High Added Value Molecules Research Articles

Extraction processes of high added value molecules from wood waste: overview and comparison of processes for an eco-friendly recovery from paper industry by-product

The work aims to optimize an industrial greener extraction process of chemical components in wood waste from the paper industry. Extracts from a mixture of two species (Picea abies and Abies alba) were studied. Several parameters were found to play a key role in the extraction yield: to the conventional parameters such as the chemical composition of the extracting medium or the temperature, a key criterion was the choice of a process procedure in order to take into account the absorption of the solvent by the wood. The implementation of several operating modes, namely solid-liquid single-batch extraction, countercurrent extraction, percolation extraction, near supercritical, and supercritical fluid extraction is discussed in terms of yield and ease of implementation when scaling up.

Natural colorants from vegetable food waste: Recovery, regulatory aspects, and stability-A review.

Worldwide, approaches inspired by the Circular Economy model have been increasing steadily, generating new business opportunities such as the recovery of high-added value molecules (e.g., pigments) from vegetable food waste that may be applied as food additives (e.g., colorants). Indeed, food waste is a global problem that does not seem to be decreasing, leading to economic, environmental, and social issues. Moreover, synthetic dyes have been associated with adverse effects on human health, encouraging research to explore much safer, natural, and eco-friendly pigments. This state-of-the-art review gives a brief overview of the regulatory aspects concerning food waste, Circular Economy, and natural versus synthetic colorants. We have critically reviewed the recent advances in pigment recovery from vegetable food waste bringing back the green/unconventional extraction methods. Among them, enzyme-assisted extraction as a depth feature technique is highlighted, given that it allows the recovery of pigments in a mild, selective, efficient, and sustainable way. Furthermore, the stability issue of the different natural colorants has been critically discussed in relation to the extraction and application conditions. Several and tailored stabilization methods have been described and reported for each pigment although additional research is necessary on their long-lasting stabilization and utilization in food matrices. PRACTICAL APPLICATION: This review focuses on the main types of natural pigments in vegetable food waste, their legislative framework, extraction technologies and strategies to improve the stability , as well as their possible applications.

Wood Waste from Fruit Trees: Biomolecules and Their Applications in Agri-Food Industry.

In the European Union (EU), a total of 11,301,345 hectares are dedicated to the cultivation of fruit trees, mainly olive orchards, grapevines, nut trees (almond, walnut, chestnut, hazelnut, and pistachio), apple and pear trees, stone fruit trees (peach, nectarine, apricot, cherry, and plum), and citrus fruit trees (orange, clementine, satsuma, mandarin, lemon, grapefruit, and pomelo). Pruning these trees, together with plantation removal to a lesser extent, produces a huge amount of wood waste. A theoretical calculation of the wood waste in the European Union estimates approximately 2 and 25 million tons from wood plantation removal and pruning, respectively, per year. This wood waste is usually destroyed by in-field burning or crushing into the soil, which result in no direct economic benefits. However, wood from tree pruning, which is enriched in high added-value molecules, offers a wide spectrum of possibilities for its valorization. This review focuses on the contribution of wood waste to both sustainability and the circular economy, considering its use not only as biomass but also as a potential source of bioactive compounds. The main bioactive compounds found in wood are polyphenols, terpenes, polysaccharides, organic compounds, fatty acids, and alkaloids. Polyphenols are the most ubiquitous compounds in wood. Large amounts of hydroxytyrosol (up to 25 g/kg dw), resveratrol (up to 66 g/kg dw), protocatechuic acid (up to 16.4 g/kg), and proanthocyanins (8.5 g/kg dw) have been found in the wood from olive trees, grapevines, almond trees and plum trees, respectively. The bioactivity of these compounds has been demonstrated at lower concentrations, mainly in vitro studies. Bioactive compounds present antioxidant, antimicrobial, antifungal, biostimulant, anti-inflammatory, cardioprotective, and anticarcinogenic properties, among others. Therefore, wood extracts might have several applications in agriculture, medicine, and the food, pharmaceutical, nutraceutical, and cosmetics industries. For example, olive tree wood extract reduced thrombin-induced platelet aggregation in vitro; grapevine tree wood extract acts a preservative in wine, replacing SO2; chestnut tree wood extract has antifungal properties on postharvest pathogens in vitro; and stone tree wood extracts are used for aging both wines and brandies. Moreover, the use of wood waste contributes to the move towards both a more sustainable development and a circular economy.

