 is an inducer of Th17 cells, it is likely that polyphenols may suppress the sources of this cytokineviaproduction of IL-10. Accordingly, polyphenols decreased IL-1βand IL-6 release in comparison to H controls.

Background: In mice, postnatal immune development has previously been investigated, and evidence of a delayed maturation of the adaptive immune response has been detected. Methods: In this study, the effects of red grape polyphenol oral administration on the murine immune response were explored using pregnant mice (TAG/F3 transgenic and wild type (wt) mice) as the animal model. The study was performed during pregnancy as well as during lactation until postnatal day 8. Suckling pups from polyphenol-administered dams as well as day 30 post-weaning pups (dietary-administered with polyphenols) were used. Polyphenol effects were evaluated, measuring splenic cytokine secretion. Results: Phorbol myristate acetate-activated splenocytes underwent the highest cytokine production at day 30 in both wt and TAG/F3 mice. In the latter, release of interferon (IFN)-&gamma, and tumor necrosis factor (TNF)-&alpha, was found to be higher than in the wt counterpart. In this context, polyphenols exerted modulating activities on day 30 TAG/F3 mice, inducing release of interleukin (IL)-10 in hetero mice while abrogating release of IL-2, IFN-&gamma, TNF-&alpha, IL-6, and IL-4 in homo and hetero mice. Conclusion: Polyphenols are able to prevent the development of an inflammatory/allergic profile in postnatal TAG/F3 mice.

This research shows that carbon dioxide supercritical fluid (CO2-SF) is an emerging technology for the extraction of high interest compounds for applications in the manufacturing of pharmaceuticals, nutraceuticals, and cosmetics from microalgae. The purpose of this study is to recover fatty acids (FAs) and, more precisely, eicosapentaenoic acid (EPA) from Nannochloropsis gaditana biomass by CO2-SF extraction. In the paper, the effect of mechanical pre-treatment was evaluated with the aim of increasing FAs recovery. Extraction was performed at a pressure range of 250&ndash, 550 bars and a CO2 flow rate of 7.24 and 14.48 g/min, while temperature was fixed at 50 or 65 &deg, C. The effect of these parameters on the extraction yield was assessed at each extraction cycle, 20 min each, for a total extraction time of 100 min. Furthermore, the effect of biomass loading on EPA recovery was evaluated. The highest EPA extraction yield, i.e., 11.50 mg/g, corresponding to 27.4% EPA recovery, was obtained at 65 &deg, C and 250 bars with a CO2 flow rate of 7.24 g/min and 1.0 g biomass loading. The increased CO2 flow rate from 7.24 to 14.48 g/min enhanced the cumulative EPA recovery at 250 bars. The purity of EPA could be improved by biomass loading of 2.01 g, even if recovery was reduced.

This research shows that carbon dioxide supercritical fluid (CO2-SF) is an emerging technology for the extraction of high interest compounds for applications in the manufacturing of pharmaceuticals, nutraceuticals, and cosmetics from microalgae. The purpose of this study is to recover fatty acids (FAs) and, more precisely, eicosapentaenoic acid (EPA) from Nannochloropsis gaditana biomass by CO2-SF extraction. In the paper, the effect of mechanical pre-treatment was evaluated with the aim of increasing FAs recovery. Extraction was performed at a pressure range of 250–550 bars and a CO2 flow rate of 7.24 and 14.48 g/min, while temperature was fixed at 50 or 65 °C. The effect of these parameters on the extraction yield was assessed at each extraction cycle, 20 min each, for a total extraction time of 100 min. Furthermore, the effect of biomass loading on EPA recovery was evaluated. The highest EPA extraction yield, i.e., 11.50 mg/g, corresponding to 27.4% EPA recovery, was obtained at 65 °C and 250 bars with a CO2 flow rate of 7.24 g/min and 1.0 g biomass loading. The increased CO2 flow rate from 7.24 to 14.48 g/min enhanced the cumulative EPA recovery at 250 bars. The purity of EPA could be improved by biomass loading of 2.01 g, even if recovery was reduced.

Hepatopancreas is an accessory organ associated with the liver in some fish, even including sea bass (Dicentrharcus labrax L.). Hepatopancreas contains an exocrine portion but until now its function has poorly been investigated.Here, European farmed sea bass have been treated with a feed enriched in polyphenols extracted from seeds of red grape (Nero di Troia cultivar) at two different doses (100 and 200 mg/kg, respectively) from day 273 to day 323. In fish samples, hepatopancreas area sizes have been measured to evaluate the effects of this dietary regimen on its morphology.Quite interestingly, in treated fish area sizes of hepatopancreas were higher than those detected in untreated fish. Two hundred mg dose of polyphenols was more effective than that of 100 mg/kg polyphenols. Finally, hepatic polyphenol concentration was diminished in fish receiving 100 mg dose polyphenols and normalized with 200 mg dose in comparison to untreated fish. This evidence suggests the utilization of polyphenols for liver function, even including hepatopancreas development.Our data suggest an expansion of hepatopancreas induced by polyphenol administration that is also associated with less mortality in farmed fish.

