A bi-enzymatic cascade to yield pyruvate as co-substrate for l-tyrosine production

Efficient production of inositol from glucose via a tri-enzymatic cascade pathway

Inositol is an essential intermediate in cosmetics, food, medicine and other industries. However, developing an efficient biotransformation system for large-scale production of inositol remains challenging. Herein, a tri-enzymatic cascade route with three novel enzymes including polyphosphate glucokinase (PPGK) from Thermobifida fusca, inositol 3-phosphate synthase (IPS) from Archaeoglobus profundus DSM 5631 and inositol monophosphatase (IMP) from Thermotoga petrophila RKU-1 was designed and reconstructed for the production of inositol from glucose. The problem of poor cooperativity of the cascade reactions was addressed by ribosome binding site (RBS) optimization of PPGK and replication of IPS. Under the optimum biotransformation conditions, the engineered whole-cell immobilized with colloidal chitin transformed 120 g/L glucose to 110.8 g/L inositol with 92.3% conversion in four cycles of reuse, representing the highest titer of inositol to date. Furthermore, this is the first study for inositol production using a three-enzyme coordinated immobilized single-cell.

Detection and Structural Characterization of SFAHFA Homologous Series in Mouse Colon Contents by LTQ-Orbitrap-MS and Their Implication in Influenza Virus Infection

Fatty acid esters of hydroxy fatty acids (FAHFAs) are a new class of endogenous lipids with promising physiological functions in mammals. We previously introduced a new type of lipids to this family called short-chain fatty acid esters of hydroxy fatty acids (SFAHFAs), branching specific to the C2 carbon of a long-chain fatty acid (≥C20). In this study, we discovered a homologous series of SFAHFAs comprising C16-C26 hydroxy fatty acids esterified with short-chain fatty acids (C2-C5) in mouse colon contents. The detected SFAHFAs were characterized by high-resolution mass spectrometry with MSn analysis. The double-bond position of monounsaturated SFAHFAs was determined by the epoxidation reaction of samples with m-chloroperoxybenzoic acid and their MSn analysis. Further, the measurement of SFAHFA concentration in the colon contents of mice infected with influenza A/Puerto Rico/8/34 (H1N1; PR8) virus revealed a significant increase in their levels compared to native control. A strong correlation was observed between hydroxy fatty acid and SFAHFAs. Detection, characterization, and profiling of these new SFAHFA levels in relation with pandemic H1N1; PR8 influenza virus will contribute to the in-depth study of their function and metabolism.