Title: Isolation,selection and characterization of low-temperature organic-pollutant-degrading bacteria in sea cucumber ponds
Abstract: Low-temperature organic-pollutant-degrading bacteria were isolated from sea cucumber(Apostichopus japonicus) outdoor rearing ponds after enriching the liquid sea cucumber feed-medium and acclimating at(16±1)℃.All of the bacterial strains were preliminarily selected by evaluating their aerobic growth on sea cucumber feed-medium and verifying their specificity for the sea cucumber.The bacteria were finally selected by evaluating their ability to degrade organic pollutants(COD) and ammonia nitrogen(NH4+-N) in the feed-medium,with an inoculation of 1.0×106 cfu/mL.Culture conditions were(16±1)℃,pH 8.0 and a shaking rate of 160 r/min.After screening of 17 bacterial isolates,three bacterial strains(DR7,DR8 and DR11) were selected.These strains were able to degrade the feed over 5 d with COD removal rates of 37.7%,50.0% and 21.0%,and NH4+-N removal rates of 95.0%,98.0% and 99.8%,respectively.From morphological and physio-biochemical analyses,and 16S rRNA sequence similarity analysis,strains DR7 and DR11 were identified as Pseudomonas sp.,and strain DR8 as Para-coccus sp.The time course of degradation of the feed was observed by examination of the concentrations of the organic pollutants and ammonia-nitrogen in the liquid sea cucumber-feed-medium between 0 d and 6 d.Bacterial cultivation time had a significant effect on the feed-degrading activities of the three strains(P0.05).Based on the dynamics of feed degradation,strain DR8 was considered to be the most effective of the three strains.Significant differences(P0.05) were also observed in the combined feed-degrading capacities of mixtures of the strains.The optimal combination was considered to be DR8 + DR11.However,the overall feed-degrading abilities of the combined strains were not much better than that of the single strain.We conclude that the 3 low-temperature or-ganic-pollutant-degrading bacteria screened in this study are useful bacterial resources,which could show good potential for pollution control in sea cucumber culture ponds and the development of probiotics for sea cucumber culture.
Publication Year: 2012
Publication Date: 2012-01-01
Language: en
Type: article
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Cited By Count: 2
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