Search

Developing a highly efficient and ecofriendly system to produce desired products from waste can be considered important to a sustainable society. Here, we report for the first time high-yield production of lycopene through metabolically engineering an extremophilic microorganism, Deinococcus radioduransR1, from corn steep liquor (CSL) and glycerol. First, the crtLmgene-encoding lycopene cyclase was deleted to prevent the conversion of lycopene to γ-carotene. Then, the crtBgene-encoding phytoene synthase and the dxsgene-encoding 1-deoxy-d-xylulose 5-phosphate synthase were overexpressed to increase carbon flux toward lycopene. The engineered ΔcrtLm/crtB+dxs+D. radioduransR1 could produce 273.8 mg/L [80.7 mg/g dry cell weight (DCW)] and 373.5 mg/L (108.0 mg/g DCW) of lycopene from 10 g/L of glucose with 5 g/L of yeast extract and 9.9 g/L of glucose with 20 g/L of CSL, respectively. Moreover, the lycopene titer and content were increased by 26% (470.6 mg/L) and 28% (138.2 mg/g DCW), respectively, when the carbon source was changed to glycerol. Finally, fed-batch fermentation of the final engineered strain allowed the production of 722.2 mg/L (203.5 mg/g DCW) of lycopene with a yield and productivity of 20.3 mg/g glycerol and 6.0 mg/L/h, respectively, from 25 g/L of CSL and 35.7 g/L of glycerol.

The efficient treatment of radioactive waste arising from nuclear accidents and overuse of radioisotopes has become an important issue, and much effort has been devoted to protecting the environment from such toxic radioactive materials. Among them, radioactive iodine in water is regarded as one of the most palpable threats to humans, as it is generated by post-use in medical and industrial applications. Although a few adsorbents and purification processes have been reported, the development of a better desalination method that is able to provide high removal efficiency, ion-selectivity, and reusability is still in demand. Herein, we report a hybrid composite membrane, composed of gold nanoparticles and cellulose acetate membranes, which has the potential to be used for efficient desalination of radioactive iodine. A single filtration process using this membrane provided high removal efficiency with more than two orders of magnitude iodide anion removal within a minute and excellent ion-selectivity. Moreover, the same operation can be applied several times without significant decrease of its performance. Therefore, it is anticipated that our work will be a new avenue for desalination of radioactive iodine in various aqueous media.

A coronavirus disease (COVID-19) outbreak associated with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been spreading widely through person-to-person transmission. Various detection approaches have been developed involving quantitative polymerase chain reaction (qPCR) methods, CRISPR-based systems, and direct targeting of specific coronavirus proteins. However, there have only been a few reports on the detection of RNA-dependent RNA polymerase (RdRP), the primer-independent RNA-replicable protein produced by the RNA genes of coronavirus. Here, we introduce a novel diagnostic methodology for COVID-19 using the RNA-directed and de novoRNA replicable function of RdRP. We devised an RNA platform for RdRP-induced transcription (RPRIT) that includes an RNA template that can be directly transcribed by RdRP. By utilizing RPRIT, the presence of RdRP can be readily confirmed within 30 min using isothermal incubation without PCR. This RdRP detection method can provide a new route for rapid diagnosis of RNA virus-infected patients.