Detoxification of olive oil mill wastewaters by liquid-liquid extraction with natural deep eutectic solvents

Olive oil mill wastewaters (OOMWs) are the main waste stream of olive processing into olive oil and, although the polyphenolic fraction contained therein can find numerous uses as a nutraceutical and cosmeceutical ingredient, they still have a very hard time to be considered a byproduct rather than a waste. The deployment of this large volume resources has, so far, been hindered by the fact that the polyphenolic mixture that can be extracted from it also contained phenol, which is highly toxic for humans, thus requiring a purification step which adds up to the complexity and cost of the separation. A method capable of separating the toxic compound directly from the liquid stream would therefore be highly desirable. In this work the hydrophobic character of three hydrophobic natural deep eutectic solvents (NaDES) recently developed by Florindo et al. (2017 and 2018), which are composed by pairs of substances among C8 and C12 fatty acids and menthol, has been used to investigate Liquid-Liquid Extraction for detoxifying olive mill wastewaters (OMW) from endogenous phenol. Explorative experiments were carried out on a synthetic mixture containing water, tyrosol (representing desired polyphenols) and phenol, representing a model OMW, at different pH of the treated mixture. Experimental results show that the C8:C12 NaDES exhibits the most favourable extraction features among the three solvents and that neutral pH yields an optimal selectivity

Antioxidant extraction and bioactivity preservation from winery by-products by Natural Deep Eutectic Solvents (NaDES)

In recent times, the feasibility of sourcing the bioactivity and health-promoting activity of anthocyanins, flavanols, stilbenes and phenolic acids from viticulture and winery by-products was explored. In particular, pomace, wine lees, and pruning stalks attracted a great deal of interest among scientists, technologists, and businesses. Traditional solid-liquid extraction methods employ hazardous solvents, such as hydrocarbons, alcohols and chloro-alkanes. As an attempt to convey compliance to the pillars of Green Chemistry, the possibility to choose innovative eco-friendly solvents was evaluated. Furthermore, this approach could preserve the activity of the bioactive compounds for possible applications in food, pharmaceutical, cosmetic and phytosanitary domains. In this work, natural deep eutectic solvents (NaDES) were used to investigate Solid-Liquid Extraction of phenolic species from Merlot marc. Two different operating temperatures were tested and the influence of biomass grinding was investigated. Experimental results show that both kinetic and final anthocyanins extraction efficiency are positively affected by biomass grinding and by temperature increase

Combined clean hydrogen production and bio-active compounds recovery from spent coffee grounds. A multi-perspective analysis

This study deals with the process simulation of an integrated system for energy production and valuable compounds recovery from spent coffee ground biomass and plasmix (non-recyclable plastic waste). The devised process consists of three maine units: a sub-critical water extraction column for the recovery of bio-compounds, an oxy-combustor of residual biomass and plasmix streams coupled with a production power energy unit, and a solid oxide electrolyzer (SOEC) for the production of pure H2 and O2. The process was exhaustively analyzed from an energy, exergy, environmental and economic point of view. The results of the analysis provided energy and exergy efficiencies higher than 60%, and the environmental analysis (CO2-cycle analysis) demonstrated a significant advantage of the process with respect to other hydrogen production methods. Finally, the feasibility of a plant with no net Greenhouse Gas emissions was shown to markedly depend on the costs associated to renewable energy sources

Techno-economic evaluation of heterotrophic microalgal cultivation approaches

This work focuses the attention on the evaluation of different heterotrophic microalgal cultivation approaches, finding the best process solution to achieve the accumulation of high value-added metabolites, such as astaxanthin and polyunsaturated fatty acids (PUFA), trying also to use a wastewater as carbon source. Three different approaches are evaluated: 1) Classical batch cultivation in sterilized fermenter; 2) Impulse nutrient feeding without sterilizing the reactor; 3) Impulse nutrient approach coupled with wastewaters’ usage in two different parallel reactors. This latter strategy is the one adopted in the European Project MEWLIFE (MicroalgaE biomass from phototrophic-heterotrophic cultivation using olive oil Wastewaters) that aims to produce microalgal biomass in an integrated photo-heterotrophic cultivation system using preconcentrated (in a membrane filtration plant) olive oil mill wastewater (OOMWW) as carbon source for growing algae, thus contributing to waste reuse and valorisation. Thanks to the Aspen Custom Modeler software, it is possible to write codes to represent the fermentation units, which are normally not present in the databases of most common simulators. Finally, a technical-economic analysis is conducted to evaluate the most advantageous process. At present, the pulse technique represents an extremely promising strategy with margins of improvement, deserving thus further investigation

METODO DI ESTRAZIONE E RECUPERO DI ASTAXANTINA DA BIOMASSE

Il metodo riguarda la possibilità di estrarre astaxantina da biomasse che ne contengono, solubilizzandola in un solvente atossico, e ottenerla in forma separata, in misura quantitativa

An innovative simplified one-pot process for Astaxanthin purification from Paracoccus carotinifaciens

Astaxanthin (ASX) is a carotenoid with several applications in the food and pharmaceutical fields which is recognised as having a higher physiological and commercial value when it is biologically rather than chemically sourced. This work experimentally investigates the bio-fractionation of biomass of the Paracoccus carotinifaciens bacterium by extraction with the switchable hydrophilicity solvent N,N-dimethyl cyclohexylamine (DMCHA) to obtain ASX and related carotenoids in separate form. This is done by means of a sequential process carried out in a single apparatus. DMCHA gave an extraction yield in terms of equivalent ASX extracted per unit mass of processed dry microbial biomass (62.5 %) higher than acetone (48 %) and ethanol (14 %). After the DMCHA was washed from the extract with carbonated water, 88.2 % of the extracted ASX was recovered. The possibility of extracting carotenoids with recycled solvent with a minor (-7.7%) efficiency drop was also demonstrated, as was the lower energy footprint of DMCHA-based than competing volatile solvent-based extraction processes