地衣芽孢杆菌对养殖水体氨氮、残饵降解特性研究

STUDY ON THE CHARACTERISTICS OF THE AMMONIA-NITROGEN AND RESIDUAL FEEDS DEGRADATION IN AQUATIC WATER BY BACILLUS LICHENIFORMIS

试验对从健康养殖大黄鱼肠道中分离筛选到的一株益生地衣芽孢杆菌X3914的氨氮、残饵降解特性进行了研究。结果表明,X3914菌株降解氨氮的最适温度、盐度和pH分别为30℃、2.0%和7.0,在氨氮初始浓度为100 mg/L时,24h内的氨氮降解率达到36.2%。通过向添加1%饲料的大黄鱼养殖用水中接种1%和5%(体积比)的菌量(菌浓度约为9.0×108 cfu/L)来研究地衣芽孢杆菌浓度对降解饲料中蛋白质、淀粉的影响。结果表明,接种5%菌量的降解率均高于1%菌量的降解率,其中,48h内接种5%菌量的蛋白质和淀粉的降解率分别为35.2%和52.6%。X3914菌株具有较好的氨氮、饲料蛋白质和淀粉的降解能力,在水产养殖上具有潜在的应用价值。

It is well known that ammonia-nitrogen is one of the toxic factors to affect the growth performances and in-crease the susceptibility of the aquatic animal in the culture ponds water.With the development of aquaculture,the in-tensive and high-density culture aggravate the serious pollution problem of the ammonium nitrogen;however,the tradi-tional physical and chemical methods to remove the ammonia-nitrogen will be cut down for the secondary pollution step by step.Meanwhile,the biological methods to remove ammonia-nitrogen and bioremediation have attracted much more attentions from the scientists for the characteristics of high-efficiency,low cost,no residue and environmental friendly,which become more and more popular in the practices.The present studies were focused on the Bacillus subtitles,Ba-cillus cereus and Sporolactobacillus.Large yellow croaker（Pseudosciaena crocea） is one of the traditional Chinese Four Seafood that is the offshore main economic fishes,which culture widely in the China eastern offshore.In the pre-sent experiment,a Bacillus licheniformis strain X3914 as a potential probiotics was isolated from gastrointestinal tract of healthy large yellow croaker（Pseudosciaena crocea） cultured in Xiangshan,Zhejiang Province.The aim of the study is to explore the degradation rules of ammonia-nitrogen,protein and starch of residual feeds by Bacillus licheniformis strain X3914,which probably offers the guidance to the practices in aquaculture.In the present experiment,the ability to remove the ammonia-nitrogen of the Bacillus licheniformis strain X3914 was tested in the simulated waste water,the results indicated that the growth of the strain X3914 was synchronized with the degradation of ammonia-nitrogen and degradation rate of ammonia-nitrogen reached to 36.2% in 24h.Furthermore,Ammonia-nitrogen containing the ammonium ions,and ammonia molecules,as the toxicity of ammonium ions was in-fluenced significantly by environmental factors,such as temperature,salinity and pH.The results showed that the opti-mum temperature,salinity and pH for strain X3914 to degrade ammonia-nitrogen were 30℃,2% and 7,respectively.The degradation rate reached to 36.2% in 24h when the initial concentration of ammonia-nitrogen was 100 mg/L.The degradation characteristics of strain X3914 on protein and starch of residual feeds remains in the 1% of feed water when the inoculum of X3914 strain were 5% and 1%（the initial concentration of strain X3914 was 9.0×108 cfu/L）were also tested,respectively.The results indicated that 5% inoculum of strain X3914 resulted in higher degradation rate than that of 1% inoculum,and the degradation rate of protein and starch of residual feeds in 48h were 35.2% and 52.6% respec-tively when the inoculum of Bacillus licheniformis was 5%.In conclusion,Bacillus licheniformis strain X3914,isolated from the healthy large yellow croaker（Pseudosciaena crocea）,could degrade not only the ammonia in the simulated waste water in high-efficiency,but also the protein and starches of residual feeds.So,it was supposed that Bacillus licheniformis strain X3914,as the potential probiotics,would be applied in the aquaculture practices.