A Two-Compartment Fermentation System to Quantify Strain-Specific Interactions in Microbial Co-Cultures.

To fulfil the growing interest in investigating microbial interactions in co-cultures, a novel two-compartment bioreactor system was developed, characterised, and implemented. The system allowed for the exchange of amino acids and peptides via a polyethersulfone membrane that retained biomass. Further system characterisation revealed a Bodenstein number of 18, which hints at backmixing.

Identifying and Engineering Bottlenecks of Autotrophic Isobutanol Formation in Recombinant by Systemic Analysis.

(, CLJU) is natively endowed producing acetic acid, 2,3-butandiol, and ethanol consuming gas mixtures of CO, CO, and H (syngas). Here, we present the syngas-based isobutanol formation using harboring the recombinant amplification of the "Ehrlich" pathway that converts intracellular KIV to isobutanol. Autotrophic isobutanol production was studied analyzing two different strains in 3-L gassed and stirred bioreactors.

Electron availability in CO , CO and H mixtures constrains flux distribution, energy management and product formation in Clostridium ljungdahlii.

Acetogens such as Clostridium ljungdahlii can play a crucial role reducing the human CO footprint by converting industrial emissions containing CO , CO and H into valuable products such as organic acids or alcohols. The quantitative understanding of cellular metabolism is a prerequisite to exploit the bacterial endowments and to fine-tune the cells by applying metabolic engineering tools. Studying the three gas mixtures CO  + H , CO and CO + CO  + H (syngas) by continuously gassed batch cultivation experiments and applying flux balance analysis, we identified CO as the preferred carbon and electron source for growth and producing alcohols.

Continuous Adaptive Evolution of a Fast-Growing Strain Independent of Protocatechuate.

is a commonly applied host for the industrial production of amino acids. While valued for its robustness, it is somewhat inferior to competing strains such as because of the relatively low growth rate of 0.40 h in synthetic, industrial media.

Transcriptional response of Escherichia coli to ammonia and glucose fluctuations.

In large-scale production processes, metabolic control is typically achieved by limited supply of essential nutrients such as glucose or ammonia. With increasing bioreactor dimensions, microbial producers such as Escherichia coli are exposed to changing substrate availabilities due to limited mixing. In turn, cells sense and respond to these dynamic conditions leading to frequent activation of their regulatory programmes.

Switching between nitrogen and glucose limitation: Unraveling transcriptional dynamics in Escherichia coli.

Transcriptional control under nitrogen and carbon-limitation conditions have been well analyzed for Escherichia coli. However, the transcriptional dynamics that underlie the shift in regulatory programs from nitrogen to carbon limitation is not well studied. In the present study, cells were cultivated at steady state under nitrogen (ammonia)-limited conditions then shifted to carbon (glucose) limitation to monitor changes in transcriptional dynamics.

Engineering E. coli for large-scale production - Strategies considering ATP expenses and transcriptional responses.

Microbial producers such as Escherichia coli are evolutionarily trained to adapt to changing substrate availabilities. Being exposed to large-scale production conditions, their complex, multilayered regulatory programs are frequently activated because they face changing substrate supply due to limited mixing. Here, we show that E.

CO₂ /HCO₃⁻ perturbations of simulated large scale gradients in a scale-down device cause fast transcriptional responses in Corynebacterium glutamicum.

The exploration of scale-down models to imitate the influence of large scale bioreactor inhomogeneities on cellular metabolism is a topic with increasing relevance. While gradients of substrates, pH, or dissolved oxygen are often investigated, oscillating CO2/HCO3 (-) levels, a typical scenario in large industrial bioreactors, is rarely addressed. Hereby, we investigate the metabolic and transcriptional response in Corynebacterium glutamicum wild type as well as the impact on L-lysine production in a model strain exposed to pCO2 gradients of (75-315) mbar.

mer-[3-Phenyl-5-(2-pyridyl-κN)-1,2,4-triazol-1-ido-κN]bis-(2-quinolylphenyl-κC,N)iridium(III) deuterochloro-form disolvate.

In the title compound, [Ir(C(13)H(9)N(4))(C(15)H(10)N)(2)]·2CDCl(3), the coordination at iridium is octa-hedral, but with narrow ligand bite angles ranging from 74.85 (8) to 83.99 (8)°.

mer-Bis[2-(1,3-benzothiazol-2-yl)phenyl-κC,N][3-phenyl-5-(2-pyridyl)-1,2,4-triazol-1-ido-κN,N]iridium(III) deuterochloro-form 3.5-solvate.

In the title compound, [Ir(C(13)H(9)N(4))(C(13)H(8)NS)(2)]·3.5CDCl(3), the coordination at iridium is octa-hedral, but with narrow ligand bite angles. The bond lengths at iridium show the expected trans influence, with the Ir-N bonds trans to C being appreciably longer than those trans to N.

Efficient and long-time stable red iridium(III) complexes for organic light-emitting diodes based on quinoxaline ligands.

We report the design and characterization of three heteroleptic orange-red phosphorescent iridium(III) complexes bearing two 2-(4-fluorophenyl)-3-methyl-quinoxaline (fpmqx) cyclometalated ligands combined with three different ancillary ligands, triazolylpyridine (trz), picolinate (pic), and acetylacetonate (acac). All of these complexes emit an orange to red color in the spectral range of 605-628 nm in dichloromethane. Strong spin-orbit coupling of the iridium atom allows the formally forbidden mixing of singlet and triplet states.

Dynamic response of the expression of hxt1, hxt5 and hxt7 transport proteins in Saccharomyces cerevisiae to perturbations in the extracellular glucose concentration.

Glucose transport in Saccharomyces cerevisiae relies on a multi-factorial uptake system. The modulation of its efficiency depends on the differential expression of various sets of hexose transport-related proteins whose glucose affinity differs considerably. The expression of three different glucose transport proteins (HXT1, HXT5 and HXT6/7 with low-, intermediate- and high-affinity, respectively) was monitored as a result of modified extracellular glucose concentrations.

Highly efficient enzymatic synthesis of 2-monoacylglycerides and structured lipids and their production on a technical scale.

We report here a two-step process for the high-yield enzymatic synthesis of 2-monoacylglycerides (2-MAG) of saturated as well as unsaturated fatty acids with different chain lengths. The process consists of two steps: first the unselective esterification of fatty acids and glycerol leading to a triacylglyceride followed by an sn1,3-selective alcoholysis reaction yielding 2-monoacylglycerides. Remarkably, both steps can be catalyzed by lipase B from Candida antarctica (CalB).

Diamond planar refractive lenses for third- and fourth-generation X-ray sources.

The fabrication and testing of planar refractive hard X-ray lenses made from bulk CVD diamond substrates is reported. The lens structures were generated by electron-beam lithography and transferred by reactive-ion etching into the diamond. Various lens designs were fabricated and tested at 12.