纳豆芽孢杆菌NT-6固态发酵罗非鱼下脚料条件优化及产脂肽组分分析

利用纳豆芽孢杆菌（Bacillus natto）NT-6，以罗非鱼下脚料为主要基质，进行固态发酵生产抗菌营养复合型活性肽，以提高抗菌脂肽产量为目的，对培养基和发酵条件进行优化。在对产生的脂肽组分进行分析的基础上，采用高效液相色谱-质谱定量检测法，通过单因素试验和响应面设计优化固态发酵工艺条件。结果表明：利用罗非鱼下脚料为主要基质固态发酵生产的抗菌脂肽组分主要包括表面活性素（m/z分别为995.20、1 008.20、1 058.20）、伊枯草菌素（m/z分别为1 044.30、1 071.20）。优化后的最佳工艺参数为罗非鱼下脚料与麸皮配比3.48∶1（m/m）、初始基质水分含量69.34%（质量分数）、发酵时间61.69 h、发酵温度28.97 ℃、甘蔗渣添加量6%（质量分数）、接种量5 mL/100 g，此条件下抗菌脂肽产量达7.32 g/kg，实际验证结果为7.29 g/kg，相对于优化前提升了7.5 倍，产生的脂肽含有多种脂肽组分。

Component Analysis of Antimicrobial Lipopeptides from Solid-State Fermentation of Tilapia Processing Byproducts with Bacillus natto NT-6 and Optimization of Fermentation Conditions

In this study, tilapia processing byproducts were used as the major substrate for solid-state fermentation
to produce composite active peptides with antimicrobial and nutritional properties. In order to improve the yield of
antimicrobial lipopeptides, the medium and fermentation conditions were optimized. The lipopeptide components generated
were analyzed and quantitated by a high performance liquid chromatography-mass spectrometry method. The optimization
was performed by applying one-factor-at-a-time method and response surface methodology. The results showed that the
main antimicrobial lipopeptides produced were surfactin (m/z 995.20, 1 008.20 and 1 058.20, respectively) and iturin (m/z
1 044.30 and 1 071.20, respectively). Under the optimized conditions: tilapia processing byproducts to wheat bran
ratio of 3.48:1 (m/m), initial moisture content of 69.34%, fermentation time of 61.69 h, fermentation temperature of
28.97 ℃, amount of sugarcane bagasse of 6% and inoculum volume of 5 mL/100 g, the yield of antimicrobial lipopeptides
reached up to 7.32 g/kg (the actual yield was 7.29 g/kg), which increased 8.5 folds compared with that before optimization.
The product obtained was found to consist of a mixture of lipopeptides.