My research includes three topics
Topic 1: Harmful algal blooming and ecological restoration
Harmful algae blooming is a serious environmental problem worldwide. Many variants of Microcystis produce scum, toxins, and hypoxia as well as bad tastes and odors, and the accumulation of toxins in the aquatic food web threatens the health of human beings. Submerged macrophytes could maintain algae densities at relatively low levels in natural water bodies, and the allelopathic interaction was considered as an important reason. Previous studies in our lab confirmed that pyrogallic acid (PA), a potent polyphenolic allelochemical secreted by submerged macrophyte Myrophyllum spicatum, could effectively inhibit the growth of Microcystis aeruginosa. However, the underlying inhibitory mechanism was unclear. My Ph.D. research was to uncover how PA inhibited the growth of Microcystis aeruginosa. This was of great importance to understand how aquatic plant and algae chemical-ecologically interact in aquatic ecosystem and develop biological method to control the outbreak of harmful algal bloom.
Using a toxicology and molecular biology approach, I checked the morphological (TEM observation), physiological and biochemical change of M. aeruginosa cells under exposure to different doses of pyrogallic acid. From molecular to enzyme level, my study confirmed the existence of programmed cell death pathway in M. aeruginosa, and this pathway can be initiated by ROS, which was induced by allelochemical. This study provided an insight into understanding the occurrence and demise of harmful algal bloom in ecosystem system. It also provided scientific evidence to support the concept of using submerged macrophyte in the water body to control the Microcystis blooming. Currently, ecological projects (re-establish the submerged macrophyte in the lake) are widely conducting in Chinese lakes, such as West Lake in Hangzhou (Bai G et al. Spatial and seasonal variation of water parameters, sediment properties, and submerged macrophytes after ecological restoration in a long-term (6 year) study in Hangzhou West Lake in China: submerged macrophyte distribution influenced by environmental variables. Water Research, 2020: 116379.).
Methodologies for intracellular ROS measurement, caspase-3(-like) activity detection and DNA strand breaks measurement were established in Microsystis. aeruginosa based on flow cytometry and plate reader. I established fluroscence assisted DNA unwinding for quantification of DNA strand breaks in M. aeruginosa cells. This method had been granted as a Chinese invention patent (CN Patent CN105) in 2019.
Publications & Books & Patents related this work:
1)Lu, Z.Y., Sha, J., Tian, Y., Zhang, X.Z., Liu, B.Y., & Wu, Z.B. (2017). Polyphenolic allelochemical pyrogallic acid induces caspase-3 (like)-dependent programmed cell death in the cyanobacterium Microcystis aeruginosa. Algal Research, 21, 148-1552)
2)Lu, Z.Y., Zhang, Y., Gao, Y.N., Liu, B.Y., Sun, X., He, F., Zhou, Q.H., Wu, Z.B. (2016). Effects of pyrogallic acid on Microcystis aeruginosa: oxidative stress related toxicity. Ecotoxicology and Environmental Safety, 132, 413-41
3) Lu, Z.Y., Liu, B. Y., He, Y., Chen, Z. L., Zhou, Q. H., & Wu, Z. B. (2014). Effects of daily exposure of Cyanobacterium and Chlorophyte to low-doses of Pyrogallol. Allelopathy Journal, 34(2), 195-205.
4) 鲁志营,高云霓,孙雪梅,刘碧云,张甬元,吴振斌.水生植物感抑藻机理研究进展.环境科学与技术[J]. 2013, 36(9): 64-69.
5) 编写专著《大型水生植物对藻类的化感作用》中第四章"化感物质触发藻类细胞程序性死亡",pp120-139, 吴振斌等. 北京: 科学出版社(2016 年 1 月出版)
6) 吴振斌,鲁志营,郭伟杰,刘碧云,贺锋,周巧红,张甬元.发明专利《一种焦性没食子酸在抑制藻类生长中的应用》专利号:Z L 201310023374 .0
7) 吴振斌,鲁志营,刘碧云,何燕,贺锋,周巧红,徐栋,张甬元.发明专利《一种利用荧光检测微囊藻细胞DNA损伤的方法》 专利号:2016101091952.