BACKGROUND Nickel (Ni) is widely distributed in the environment and continuous exposure to this metal may lead to pathological manifestations, such as the human allergic contact dermatitis. METHODS The in vitro effects of Ni on human healthy non allergic peripheral blood mononuclear cells (PBMCs) in the absence or presence of red grape polyphenols have been evaluated. In the culture supernatants, levels of cytokines have been determined by ELISA, while nitric oxide (NO) concentration has been evaluated by a colorimetric procedure. RESULTS Ni per se did not affect release of interferon-γ, interleukin (IL)-4 and IL-10. Instead, this metal dramatically reduced production of IL-17 which was restored by the supplementation of polyphenols. Finally, while Ni significantly increased generation of NO, polyphenols reduced production of this compound. CONCLUSION Taken together, all these data may indicate a preventative role of polyphenols against Ni exposure in non allergic to Ni individuals, also confirming the immunomodulating role of these natural products. The interaction Ni/polyphenols/lipopolysaccharides will also be discussed.

BACKGROUND Nickel (Ni) is a metal largely present in the environment and prolonged exposure to it may lead to multiple pathological conditions in human subjects. Among these, the most frequent is allergic contact dermatitis. METHODS Peripheral blood mononuclear cells isolated from 25 patients with Ni-dependent contact dermatitis were evaluated in terms of cytokine release and nitric oxide (NO) production in the presence or absence of two doses (3 and 5 µg, respectively) of polyphenols. RESULTS Polyphenols were able to reduce the increased release of interferon-γ and interleukin (IL)-4, while maintaining the equilibrium between IL-10 and IL-17. At the same time, exaggerated release of NO was reduced by polyphenol supplementation. CONCLUSION In view of their anti-inflammatory activities, polyphenols may represent a potential therapeutic tool to treat Ni-sensitized patients.

Here, the oxoglutarate carrier, already isolated from various sources and described in the literature, has been purified from rat brain and reconstituted in proteoliposomes for an accurate kinetic study. The rate of uptake of labelled oxoglutarate and malate has been measured in various conditions, essentially in double substrate experiments. The data so obtained fit the hypothesis that the carrier operates by a uniport-exchange mechanism and provide significant values for the kinetic constants and the equilibrium constants implied in the process. Their analysis leads to the conclusion that the carrier is maximally efficient in the exchange between external malate and internal oxoglutarate, as required by the malate/aspartate shuttle, which should be the main role of the oxoglutarate carrier in brain mitochondria.

The adenine nucleotide carrier from Jerusalem artichoke (Helianthus Tuberosus L.) tubers mitochondria was solubilized with Triton X-100 and purified by sequential chromatography on hydroxapatite and Matrex Gel Blue B in the presence of cardiolipin and asolectin. SDS gel electrophoresis of the purified fraction showed a single polypeptide band with an apparent molecular mass of 33 kDa. When reconstituted in liposomes, the adenine nucleotide carrier catalyzed a pyridoxal 5′-phosphate-sensitive ATP/ATP exchange. It was purified 75-fold with a recovery of 15% and a protein yield of 0.18% with respect to the mitochondrial extract. Among the various substrates and inhibitors tested, the reconstituted protein transported only ATP, ADP, and GTP and was inhibited by bongkrekate, phenylisothiocyanate, pyridoxal 5′-phosphate, mersalyl and p-hydroxymercuribenzoate (but not N-ethylmaleimide). Atractyloside and carboxyatractyloside (at concentrations normally inhibitory in animal and plant mitochondria) were without effect in Jerusalem artichoke tubers mitochondria. V max of the reconstituted ATP/ATP exchange was determined to be 0.53 μmol/min per mg protein at 25°C. The half-saturation constant K m and the corresponding inhibition constant K i were 20.4 μM for ATP and 45 μM for ADP. The activation energy of the ATP/ATP exchange was 28 KJ/mol between 5 and 30°C. The N-terminal amino acid partial sequence of the purified protein showed a partial homology with the ANT protein purified from mitochondria of maize shoots.

The citrate carrier from maize(Zea mays) shoot mitochondria was solubilized with Triton X-100 and purified by sequential chromatography on hydroxyapatite and hydroxyapatite/celite in the presence of cardiolipin. SDS-gel electrophoresis of the purified fraction showed a single polypeptide band with an apparent molecular mass of 31 kD. When reconstituted into liposomes, the citrate carrier catalyzed a pyridoxal 5′-P-sensitive citrate/citrate exchange. It was purified 224-fold with a recovery of 50% and a protein yield of 0.22% with respect to the mitochondrial extract. In the reconstituted system the purified citrate carrier catalyzed a first-order reaction of citrate/citrate (0.065 min−1) or citrate/malate exchange (0.075 min−1). Among the various substrates and inhibitors tested, the reconstituted protein transported citrate,cis-aconitate, isocitrate, l-malate, succinate, malonate, glutarate, α-ketoglutarate, oxaloacetate, and α-ketoadipate and was inhibited by pyridoxal 5′-P, phenylisothiocyanate, mersalyl, andp-hydroxymercuribenzoate (but notN-ethylmaleimide), 1,2,3-benzentricarboxylate, benzylmalonate, and butylmalonate. The activation energy of the citrate/citrate exchange was 66.5 kJ/mol between 10°C and 35°C; the half-saturation constant (Km) for citrate was 0.65 ± 0.05 mm and the maximal rate (Vmax) of the citrate/citrate exchange was 13.0 ± 1.0 μmol min−1 mg−1 protein at 25°C.