Pigments’ analysis of Citrus juicing making by‐products by LC‐MS/MS and LC‐DAD

Citrus fruits Cold Press Essential Oils (CPEOs) constitute a low-cost by-product produced during the juice making process that are composed by a volatile and a non-volatile fraction. Their non-volatile fractions are rich in valuable secondary metabolites, such as carotenoids, coumarins, psoralens and flavonoids [1,2]. Study herein concerns the development of a quantitative method for their carotenoids analyses using the LC-MS/MS and LC-DAD methodology.•CPEOs carotenoids content was characterized quantitatively.•Natural carotenoids β-cryptoxanthin, lutein and zeaxanthin were determined as the most abundant high added value molecules.

Selective Chemical Upcycling of Mixed Plastics Guided by a Thermally Stable Organocatalyst

AbstractChemical recycling of plastic waste represents a greener alternative to landfill and incineration, and potentially offers a solution to the environmental consequences of increased plastic waste. Most plastics that are widely used today are designed for durability, hence currently available depolymerisation methods typically require harsh conditions and when applied to blended and mixed plastic feeds generate a mixture of products. Herein, we demonstrate that the energetic differences for the glycolysis of BPA‐PC and PET in the presence of a protic ionic salt TBD:MSA catalyst enables the selective and sequential depolymerisation of these two commonly employed polymers. Employing the same procedure, functionalised cyclic carbonates can be obtained from both mixed plastic wastes and industrial polymer blend. This methodology demonstrates that the concept of catalytic depolymerisation offers great potential for selective polymer recycling and also presents plastic waste as a “greener” alternative feedstock for the synthesis of high added value molecules.

Selective Chemical Upcycling of Mixed Plastics Guided by a Thermally Stable Organocatalyst.

Chemical recycling of plastic waste represents a greener alternative to landfill and incineration, and potentially offers a solution to the environmental consequences of increased plastic waste. Most plastics that are widely used today are designed for durability, hence currently available depolymerisation methods typically require harsh conditions and when applied to blended and mixed plastic feeds generate a mixture of products. Herein, we demonstrate that the energetic differences for the glycolysis of BPA-PC and PET in the presence of a protic ionic salt TBD:MSA catalyst enables the selective and sequential depolymerisation of these two commonly employed polymers. Employing the same procedure, functionalised cyclic carbonates can be obtained from both mixed plastic wastes and industrial polymer blend. This methodology demonstrates that the concept of catalytic depolymerisation offers great potential for selective polymer recycling and also presents plastic waste as a "greener" alternative feedstock for the synthesis of high added value molecules.

Plant Secondary Metabolites: An Opportunity for Circular Economy.

Moving toward a more sustainable development, a pivotal role is played by circular economy and a smarter waste management. Industrial wastes from plants offer a wide spectrum of possibilities for their valorization, still being enriched in high added-value molecules, such as secondary metabolites (SMs). The current review provides an overview of the most common SM classes (chemical structures, classification, biological activities) present in different plant waste/by-products and their potential use in various fields. A bibliographic survey was carried out, taking into account 99 research articles (from 2006 to 2020), summarizing all the information about waste type, its plant source, industrial sector of provenience, contained SMs, reported bioactivities, and proposals for its valorization. This survey highlighted that a great deal of the current publications are focused on the exploitation of plant wastes in human healthcare and food (including cosmetic, pharmaceutical, nutraceutical and food additives). However, as summarized in this review, plant SMs also possess an enormous potential for further uses. Accordingly, an increasing number of investigations on neglected plant matrices and their use in areas such as veterinary science or agriculture are expected, considering also the need to implement “greener” practices in the latter sector.

Amino acids, fatty acids, and peptides in microalgae biomass harvested from phycoremediation of swine wastewaters

Algae-based wastewater tertiary treatment systems have been drawing attention to eco-friendly companies due to high remediation effectiveness and production of valuable raw material. The amino acids, fatty acids, and peptides from microalgae harvested from a pilot-scale phycoremediation system treating swine wastewater were determined. The maximum microalgae concentration of 247 ± 3.4 mg L−1 was obtained after 11 days when phosphate and ammonium were completely removed. The AA content showed relatively high concentrations (as % of total protein) of essential amino acids such as leucine (4.1), lysine (2.5), phenylalanine (2.6), and threonine (2.4). The fatty acid profile was composed of 5.3% polyunsaturated (as C18:2 and C18:3) and ~ 10% of unsaturated (mainly C16:1 and C18:1). About 25 bioactive peptides related to antioxidative, anti-inflammatory, and anticarcinogenic properties were found. Therefore, microalgae biomass produced during phycoremediation of swine wastewaters seems promising as a source of alternative feedstock with high-added value molecules.

