The aim of this work was to evaluate a previously-developed model on supercritical fluid extraction (SFE) for carotenoid recovery from carrot peels on various carotenoid-rich fruit and vegetable ...wastes. To this end, 15 matrices, including flesh and peels of sweet potato, tomato, apricot, pumpkin and peach, as well as flesh and wastes of green, yellow and red peppers, were submitted to SFE under optimised conditions (59 °C, 350 bar, 15 g/min CO₂, 15.5% (
) ethanol as co-solvent, 30 min of extraction time). The obtained extracts were characterised for their total carotenoid content, antioxidant activity and total carotenoid recovery (TCR). TCR values were greater than 90%
for most samples, with β-carotene being the most successfully extracted compound (TCRs 88⁻100%
). More polar carotenoids, such as lutein and lycopene, exhibited lower TCRs. A comparison with literature data suggested that carotenoid extraction is partially dependent on the composition of vegetable matrices, specifically on polysaccharide and moisture content. The results indicated that the optimised SFE conditions can be used as a general model for carotenoid extraction from various fruit and vegetable matrices and as a viable method for adding value to these waste streams by generating carotenoid-rich extracts.
Bacterial cellulose (BC) has attracted much research interest, delivering a combination of exclusive properties, such as flexibility, hydrophilicity, crystallinity, and a three-dimensional network. ...In this study, the effects of carbon source and cultivation conditions on BC production by the bacterium Komagataeibacter xylinus subsp. sucrofermentans DSM 15973 were assessed. Fructose was the most suitable carbon source and high BC concentrations up to 31 g/L were achieved in substrates with 60 g/L fructose, under static culture conditions. Notably, BC production was equally high under the same fermentation conditions in agitated cultures (~30 g/L). Moreover, the effectiveness of NaOH and NaOCl solutions in BC purification, and their potential impact on BC structure and properties were explored. The combination of weak NaOH and sodium hypochlorite (NaOCl) was proved an effective purification method, preserving the fibre structure and crystallinity of BC.
Intermolecular copigmentation denotes the interaction between colored anthocyanins and the colorless copigment, which is not bound covalently to the anthocyanin molecule. This is the first study to ...investigate the effect of intermolecular copigmentation on the stability of individual anthocyanins from dried blackcurrant pomace (DBP) using four pure phenolic acids as copigments (ferulic, caffeic, chlorogenic, and rosmarinic acid). Studies were performed at pH 3.0 and pH 6.0, with a copigment/anthocyanin extract molar ratio of 5:1, during storage at 20 °C. At both pH 3.0 and 6.0, rosmarinic acid showed the strongest hyperchromic and bathochromic effects (p < 0.05) on day 0. However, rosmarinic acid showed low stability during storage. At pH 3.0, chlorogenic acid and control samples were capable of maintaining very high levels of total anthocyanin stability during storage (p < 0.05). On the other hand, ferulic acid and control samples had the longest estimated half-life during storage at pH 6.0. Intermolecular copigmentation successfully increased the half-life, color retention, and antioxidant activity of the anthocyanin solution, with cyanidin-3-O-glucoside (C3G) exhibiting the highest stability at both pH values. Overall, anthocyanins from DBP, in combination with chlorogenic or ferulic acid, showed potential for use in commercial food applications.
Circular economy and bioeconomy concepts have been introduced within an EU framework to sustainably overcome the dominant development model of "take, make, and dispose", which has contributed to ...current economic, environmental, and societal burdens ....
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•Microbial d-lactic acid was successfully purified via multistep purification process.•Anion exchange resin is a key tool for microbial d-lactic acid purification (92% purity).•PLA ...was synthesised via azeotropic (direct) polycondensation technique.•Low molecular weight PLA (3010 Da) was obtained.
