Browsing by Author "Zhu, Jinyong"

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    Enhanced Aquaculture Wastewater Treatment Using Water Spinach (Ipomoea Aquatica Forsskal) and Exogenous Compound Bacteria
    (Elsevier, 2024) Xu, Jiaojiao; Nicholaus, Regan; Wang, Yangcai; Yang, Wen; Zhu, Jinyong; Zheng, Zhongming
    Bioremediation technology has been widely recognized as a sustainable treatment method for purifying aqua culture wastewater. We established two types of ecological floating beds, one with water spinach (WS) only and another with water spinach combined with exogenous compound bacteria (WS-ECB) for the treatment of the Pacific white shrimp aquaculture wastewater of low-salinity. The exogenous compound bacteria used in this study was composed of Rhodopseudomonas palustris and Bacillus subtilis in a certain proportion. Microbial com munity dynamics were analyzed by using high-throughput sequencing of 16S rRNA and water quality was determined. Both two treatments were effective in the remediation of aquaculture wastewater. The removal efficiencies of CODMn, TN and TP in the WS group were 34.33 %, 66.54 % and 73.01 %, respectively, and the removal efficiency of NH4 + in the WS-ECB group was 93.79 %. Furthermore, the addition of water spinach and exogenous compound bacteria increased the abundance of some bacteria that are involved in regulating water quality and altered the succession of microbial communities. The microbial communities were shaped by both stochastic processes (including limited dispersal) and deterministic processes (including environmental condi tions and biotic interactions). Importantly, stochastic processes dominated the assembly of both water and rhizosphere microbial communities in different treatments, while deterministic processes contributed more to the rhizosphere microbial community in the WS-ECB than in the WS. Overall, our study emphasizes that plant and microbial remediation was a potential and effective approach to remove the nutrients of water, and clarifies the bacterial community dynamics and assembly mechanisms during aquaculture wastewater treatment processes.
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    Exogenous Compound Bacteria Enhance the Nutrient Removal Efficiency of Integrated Bioremediation Systems: Functional Genes and Microorganisms Play Key Roles
    (ELSEVIER, 2024) Wei, Yingzhen; Zhu, Jinyong; Shen , Ding; Yang, Wen; Nichola, Regan; Wang , Yangcai; Zheng, Zhongming; Lukwambe, Betina
    With the continuous development of intensive mariculture, the application of the integrated bioremediation system of aquaculture wastewater (IBSAW) is increasingly promoted. However, the process and nutrients removal performance of the IBSAW need to be further optimized due to its immature technologies. In this study, exogenous compound bacteria (ECB) were added to IBSAW to investigate its pollutants removal efficiency and the relevant mechanisms. High-throughput sequencing and Geochip gene array were used to analyze the cor relation between nutrients and bacteria, and the abundance of N and P cycling genes were quantified. Multi variable statistics, dimensionality reduction analysis, and network analysis were applied to explore the mechanisms of IBSAW operation. The results showed that the nutrients decreased significantly after adding ECB, with the brush treatment group significantly outperforming the ceramsite in removing NO 3 has an advantage in removing NO 2 and PO 4 3 . Ceramsite -N. The addition of ECB and different substrates significantly affected the composition of bacterial communities. The contents of nosZ and nirKS related to denitrification in the treatment groups were significantly higher than those in the control group, and the contents in the brush treatment group were significantly higher than that of ceramsite. The biomarkers Psychroserpens and Ruegeria on the biofilm of the brush treatment group were positively correlated with nirKS, while Mycobacterium, Erythrobacter and Paracoccus, Pseudohaliea in the ceramsite group were positively correlated with nirS and nirK, respectively. Therefore, it is speculated that the ECB significantly promoted the increase of denitrification bacteria by affecting the compo sition of bacterial communities, and the ECB combined with functional genera improved the efficiency of nu trients removal in the system. This study provided a reference for understanding the process and mechanism of nutrients removal, optimizing the wastewater purification technology of the IBSAW and improving the perfor mance of the system.
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    Impacts of bioturbation by Venus clam Cyclina sinensis (Gmelin, 1791) on benthic metabolism and sediment nutrient dynamics in a shrimp-clam polyculture pond.
    (ICAR, 2020-09-03) Nicholaus, Regan; Lukwambe, Betina; Mwakalapa, Eliezer Brown; Yang, Wen; Zhu, Jinyong; Zheng, Zhongming
    Dynamics of benthic inorganic nutrients are key biogeochemical components of sediment metabolism and ecosystems. This study investigated the roles of the bivalve Cyclina sinensis (Gmelin, 1791) and its influence on benthic metabolism, nutrient f luxes and sediment oxygen consumption (SOC) in a shrimp-clam polyculture system in comparison with shrimp culture ponds without incorporating clams, in Ningbo Zhejiang China. The benthic inorganic nutrients fluxes (ammonium-NH4 +, nitrate plus nitrite-NO3-+NO2- and phosphate-PO4 3-) and SOC were measured across the sediment-water interface with dark incubation experiments. The results showed that there were significantly higher nutrient fluxes from the sediment into the overlying water (p<0.05 ) in the treatment ponds in the order of NH4 + > PO4 3- > NO3- + NO2-. The SOC varied significantly (p0.05) and was three times higher than that of the control ponds. Water quality (dissolved oxygen, pH, chlorophyll-a and salinity) recorded showed slight variations over time but were not significantly different (p>0.05) between the control and treatment ponds.Sediment organic matter and chlorophyll-a concentration measured in the shrimp-clam ponds varied significantly (p<0.05)as compared to control ponds. The results of this study suggest that the bioturbation activities by C. sinensis promoted the SOC, sediment organic matter degradation and mineralisation process that increased the exchange of nutrients and oxygen uptake between the sediment and the overlying water.