Combination of non-sterilized wastewater purification and high-level CO2 bio-capture with substantial biomass yield of an indigenous Chlorella strain.

The indigenous microalga Chlorella sorokiniana NBU-3 grown under air, 5 %, 15 %, and 25 % CO2 supply was evaluated to determine its potential for flue gas bio-capture, nutrient removal capacity and biomass yield using non-sterilized wastewater as growth medium. The results indicated that C. sorokiniana NBU-3 exhibited high nutrient removal efficiency (>95 % for NH4+-N, TN and TP) with either air or CO2 aeration. 5 %-15 % CO2 supplies promote biomass yield, nutrient utilization and CO2 biofixation of C. sorokiniana NBU-3. In particular, 15 % CO2 promotes C. sorokiniana NBU-3 growth in non-sterilized MW, but inhibits its growth in BG11 medium, indicating the importance of non-sterilized MW and high CO2 aeration concurrence for C. sorokiniana NBU-3 economically practical cultivation. Moreover, the highest values of lipid (27.84 ± 2.12 %) and protein (32.65 ± 4.11 %) contents were obtained in MW with 15 % CO2 aeration. Conceivably, microalgal-bacterial symbiosis may help C. sorokiniana NBU-3 tolerate high concentration of CO2 and promote microalga growth. The succession of the community diversity toward the specific functional bacterial species such as Methylobacillus and Methylophilus (Proteobacteria) which were predicted to possess the function of methylotroph, methanol oxidation and ureolysis would help facilitate the microalgal-bacterial symbiosis and promote the microalgae biomass accumulation with high dosage of CO2 aeration. Overall, these findings clearly highlight the potential of this indigenous microalga C. sorokiniana NBU-3 for industrial-emission level CO2 mitigation and commercial microalga biomass production in MW.

[Toxic Effect of Nano-ZnO in Liver of Zebrafish].

For acute toxicity test, zebrafish were respectively exposed to the different concentrations of nano-ZnO (0, 0.05, 0.1, 5, 10, 25, 50 mg x L(-1)) for 4, 24 and 96 h. The superoxide dismutase (SOD), malondialdehyde (MDA), and catalase (CAT) in the liver of zebrafish were studied, and the relative expression of Bcl-2, Bax, p53 and MDM2 in liver were also determined. Anatomical structure of the zebrafish liver was determined after exposure to nano-ZnO for 7, 15 and 30 d. Compared with the control group, the liver of the experimental groups showed obvious difference in following aspects: (1) oedema, cytoplastic vacuolation, and pyknotic nucleus were observed; (2) the number of hepatic macrophages deposited and the sinus clearance were increased; (3) the MDA contents and the activity of SOD were increased; (4) however, the activity of CAT was decreased; (5) the mRNA expression level of genes Bax/Bcl-2 ratio and p53 of stressed groups were up-regulated; the mRNA expression level of gene MDM2 down-regulation can be observed in the low concentration groups while the mRNA expression level of gene MDM2 was up-regulated in the high concentration groups. The results suggested that, the oxidative damage of nano-ZnO to the zebrafish liver was caused by the increase of oxidative stress, which made the change of antioxidant enzyme activity, induced the expression of cell apoptosis genetic and cell apoptosis, and caused the change of organizational structure of liver.

Comparative study of pathological lesions induced by multiwalled carbon nanotubes in lungs of mice by intratracheal instillation and inhalation.

The pathological lesions induced by multiwalled carbon nanotubes (MWCNTs) in bronchi and alveoli of mice were studied by intratracheal instillation and inhalation. In instillation groups, the dose was 0.05 mg MWCNTs/mouse. Similar size clumps of MWCNTs were distributed in bronchi and alveoli. The clumps led to inflammation to the lining wall of bronchi and severe destruction to alveolar netted structure around them. In the inhalation groups, the mice were exposed to aerosolized MWCNTs with mean concentration of 32.61 mg/m(3), the intralung deposition dose were roughly 0.07, 0.14, and 0.21 mg in the 8-day group, 16-day group, and 24-day group, respectively. Most of aggregations of MWCNTs in the alveoli were smaller than that in bronchi. The aggregations induced proliferation and thickening of alveolar walls. With the exception of these moderate pathological lesions, the general alveolar structure was still remained. The preliminary study demonstrated a difference in lung pathological lesions induced by instilled MWCNTs and inhaled ones, which may be due to the different size and distribution of aggregations of MWCNTs in lung.