A multi-step process was developed for microbial d-lactic acid purification, followed by poly-d-lactic acid (PDLA) synthesis via azeotropic polycondensation process. Several anion exchange resins were screened for their binding capacity using model lactic acid solutions. Amberlite® IRA67 (weak base anion exchange resin) showed the highest lactic acid adsorption, with maximum adsorption capacity, qmax, of 136.11 mg lactic acid / g of resin, and was further selected to purify D-lactic acid from DDGS hydrolysates through a three-step process; (1) treatment with 7% w/v activated carbon, (2) acidification of fermentation broth (Amberlite® IRA120) and (3) adsorption of lactic acid by anion exchange (Amberlite® IRA67). At the end of the purification process, 80.4% (w/w) D-lactic acid was recovered with 91.8% (w/w) purity, indicating the effectiveness of the developed downstream process. Furthermore, a clear yellowish solid polymer with a molecular weight of 3010 Da was obtained, suitable for applications in biomedical and agricultural sectors.
Fifteen eukaryotic microorganisms were tested for their ability to assimilate biodiesel derived waste glycerol and convert it into value-added metabolic products. For this purpose yeast and ...Zygomycetes strains were cultivated in nitrogen-limited raw glycerol-based media (initial glycerol concentration 30 g/L). Yeasts tested accumulated restricted lipid quantities (up to ∼22%, wt/wt, in the case of
Rhodotorula sp), while differentiations in their fatty acid composition were recorded in relation to the yeast strains employed and the fermentation time. On the contrary, fungi accumulated higher quantities of lipid inside their mycelia (ranging between 18.1 and 42.6%, wt/wt, of dry biomass) that contained in variable amounts the medically important GLA (
γ-linolenic acid). Moreover,
Yarrowia lipolytica,
Pichia membranifaciens and
Thamnidium elegans were further studied in media having increased initial glycerol concentrations. In these conditions
Y. lipolytica secreted significant amounts of acetic acid (29.2 g/L), as well as mannitol (19.4 g/L) while
P. membranifaciens reached 28.4 g/L of biomass at glycerol concentration 90 g/L.
T. elegans produced 11.6 g/L of oil, with 71.1%, wt/wt, of fat in biomass, while the maximum concentration of GLA was 371 mg/L. Detailed analysis of
T. elegans lipids indicated that the phospholipids fraction was particularly rich in polyunsaturated fatty acids.
► Extensive screening of Zygomycetes and yeast strains grown on waste glycerol. ► Extensive kinetic analysis of microbial growth parameters during growth of eukaryotic strains on glycerol. ► Production of acetic acid from glycerol waste by
Yarrowia lipolytica. ► Production of single-cell protein from glycerol waste by
Pichia membranifaciens. ► High production of single-cell oil from glycerol waste by
Thamnidium elegans.
This study aimed to investigate and evaluate the effect of processing (soaking, boiling, and roasting) on the phytochemical content of melon seeds. Two varieties of melon seeds (Galia and Cantaloupe) ...were processed by three processing methods including soaking, boiling, and roasting, and analysed in terms of their proximate composition, mineral content, anti-nutritional compounds, as well as fatty acid and amino acid contents. Soaking and boiling reduced the tannins content by 13 % - 20 %, 10 % - 26 %, respectively. Boiling had a positive effect on the extractability of lipid, while it resulted in a slight decrease in protein content (by approximately 6 %) and a significant potassium loss (up to 36 % decrease; p < 0.05). Roasting enhanced mineral content (especially in zinc and iron), but increased tannins by 40 % - 114 % and phytic acid contents by 3 % - 5 %. Of the three processing methods, roasting was most effective in remaining the nutritional value of melon seeds, and boiling was most effective in reducing tannins content. Overall, this study could guide the development of appropriate melon seed processing method to retain high nutritional value.
