Martin Gede

Membrane technology has numerous applications in potable water generation, wastewater (WW) reuse, desalination, and many others. However, the manufacture of membranes generates solvent-contaminated WW, especially via the non-solvent-induced phase separation method. Here, we tested the suitability of different microalgae to clean up membrane manufacturing WW and reuse it for subsequent membrane fabrication. Specifically, we determined the toxicity of six organic solvents to four different microalgae (Tetradesmus, Scenedesmus, Chlamydomonas, and Galdieria) and observed that all were able to tolerate solvent contaminant concentrations common to membrane manufacture with varying growth rates. Removal of triethyl phosphate varied greatly between strains, with >50% removal by cultures of Chlamydomonas and Galdieria, whereas PolarClean was almost entirely removed by Chlamydomonas, Tetradesmus and Scenedesmus. The four algae mentioned above, and two others, Monoraphidium and Chlorella were additionally grown in contaminated membrane manufacture WW, where the Tetradesmus, Scenedesmus and Chlorella removed PolarClean entirely, regardless of CO₂ supplementation. The reuse of Scenedesmus-treated WW in a subsequent membrane fabrication did not affect the physicochemical properties of produced membranes, and the morphology of these membranes was comparable to control conditions. We observed that using photosynthetic microbes to clean membrane manufacture WW enables the generation of their valuable biomasses and the reuse of treated water for further membrane fabrication. Our results indicate that coupling biodegradable solvents and algal cultivation can enable circularity and reduce solvent emissions from membrane manufacturing processes.

Because of environmental impact, there is a great need for chemosensors, especially for toxic heavy metals such as lead. The conventional instrumental analytical techniques rarely provide an available real-time sensing platform, thus the development of highly selective and stable synthetic chemosensor molecules is of great importance. Acridono-18-crown-6 ethers have such properties, and much research has proven their outstanding applicability in various supramolecular devices. In this present work, we aimed to enable their covalent immobilization capability by synthesizing functionalized derivatives while preserving the favored molecular recognition ability. Several new macrocycle analogues were synthesized, while synthetization difficulties and design aspects were also dealt with. The selectivity of the macrocycle analogues was studied using UV–Vis spectroscopy and compared with that of the parent compounds. The ultimate crown ether derivative showed high Pb²⁺-selectivity, reversibility (decomplexation by extraction with water) and stability.

Certain endangered Thymelaeaceous trees are major sources of the fragrant and highly valued resinous agarwood, comprised of hundreds of oxygenated sesquiterpenoids (STPs). Despite growing pressure on natural agarwood sources, the chemical complexity of STPs severely limits their synthetic production. Here, we catalogued the chemical diversity in 58 agarwood samples by two-dimensional gas chromatography–mass spectrometry and used synthetic biology to produce subsets of the complex STP mixtures found in agarwood. We improved STP yields in the unicellular alga Chlamydomonas reinhardtii by 25-fold through combinatorial engineering to biosynthesise nine macrocyclic STP backbones found in agarwood. A bioprocess following green-chemistry principles was developed that exploits ‘milking’ of STPs without cell lysis, solvent–solvent STP extraction, solvent–STP nanofiltration, and bulk STP oxy-functionalisation to obtain terpene mixtures like those of agarwood. This green bioprocess allows total solvent recycling and continuous production. Our synthetic biology and green bioprocess approach enables a more sustainable synthesis of complex, fragrant terpenes as an alternative to their exploitation from natural sources.

Certain endangered Thymelaeaceous trees are major sources of the fragrant and highly valued resinous agarwood, comprised of hundreds of oxygenated sesquiterpenoids (STPs). Despite growing pressure on natural agarwood sources, the chemical complexity of STPs severely limits synthetic production. Here, we catalogued the chemical diversity in 58 agarwood samples by two-dimensional gas chromatography–mass spectrometry and partially recreated complex STP mixtures through synthetic biology. We improved STP yields in the unicellular alga Chlamydomonas reinhardtii by combinatorial engineering to biosynthesise nine macrocyclic STP backbones found in agarwood. A bioprocess following green-chemistry principles was developed that exploits ‘milking’ of STPs without cell lysis, solvent–solvent STP extraction, solvent–STP nanofiltration, and bulk STP oxy-functionalisation to obtain terpene mixtures like those of agarwood. This process occurs with total solvent recycling and enables continuous production. Our synthetic-biology approach offers a sustainable alternative to harvesting agarwood trees to obtain mixtures of complex, fragrant, oxygenated STPs.

Novel enantiopure azacrown [(R,R)-1 and (S,S)-1] and diazacrown [(R,R)-2–(R,R)-4 and (S,S)-2–(S,S)-4] ethers containing a pyrene fluorophore unit and two phenyl groups at their chiral centers were obtained in multistep syntheses. The action of these chemosensors is based on the photoinduced electron transfer (PET) process, thus they show fluorescence enhancement in the presence of protonated primary amines and amino acid esters. Their recognition abilities toward the enantiomers of 1-phenylethylamine hydrogen perchlorate (PEA), 1-(1-naphthyl) ethylamine hydrogen perchlorate (NEA), phenylglycine methyl ester hydrogen perchlorate (PGME), and phenylalanine methyl ester hydrogen perchlorate (PAME) were examined in acetonitrile using fluorescence spectroscopy.