A method for rapid reconstitution of ADP/ATP carrier from Jerusalem artichoke (Helianthus tuberosus L.) tubers mitochondria in proteoliposomes is described. The method is based on the well known property of the Amberlite resin to absorb the detergent allowing proteoliposome formation. This has been achieved by a micro-batchwise technique, using a rotating plate stirrer. An evaluation of the optimal conditions, in comparison with the more usual column method is presented. The purified ADP/ATP carrier, incorporated in proteoliposomes by this method, shows a high transport activity and a higher specific activity with respect to proteoliposomes obtained by the column procedure. Furthermore the proteoliposomal preparations are more homogeneous in size, with a diameter ranging from 300 to 350 nm. The method is suitable for the reconstitution of other membrane transport proteins.

Jerusalem artichoke (Helianthus tuberosus L.) tubers were reported to be tolerant to cold and freezing. The aim of this study was to perform a kinetic characterization of the mitochondrial dicarboxylate–tricarboxylate carrier (HtDTC) and to assess a possible involvement of this carrier in the cold tolerance of tubers. The HtDTC was purified from isolated mitochondria by sequential chromatography on hydroxylapatite/celite and Matrex Gel Orange A. SDS gel electrophoresis of the purified fraction showed a single polypeptide band with an apparent molecular mass of 31.6 kDa. A polyclonal antibody raised against the tobacco DTC cross-reacted with the purified protein on Western blot analysis. In gel trypsin, digestion of the purified HtDTC yielded peptides that exhibited strong amino acid sequence similarity to previously identified plant DTCs. Furthermore, using degenerate primers, a portion of the Htdtc cDNA was amplified and sequenced; this cDNA encoded for a protein with high sequence similarity to known plant homolog DTCs. When reconstituted in liposomes loaded with dicarboxylate (2-oxoglutarate, malate, malonate, succinate, and maleate) or tricarboxylate anions (citrate, trans-aconitate, and isocitrate), the purified HtDTC transported all these anions in exchange with external [14C]2-oxoglutarate. A kinetic characterization of HtDTC was performed: (a) the half-saturation constant K m and the V max at 25∘C of the 2-oxoglutarate/2-oxoglutarate exchange by reconstituted HtDTC were found to be 360 μM and 10.9 μmol/(min mg protein), respectively; (b) the activation energy E a of the succinate/2-oxoglutarate exchange by the reconstituted HtDTC was found to be 50.7 kJ/mol constant between −5 and 35∘C. Similarly, the activation energy E a of succinate respiration of isolated Jerusalem artichoke mitochondria, measured between −2 and 35∘C, was shown to be constant (65.3 kJ/mol). The physiological relevance of kinetic properties and temperature dependence of transport activities of HtDTC is discussed with respect to the cold tolerance ability of Jerusalem artichoke tubers.

The adenine nucleotide carrier from Jerusalem artichoke (Helianthus tuberosus L.) tubers mitochondria was solubilized with Triton X-100 and purified by sequential chromatography on hydroxapatite and Matrex Gel Blue B in the presence of cardiolipin and asolectin. SDS gel electrophoresis of the purified fraction showed a single polypeptide band with an apparent molecular mass of 33 kDa. When reconstituted in liposomes, the adenine nucleotide carrier catalyzed a pyridoxal 5'-phosphate-sensitive ATP/ATP exchange. It was purified 75-fold with a recovery of 15% and a protein yield of 0.18% with respect to the mitochondrial extract. Among the various substrates and inhibitors tested, the reconstituted protein transported only ATP, ADP, and GTP and was inhibited by bongkrekate, phenylisothiocyanate, pyridoxal 5'-phosphate, mersalyl and p-hydroxymercuribenzoate (but not N-ethylmaleimide). Atractyloside and carboxyatractyloside (at concentrations normally inhibitory in animal and plant mitochondria) were without effect in Jerusalem artichoke tubers mitochondria. Vmax of the reconstituted ATP/ATP exchange was determined to be 0.53 micromol/min per mg protein at 25 degrees C. The half-saturation constant Km and the corresponding inhibition constant Ki were 20.4 microM for ATP and 45 microM for ADP. The activation energy of the ATP/ATP exchange was 28 KJ/mol between 5 and 30 degrees C. The N-terminal amino acid partial sequence of the purified protein showed a partial homology with the ANT protein purified from mitochondria of maize shoots.