MOESM1 of Microbial biosynthesis of lactate esters

Additional file 1: Table S1. Summary of high cell density cultures of EcJW101, EcJW102, EcJW103, EcJW104, and EcJW105 with addition of glucose and various alcohols after 24 h. The subscripts i and f are referred to the initial (0 h) and final (24 h) time of the culture, respectively. Table S2. Summary of titer, specific productivity, and yield of esters in high cell density cultures of EcJW101, EcJW102, EcJW103, EcJW104, and EcJW105 with addition of glucose and various alcohols after 24 h. The acyl acetate and acyl lactate columns correspond to the acyl alcohols added. For example, with the exogenous addition of ethanol, the acyl acetate, and acyl lactate columns represent ethyl acetate, and ethyl lactate, respectively. Table S3. (A) Summary of high cell density cultures of EcDL002, EcJW201, and EcJW202 after 24 h. (B) Summary of bioreactor batch fermentation of EcJW201 after 18 h. The subscripts i and f are referred to the initial (0 h) and final (24 h) time of the culture, respectively. Table S4. Summary of high cell density cultures of EcJW106-108 and EcJW203-208 with different concentrations of IPTG (0.01, 0.1, or 1.0 mM) after 24 h. The subscripts i and f are referred to the initial (0 h) and final (24 h) time of the culture, respectively. Table S5. Summary of titer, specific productivity, and yield of esters in high cell density cultures of EcJW106-108 and EcJW203-208 with different concentrations of IPTG (0.01, 0.1, or 1.0 mM) after 24 h. Table S6. Summary of high cell density cultures of EcJW209-212 with or without addition of ethanol (2 or 10 g/L) after 24 h. (A) OD600, pH, glucose, lactate, and ethanol. (B) Titer, specific productivity, and yield of esters. The subscripts i and f are referred to the initial (0 h) and final (24 h) time of the culture, respectively. Table S7. Summary of high cell density cultures of EcJW213-221 after 24 h. (A) OD600, pH, glucose, lactate, and ethanol. (B) Titer, specific productivity, and yield of esters. The subscripts i and f are referred to the initial (0 h) and final (24 h) time of the culture, respectively. Table S8. Summary of high cell density cultures of EcJW109-117 after 24 h. (A) OD600, pH, glucose, lactate, and ethanol. (B) Titer, specific productivity, and yield of esters. The subscripts i and f are referred to the initial (0 h) and final (24 h) time of the culture, respectively

MOESM2 of Microbial biosynthesis of lactate esters

Additional file 2: Figure S1. Expression of the recombinant enzymes in engineered E. coli strains. The positions corresponding to the overexpressed proteins are indicated by arrowheads. Lane M represents protein ladder while lanes T, S, and I are referred to total, soluble, and insoluble proteins, respectively. ①~③, Pyruvate-to-lactate ester module; ④~⑤, Ethanol module; ⑥~⑩, Isobutanol module. Protein sizes were predicted with their amino acids sequences. Figure S2. Effect of lactate esters on cell growth. (A) Specific growth rates of EcDL002 with or without addition of lactate esters. (B) logP values of characterized lactate esters. The values were obtained from http://www.thegoodscentscompany.com . (C–H) Growth curves of EcDL002 with or without addition of (C) n-ethyl lactate (NEL), (D) n-propyl lactate (NPL), (E) n-butyl lactate (NBL), (F) i-butyl lactate (IBL), (G) i-amyl lactate (IAL), and (H) benzyl lactate (BZL). Figure S3. Design of (A) upstream module and (B) downstream module of the ethyl lactate pathway. The RBS Calculator v2.0 software was used to generate synthetic RBS sequences. For the upstream, four synthetic RBS sequences were generated with predicted translation initiation rates at 0.33 and 0.03 between the PAY1 or PAY3 promoter and pdc start codon. For the downstream, six synthetic RBS sequences were generated with predicted translation initiation rates at 90, 9000, and 90000 a.u. between the PT7 promoter and pct or VAAT start codon. Figure S4. (A) Correlation between ester production and the amount of added ethanol in high cell density cultures of EcJW209-212. (B) Correlation between ester production and the RBS strength for VAAT expression in high cell density culture of EcJW213-221

