Phytohormone Supplementation for Nutrient Removal from Mariculture Wastewater by <i>Oocystis borgei</i> in Sequential Batch Operation
Yang Liu,
Chengcheng Deng,
Xinyue Song,
Zhangxi Hu,
Feng Li,
Yulei Zhang,
Changling Li,
Xianghu Huang,
Ning Zhang
Affiliations
Yang Liu
Laboratory of Algae Resource Development and Aquaculture Environment Ecological Restoration, Fisheries College, Guangdong Ocean University, Zhanjiang 524088, China
Chengcheng Deng
Laboratory of Algae Resource Development and Aquaculture Environment Ecological Restoration, Fisheries College, Guangdong Ocean University, Zhanjiang 524088, China
Xinyue Song
Laboratory of Algae Resource Development and Aquaculture Environment Ecological Restoration, Fisheries College, Guangdong Ocean University, Zhanjiang 524088, China
Zhangxi Hu
Laboratory of Algae Resource Development and Aquaculture Environment Ecological Restoration, Fisheries College, Guangdong Ocean University, Zhanjiang 524088, China
Feng Li
Laboratory of Algae Resource Development and Aquaculture Environment Ecological Restoration, Fisheries College, Guangdong Ocean University, Zhanjiang 524088, China
Yulei Zhang
Laboratory of Algae Resource Development and Aquaculture Environment Ecological Restoration, Fisheries College, Guangdong Ocean University, Zhanjiang 524088, China
Changling Li
Laboratory of Algae Resource Development and Aquaculture Environment Ecological Restoration, Fisheries College, Guangdong Ocean University, Zhanjiang 524088, China
Xianghu Huang
Laboratory of Algae Resource Development and Aquaculture Environment Ecological Restoration, Fisheries College, Guangdong Ocean University, Zhanjiang 524088, China
Ning Zhang
Laboratory of Algae Resource Development and Aquaculture Environment Ecological Restoration, Fisheries College, Guangdong Ocean University, Zhanjiang 524088, China
To enhance the nutrient removal efficiency of Oocystis borgei for mariculture wastewater (MW), the effects and processes of three phytohormones on nitrogen and phosphorus removal from synthetic mariculture wastewater (SMW) by O. borgei under sequential batch operation were compared. The findings revealed that the supplementation with 10−6 M 3-indoleacetic acid (IAA), gibberellic acid (GA3), and zeatin (ZT) resulted in the most effective elimination, while there was no appreciable difference among them. The nitrogen and phosphorus indices of the effluent dramatically reduced (p 3−-N > PO43−-P > NH4+-N > NO2−-N. The removal rates for NH4+-N and PO43−-P were 0.72–0.74 mg·L−1·d−1 and 1.26–1.30 mg·L−1·d−1, respectively. According to physiological studies, phytohormones enhanced the levels of photosynthetic pigments and chlorophyll fluorescence parameters (Fv/Fm and φPSII), thereby improving photosynthetic activity. Additionally, they stimulated Nitrate Reductase (NR) and Glutamine Synthetase (GS) activities to promote nitrogen metabolism and increased Superoxide Dismutase (SOD), Catalase (CAT), and carotenoid contents to mitigate oxidative stress damage caused by abiotic stress. These activities contribute to the proliferation of O. borgei, which in turn resulted in an increase in the assimilation of nitrogen and phosphorus from SMW. In conclusion, phytohormone supplementation significantly increased nutrient removal from SMW by O. borgei in a sequential batch reactor, which has potential application in MW treatment.
