China
Africa
Explore chapters and articles related to this topic
Polymeric Materials Obtained through Biocatalysis
Published in Severian Dumitriu, Valentin Popa, Polymeric Biomaterials, 2020
Florin Dan Irimie, Csaba Paizs, Monica Ioana Tosa
The most studied lactone was ε-caprolactone. Although it has a lower reactivity, as compared to four-membered lactones and to macrolides, using of lipases conducted to good results. When using Porcine Pancreas Lipase in the polymerization of ε-caprolactone to heptanes, a polymer with an average molecular mass Mn = 2300 was obtained in 4 days at 65°C. Lipases from other sources have been also tested. Among them, C. antarctica lipase B (CALB) used as a commercial product immobilized on acrylic resin (Novozym 435) proved to be the most efficient. The performance parameters were clearly superior to other tested lipases. Thus, in a bulk polymerization, the percentage ratio enzyme/monomer lowered from 20%–50% to 1%, and the reaction time was reduced to 10 h, at a working temperature of 60°C [72].
Environmental Fate and Transport of Solvent-Stabilizer Compounds
Published in Thomas K.G. Mohr, William H. DiGuiseppi, Janet K. Anderson, James W. Hatton, Jeremy Bishop, Barrie Selcoe, William B. Kappleman, Environmental Investigation and Remediation, 2020
Thomas K.G. Mohr, James Hatton
The pathway for aerobic degradation of 1,4-dioxane parallels that of THF, which involves oxygenase-mediated hydroxylation of the carbon present in the no. 2 position on the dioxane ring and its subsequent dehydrogenation to form the lactone ring. Hydroxylation is any process that introduces one or more hydroxyl groups (-OH) into a compound (or radical), thereby oxidizing it. In biochemistry, hydroxylation reactions are often facilitated by enzymes called hydroxylases. A lactone is a cyclic ester. After opening the lactone ring, intermediary metabolism pathways may begin (Zenker, 2006).
Carboxylic Acids, Carboxylic Acid Derivatives, and Acyl Substitution Reactions
Published in Michael B. Smith, A Q&A Approach to Organic Chemistry, 2020
A lactone is a cyclic ester. Reaction of an ester with an amine leads to formation of a cyclic amide, a lactam. When δ-valerolactone is heated with ammonia, the product is δ-valerolactam (piperidin-2-one). Similarly, when δ-valerolactam is heated with methylamine, N-methyl-2-piperidone is the product. Depending on the size of the ring, lactones of greater than eight members give an open chain amino acid.
Synergistic effect of Fusarium lateritium LP7 and Trichoderma viride LP5 promotes ethoxylated oleyl-cetyl alcohol biodegradation
Published in Journal of Environmental Science and Health, Part A, 2020
The ability of tested pure cultures and consortium to produce different carbohydrates is in line with the results of other authors which revealed production of different carbohydrates by filamentous fungi and establish a link between their production, the types of fungal strain and experimental conditions.[22] The current study indicates that addition EOCA in growth medium of could be used as inducer for production of some specific carbohydrates such as xylose, mannose, maltose and lactone. Maltose is used in the manufacture of dietetic and sports food stuffs, bread, wine, preserves and beverages. Furthermore, maltose is utilized in microbiology and pharmacology.[23,24] As a diabetic sweetener, D-xylose can be used in a wide variety of industries including: food production, beverage, pharmaceutical, cosmetics, and various other industries.[25] Carbohydrate lactones have found broad application as building blocks for the synthesis of important bioactive compounds and natural products.[26] D-mannose has been widely used in the food, pharmaceutical and poultry industries, acting as a source of dietary supplements, starting material for the synthesis of drugs and blocking colonization in animal feeds.[27]