Novel blue fluorescent carbon dots (CDs- CP ) deriving from yeast Cryptococcus podzolicus 5–2 were successfully prepared via a facile and green hydrothermal synthesis method. It exhibited uniform particle size and possessed good excitation-dependent characteristic. The dead bacterial cells were selectively labled by the CDs- CP , but the live ones not, indicating good potential for the live/dead bacterial differentiation. It was found that the prepared CDs- CP showed low biotoxicity and excellent biocompatibility with multicolour fluorescence emission properties, which provided a new insight on the bioimaging application. In addition, the prepared CDs- CP exhibits high selectivity and sensitivity in Ag(I), 2,4-dinitrophenol (2,4-DNP) and 4-nitrophenol (4-NP) detection with excellent linear ranges of 0–15 μM (R 2 = 0.9945), 0–30 μM (R 2 = 0.9959) and 0–37.5 μM (R 2 = 0.9982), respectively. The low detection limits of Ag(I), 2,4-DNP and 4-NP were 113.57 nM, 73.36 nM and 86.47 nM, respectively. It revealed that static quenching mechanism dominated in Ag(I) quenching of the CDs- CP fluorescent, while those of 2,4-DNP and 4-NP were inner filter effect. The fluorescent CDs- CP was successfully applied to determine the Ag(I), 2,4-DNP and 4-NP in real water samples with satisfactory results. Therefore, it is a good candidate for bioimaging application and environmental pollutant detection.
Mou Tang,Wenting Zhou,Yi Liu,Jiabao Yan,Zhiwei Gong
N -acetylglucosamine (GlcNAc), the monomeric constituent of chitin, is rarely studied for lipid production by oleaginous species. This study demonstrated that Cryptococcus curvatus had a great capacity to convert GlcNAc into lipid with high yield using a two-stage production process. Optimal inoculum age and inoculation size strongly improved the two-stage lipid production efficiency. More interestingly, this process rendered superior lipid production under non-sterile condition. The acetate liberated from GlcNAc was consumed timely, while the NH 4 + released was rarely assimilated. Lipid titre, lipid content and lipid yield reached 9.9 g/L, 56.9% and 0.23 g/g, respectively, which were significantly higher than those from the conventional process where cell growth and lipid accumulation were coupled. The resulting lipid samples had similar fatty acid compositional profiles to those of vegetable oil, suggesting their potential for biodiesel production. These findings strongly supported the two-stage process as an attractive strategy for better techno-economics of the chitin-to-biodiesel routes.
危险品化学品经营许可证（带存储）