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The indole scaffold is a recurring structure in multiple bioactive heterocycles and natural products. Substituted indoles like the amino acid tryptophan serve as a precursor for a wide range of natural products with pharmaceutical or agrochemical applications. Inspired by the versatility of these compounds, medicinal chemists have for decades exploited indole as a core structure in the drug discovery process. With the aim of tuning the properties of lead drug candidates, regioselective halogenation of the indole scaffold is a common strategy. However, chemical halogenation is generally expensive, has a poor atom economy, lacks regioselectivity, and generates hazardous waste streams. As an alternative, in this work we engineer the industrial workhorse Saccharomyces cerevisiae for the de novo production of halogenated tryptophan and tryptamine derivatives. Functional expression of bacterial tryptophan halogenases together with a partner flavin reductase and a tryptophan decarboxylase resulted in the production of halogenated tryptophan and tryptamine with chlorine or bromine. Furthermore, by combining tryptophan halogenases, production of di-halogenated molecules was also achieved. Overall, this works paves the road for the production of new-to-nature halogenated natural products in yeast.

The present disclosure relates to methods for production of 4-hydroxytryptamine and derivatives thereof in a yeast cell. Herein are also disclosed methods for production of halogenated tryptophans and derivatives thereof in a cell. Herein are also disclosed methods for production of methylated tryptamine. The disclosure also provides nucleic acid constructs and cells useful for performing the present methods.

Although commercial membranes are well established materials for water desalination and wastewater treatment, modification on commercial membranes is still necessary to deliver high-performance with enhanced flux and/or selectivity and fouling resistance. A modification method with plasma techniques has been extensively applied for high-performance membrane production. The paper presents a mechanistic review on the impact of plasma gas and polymerization, at either low pressure or atmospheric pressure on the material properties and performance of the modified membranes. At first, plasma conditions at low-pressure such as plasma power, gas or monomer flow rate, reactor pressure, and treatment duration which affect the chemical structure, surface hydrophilicity, morphology, as well as performance of the membranes have been discussed. The underlying mechanisms of plasma gas and polymerization have been highlighted. Thereafter, the recent research in plasma techniques toward membrane modification at atmospheric environment has been critically evaluated. The research focuses of future plasma-related membrane modification, and fabrication studies have been predicted to closely relate with the implementation of the atmospheric-pressure processes at the large-scale.

Treating wastewater from textile plants using membrane distillation (MD) has great potential due to the high-salinity wastes and availability of waste heat. However, textile wastewaters also contain surfactants, which compromise the essential hydrophobic feature of the membrane, causing membrane wetting. To address this wetting issue, a custom-made membrane consisting of a hydrophilic layer coated on hydrophobic polytetrafluoroethylene (PTFE) was tested on textile wastewater in a pilot MD setup, and compared with a conventional hydrophobic PTFE membrane. The test was carried out with a feed temperature of 60 °C, and a permeate temperature of 45 °C. The overall salt rejection of both membranes was very high, at 99%. However, the hydrophobic membrane showed rising permeate electrical conductivity, which was attributed to wetting of the membrane. Meanwhile, the hydrophilic-coated membrane showed continually declining electrical conductivity demonstrating an intact membrane that resisted wetting from the surfactants. Despite this positive result, the coated membrane did not survive a simple sodium hydroxide clean, which would be typically applied to a membrane process. This brief study showed the viability of membrane distillation membranes on real textile wastewaters containing surfactants using hydrophilic-coated hydrophobic PTFE, but the cleaning process required for membranes needs optimization.

