Water pollution and high atmospheric carbon dioxide concentration have become major ecological problems which harm the whole world. Bioremediation is considered to be the most promising water ecology treatment measure, but it still has some limitations. It needs to add certain chemical reagents to assist treatment, which requires a lot of energy, and is sometimes not as effective as it could be. Increasing ocean carbon sinks has been recognised as one of the most effective measures to reduce atmospheric CO2 concentrations. However, how to increase ocean carbon sinks is still widely discussed, which is often expensive and has limited carbon sequestration capacity.
Focusing on water ecology restoration and greenhouse effect management, we found that the intersection of these two environmental problems management methods. With its strong carbon sequestration ability and water eutrophication treatment ability, the cultivation of Phaeodactylum tricornutum in wastewater can not only make it grow normally by absorbing nitrogen and phosphorus elements, but also absorb a large amount of carbon dioxide, so as to alleviate the atmospheric carbon sink pressure. Meanwhile, we also found that the lipid content of the constructed transgenic algae strain was significantly increased.
It is relatively simple to implement the measures of using Phaeodactylum tricornutum to control the ecological environment. As one of the most widespread plankton in the ocean, Phaeodactylum tricornutum can use both free carbon dioxide and bicarbonate through the CCM mechanism. The aquatic carbon pump effect based on this mechanism has a great impact on the global carbon sink, it can effectively relieve pressure on atmospheric carbon sinks. The growth of algae itself will absorb nitrogen and phosphorus elements, and in the process of forming stable carbon sinks, the formed calcium carbonate will co-precipitate with phosphorus in the water, further strengthening the removal of phosphorus. It is of great significance to use the synergistic effect of carbon, nitrogen and phosphorus and use synthetic biological means to build transgenic algae strains, improve their carbon fixation and nitrogen removal capacity, and achieve the co-deposition of carbon, nitrogen and phosphorus, which is to achieve the goal of carbon neutralization and water eutrophication management.
We have established a microalgae factory site selection model with the target of largest rate of fixed carbon dioxide. Based on the selection results, we further established a comprehensive water quality evaluation model in Fujian. Based on the evaluation results, the worst-scoring Longjiang predictive model was established. At the same time, we combined with cellular automata algorithms to simulate the diffusion of water system pollutants before and after the addition of microalgae.
Our models combine computer science and modeling the classic computer algorithm to achieve cross-disciplinary cooperation. We provide support for each stage of the microalgae project which including microalgae factory site selection, water quality analysis and prediction of microalgae water purification, simulation of microalgae water purification system, etc. And we provide certain strategies for the future promotion of microalgae products.
Our results have also been recognized from the corporate side. The Shenliu Group, which produces spirulina products in Fujian, has given us positive feedback on our method of treating wastewater with microalgae. In addition, we plan to contact more related manufacturers to promote more of our subsequent projects into the public eye, to help companies generate profits, and to focus on achieving more substantial results for environmental protection.
On the other hand, our project provides methodological guidance and assistance to wastewater treatment plants to carry out their treatment work. Our members visited wastewater treatment plants in cities, learned about the treatment methods they were using, and communicated the results and ideas from our lab to the plant managers. It was clear that this new and environmentally friendly method of treatment was a real eye-opener. Unlike the previous method of treatment with chemicals, this method succeeded in protecting the water environment and confirmed our many efforts to achieve sustainable development. We have helped the plant to achieve a harmless treatment, which is in line with our intention to protect the environment and has a key positive impact.
We choose immobilized cell technology. Our experimental materials - Phaeodactylum tricornutum were made into algal spheres using sodium alginate as the embedding material. At the same time, material exchange can still be carried out between the inside and outside of the algal sphere, which will not affect the normal growth of Phaeodactylum tricornutum. Experiments proved that no microalgae escaped within 21 days after the algal spheres were made. In the future, we will also conduct more experiments with the photobioreactor we designed and built.
At the same time, a photobioreactor was designed and manufactured to provide a closed environment for microalgae culture and isolate microalgae from the environment. The bioreactor is equipped with an ultraviolet lamp to inactivate microalgae when necessary. In addition, the equipment is equipped with three water outlets at different positions. In addition to the basic function of changing water, it also has the function of collecting algae beads at different positions.
While it is easy to use transgenic technology to build engineered algae strains to improve carbon sequestration and nitrogen and phosphorus uptake rates, we still face the long-term test of genetic engineering ethics, and we hope to build a more complete biosafety system to protect natural ecology and organisms from disturbance.