Using a toxicology and molecular biology approach, I checked the morphological (TEM observation), physiological and biochemical change of M. aeruginosa cells under exposure to different doses of pyrogallic acid. From molecular to enzyme level, my study confirmed the existence of programmed cell death pathway in M. aeruginosa, and this pathway can be initiated by ROS, which was induced by allelochemical. This study provided an insight into understanding the occurrence and demise of harmful algal bloom in ecosystem system. It also provided scientific evidence to support the concept of using submerged macrophyte in the water body to control the Microcystis blooming. Currently, ecological projects (re-establish the submerged macrophyte in the lake) are widely conducting in Chinese lakes, such as West Lake in Hangzhou (Bai G et al. Spatial and seasonal variation of water parameters, sediment properties, and submerged macrophytes after ecological restoration in a long-term (6 year) study in Hangzhou West Lake in China: submerged macrophyte distribution influenced by environmental variables. Water Research, 2020: 116379.).
Methodologies for intracellular ROS measurement, caspase-3(-like) activity detection and DNA strand breaks measurement were established in Microsystis. aeruginosa based on flow cytometry and plate reader. I established fluroscence assisted DNA unwinding for quantification of DNA strand breaks in M. aeruginosa cells. This method had been granted as a Chinese invention patent (CN Patent CN105) in 2019.
Publications & Books & Patents related this work:
1)Lu, Z.Y., Sha, J., Tian, Y., Zhang, X.Z., Liu, B.Y., & Wu, Z.B. (2017). Polyphenolic allelochemical pyrogallic acid induces caspase-3 (like)-dependent programmed cell death in the cyanobacterium Microcystis aeruginosa. Algal Research, 21, 148-1552)
2)Lu, Z.Y., Zhang, Y., Gao, Y.N., Liu, B.Y., Sun, X., He, F., Zhou, Q.H., Wu, Z.B. (2016). Effects of pyrogallic acid on Microcystis aeruginosa: oxidative stress related toxicity. Ecotoxicology and Environmental Safety, 132, 413-41
3) Lu, Z.Y., Liu, B. Y., He, Y., Chen, Z. L., Zhou, Q. H., & Wu, Z. B. (2014). Effects of daily exposure of Cyanobacterium and Chlorophyte to low-doses of Pyrogallol. Allelopathy Journal, 34(2), 195-205.
4) 鲁志营,高云霓,孙雪梅,刘碧云,张甬元,吴振斌.水生植物感抑藻机理研究进展.环境科学与技术[J]. 2013, 36(9): 64-69.
5) 编写专著《大型水生植物对藻类的化感作用》中第四章"化感物质触发藻类细胞程序性死亡",pp120-139, 吴振斌等. 北京: 科学出版社(2016 年 1 月出版)
6) 吴振斌,鲁志营,郭伟杰,刘碧云,贺锋,周巧红,张甬元.发明专利《一种焦性没食子酸在抑制藻类生长中的应用》专利号:Z L 201310023374 .0
7) 吴振斌,鲁志营,刘碧云,何燕,贺锋,周巧红,徐栋,张甬元.发明专利《一种利用荧光检测微囊藻细胞DNA损伤的方法》 专利号:2016101091952.
Topic 2: Algae and sustainable future
(1) Algal culture media reuse
Huge consumption to water is one of the biggest obstacles in the path of algae commercialization. Substantial amounts of water are used in microalgae cultivation, negatively influencing economic viability and environmental sustainability. Reusing cultivation water is recognized as a promising solution to reduce costs and the environmental impacts associated with water usage, nutrient consumption, and algal wastewater treatment. The biggest challenge to reuse algae culture media is the growth inhibition of reused media. My postdoctoral work at Centre for biotechnology and biofuel was to investigate what caused the growth inhibition and how to remove it. Firstly, through absorption experiments of activated carbon, I confirmed organic matter in the reused media was the main cause of growth inhibition for target algal strain. Secondly, through adding ultraviolet (UV) detector after XAD-7HP/ XAD-4 resin column, I established an innovative method that could fractionate organic matter into more sub-fractions based on its hydrophilic and hydrophobic features. Using this method, the organic matter in reused media were fractionated into 12 sub-fractions. Finally, through growth inhibition test and identification of chromatograph-mass spectrometer, the growth inhibitor was clarified, which contained fatty acid, phenol, alicyclic compound and thioester (Figure below).