Hydrate-Phase Equilibria and ¹³C NMR Studies of Binary (CH₄ + C₂H₄) and (C₂H₆ + C₂H₄) Hydrates

Three-phase equilibria of hydrate + liquid water + vapor phases were investigated at various gas compositions for binary gas mixtures of (CH₄ + C₂H₄) and (C₂H₆ + C₂H₄). Hydrate-phase equilibria of the binary (CH₄ + C₂H₄) hydrate show significant changes with changing composition, whereas those of binary (C₂H₆ + C₂H₄) hydrates show little difference because of the similar physical properties of the two guest species. In addition to macroscopic equilibrium measurements, solid-state ¹³C NMR spectra of hydrate samples were collected to identify both cavity occupancies of guest components and hydrate structures. For the binary (CH₄ + C₂H₄) hydrate, the large-cavity occupancy of C₂H₄ molecules increased nonlinearly with increasing C₂H₄ concentration, which supports nonlinear shifts of the equilibrium curves. Meanwhile, the large-cavity occupancy of C₂H₄ molecules from the (C₂H₆ + C₂H₄) gas mixtures increased linearly with increasing C₂H₄ concentration, which is attributed to linear changes in the distribution or density

Temperature-Dependent Structural Transitions in Methane–Ethane Mixed Gas Hydrates

A thermodynamic interpretation of the interconversion between structures I and II occurring in methane (CH₄) + ethane (C₂H₆) mixed gas hydrates is of great importance from both fundamental and applied perspectives. The present study experimentally confirms the predicted temperature dependence of structural changes in the lower transition region (72–74 mol % of CH₄ balanced with C₂H₆) of the CH₄ + C₂H₆ + H₂O system. The measurements of phase equilibria and Raman spectra, at the macroscopic and microscopic levels, respectively, reveal the phase transition point at which the structural rearrangements occur. The isothermal data reported here clearly demonstrate significant changes of transition behavior from sII inhibition to sII promotion in accordance with increased equilibrium temperatures. This solid–solid transition trend may be dictated by the peculiar structural feature of the CH₄ + C₂H₆ mixed gas hydrates on the basis of the comprehensive experimental and theoretical data published previously. The predominance of CH₄ over C₂H₆ in cage occupancy may lead to a change in guest molecules playing a dominant role in determining the preferential hydrate structure

MOESM1 of Single mutation at a highly conserved region of chloramphenicol acetyltransferase enables isobutyl acetate production directly from cellulose by Clostridium thermocellum at elevated temperatures

Additional file 1. Additional Figures S1–S6 and Tables S1, S2

Competing Occupation of Guest Molecules in Hydroquinone Clathrates Formed from Binary C₂H₄ and CH₄ Gas Mixtures

When reacted with pure ethylene (C₂H₄) and pure methane (CH₄) at 2.0 and 4.0 MPa, respectively, pure hydroquinone (HQ) was converted into β-form clathrate compounds. Experimental solid-state ¹³C NMR spectra and powder X-ray diffraction patterns provided direct evidence of C₂H₄ and CH₄ enclathration in the β-form HQ clathrates. On the basis of cage occupancy from the solid-state ¹³C NMR spectra, C₂H₄ (cage occupancies of 0.81–0.88) molecules are more likely to occupy the clathrate cages than CH₄ molecules (cage occupancies of 0.38–0.39). The selective occupation by C₂H₄ was also observed for HQ clathrates formed from C₂H₄ and CH₄ gas mixtures of 10, 30, 50, 70, and 90 mol % concentrations of C₂H₄. The experimental results from this study could be applied to a clathrate-based process for separating and concentrating C₂H₄ from gas mixtures

Influence of Ti⁴⁺ on the Electrochemical Performance of Li-Rich Layered Oxides - High Power and Long Cycle Life of Li₂Ru_1–<i>x</i>Ti_<i>x</i>O₃ Cathodes

