Production of Acetone–Butanol–Ethanol (ABE) in Direct Fermentation of Cassava by Clostridium saccharoperbutylacetonicum N1-4

In this work, acetone–butanol–ethanol (ABE) fermentation characteristics of cassava starch and cassava chips when using Clostridium saccharoperbutylacetonicum N1-4 was presented. The obtained results in batch mode using a 1-L fermenter showed that C. saccharoperbutylacetonicum N1-4 was a hyperamylolytic strain and capable of producing solvents efficiently from cassava starch and cassava chips, which was comparable to when glucose was used. Batch fermentation of cassava starch and cassava chips resulted in 21.0 and 19.4 g/L of total solvent as compared with 24.2 g/L of total solvent when using glucose. Solvent productivity in fermentation of cassava starch was from 42% to 63% higher than that obtained in fermentation using corn and sago starches in the same condition. In fermentation of cassava starch and cassava chips, maximum butanol concentration was 16.9 and 15.5 g/L, respectively. Solvent yield and butanol yield (based on potential glucose) was 0.33 and 0.41, respectively, for fermentation of cassava starch and 0.30 and 0.38, respectively for fermentation using cassava chips.     

Unconventional Magnetic and Resistive Hysteresis in an Iodine‐Bonded Molecular Conductor

Simultaneous manipulation of both spin and charge is a crucial issue in magnetic conductors. We report on a strong correlation between magnetism and conductivity in the iodine‐bonded molecular conductor (DIETSe)₂FeBr₂Cl₂ [DIETSe=diiodo(ethylenedithio)tetraselenafulvalene], which is the first molecular conductor showing a large hysteresis in both magnetic moment and magnetoresistance associated with a spin‐flop transition. Utilizing a mixed‐anion approach and iodine bonding interactions, we tailored a molecular conductor with random exchange interactions exhibiting unforeseen physical properties.     

Use of ring-repeller, double-skimmer electrodes for efficient ion focusing in mass spectrometry.

The design and construction of a new type of time-of-flight mass spectrometer is described. The instrument was designed to improve the ionization efficiency and to efficiently detect ions. The system performance was evaluated using the SIMION software, and was compared with the experimental results. The shapes of the repeller, extraction, and ground electrodes had a strong effect on the trajectory of ions in the processes of ion acceleration and focusing. The major difference between the theory and the experiment can be attributed to space-charge effects.     

Azetidine‐Containing Alkaloids Produced by a Quorum‐Sensing Regulated Nonribosomal Peptide Synthetase Pathway in Pseudomonas aeruginosa

Pseudomonas aeruginosa displays an impressive metabolic versatility, which ensures its survival in diverse environments. Reported herein is the identification of rare azetidine‐containing alkaloids from P. aeruginosa PAO1, termed azetidomonamides, which are derived from a conserved, quorum‐sensing regulated nonribosomal peptide synthetase (NRPS) pathway. Biosynthesis of the azetidine motif has been elucidated by gene inactivation, feeding experiments, and biochemical characterization in vitro, which involves a new S‐adenosylmethionine‐dependent enzyme to produce azetidine 2‐carboxylic acid as an unusual building block of NRPS. The mutants of P. aeruginosa unable to produce azetidomonamides had an advantage in growth at high cell density in vitro and displayed rapid virulence in Galleria mellonella model, inferring functional roles of azetidomonamides in the host adaptation. This work opens the avenue to study the biological functions of azetidomonamides and related compounds in pathogenic and environmental bacteria.     

