Transcriptomics analysis and fed-batch regulation of high astaxanthin-producing Phaffia rhodozyma/Xanthophyllomyces dendrorhous obtained through adaptive laboratory evolution.

Astaxanthin has high utilization value in functional food because of its strong antioxidant capacity. However, the astaxanthin content of Phaffia rhodozyma is relatively low. Adaptive laboratory evolution is an excellent method to obtain high-yield strains. TiO2 is a good inducer of oxidative stress. In this study, different concentrations of TiO2 were used to domesticate P. rhodozyma, and at a concentration of 1000 mg/L of TiO2 for 105 days, the optimal strain JMU-ALE105 for astaxanthin production was obtained. After fermentation, the astaxanthin content reached 6.50 mg/g, which was 41.61% higher than that of the original strain. The ALE105 strain was fermented by batch and fed-batch, and the astaxanthin content reached 6.81 mg/g. Transcriptomics analysis showed that the astaxanthin synthesis pathway, and fatty acid, pyruvate, and nitrogen metabolism pathway of the ALE105 strain were significantly upregulated. Based on the nitrogen metabolism pathway, the nitrogen source was adjusted by ammonium sulphate fed-batch fermentation, which increased the astaxanthin content, reaching 8.36 mg/g. This study provides a technical basis and theoretical research for promoting industrialization of astaxanthin production of P. rhodozyma. ONE-SENTENCE SUMMARY: A high-yield astaxanthin strain (ALE105) was obtained through TiO2 domestication, and its metabolic mechanism was analysed by transcriptomics, which combined with nitrogen source regulation to further improve astaxanthin yield.

The identification of biotransformation pathways for removing fishy malodor from Bangia fusco-purpurea using fermentation with Saccharomyces cerevisiae.

The yeast Saccharomyces cerevisiae is effective in reducing the fishy malodor of sea products. However, the biotransformation pathways are still unclear. The seaweed B. fusco-purpurea was taken as an example to investigate the chemical transformation pathways for the deodorization process with S. cerevisiae fermentation. Sensory evaluation, GC-MS, GC-MS-O and odor activity value (OAV) analyses showed the fishy odorants were 1-octen-3-ol, (E)-2-nonenal, 2,4-decadienal, 2-pentylfuran, 2-octen-1-ol and nonanal. The removal of fishy malodor was related to the reactions of reduction, dehydrogenation, deformylation-oxygenation and ester syntheses via catalysis of aldehyde dehydrogenase, alcohol dehydrogenases, epoxide hydrolase, aldehyde deformylating-oxygenase, enone reductase, oxidases, dehydrogenases, aldo-keto reductases, ester synthase and acyltransferase. Interestingly, for the first time, it was found that 3,5-octadien-2-one transformed to 6-octen-2-one; and 2-pentylfuran transformed to o-cymene and hexyl acetate. Our findings enrich the knowledge for the removal of fishy malodor from sea products such as seaweeds.

Two novel lead(II) carboxyphosphonates with a layered and a 3D framework structure: syntheses, crystal structures, reversible dehydration/hydration, and luminescence properties.

Two novel lead(II) carboxyphosphonates with a layered and a 3D framework structure, namely, [Pb2Cl3(H2L)]·H2O (1) and [Pb2(HL)(HBTC)] (2) (H3L = H2O3PCH2-NC5H9-COOH, H3BTC = 1,3,5-benzenetricarboxylic acid), have been synthesized under hydrothermal conditions and structurally characterized. For compound 1, the interconnection of Pb(1)O2Cl3, Pb(2)O2Cl3, and CPO3 polyhedra via corner- and edge-sharing forms a 1D chain. The adjacent chains connect with each other by sharing the chloride anion, thereby generating a 2D layered structure in the ab-plane. The lattice water molecules are located between adjacent layers. Compound 2 exhibits a 3D pillared-layered structure. The Pb(1)O5, Pb(2)O5, and CPO3 polyhedra are interconnected into a 1D double chain via corner- and edge-sharing, which is further linked to adjacent chains through carboxyphosphonate ligands to form a 2D double layer structure. Neighboring double layers are bridged through the second linkers HBTC(2-), leading to a 3D pillared-layered structure with a 1D channel system along the a-axis. An interesting feature of compound 1 is the presence of the dehydration/hydration properties. It is worth noting that compound 2 can be stable up to a high temperature. The luminescent properties of compounds 1 and 2 have also been studied.

A series of novel lanthanide carboxyphosphonates with a 3D framework structure: synthesis, structure, and luminescent and magnetic properties.

By introduction of 1,4-benzenedicarboxylic acid as the second organic ligand, a series of novel lanthanide carboxyphosphonates with a 3D framework structure, namely, [Ln(3)(H(2)L)(HL)(2)(bdc)(2)(H(2)O)]·7H(2)O (Ln = La (1), Ce (2), Pr (3), Nd (4), Sm (5), Eu (6), Gd (7), Tb (8); H(3)L = H(2)O(3)PCH(2)NC(5)H(9)COOH; H(2)bdc = HOOCC(6)H(4)COOH) have been synthesized under hydrothermal conditions. Compounds are isostructural and feature a 3D framework in which Ln(III) polyhedra are interconnected by bridging {CPO(3)} tetrahedra into 2D inorganic layers parallel to the ab plane. The organic groups of H(2)L(-) are grafted on the two sides of the layer. These layers are further cross-linked by the bdc(2-) ligands from one layer to the Ln atoms from the other into a pillared-layered architecture with one-dimensional channel system along the a axis. The thermal stability of compounds has been investigated. Luminescent properties of compounds , and the magnetic properties of compound have also been studied.