Spent brewer's yeast as a source of high added value molecules: a systematic review on its characteristics, processing and potential applications.

Development of new strategies to add-value to agro-industrial by-products are of environmental and economical importance. Innovative and low-cost sources of protein and bioactive peptides have been explored worldwide. Spent brewer's yeast (SBY) is the second most relevant by-product from the brewing industry, and despite its nutritional (about 50% protein, dry weight) and technological potential, it is still underused or needs to be disposed of. SBY cells need to be disrupted to release intracellular and cell wall proteins. This procedure has been performed using autolysis, glass bead milling, enzymatic hydrolysis and ultrasound processing. Enzymatic treatment is usually performed without prior purification and is a challenging process, which involves multiple factors, but has been successfully used as a strategy to add value to agro-industrial by-products. Scope and approach: in this review, we particularly focused on enzymatic hydrolysis as a strategy to promote SBY valorisation, illustrating the state-of-the-art processes used to produce protein extracts from this material as well as exploring fundamental concepts related to the particularities of yeast cell disruption and protein hydrolysis. Furthermore, innovative applications of value-added yeast by-products in food, biotechnological and pharmaceutical industries are presented and discussed. Key findings and conclusions: the discovery of valuable compounds found in spent yeasts as well as the development of new processing methodologies have been widening the possibilities of reuse and transformation of SBY as an ingredient and innovative matrix. Once released, yeast proteins and peptides may be applied as an innovative non-animal protein source or a functional and bioactive ingredient.

Towards a more sustainable circular bioeconomy. Innovative approaches to rice residue valorization: The RiceRes case study

The paper reports an overview of the RiceRes project aiming at the multivalorization of all the wastes of the rice value chain, namely straw, husk and bran in order to improve resources eco-efficiency.A wide range of bio-products and bio-materials with different added value has been produced starting from these wastes in the framework of the RiceRes project. Among them, insulating materials for green building have been obtained from rice straw mixed with waste wool, biofillers from husk for polymer composites, mono- and di-glyceride mixtures and high-added value molecules for the food industry from bran.

Alcoholic fermentation as a potential tool for coffee pulp detoxification and reuse: Analysis of phenolic composition and caffeine content by HPLC-DAD-MS/MS

High-performance liquid chromatography with diode array (HPLC-DAD) and liquid chromatograph triple quadrupole mass spectrometry (HPLC-MS/MS) were used to characterize raw and fermented coffee pulps in terms of their phenolic composition and caffeine content. The qualitative analysis showed no significant differences between the raw and the fermented pulps. Free hydroxycinnamic acids (HAs) were mainly chlorogenic acids, with 5-caffeoylquinic acid as the major compound. Bound HAs released caffeic acids during alkaline hydrolysis, and no bound ferulic and p-coumaric acids were detected. The fermentation process allowed the detoxification of the pulp from caffeine by 50%, while significantly reducing the amounts of residue by 64%. Moreover, the fermented products could be further processed to provide high added-value molecules with potential industrial applications, providing a new source of income for the small coffee producers.

Chemical composition and physicochemical characterization for cabbage and pineapple by-products flour valorization

Cabbage stalks (CSF) and pineapple crowns (PCF) were collected after fresh-cut processing and transformed into flour by drying in oven. Both flours presented greenish colors and heterogeneous particles (30–150 μm). CSF and PCF presented similar aw (0.43) and moisture (10%). CSF presented higher mineral content (18.1 g.100 g-1), especially for Ca (1671.11 mg.100 g-1) and K (8582.93 mg.100 g-1), than PCF (5.9 g.100 g-1) that presented also high content of K (2250.62 mg.100 g-1). PCF and CSF presented great fiber content (67.22 and 42.67 g.100 g-1, respectively), especially insoluble fiber (about 87% of total fiber). Malto-oligosaccharides were identified in PCF and no fructo-oligosaccharides was detected. The ethanolic extract of PCF was considered as cytotoxic, while the aqueous extracts were considered safe. Thus, the direct recovery of high-added value molecules can be obtained by water extraction of CSF and PCF, specially focusing in the great levels of fiber and mineral compounds.

Organic synthesis of high added value molecules with MOF catalysts.