Background: Microbial production of nitrogen containing compounds requires a high uptake flux and assimilation of the N-source (commonly ammonium), which is generally coupled with ATP consumption and negatively influences the product yield. In the industrial workhorse Saccharomyces cerevisiae, ammonium (NH4 +) uptake is facilitated by ammonium permeases (Mep1, Mep2 and Mep3), which transport the NH4 + ion, resulting in ATP expenditure to maintain the intracellular charge balance and pH by proton export using the plasma membrane-bound H+-ATPase. Results: To decrease the ATP costs for nitrogen assimilation, the Mep genes were removed, resulting in a strain unable to uptake the NH4 + ion. Subsequent analysis revealed that growth of this Δmep strain was dependent on the extracellular NH3 concentrations. Metabolomic analysis revealed a significantly higher intracellular NHX concentration (3.3-fold) in the Δmep strain than in the reference strain. Further proteomic analysis revealed significant up-regulation of vacuolar proteases and genes involved in various stress responses. Conclusions: Our results suggest that the uncharged species, NH3, is able to diffuse into the cell. The measured intracellular/extracellular NHX ratios under aerobic nitrogen-limiting conditions were consistent with this hypothesis when NHx compartmentalization was considered. On the other hand, proteomic analysis indicated a more pronounced N-starvation stress response in the Δmep strain than in the reference strain, which suggests that the lower biomass yield of the Δmep strain was related to higher turnover rates of biomass components., BT/Cell Systems Engineering, ChemE/Organic Materials and Interfaces, BT/Analytical Biotechnology, BT/Industrial Microbiology

Meat rendering operations produce stick water waste which is rich in proteins, fats, and minerals. Membrane distillation (MD) may further recover water and valuable solids, but hydrophobic membranes are contaminated by the fats. Here, commercial hydrophobic polytetrafluorethylene (PTFE) membranes with a hydrophilic polyurethane surface layer (PU-PTFE) are used for the first time for direct contact MD (DCMD) on real poultry, fish, and bovine stick waters. Metal membrane microfiltration (MMF) was also used to capture fats prior to MD. Although the standard hydrophobic PTFE membranes failed rapidly, PU-PTFE membranes effectively processed all stick water samples to colourless permeate with sodium rejections >99%. Initial clean solution fluxes 5–6 L/m2/h declined to less than half during short 40% water recovery tests for all stick water samples. Fish stick water uniquely showed reduced fouling and up to 78% water recovery. Lost flux was easily restored by rinsing the membrane with clean water. MMF prior to MD removed 92% of fats, facilitating superior MD performance. Differences in fouling between stick waters were attributed to temperature polarisation from higher melt temperature fats and relative proportions to proteins. Hydrophilic coated MD membranes are applicable to stick water processing but further studies should consider membrane cleaning and longer-term stability.

In this study it was proposed to investigate the use of 3D metal oxides (specifically titanium oxides) as potential electrode materials for lithium ion batteries. Three different approaches were taken: mesoporous materials to increase the surface area and improve the capacity; nanocrystalline materials to increase the surface area and to investigate any changes that may occur using nanocrystals; and microporous materials that are more open, allowing rapid diffusion of lithium and higher capacities.Of the three categories of materials studies, mesoporous TiO2 was the least promising with low reversible capacities (20 mAh·g-1) due to densification resulting in a loss of surface area.In nanocrystalline rutile an irreversible phase change occurred upon initial intercalation, however after this intercalation occurred reversibly in a single phase mechanism giving capacities of 100 mAh·g-1. A trend in intercalation potential was observed with crystallite size that was related to the ability of the structure to relax and accept lithium. Doping of rutile yielded no real improvement. Brookite gave only low capacities from a single phase intercalation mechanism. TiO2 films produced by a novel electrochemical technique showed that while amorphous films give greater capacities, more crystalline (anatase) films give greater reversibility.Overall, microporous titanosilicates showed the most promise with sitinakite giving a reversible capacity of 80 mAh·g-1 after twenty cycles or double this when dried. The intercalation was found to occur by two steps that generate large changes in crystallite size explaining the capacity fade witnessed. While doping did not improve the performance, cation exchange has proven beneficial.The remaining titanosilicates did not perform as well as sitinakite, however a trend was observed in the intercalation potentials with the wavenumber of the Ti-O Raman stretch. This was due to the covalent nature of the bonding. Upon reduction an electron is added