Achieving the regioselective hydroformylation of linear α-olefins to linear aldehydes using solid catalysts with regioselectivities comparable to the corresponding homogeneous process is a great challenge in the chemical industry. Despite the tremendous efforts devoted to this research topic, most of the reported heterogeneous metal catalysts still give considerably lower regioselectivities than well-established homogeneous metal catalysts. Here we show the design of efficient Rh-zeolite catalysts, in which subnanometre Rh clusters are selectively confined in the sinusoidal ten-membered-ring channels of MFI zeolite, for the hydroformylation of long-chain linear α-olefins (C 6 –C 12 ) into linear aldehydes with very high linear-to-branched aldehyde ratios (up to 400). The exceptional catalytic performances result from the involvement of the MFI zeolite framework as a rigid solid ligand that accommodates subnanometre Rh clusters in the sinusoidal channels of the MFI zeolite.
Microbial interactions play an important role in regulating the metabolic function of fermented food communities, especially the production of key flavor compounds. However, little is known about specific molecular mechanisms that regulate the production of key flavor compounds through microbial interactions. Here, we designed a synthetic consortium containing Debaryomyces hansenii D1, Staphylococcus xylosus S1, and Pediococcus pentosaceus PP1 to explore the mechanism of the microbial interactions underlying the branched-chain aldehydes production. In this consortium, firstly, D. hansenii secreted amino acids that promoted the growth of P. pentosaceus and S. xylosus . Specifically, D. hansenii D1 secreted alanine , aspartate, glutamate, glutamine, glycine, phenylalanine , serine , and threonine , which were the primary nutrients for bacterial growth. P. pentosaceus PP1 utilized all these eight amino acids through cross-feeding, whereas S. xylosus S1 did not utilize aspartate and serine. Furthermore, D. hansenii D1 promoted the production of branched-chain aldehydes from S. xylosus and P. pentosaceus through cross-feeding of α-keto acids (intermediate metabolites). Thus, the accumulation of 2-methyl-butanal was promoted in all co-culture. Overall, this work revealed the mechanism by which D. hansenii and bacteria cross-feed to produce branched-chain aldehydes in fermented sausages .
危险品化学品经营许可证（带存储）