Reaction of Sulfur and Oxygen-Bridged 8-Quinolinolato Trinuclear Molybdenum Cluster [Mo<Subscript>3</Subscript>OS<Subscript>3</Subscript>(qn)<Subscript>3</Subscript>(H<Subscript>2</Subscript>O)<Subscript>3</Subscript>]<Superscript>+</Superscript> with Acetylene Carboxylic Acids

The reaction of a sulfur and oxygen-bridged 8-quinolinolato trinuclear molybdenum cluster [Mo₃OS₃(qn)₃(H₂O)₃]⁺ (3; Hqn = 8-quinolinol) with equimolar amounts of acetylene carboxylic acid, 4-pentynoic acid, 5-hexynoic acid, acetic acid, and pimelic acid gave clusters having μ-carboxylato groups, [Mo₃OS₃(qn)₃(H₂O)(μ-HC≡CCOO)] (6), [Mo₃OS₃(qn)₃(H₂O)(μ-HC≡C(CH₂)₂COO)] (7), [Mo₃OS₃(qn)₃(H₂O)(μ-HC≡C(CH₂)₃COO)] (8), [Mo₃OS₃(qn)₃(H₂O)(μ-CH₃COO)] (4), and [{Mo₃OS₃(qn)₃(C₂H₅OH)}₂(μ-C₇H₁₀O₄)] (5), respectively. X-ray structural analyses, ¹H NMR, and electronic spectra of these clusters made clear that each of the COO⁻ groups of the reagents bridges two Mo atoms in each cluster and that no adduct formation occurred at the sulfurs in the clusters. The reaction of 3 with a large excess-molar amount (50 times) of acetylene carboxylic acid gave [Mo₃OS(μ₃-SCH=C(COOH)S)(qn)₃(H₂O)(μ-HC≡CCOO)] (9) with two molecules of acetylene carboxylic acid, one acting as a carboxylato bridge and the other in adduct formation, as supported by the electronic and ¹H NMR spectra. The corresponding aqua cluster [Mo₃OS₃(H₂O)₉]⁴⁺ (1), on the contrary, reacts with acetylene carboxylic acid to give adduct [Mo₃OS(μ₃-SCH=C(COOH)S)(H₂O)₉]⁴⁺ (2). Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Synthesis and characterization of isomanolonitrile dithiolato palladium complexes. Crystal structure of (PPh3)2Pd(S2C4N2) and (Et4N)2WS4Pd(S2C4N2)

A series of isomalononitrile dithiolato palladium complexes, (PPh₃)₂Pd(1-mnt) (1), [P(OPh)₃]₂Pd(i-mnt) (2), (PPh₃)(py)Pd(i-mnt)·CH₃CN (4), (Et₄N)₂Pd(i-mnt)₂ (4) and (Ph₄As)₂Pd(i-mnt)₂ (5) were synthesized and characterized by elemental analysis and IR spectroscopy. The reaction between (Et₄N)₂Pd(i-mnt)₂ (4) and (Et₄N)₂WS₄ gave a mixed metal cluster (Et₄N)₂WS₄Pd(i-mnt) (6). The crystallographically determined structures of 1 and 6 are reported.     

Rate acceleration of organic reaction by immediate solvent evaporation

Several types of organic reactions were accelerated by immediate evaporation of solvents because of remarkable enhancement of molecule-to-molecule contacts between reactants.     

A direct method for the separation and quantification of bile acid acyl glycosides by high-performance liquid chromatography with an evaporative light scattering detector

A direct method for the separation and quantification of a series of bile acid acyl glycosides using high-performance liquid chromatography coupled to an evaporative light scattering detector (HPLC-ELSD) is described. Complete separation of each of 15 bile acid acyl 24-alpha-glucosides and their 24-beta-anomers and 24-beta-galactosides was achieved by the stepwise gradient elution mode on a C18 column using a mixture of acetonitrile-methanol (8:2, v/v) and 1% aqueous acetic acid as the mobile phase. 24-beta-Galactosides were always eluted faster than the corresponding 24-beta-glucosides, which eluted after the corresponding 24-alpha-anomers. Calibration curves of different 24-beta-galactosides were linear over a range of 0.2-40 nmol of injected amount and the detection limits (S/N > 3) were from 0.08 to 0.1 nmol. The present HPLC-ELSD method may provide an insight into the separation and quantification of the biologically interesting neutral bile acids.