Two-step continuous-flow synthesis of α-terpineol

α-Terpineol is a monoterpene naturally present in essential oils, of high value on the market as it is a compound widely used as a flavoring, aromatic substance in the cosmetics and food industry. This study aims to produce α-terpineol by two different synthetic strategies, using both batch and continuous flow systems, focusing on the optimization of the process, improving the reaction conversion and selectivity. The first strategy adopted was a one-stage hydration reaction of α-pinene by an aqueous solution of chloroacetic acid (molar ratio 1:1 between pinene and the acid) in continuous flow conditions. This reaction was carried out at 80 ºC with a residence time of 15 min, obtaining good values of conversion (72 %) and selectivity (76 %), and productivity of 0.67 Kg.day-1. The second strategy accomplished was a two-step cascade reaction with limonene as starting material, where the first step is a chemo specific double bond addition using trifluoroacetic acid, and the second step is the basic hydrolysis of the ester promoted by a solution of sodium hydroxide (2.25 M) in methanol (1:1). This reaction was adapted to a continuous flow condition, where all steps happen in a residence time of 40 min, at 25 ºC, with no quenching between steps required, giving a conversion of 97 % and selectivity of 81 %, with productivity of 0.12 Kg.day-1.

Propolis and Its Potential to Treat Gastrointestinal Disorders

There are a number of disorders that affect the gastrointestinal tract. Such disorders have become a global emerging disease with a high incidence and prevalence rates worldwide. Inflammatory and ulcerative processes of the stomach or intestines, such as gastritis, ulcers, colitis, and mucositis, afflict a significant proportion of people throughout the world. The role of herbal-derived medicines has been extensively explored in order to develop new effective and safe strategies to improve the available gastrointestinal therapies that are currently used in the clinical practice. Studies on the efficacy of propolis (a unique resinous aromatic substance produced by honeybees from different types of species of plants) are promising and propolis has been effective in the treatment of several pathological conditions. This review, therefore, summarizes and critiques the contents of some relevant published scientific papers (including those related to clinical trials) in order to demonstrate the therapeutic value of propolis and its active compounds in the treatment and prevention of gastrointestinal diseases.

Interfacial surface investigation of super-critical water gasification of corn cob

Super-critical water gasification of biomass is a promising technology for hydrogen production. In order to achieve high hydrogen yield and complete gasification, the operating parameters were investigated and the solid residual was analyzed to study the reaction bottleneck by Fourier transform infrared spectroscopy and scanning electron microscopy. The experimental results showed that most organic functional groups in corn cob were consumed by super-critical water above 500?C, however, the aromatic substance and cyclic ketone were remained. The K2CO3 has the best catalytic effect due to the formation of pore structure in the residual particle surface. The carbon gasification efficiency of 97.97% and the hydrogen yield was 50.28 mol/kg.

Role of the Phenylalanine-Hydroxylating System in Aromatic Substance Degradation and Lipid Metabolism in the Oleaginous Fungus Mortierella alpina

ABSTRACTMortierella alpinais a filamentous fungus commonly found in soil that is able to produce lipids in the form of triacylglycerols that account for up to 50% of its dry weight. Analysis of theM. alpinagenome suggests that there is a phenylalanine-hydroxylating system for the catabolism of phenylalanine, which has never been found in fungi before. We characterized the phenylalanine-hydroxylating system inM. alpinato explore its role in phenylalanine metabolism and its relationship to lipid biosynthesis. Significant changes were found in the profile of fatty acids inM. alpinagrown on medium containing an inhibitor of the phenylalanine-hydroxylating system compared toM. alpinagrown on medium without inhibitor. Genes encoding enzymes involved in the phenylalanine-hydroxylating system (phenylalanine hydroxylase [PAH], pterin-4α-carbinolamine dehydratase, and dihydropteridine reductase) were expressed heterologously inEscherichia coli, and the resulting proteins were purified to homogeneity. Their enzymatic activity was investigated by high-performance liquid chromatography (HPLC) or visible (Vis)-UV spectroscopy. Two functional PAH enzymes were observed, encoded by distinct gene copies. A novel role for tetrahydrobiopterin in fungi as a cofactor for PAH, which is similar to its function in higher life forms, is suggested. This study establishes a novel scheme for the fungal degradation of an aromatic substance (phenylalanine) and suggests that the phenylalanine-hydroxylating system is functionally significant in lipid metabolism.

Fractionation and characterization of sludge bacterial extracellular polymers by FT-IR, 13C-NMR, 1H-NMR

Sludge bacterial extracellular (BEP) polymers exhibit a strong affinity with metals in addition to their role in the bioflocculation of activated sludge. It is of utmost importance in elucidating the chemical characterization of sludge BEP prior to a better understanding of its environmental behavior. Sludge BEP extracted from activated sludge was characterized by FT-IR, 1H-NMR, and 13C-NMR and fractionated into 6 fractions (hydrophilic acid, base, and neutral; and hydrophobic acid, base, and neutral). The results indicated that sludge BEP contained more polysaccharides but fewer amino acids or proteinaceous materials compared to dissolved organic matter (DOM) derived from sludge. No aromatic substance was found in sludge BEP as indicated by NMR. Sludge BEP was dominated by hydrophilic fractions, accounting for 65% of total DOC of sludge BEP and hydrophilic neutral constituted about 58% of the hydrophilic fraction. The chemical fraction and characterization indicated that sludge BEP might exhibit a higher capability in enhancing the transport of the associated contaminants through porous media than that of sludge DOM.