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AEI
Aquaculture Environment Interactions

    AEI prepress abstract   -  DOI: https://doi.org/10.3354/aei00364

    Enhancement of biochar-immobilized isolated Sphingomonas sp. and Acinetobacter sp. for nutrients removal and its potential application in crab (Eriocheir sinensis) aquaculture

    Yalu Shao, Hua Zhong*, Xinyu Mao, Hongwei Zhang

    *Corresponding author:

    ABSTRACT: Water exchange frequency and eutrophication risk reduction to surrounding water bodies have always been water-quality control issues in recirculating aquaculture systems. In this study, maize straw biochar prepared through pyrolysis was shown to possess great potential for both bacterial immobilization and pollutant adsorption. Heterotrophic bacteria strains of Sphingomonas sp. PDD-57b-25 and Acinetobacter towneri were isolated in situ from wastewater for pollutant remediation through a 16S rDNA-based method, which has been rarely reported to date. The selected strains had higher ammonia nitrogen (NH4+-N, 63%), nitrite nitrogen (NO2-N, 38%), nitrate nitrogen (NO3-N, 25%) and total phosphorus (TP) (35%) assimilation capacities than those of widely applied bacteria under similar medium conditions. In addition, more NH4+-N (16%), NO2-N (14%), NO3-N (17%) and TP (19%) could be removed by biochar-immobilized isolated strains than dissociated strains, which may offer a notable enhancement for water-quality control during the recirculating aquaculture. With certain addition (4 g l-1) of biochar-immobilized Sphingomonas sp. PDD-57b-25 and Acinetobacter towneri, the dissolved inorganic nitrogen (approximately 0.45 mg l-1) and phosphorous (approximately 0.09 mg l-1) contents were maintained below the clean water threshold of recirculating crab (Eriocheir sinensis) aquaculture. Furthermore, the added strains exhibited a high bio-safety and could improve the yield and quality of crabs by different degrees. The obtained results indicated the potential applicability of biochar-immobilized Sphingomonas sp. PDD-57b-25 and Acinetobacter towneri in agricultural sewage treatments. Further, the experimental methodology developed may be applied as a guidance for the exploration of new genes for practical aquaculture.