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2,3-Butanediol (2,3-BD) is a promising platform chemical, produced from microbial cells. Oxygen availability is a crucial factor driving the formation and proportion of 2,3-BD and acetoin in 2,3-BD ...producing bacterial strains. In this study, the ability of B. subtills GD5 to produce 2,3-BD in optimized sucrose-based media was evaluated, by investigating the impact of carbon to nitrogen (C/N) ratio and the effectiveness of alternative low-cost nitrogen sources (corn steep liquor, soybean meal, and ammonium sulphate). Subsequently, different dissolved oxygen (DO) controlling regimes were assessed in batch bioreactor fermentations. The best fermentation outcomes were obtained with uncontrolled DO, achieving 5.88 g/L of optically pure (R,R)-2,3-BD (~100% purity), accompanied by a production yield of 0.43 g/g, and a productivity of 0.2 g/L/h. Additionally, the influence of the DO controlling regime on B. subtills key enzymes involved in the reverse activity of acetoin reductase was also monitored. A fed-batch process under the most suitable DO conditions was carried out to improve 2,3-BD production, achieving 42.31 g/L 2,3-BD with a production yield of 0.52 g/g. Thus, B. subtilis GD5 is a promising strain for the efficient production of pure chiral (R,R)-2,3-BD under uncontrolled DO conditions, using alternative low-cost nitrogen sources.
•Novel approach based on HIC for the purification of carotenoid-rich extracts.•Novel data on carotenoid adsorption kinetics in batch and in column.•Carotenoid global recovery was ∼90% in batch and ...∼70% in column.•Purification factor of 4.7 for carotenoid and 2.1 for antioxidant activity.
Supercritical fluid extraction (SFE) has been widely used for extracting several valuable phytochemicals, including carotenoids. However, there is a scarcity of works dealing with the purification of SFE extracts. The aim of this work was to assess the feasibility and efficiency of a hydrophobic interaction chromatography (HIC) protocol for purifying carotenoid-rich extracts obtained by SFE. Initial batch experiments were carried out to calculate the resin adsorption capacity and adsorption kinetics. Subsequent runs were performed in a manually-packed chromatographic column, using the Amberlite XAD-1180N resin, where breakthrough curves and adsorption isotherms were obtained and fitted to the Langmuir model. The antioxidant activity and carotenoid degradation rates were monitored throughout the processes. In batch, the resin presented a maximum carotenoid adsorption capacity of 1.89 μg/mg, while in column, this value increased to 10.4 μg/mg. The global carotenoid adsorption rate was 93.3% and the elution rate, 94.7%, resulting in a global recovery of 88.4% for total carotenoids and 92.1% for carotenes. The Langmuir model fitted well the experimental data. Analysis of the extracts demonstrated that a 5.5-fold reduction in extract mass was achieved, accompanied by a 4.7-fold and 2.1-fold increase in carotenoid concentration and antioxidant activity, respectively. This work presents a novel process based on preparative HIC for the purification of carotenoid extracts and provides a fundamental understanding on process performance. It is potentially scalable and can be implemented in extraction and purification of carotenoids from natural sources, as an alternative to their production through chemical synthesis.
In the last three decades, greener technologies have been used, aiming at extracting phenolic compounds from vegetable matrices due to the inherent advantages compared to organic solvent-based ...methodologies. In this work, supercritical CO2 was investigated for recovering phenolic acids from potato peels. Following screening runs for assessing the significant extraction parameters, a Central Composite Design of Experiments was carried out aiming at process optimization, with methanol concentration (MeOH, %) and CO2 flow rate (qCO2, g/min) as independent variables. Both parameters were deemed to impart a significant effect on the final response. Although the major phenolic acid in potato peels is chlorogenic acid (CGA), the main compound extracted was caffeic acid (CFA), present at a concentration of 0.75 mg/g dry peel in the extracts. The optimum extraction conditions were 80 °C, 350 bar, MeOH 20%, and flow rate of 18.0 g/min, which enabled a total phenolic recovery of 37% and a CFA recovery of 82%. The antioxidant activity of the supercritical fluid extraction (SFE) extracts was also measured, with the highest scavenging capacity reaching 73%. The need for using mixtures of water and organic solvents as co-solvents in SFE to enable CGA recovery seems necessary, possibly due to its better dissolution in aqueous solutions than in pure solvents.
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