Other study was about the pretreatment of reused media. I employed UV based advanced oxidation to transfer the growth inhibitory fraction in the reused media into bioavailable small molecule fractions, which were utilized by algae as carbon source and promoted its growth (Figure below). Based on the knowledge obtained in this study, we proposed an integrated approach for water reuse and harvesting methods with regard to desired algal end products (Fig. 3). This work was presented at the 8th & 9th International Conference on Algal Biomass, Biofuels and Bioproducts in 2018 and 2019 respectively.
Publications & Books & Patents related this work:
(1) Lu, Z.Y., Loftus, S., Sha, J., Wang, W., Park, M., Zhang, X., Johnson, Z., Hu, Q. (2020). Water reuse for sustainable microalgae cultivation: Current knowledge and future directions. Resources, Conservation and Recycling, 161, 104975
(2) Lu, Z.Y.*, Jun, S., Wang, W., Li, Y., Chen, Y., Zhang, X*., Hu, Q. (2019). Identification of auto-inhibitors in the reused culture media of Scenedesmus acuminatus, Algal research, 44: 101665. (* Corresponding author).
(3) Sha, J. , Lu, Z.Y. , Ye, J., Wang, G.H., Hu, Q., Chen., Y., Zhang, X. (2019). The Inhibition Effect of Recycled
Scenedesmus acuminatus Culture Media: Influence of Growth Phase and Inhibitor Removal. Algal research,42, 101612. (#, Co-first author).
(4) Wang, W., Sha, J., Lu, Z.Y.*., Shao, S., Sun, P., Hu, Q., & Zhang, X*. (2018). Implementation of UV- based advanced oxidation processes in algal medium recycling. Science of the Total Environment, 634, 243-250 (* Corresponding author)
(5) Zhang, X.Z , Lu, Z. , Wang, Y.F., Wensel, P., Sommerfeld, M., & Hu, Q. (2016). Recycling Nannochloropsis oceanica culture media and growth inhibitors characterization. Algal Research, 20, 282-290 (#,Co-first author))
(6) 张学治, 沙君, 鲁志营, 胡强. 发明专利 《一种高通量检测微藻生长测试的装置》 专利号:2016.20947536.9
(1) Lu, Z.Y., Loftus, S., Sha, J., Wang, W., Park, M., Zhang, X., Johnson, Z., Hu, Q. (2020). Water reuse for sustainable microalgae cultivation: Current knowledge and future directions. Resources, Conservation and Recycling, 161, 104975
(2) Lu, Z.Y.*, Jun, S., Wang, W., Li, Y., Chen, Y., Zhang, X*., Hu, Q. (2019). Identification of auto-inhibitors in the reused culture media of Scenedesmus acuminatus, Algal research, 44: 101665. (* Corresponding author).
(3) Sha, J. , Lu, Z.Y. , Ye, J., Wang, G.H., Hu, Q., Chen., Y., Zhang, X. (2019). The Inhibition Effect of Recycled
Scenedesmus acuminatus Culture Media: Influence of Growth Phase and Inhibitor Removal. Algal research,42, 101612. (#, Co-first author).
