A Study of the Catalytic Properties of Synthetic Aluminosilicates of Different Morphologies in Cracking Reactions of the Byproducts of Isoprene Synthesis

The catalytic activity of synthetic samples of aluminosilicates of various morphologies and chemical compositions in a cascade of reactions that are byproducts (BPs) in the decomposition process of 4,4‑dimethyl-1,3-dioxane is studied. Aluminosilicates with montmorillonite structures (Na0.2Al1.8Mg0.2Si4O10(OH)2⋅nH2O, Mg3Si4O10(OH)2⋅nH2O), and kaolinite (Al2Si2O5(OH)4) with the spherical and platy morphologies of particles, as well as their porous-textural characteristics and surface properties, are studied. It is shown that the specific surface area of the studied samples, depending on the composition, varies from 11 to 470 m2/g, and the content of aluminum oxide in the samples ranged from 0 to 24 wt %. It is found that layered silicates with a montmorillonite structure contribute to reducing the gasification of organic raw materials and increasing the yield of isoprene. Kaolinite with a spherical morphology of particles increases the yield of formaldehyde, and with a platy morphology of particles, it increases the degree of decomposition of heteroatomic and cyclic compounds.

Anaerobic Production of Isoprene by Engineered Methanosarcina Species Archaea

ABSTRACT Isoprene is a valuable petrochemical used for a wide variety of consumer goods, such as adhesives and synthetic rubber. We were able to achieve a high yield of renewable isoprene by taking advantage of the naturally high-flux mevalonate lipid synthesis pathway in anaerobic methane-producing archaea (methanogens). Our study illustrates that by genetically manipulating Methanosarcina species methanogens, it is possible to create organisms that grow by producing the hemiterpene isoprene. Mass balance measurements show that engineered methanogens direct up to 4% of total carbon flux to isoprene, demonstrating that methanogens produce higher isoprene yields than engineered yeast, bacteria, or cyanobacteria, and from inexpensive feedstocks. Expression of isoprene synthase resulted in increased biomass and changes in gene expression that indicate that isoprene synthesis depletes membrane precursors and redirects electron flux, enabling isoprene to be a major metabolic product. Our results demonstrate that methanogens are a promising engineering chassis for renewable isoprene synthesis. IMPORTANCE A significant barrier to implementing renewable chemical technologies is high production costs relative to those for petroleum-derived products. Existing technologies using engineered organisms have difficulty competing with petroleum-derived chemicals due to the cost of feedstocks (such as glucose), product extraction, and purification. The hemiterpene monomer isoprene is one such chemical that cannot currently be produced using cost-competitive renewable biotechnologies. To reduce the cost of renewable isoprene, we have engineered methanogens to synthesize it from inexpensive feedstocks such as methane, methanol, acetate, and carbon dioxide. The “isoprenogen” strains we developed have potential to be used for industrial production of inexpensive renewable isoprene.

Study on heteropolyacid-based catalysts with high activity and reusability for isoprene synthesis from formaldehyde and isobutene

Silica supported heteropolyacid catalysts with different pore structures were synthesis via impregnation method using silicalite-1 with three-dimensional MFI structure, two-dimensional hexagonal SBA-15 and amorphous silica as the supports. And those...