抗荧光假单胞菌Carnobacterium spp.LB1培养发酵条件的优化

为了改善和优化海产品源肉食杆菌(Carnobacterium)spp.LB1产有效抑菌代谢产物的培养发酵条件,提高对荧光假单胞菌(Pseudomonas fluorescens)的抑菌效果。基于单因素试验,从对Carnobacterium spp.LB1抑菌效果有影响的5个因素中筛选出3个显著影响因素,运用Design-Expert软件的Box-Behnken试验设计原则研究3个显著影响因素的重要水平和交互作用。结果表明:Carnobacterium spp.LB1的最佳培养发酵条件:初始pH 6.22、温度28.6℃、葡萄糖质量分数3%。在最优培养条件下,Carnobacterium spp.LB1的浓缩发酵液在15 h和18 h对P.fluorescens的抑菌率分别为80.7%、86.3%,其抑菌机理是Carnobacterium spp.LB1破坏了P.fluorescens的细胞壁,导致其通透性增大,碱性磷酸酶大量溢出,使其代谢紊乱,从而抑制了P.fluorescens的生长。同时,最优发酵条件下获得的实验结果平均值与模型预测值基本吻合,进而说明所建立回归模型是可靠的。

Optimization of Culture Conditions of Carnobacterium spp. LB1 for Enhanced Production ofAnti-Pseudomonas fluorescens Metabolites

This study aimed to optimize the culture conditions for Carnobacterium spp. LB1, isolated from the ribbonfishintestine, to produce anti-Pseudomonas fluorescens metabolites. By using one-factor-at-a-time method, three of the fivefactors were selected for their significant influences on the antibacterial activity. A Box-Behnken design was applied toevaluate the effects of interaction among the chosen variables and optimize them. The optimum culture conditions obtainedwere as follows: initial pH, 6.22; temperature, 28.6 ℃; and glucose concentration, 3%, where the percentage inhibitionof concentrated fermentation broth harvested after 15 and 18 h against Pseudomonas fluorescens were 80.7% and 86.3%,respectively. The antibacterial mechanism was due to increased cell wall permeability and leakage of a large amount ofalkaline phosphatase (AKP) after the destruction of the cell wall of Pseudomonas fluorescens, leading to metabolic disorders.Finally, the experimental results obtained under the optimized fermentation conditions were in good agreement with themodel predictions, indicating that the established model in this study was feasible.