177,029 research outputs found
Chemical Profile and Antioxidant Properties of Extracts and Essential Oils from Citrus × limon (L.) Burm. cv. Femminello Comune
No full textCitrus × limon cv. Femminello Comune (Rutaceae) from Rocca Imperiale (Italy), one of the six Protected Geographical Indication (PGI) Italian lemon crops, has been recently received renewed interest. In this work, fresh and dried peels and leaves were extracted by hydrodistillation, supercritical fluid extraction (SFE), and Soxhlet apparatus. Chemical profile was assessed by gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS). Except for leaves extracts obtained by Soxhlet apparatus, the monoterpene hydrocarbons fraction dominated. Limonene, γ-terpinene, and β-pinene were the main identified compounds. The antioxidant activity was investigated using different in vitro assays namely 2,2-diphenyl-1-picrylhydrazyl (DPPH), ABTS, ferric reducing ability power (FRAP), and β-carotene bleaching test. In DPPH test, the essential oil obtained by hydrodistillation of fresh peel exhibited the highest activity (IC50 of 1.17 mg/ml). Leaves extracted by SFE showed a good activity in both DPPH and β-carotene bleaching test with IC50 values of 2.20 and 6.66 mg/ml, respectively. Monoterpene hydrocarbons fraction exhibited a positive Pearson's correlation coefficient with all antioxidant assays. Leaves, often considered waste material, should be considered from a different point because they represent a matrix of indisputable interest. © 2016 Verlag Helvetica Chimica Acta AG, Zürich
Biomass production potential of long-term switchgrass stands, an environmental friendly bio-energy crop for future
No full textThe present work reports the results of the experiment on long term evaluation of 18 genotypes of Switchgrass at field level under the climatic conditions of South Italy. The main purpose of this work was to study the cultivation techniques and evaluate other than the biomass productivity also the adaptability of Switchgrass varieties (upland and lowland ones) for a long period of time under Mediterranean climate. © 2008, Page Press Publications. All rights reserved
Le tecnologie colturali "senza suolo" per i sistemi serra. Manuale operativo per le colture vegetali idroponiche.
No full textA New Method for Selective Extraction of Torularhodin from Red Yeast Using CO2-SFE Technique
Get PDFTorularhodin is a dark pink colored carotenoid belonging to the xanthophylls group that can be biologically synthesized by red yeasts, especially by Rhodotorula and Sporobolomyces genera. The growing interest in this molecule is due to its biological activities such as antioxidant, anticholesterolemic, anti-inflammatory, antimicrobial, and anticancer. To satisfy potential commercial markets, numerous methods have been proposed to develop a cost-effective and environmentally friendly downstream process for the purification of torularhodin. However, obtaining high purity products without resorting to the use of toxic solvents, which can leave residues in the final preparations, remains a major challenge. In this context, the present study aimed to develop a new efficient method for the isolation of torularhodin from the red yeast Rhodotorula strain ELP2022 by applying the extraction technique with supercritical CO2 (CO2-SFE) in two sequential steps. In particular, in the first step, the dried lysed biomass of yeast was subjected to the action of CO2 in supercritical conditions (CO2SC) as sole solvent for extraction of apolar carotenoids. In the second step, the residual biomass was subjected to the action of CO2SC using ethanol as a polar co-solvent for the extraction of torularhodin. Both steps were carried out at different operating parameters of temperature (40 and 60 °C) and pressure (from 300 to 500 bar) with a constant CO2 flow of 6 L min−1. Regardless of the operating conditions used, this method allowed to obtain an orange-colored oily extract and a red-colored extract after the first and second step, respectively. In all trials, torularhodin represented no less than 95.2% ± 0.70 of the total carotenoids in the red extracts obtained from the second step. In particular, the best results were obtained by performing both steps at 40 °C and 300 bar, and the maximum percentage of torularhodin achieved was 97.9% ± 0.88. Since there are no data on the selective recovery of torularhodin from red yeast using the SFE technique, this study may be a good starting point to optimize and support the development of industrial production of torularhodin by microbial synthesis. This new method can significantly reduce the environmental impact of torularhodin recovery and can be considered an innovation for which an Italian patent application has been filed. In a circular bioeconomy approach, this method will be validated up to a pilot scale, culturing the strain Rhodotorula spp. ELP2022 on low-cost media derived from agri-food wastes. Graphical Abstract: (Figure presented.