Li-rich layered oxides are the most attractive cathodes for lithium-ion batteries due to their high capacity (>250 mAh g^–1). However, their application in electric vehicles is hampered by low power density and poor cycle life. To address these, layered Li₂Ru_0.75Ti_0.25O₃ (LRTO) was synthesized and the influence of electroinactive Ti⁴⁺ on the electrochemical performance of Li₂RuO₃ was investigated. LRTO exhibited a reversible capacity of 240 mAh g^–1 under 14.3 mA g^–1 with 0.11 mol of Li loss after 100 cycles compared to 0.22 mol of Li for Li₂Ru_0.75Sn_0.25O₃. More Li⁺ can be extracted from LRTO (0.96 mol of Li) even after 250 cycles at 143 mA g^–1 than Li₂RuO₃ (0.79 mol of Li). High reversible Li extraction and long cycle life were attributed to structural stability of the Li<i>M</i>₂ layer in the presence of Ti⁴⁺, facilitating the lithium diffusion kinetics. The versatility of the Li₂<i>M</i>O₃ structure may initiate exploration of Ti-based Li-rich layered oxides for vehicular applications

Doped Lanthanum Nickelates with a Layered Perovskite Structure as Bifunctional Cathode Catalysts for Rechargeable Metal–Air Batteries

Rechargeable metal–air batteries have attracted a great interest in recent years because of their high energy density. The critical challenges facing these technologies include the sluggish kinetics of the oxygen reduction–evolution reactions on a cathode (air electrode). Here, we report doped lanthanum nickelates (La₂NiO₄) with a layered perovskite structure that serve as efficient bifunctional electrocatalysts for oxygen reduction and evolution in an aqueous alkaline electrolyte. Rechargeable lithium–air and zinc–air batteries assembled with these catalysts exhibit remarkably reduced discharge–charge voltage gaps (improved round-trip efficiency) as well as high stability during cycling

2‑Propanol As a Co-Guest of Structure II Hydrates in the Presence of Help Gases

The enclathration of 2-propanol (2-PrOH) as a co-guest of structure II (sII) hydrates in the presence of CH₄ and CO₂ was experimentally verified with a focus on macroscopic phase behaviors and microscopic analytical methods such as powder X-ray diffraction (PXRD) and NMR spectroscopy. 2-PrOH functioned as a hydrate promoter in the CH₄ + 2-PrOH systems, whereas it functioned as an apparent hydrate inhibitor in the CO₂ + 2-PrOH systems despite the inclusion of 2-PrOH in the hydrate lattices. From the PXRD patterns, both double CH₄ + 2-PrOH and double CO₂ + 2-PrOH hydrates were identified to be cubic (<i>Fd</i>3<i>m</i>) sII hydrates. From the ¹³C NMR spectra, it was found that, at a lower 2-PrOH concentration, the small 5¹² cages of the sII hydrate were occupied by CH₄ molecules only, whereas the large 5¹²6⁴ cages were shared by CH₄ and 2-PrOH molecules. However, at a stoichiometric concentration, the large cages were occupied by 2-PrOH molecules only, and the corresponding chemical formula for this concentration is 1.50CH₄·0.98 2-PrOH·17H₂O

Carbon‑, Binder‑, and Precious Metal-Free Cathodes for Non-Aqueous Lithium–Oxygen Batteries: Nanoflake-Decorated Nanoneedle Oxide Arrays

Rechargeable lithium–oxygen (Li–O₂) batteries have higher theoretical energy densities than today’s lithium-ion batteries and are consequently considered to be an attractive energy storage technology to enable long-range electric vehicles. The main constituents comprising a cathode of a lithium–oxygen (Li–O₂) battery, such as carbon and binders, suffer from irreversible decomposition, leading to significant performance degradation. Here, carbon- and binder-free cathodes based on nonprecious metal oxides are designed and fabricated for Li–O₂ batteries. A novel structure of the oxide-only cathode having a high porosity and a large surface area is proposed that consists of numerous one-dimensional nanoneedle arrays decorated with thin nanoflakes. These oxide-only cathodes with the tailored architecture show high specific capacities and remarkably reduced charge potentials (in comparison with a carbon-only cathode) as well as excellent cyclability (250 cycles)