Recent examples of organic synthesis of fine chemicals and pharmaceuticals in confined spaces of MOFs are highlighted and compared with silica-based ordered porous solids, such as zeolites or mesoporous (organo)silica. These heterogeneous catalysts offer the possibility of stabilizing the desired transition states and/or intermediates during organic transformations of functional groups and (C-C/C-N) bond forming steps towards the desired functional high added value molecular scaffolds. A short introduction on zeolites, mesoporous silica and metal-organic frameworks is followed by relevant applications in which confined active sites in the pores promote single or multi-step organic synthesis of industrially relevant molecules. A critical discussion on the catalytic performances of the different types of hybrid inorganic-organic catalysts in the synthesis of O- and N-containing acyclic and heterocyclic molecules has been presented.

Upgrading of marine (fish and crustaceans) biowaste for high added-value molecules and bio(nano)-materials.

Currently, the Earth is subjected to environmental pressure of unprecedented proportions in the history of mankind. The inexorable growth of the global population and the establishment of large urban areas with increasingly higher expectations regarding the quality of life are issues demanding radically new strategies aimed to change the current model, which is still mostly based on linear economy approaches and fossil resources towards innovative standards, where both energy and daily use products and materials should be of renewable origin and 'made to be made again'. These concepts have inspired the circular economy vision, which redefines growth through the continuous valorisation of waste generated by any production or activity in a virtuous cycle. This not only has a positive impact on the environment, but builds long-term resilience, generating business, new technologies, livelihoods and jobs. In this scenario, among the discards of anthropogenic activities, biodegradable waste represents one of the largest and highly heterogeneous portions, which includes garden and park waste, food processing and kitchen waste from households, restaurants, caterers and retail premises, and food plants, domestic and sewage waste, manure, food waste, and residues from forestry, agriculture and fisheries. Thus, this review specifically aims to survey the processes and technologies for the recovery of fish waste and its sustainable conversion to high added-value molecules and bio(nano)materials.

Phytoremediation of bark-hydrolysate fermentation effluents and bioaccumulation of added-value molecules by designed microalgal consortia

Recent years marked an increased focus towards the valorization of biorefinery side-streams for the production of various high added-value molecules and platform chemicals. The present study tackles the opportunity of using liquid ethanol fermentation effluents of bark hydrolysates for microalgal conversion to various marketable molecules. Initially, 12 green microalgae strains were screened for their ability to thrive on these substrates and uptake some of the available organic compounds. Once the most suitable strains were identified, three mixed microalgal consortia were formulated and investigated in order to maximize, either individually or both simultaneously, their biomass production and phytoremediation performances. For instance, the consortium α containing Scenedesmus obliquus, Acutodesmus obliquus, Chlorella sorokiniana and Chlorella vulgaris strains was able to consume up to 70% of C5 sugars (xylose and arabinose) and 60% of C6 sugars (fucose and hexose). The uptake of these organic compounds initially present in the fermentation effluent accounted for the removal of 27% of the total organic carbon. In addition, the microalgal community produced 55 mg/L/d, 41 mg/L/d and 26 mg/L/d of carbohydrates, lipids and proteins respectively. The photosynthetic pigments accumulated in the harvested biomass comprised of 25.8 mg/L of total chlorophyll and 5.9 mg/L of carotenoids. Finally, the pyrolysis characteristics of the algal biomass were evaluated trough thermogravimetric analysis and the elemental composition was compared with conventional lignocellulosic feedstocks. Thus, this work proves the dual opportunity of both reducing the toxicity of lignocellulosic ethanol fermentation effluents as well as generating high-value biomass by employing specifically-designed microalgal populations.

An Economical, Sustainable Pathway to Indole-Containing Oxindoles: Iron-Catalyzed 1,6-Conjugate Addition in Glycerol

The search for economical, sustainable and practical pathways in synthetic science would contribute to improving resource efficiency, developing a recycling economy and driving new-type urbanization. Green synthesis has established firm ground providing the right green yardstick for development of a sustainable approach to bioactive high-added value molecules and drug discovery, and further development of sustainable manufacturing processes in the pharmaceutical industry toward a green resource efficient economy. In this study, the combination of FeCl3 and glycerol exhibits a versatile and high catalytic activity in the atom economical 1,6-conjugated addition of para-quinone methides derived from isatins with indoles using the right green yardstick. The sustainable pathway provides the preparation of bioactive indole-containing oxindoles in excellent yields with superior advantages, such as the ready availability, low price and environmentally benign character of iron catalysis, easy product separation, cheap and safe bio-renewable glycerol as a green solvent, and catalytic system recycling under mild conditions.

