Large amounts of waste and wastewater from aquaculture have negatively impacted ecosystems. Among them, shrimp aquaculture wastewater contains large amounts of nitrogen contaminants derived from feed residues in an aerobic environment. This study isolated candidate strains from adult rockworms to treat shrimp aquaculture wastewater (SAW) in an aerobic environment. Among 87 strains isolated, 25 grew well at the same temperature as the shrimp aquaculture with excellent polymer degradation ability (>0.5 cm clear zone). Six isolates (strains AL1, AL4, AL5, AL6, LA10, and PR15) were finally selected after combining strains with excellent polymer degradation ability without antagonism. 16S rRNA sequencing analysis revealed that strains AL1, AL4, AL5, AL6, LA10, and PR15 were closely related to Bacillus paramycoides, Bacillus pumilus, Stenotrophomonas rhizophila, Bacillus paranthracis, Bacillus paranthracis, and Micrococcus luteus, respectively. When these six isolates were applied to SAW, they reached a maximum cell viability of 2.06×105 CFU mL-1. Their chemical oxygen demand (CODCr) and total nitrogen (TN) removal rates for 12 h were 51.0% and 44.6%, respectively, when the CODCr/TN ratio was approximately 10.0. Considering these removal rates achieved in this study under batch conditions, these six isolates could be used for aerobic denitrification. Consequently, these six isolates from rockworms are good candidates that can be applied to the field of aquaculture wastewater treatment.

Abstract
1. INTRODUCTION
2. MATERIALS AND METHODS
    2.1. Isolation of microorganisms and cultureconditions
    2.2. Characterization and identification ofisolates
    2.3. Simulated shrimp aquaculturewastewater treatment
    2.4. Analytical methods
3. RESULTS AND DISCUSSION
    3.1. Isolation of potential microorganisms
    3.2. Characterization and identification ofisolates
    3.3. The application of six isolates to SAWtreatment
4. CONCLUSION
ACKNOWLEDGEMENTS
REFERENCES

• Ja Young Cho(Department of Biotechnology, Pukyong National University, Bacteria Research Team, Nakdonggang National Institute of Biological Resources)
• Kyoung Sook Cho(Department of Biotechnology, Pukyong National University)
• Chang Hoon Kim(Department of Marine Bio-materials and Aquaculture, Pukyong National University)
• Joong Kyun Kim(Department of Biotechnology, Pukyong National University) Corresponding author