One‐pot selective conversion of glucose is a green approach compared with petroleum‐based processes to produce 1,2‐propylene glycol (1,2‐PG), but its realization is hindered by various side reactions. Here we demonstrate a feasible strategy of Pt/SiO2@Mg(OH)2 core‐shell catalyst to achieve the 1,2‐PG yield of 53.8 % by a three‐pronged promotion, including enhancement of the glucose‐fructose isomerization and retro‐aldol condensation (RAC), as well as re‐conversion of by‐product hexitol into 1,2‐PG. We realized the in situ synthesis of the core‐shell structure using a self‐existent Mg(OH)2 base instead of an extraneous base in the hydrothermal process and it achieved a stable performance during reuse by protecting Pt from leaching.
Colorimetric gene detection based on gold nanoparticles (AuNPs) is an attractive detection format due to its 1 simplicity. Here, we report a new design for a colorimetric gene-sensing platform based on the CRISPR/Cas system 2 that has improved specificity, sensitivity, and universality. CRISPR/Cas12a and CRISPR/Cas13a have two distinct 3 catalytic activities and are used for specific target gene recognition. Programmable recognition of DNA by 4 Cas12a/crRNA and RNA by Cas13a/crRNA with a complementary sequence activates the nonspecific trans-ssDNA or 5 -RNA cleavage, respectively, thus degrading the ssDNA or RNA linkers which are designed as a hybridization 6 template for the AuNP-DNA probe pair. Target-induced trans -ssDNA or RNA cleavage leads to a distance-dependent 7 color change for the AuNP-DNA probe pair. In this platform, naked eye detection of transgenic rice, African swine 8 fever virus (ASFV), and a miRNA can be completed within 1 hour. Our colorimetric gene-sensing method shows 9 superior characteristics, such as probe universality, isothermal reaction conditions, on-site detection capability, and 1 0 sensitivity that is comparable to that of the fluorescent detection; thus, this method represents a robust next generation 1 1 gene detection platform. 1 2
To substitute fossil resources, it is necessary to investigate the conversion of biomass into 1,2-propanediol (1,2-PDO) as a high-value-added chemical. The Pt/deAl-Beta@Mg(OH)2 catalytic system is designed to obtain a higher 1,2-PDO production yield. The optimal yield of 1,2-PDO is 34.1%. The unique shell-core structure of the catalyst demonstrates stability, with a catalytic yield of over 30% after three times of use. The primary process path from glucose to 1,2-PDO, glucose-hexitol-1,2-PDO, is speculated by the experiments of intermediate product selectivity. The alkaline catalytic mechanism of the reaction process is elucidated by studying catalyst characterization and analyzing different time courses of products. The introduction of Mg(OH)2 improves the target yield by promoting the isomerization from glucose to fructose and retro-aldol condensation (RAC) conversion, with pseudo-yield increases of 76.1% and 42.1%, respectively. By studying the processes of producing lactic acid and 1,2-PDO from glucose, the glucose hydrogenolysis flow chart is improved, which is of great significance for accurately controlling 1,2-PDO production in industrial applications. The metal, acid, and alkali synergistic catalytic system constructed in this paper can provide a theoretical basis and route reference for applying biomass conversion technology in practice.
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