Genetic manipulation of microalgae for the production of bioproducts.

Microalgae have been used during the past four decades in the Bio-industries for the production of high added value products and development of useful approaches with environmental applications. The fast growing rate, simple growth requirements and using sunlight as the major source of energy are the key factors for usage of algae. In the past 15 years, a considerable progress has been made regarding the use of microalgae for production of proteins, nutraceuticals, food supplements, molecular tags for diagnostics and fixation of greenhouse gases. Nevertheless, genetic manipulation of microalgae still remains a fairly un-explored area which could boost the production of bioproducts. It is anticipated that in the near future use of microalgae will revolutionize its applications in diverse industries. The aim of this work is to present a critical review on potential of microalgae for the production of high-added value molecules, their practical applications, and the role of genetic engineering in its utilization as a unique niche in industry. In addition, current challenges within synthetic biology approaches are discussed.

Proteomic Analysis of the Chlorophyta Dunaliella New Strain AL-1 Revealed Global Changes of Metabolism during High Carotenoid Production

The green microalgae Dunaliella genus is known for the production of high added value molecules. In this study, strain AL-1 was isolated from the Sebkha of Sidi El Hani (Sousse, Tunisia). This isolate was identified both morphologically and genetically via 18S rRNA gene sequence as a member of the genus Dunaliella. Strain AL-1 was found to be closely related to Dunaliella salina, Dunaliella quartolecta and Dunaliella polymorpha with more than 97% similarity. Response surface methodology was used to maximize carotenoid production by strain AL-1 by optimizing its growth conditions. The highest carotenoid content was obtained at salinity: 51, light intensity: 189.89 μmol photons·m−2·s−1, and nitrogen: 60 mg·L−1. Proteomic profiling, using two-dimensional gel electrophoresis, was performed from standard and optimized cultures. We detected 127 protein spots which were significantly differentially expressed between standard and optimized cultures. Among them 16 protein spots were identified with mass spectrometry and grouped into different functional categories using KEGG (Kyoto Encyclopedia of Genes and Genomes) such as photosynthetic Calvin cycle, regulation/defense, energy metabolism, glycolysis, and cellular processes. The current study could be of great interest in providing information on the effect of stressful conditions in microalgae carotenoid production.

Enhanced polyhydroxyalkanoate (PHA) production from the organic fraction of municipal solid waste by using mixed microbial culture

BackgroundIn Europe, almost 87.6 million tonnes of food waste are produced. Despite the high biological value of food waste, traditional management solutions do not consider it as a precious resource. Many studies have reported the use of food waste for the production of high added value molecules. Polyhydroxyalkanoates (PHAs) represent a class of interesting bio-polyesters accumulated by different bacterial cells, and has been proposed for production from the organic fraction of municipal solid waste (OFMSW). Nevertheless, until now, no attention has been paid to the entire biological process leading to the transformation of food waste to organic acids (OA) and then to PHA, getting high PHA yield per food waste unit. In particular, the acid-generating process needs to be optimized, maximizing OA production from OFMSW. To do so, a pilot-scale Anaerobic Percolation Biocell Reactor (100 L in volume) was used to produce an OA-rich percolate from OFMSW which was used subsequently to produce PHA.ResultsThe optimized acidogenic process resulted in an OA production of 151 g kg−1 from fresh OFMSW. The subsequent optimization of PHA production from OA gave a PHA production, on average, of 223 ± 28 g kg−1 total OA fed. Total mass balance indicated, for the best case studied, a PHA production per OFMSW weight unit of 33.22 ± 4.2 g kg−1 from fresh OFMSW, corresponding to 114.4 ± 14.5 g kg−1 of total solids from OFMSW. PHA composition revealed a hydroxybutyrate/hydroxyvalerate (%) ratio of 53/47 and Mw of 8∙105 kDa with a low polydispersity index, i.e. 1.4.ConclusionsThis work showed how by optimizing acidic fermentation it could be possible to get a large amount of OA from OFMSW to be then transformed into PHA. This step is important as it greatly affects the total final PHA yield. Data obtained in this work can be useful as the starting point for considering the economic feasibility of PHA production from OFMSW by using mixed culture.

Synthetic microbiology: from analogy to methodology.

Synthetic microbiology: from analogy to methodology.