Investigating Pervaporation for In Situ Acetone Removal as Process Intensification Tool in ω-Transaminase Catalyzed Chiral Amine Synthesis.

Hydrophobic pervaporation (PV), allowing for the separation of an organic component from an aqueous stream, was investigated for in situ acetone removal from a transamination reaction. A poly(dimethylsiloxane) membrane was applied in a coupled enzymatic process at 5 L scale. Among the four components, there was no loss of donor and product amines through PV which was highly desirable. However, in addition to removal of acetone, there was also an unwanted loss of acetophenone (substrate ketone) because of PV. The coupled enzyme-PV process resulted in 13% more product formation compared to the control process (where no PV was applied) after 9 h. Results from a qualitative simulation study (based on partial vapor pressures and a vapor-liquid equilibrium of the feed solution) indicated that PV might have an advantage over direct distillation strategy for selective removal of acetone from the reaction medium. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 35: e2731, 2019.

Usefulness of endoscopic ultrasonography in the clinical suspicion of biliary disease.

BACKGROUND AND AIMS: endoscopic ultrasound (EUS) is a very sensitive and specific technique for the diagnosis of biliary diseases. This procedure has proven its usefulness in cases of high suspicion of biliary disease (history of gallstones and dilatation of the intrahepatic and/or extrahepatic bile ducts). We know less about its usefulness in cases of low suspicion of biliary pathology.The aim of this study was to assess the diagnostic accuracy of EUS in patients with low suspicion of biliary disease (patients with dilatation of the biliary tract were excluded). METHODS: 33 patients with low suspicion of biliary disease were recruited in 12 months. All of them had no biliary findings in a previous abdominal ultrasound and computer tomography scan. All of them underwent EUS and were studied prospectively. The diagnosis was confirmed by surgery and/or by ERCP in patients with positive EUS or clinical follow-up in those with normal EUS. Time of follow-up was 9 months (range, 3-12 months). RESULTS: seventeen patients (51.5%) presented with abnormal biliary findings on EUS (7 choledocholithiasis, 3 cholelithiasis, 2 choledocholithiasis + cholelithiasis and 5 microlithiasis). CONCLUSION: EUS is a useful and safe procedure for diagnosing patients with low suspicion of biliary disease.