Inhibitors derived from wheat straw hydrolysate can affect the production of succinic acid by Actinobacillus succinogenes
Get PDFLignocellulosic biomasses are promising source of fermentative sugars for the production of succinic acid. The lignocellulosic matrix must be pretreated to make the sugars available for the fermentation, but the most tested operative conditions can generate inhibitors as acetic acid, furans, phenolic compounds. Inhibitors remained an obstacle for the implementation of succinic acid production starting from recalcitrant biomasses as wheat straw. Batch tests were performed at two starting concentrations of strain, sugars (glucose, glucose and xylose) and inhibitors (acetic acid and furfural) by comparing the fermentation in standard broth medium and hydrolysate. Notwithstanding the presence of acetic acid (52.5 mg/L) and furfural (15 mg/L), succinic acid was obtained at 9*10−2 ± 7*10−3 g/L by starting from wheat straw hydrolysate that contained glucose (1.1 g/L), xylose (0.4 g/L) and without additional nitrogen source. Therefore, the study highlighted that a more concentrated inoculum was able to reduce the synergistic effect of inhibitors at their highest concentrations. The results obtained may contribute to improve succinic acid production from the biomasses that have been under-exploited but abundantly available, as wheat straw, for which solutions must be found to solve the problem of inhibitors production or to mitigate its effect on the fermentation process
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
A Review on the Valorization of Lignocellulosic Biomass for Succinic Acid Production: Strengths and Weaknesses
No full textBio-based succinic acid production holds great promise for the process sustainability through the use of renewable resources such as lignocellulosic biomass and the use of microorganisms that can utilize CO2 in fermentation processes. A critical review of the latest findings on succinic acid production from lignocellulosic biomass was discussed, by highlighting all the key aspects of optimization processes at different levels of the process from pre-treatment to succinic acid production. Chemical-physical pretreatments seemed to be the most appropriate for the pretreatment of lignocellulosic biomass, but many strategies are still needed to solve the problem of variability in initial composition, the presence of post-treatment inhibitory compounds and the use of green solvent. In addition, the saccharization-fermentation process seemed to be the most suitable for the fermentative process of hydrolysates obtained from pretreatment to produce bio-based succinic acid. Certainly new studies and strategies are still needed to overcome the weaknesses of the whole process of succinic acid production from lignocellulosic biomass
Preliminary Assessment on Actinobacillus Succinogenes Growth and Succinic Acid Production for Bioplastics
No full textSevere plastics pollution derived from the wide use and the past incorrect dispersion of petroleum-based plastics. The development of bioplastics/biopolymers with the same chemical/physical characteristics of conventional plastics can be a solution to the problems of their degradability. Polybutylene succinate was among the most investigated biopolymers for these characteristics that can be produced from bio-based succinic acid and butan-1,4-diol. Succinic acid can be produced through fermentation process using microorganisms as Actinobacillus succinogenes that were able to utilise glucose from several sources as lignocellulosic biomasses. Lignocellulosic biomass can be ideal candidates for glucose supply but the processes to release fermentable sugars can produce inhibitors (acids and furans) of the biological processes for succinic acid production. The aim of this paper was to evaluate the growth of A. succinogenes for the production of succinic acid under acetic acid and furfural at different concentration on inoculum with pre-adaptation and without adaptation. The results highlighted that pre-inoculum adaptation was essential for the growth of the strain and succinic acid production that decreased strongly under the synergistic effect of acetic acid and furfural in the broth (63% inhibition rate of growth) respect to inoculum with pre-inoculum adaptation (29% inhibition rate of growth)
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
Get PDFBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
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