中文摘要：

为了解决因凡纳滨对虾货架期短而滥用化学保鲜剂等问题,实验通过微生物发酵,柱状色谱纯化得到一种新型生物保鲜剂——纳豆菌抗菌肽APNT-6,采用牛津杯法测定了其对凡纳滨对虾腐败菌的抑菌效果,并用浸保鲜剂方式将抗菌肽应用于凡纳滨对虾保鲜,通过测定对照组和保鲜剂组在（4±1）℃贮藏过程中的pH、挥发性盐基氮（TVB-N）、细菌总数、感官评分等鲜度指标的变化规律,评价了抗菌肽对凡纳滨对虾在（4±1）℃贮藏条件下保鲜效果。结果表明,纳豆菌抗菌肽APNT-6对凡纳滨对虾中Pseudomonas、Shewanella等8株腐败菌有良好的抑菌效果,经0.5 mg/mL抗菌肽保鲜剂处理后,保鲜剂组在（4±1）℃贮藏过程中pH、挥发性盐基氮（TVB-N）和细菌总数增加缓慢,货架期延长了2-3 d。

英文摘要：

A new biological preservative—antimicrobial peptide APNT-6 produced by Bacillus natto NT-6 and purified by column chromatography will be applied in the fresh-keeping of Litopenaeus vannamei.Bacillus antimicrobial peptides are a series of lipopeptides substances produced by represented Bacillus strains of B.subtilis,B.amyloliquefaciens and B.natto,which include surfactin,iturin,fengycin,subtilin and so on.Numerous studies show that Bacillus antimicrobial peptides have a startling range of antimicrobial activities that can include action against most Gram-negative and Gram-positive bacteria,fungi,enveloped viruses,and eukaryotic parasites.Recently,our research group isolated a highly antibiotic activity and largely antimicrobial spectrum strain—B.natto NT-6 from the Chinese traditional food—lobster sauce.According to the mass spectrometry（ESI /MS /CID） analysis,we know the mainly antimicrobial substances produced by this strain is Bacillus antimicrobial peptides,mainly including surfactin,fengycin,and iturin（called after APNT-6）.Through oral acute toxicity in mice we found that its LD 50 greater than 5000 mg/kg body weight,indicating that antimicrobial peptide APNT-6 has high food safety.In this paper,the antibacterial activities of antimicrobial peptide on spoilage organisms were determined by Oxford cup assay.Then the quality changes of L.vannamei during storage at（4±1） ℃ were investigated,including the pH,total volatile basic nitrogen（TVB-N）,aerobic plate count（APC） and sensory assessment.The results showed that antimicrobial peptide APNT-6 can effectively inhibit 8 strains of spoilage organisms isolated from L.vannamei.During storage at（4±1） ℃,with the extension of storage time,the gradually increasing values of pH,TVB-N and APC of L.vannamei were observed during the 7 days storage.However,incubated 0.5 mg/mL antimicrobial peptide can effectively slow down the value increasing,which extends the shelf-life of L.vannamei by 2-3 days.