Polymorphisms in Brucella Carbonic Anhydrase II Mediate CO2 Dependence and Fitness in vivo

Effect of different CO2 concentrations on biogas upgrading and nutrient removal by microalgae-fungi co-culture

Owing to the high carbon dioxide (CO₂)-fixation efficiency, microalgae-based technology has been widely used for biogas purification. The present study explored the effect of CO₂ concentration on biogas purification by an algal-fungal-bacterial symbiotic system. Two algal-fungal-bacterial symbiotic systems were cultivated to purify four simulated biogas samples with different CO₂ concentrations. The results showed that GR24, a synthetic analog of strigolactone, stimulated the growth of the algal-fungal-bacterial symbiotic system. The optimal CO₂ concentration for the purification of the simulated biogas was 45% (V/V), and the optimal symbiotic system was Chlorella vulgaris-Ganoderma lucidum-endophytic bacteria-GR24. The maximum chemical oxygen demand (COD; 82.61 ± 7.73%), total nitrogen (TN; 81.36 ± 7.97%), total phosphorus (TP; 85.69 ± 8.19), and CO₂ (69.23 ± 6.56%) removal efficiencies were detected with the addition of 10^-9 M GR24 to the C. vulgaris-G. lucidum-endophytic bacterial symbiotic system. These findings confirmed the effect of CO₂ concentration on the purification of biogas by the algal-bacterial symbiotic system. The study provides a theoretical basis for further research on the treatment of wastewater and biogas.

Simultaneous biogas upgrading and biogas slurry treatment by different microalgae-based technologies under various strigolactone analog (GR24) concentrations

In this research, the effects of exogenous strigolactone analog (GR24) on the growth rate, daily productivity and photosynthesis of symbiotes of Chlorella vulgaris (C. vulgaris)-Ganoderma lucidum (G. lucidum)-endophytic bacteria, C. vulgaris-G. lucidum-activated sludge and C. vulgaris-G. lucidum-multi-walled carbon nanotube, and the simultaneous treatment of biogas slurry and biogas were examined. The C. vulgaris-G. lucidum-endophytic bacteria symbiote achieved the best treatment effectiveness for biogas slurry and biogas, with removal efficiencies of chemical oxygen demand, total nitrogen, total phosphorus and CO₂ of 81.4 ± 7.6%, 79.6 ± 7.6%, 82.5 ± 8.2%, and 67.3 ± 6.3% under the optimal GR24 concentration of 10^-9 M. Moreover, the treatment effects were positively correlated with growth performance and photosynthesis efficiency of the symbiote. These findings advance the development and application of symbiotic systems in the field of wastewater treatment and biogas upgrading.

Performance of different microalgae-fungi-bacteria co-culture technologies in photosynthetic and removal performance in response to various GR24 concentrations

The purification effect of two different microalgae-fungi-bacteria symbiosis technologies on biogas and biogas slurry was studied to determine the best symbiosis treatment technology and the suitable concentration of GR24. The results showed that the purification effect of biogas slurry in Chlorella vulgaris-Ganoderma lucidum-endophytic bacteria (S395-2) symbiont co-culture system was better than that of the biogas slurry in Scenedesmus obliquus-Pleurotus ostreatus-S395-2 symbionts. Following 10^-9 M GR24 treatment, Chlorella vulgaris-Ganoderma lucidum-S395-2 symbionts had elevated mean daily production rate and growth rate by 1.92 and 1.46 folds in comparison with blank group. After adjusting the GR24 level within the range of 10^-9 M-10^-7 M, Ganoderma lucidum-assisted Chlorella vulgaris-S395-2 attained higher maximal removal rates for TN, COD, CO₂, and TP by 10.78%, 14.62%, 3.86%, and 9.07%, respectively, compared to the rates when GR24 was not added.