Berberine bridge enzyme-like oxidase-catalysed double bond isomerization acts as the pathway switch in cytochalasin synthesis

Cytochalasans (CYTs), as well as their polycyclic (pcCYTs) and polymerized (meCYTs) derivatives, constitute one of the largest families of fungal polyketide-nonribosomal peptide (PK-NRP) hybrid natural products. However, the mechanism of chemical conversion from mono-CYTs (moCYTs) to both pcCYTs and meCYTs remains unknown. Here, we show the first successful example of the reconstitution of the CYT core backbone as well as the whole pathway in a heterologous host. Importantly, we also describe the berberine bridge enzyme (BBE)-like oxidase AspoA, which uses Glu538 as a general acid biocatalyst to catalyse an unusual protonation-driven double bond isomerization reaction and acts as a switch to alter the native (for moCYTs) and nonenzymatic (for pcCYTs and meCYTs) pathways to synthesize aspochalasin family compounds. Our results present an unprecedented function of BBE-like enzymes and highly suggest that the isolated pcCYTs and meCYTs are most likely artificially derived products.

Chemical conversion based on crystal facet effect of transition metal oxide and construction methods for sharp-faced nanocrystals

The in-depth researches have found that the nanocrystal facet of transition metal oxide (TMO) greatly affects its heterogeneous catalytic performance, as well as the property of photocatalysis, gas sensing, electrochemical...

A Healing Promotion Wound Dressing with Tailor-made Antibacterial Potency employing piezocatalytic processes in multi-functional nanocomposites

Developing novel antibiotics-free antibacterial strategy is essential for minimizing bacterial resistance. Materials not only kill bacterial but also promote tissue healing are especially challenging to achieve. Inspired by chemical conversion...

Toward an e-chemistree: Materials for electrification of the chemical industry

Due to our increasing awareness of the impact of climate change on our society, unit operations in our manufacturing processes, including those in chemical industry, have to be greenified and made less dependent of fossil resources. This so-called electrification of the chemical industry is still yet in its infancy but there are many scientific and technological challenges to be solved. This article provides some directions for further research for scientists in both academia and industry to move step by step to an e-chemistree. These important but far from trivial energy and materials transitions require not only the introduction of new ways of heat management and other, often not yet fully explored, chemical conversion processes in which green electrons are used, but also the development of new materials including large-scale heating coils, easily chargeable battery systems as well as catalyst materials. For each of these developments, there is the issue of materials scarcity as well as durability as the introduction of these production processes should also be cost effective and overall more sustainable than the existing ones. Graphical abstract

Turning CO/CO2-containing industrial process gas into valuable building blocks for the polyurethane industry

Provided is a concept of how the carbon content of CO/CO2-containing blast furnace gas (BFG) from steel production could be utilized in a sequence of selective chemical conversion steps to produce high value intermediates for the polymer industry.

Effect of ultrasonic welding process parameters on seam strength of PVC-coated hybrid textiles for weather protection

Using a lapped seam, PVC-coated hybrid textiles with uniform thickness were bonded by continuous ultrasonic welding and conventional joining method with the help of hot air tape welding technique for weather protection purposes. Three fundamental sewing parameters at two distinct levels and three primary welding parameters at three levels based on 6 and 12 mm welding widths were used. To consider the effect of welding and sewing parameters on seam strength, full factorial designs of experiments were designed, fabricated, and tested. The thermal behavior and possibility of chemical conversion in the welding zone under the influence of ultrasonic vibrations were examined. Variation in width of heat-affected zone of weld seam was measured. The seam strength of ultrasonic weld seam compared with that of conventional seams, and superior seam strength yielding parametric levels were assessed. The parametric influence of both joining techniques on seam quality and their tendencies in the relationship were analyzed statistically. The weld seam strength (1256.392 and 2116.93 N/50 mm) was optimized numerically and identified its trend with the variation of the weld seam. The discovered relationship led to the conclusion that the variation in the weld seam can be used to estimate the tensile strength of the weld seam through the developed effective numerical model as a non-destructive testing method, and its outcome was successful as a destructive testing method. The result shows that the ultrasonic weld seam provided a higher tensile strength ( > 75%) than the conventional seam for both evaluated welding widths and obtained statistically significant results.