(4) Wang, W., Sha, J., Lu, Z.Y.*., Shao, S., Sun, P., Hu, Q., & Zhang, X*. (2018). Implementation of UV- based advanced oxidation processes in algal medium recycling. Science of the Total Environment, 634, 243-250 (* Corresponding author)
(5) Zhang, X.Z , Lu, Z. , Wang, Y.F., Wensel, P., Sommerfeld, M., & Hu, Q. (2016). Recycling Nannochloropsis oceanica culture media and growth inhibitors characterization. Algal Research, 20, 282-290 (#,Co-first author))
(6) 张学治, 沙君, 鲁志营, 胡强. 发明专利 《一种高通量检测微藻生长测试的装置》 专利号:2016.20947536.9
(2) Large-scale algal cultivation and harvesting
Following the path of previous research, my work at Duke University as a postdoctoral associate was to develop low cost and environmental-friendly technologies for large-scale algae harvesting. I joined in the Marine AlGae Industrialization Consortium (MAGIC)-a group of ten universities and private industry partners that work together on different aspects of the project. This research spans from algae strain selection to large scale cultivation, separation of algae into basic components (e.g. oil, protein, etc.), animal feed trials, and technoeconomic and life cycle assessments. We have 5 raceway pond facilities at Duke university marine laboratory (Figure left below). My role in the project is to harvest 40 kg dry algal biomass for 8 marine algal strains at a commercially relevant scale. Under the guidance of the supervisor, I designed and established a large-scale algal membrane harvesting system. This system had a harvesting capacity of 4500L/day. I used this system to pre-concentrate algae culture by approximate 100 times, then centrifuge was used for further concentration by 6-8 times, and obtained an algal paste with a solid content of ~30% (Figure right below).
During the study at Duke marine lab, I had the opportunity to learn the methodology of microbial ecology, which was another research area of Dr. Johnson’s lab. Meanwhile, I also observed that the bacteria community affected the algae productivity of open ponds in daily cultivation. To find some meaningful answer to this question, I moved to Dr. Jeffrey Morris’s Lab at University of Alabama at Birmingham as a postdoctoral fellow. Dr. Morris is the founder of Black Queen Hypothesis.
The dependence of human societies on fossil fuels is altering the earth system and the ocean is warming and acidifying at a rate potentially unparalleled in millions of years. Marine microbes are responsible for roughly half of global primary production and support fisheries through complex marine food webs. As a result, much effort has been directed toward understanding the dynamics that control their communities and how they will be affected in the wake of global change. My current study is to investigate the interaction and co-evolution of bacteria and algae in a changing ocean. Specifically, my study is to understand how bacteria Alteromonas help Prochlorococcus to survive and maintain dominance in the ocean, and how environmental change (e.g elevated CO2) will affect this interaction. As the major primary producers in the ocean, Prochlorococcus is probably the most abundant photosynthetic organism on Earth. It plays an important role in the global carbon cycle and oxygen production. Nevertheless, due to its streamlined genomes, Prochlorococcus has to be dependent on bacteria such as Alteromonas. The detailed information about their interaction is unclear and how ocean acidification affects the destiny of Prochlorococcus is of great importance to the global carbon cycle and oxygen production. My current result has proved that the extracellular enzyme and secondary metabolites excreted by Alteromonas in the media promote the growth of Prochlorococcus. This is the first experimental evidence of the Black Queen hypothesis.
The dependence of human societies on fossil fuels is altering the earth system and the ocean is warming and acidifying at a rate potentially unparalleled in millions of years. Marine microbes are responsible for roughly half of global primary production and support fisheries through complex marine food webs. As a result, much effort has been directed toward understanding the dynamics that control their communities and how they will be affected in the wake of global change. My current study is to investigate the interaction and co-evolution of bacteria and algae in a changing ocean. Specifically, my study is to understand how bacteria Alteromonas help Prochlorococcus to survive and maintain dominance in the ocean, and how environmental change (e.g elevated CO2) will affect this interaction. As the major primary producers in the ocean, Prochlorococcus is probably the most abundant photosynthetic organism on Earth. It plays an important role in the global carbon cycle and oxygen production. Nevertheless, due to its streamlined genomes, Prochlorococcus has to be dependent on bacteria such as Alteromonas. The detailed information about their interaction is unclear and how ocean acidification affects the destiny of Prochlorococcus is of great importance to the global carbon cycle and oxygen production. My current result has proved that the extracellular enzyme and secondary metabolites excreted by Alteromonas in the media promote the growth of Prochlorococcus. This is the first experimental evidence of the Black Queen hypothesis.