南极放线菌N-1产抑菌成分的响应面优化

Optimization of active composition production from the Antarctic Actinomycete N-1 using Response Surface Methodology

目的本研究旨在对南极放线菌N-1的发酵工艺进行优化,以提高发酵液中抑菌成分的活性。方法本实验以抑菌活性(琼脂扩散法)为指导,对该菌的碳源、氮源、无机盐等培养基组成进行单因素考察,以期得到显著性影响因素,然后利用Plackett-Burman试验设计,最陡爬坡设计以及Box-Behnken组合设计对显著性影响因素进一步进行优化。结果通过这些条件的优化,最终得到南极放线菌N-1的最佳发酵条件为小米12.68g/L、NaNO36.67g/L、MgSO4.7H2O 0.31g/L、FeSO4.7H2O 0.03g/L、黄豆粉7.50g/L,CaCO30.60g/L,NaCl 20g/L,pH=6.0,温度28℃,转速200r.min-1。与优化前相比,发酵液的活性提高了5.94倍;菌体湿重提高了1.55倍。结论利用响应面法(RSM)对南极放线菌N-1的发酵条件进行优化之后,提高了该菌的菌体密度的同时,更加提高了发酵液中抑菌活性物质的抑菌能力,为活性天然产物的发现奠定了较好的基础。

Objective The fermentation conditions of the Antarctic N-1 were optimized to elevate the anti- bacterial activity of the antibacterial compounds in the fermentation broth. Methods In the present stud- y, using antibacterial activity（agar diffusion method）as index, the medium compositions （source of car- bon, nitrogen source, inorganic salt） were investigated to find out the important impact factors. Then P[ackett-Burman design （PBD） was employed to find the key ingredients of medium components, and then Box-Behnken design was implemented to determine their optimal concentrations. Result： The op- timal medium composition was determined as follows（g/L）： millet 12. 68, NaNO36.67, MgSO4 7H20 0. 31, FeSO4 7H20 0.03, soybean meal 7. 50, CaCO3 0. 60, NaC1 2. 00, pH = 6.0, temperature 28~C, the rotating speed was 200 r ~ rain 1. This optimization strategy enhanced the production of antibacteri- al active substances. Compared with the non-optimized fermentation medium, the antibacterial activity increased 5.94 times than that of the non-optimized fermentation medium, at the same time, the weight of mycelium was 1. 55 times of the previous. Conclusion The response surface methodology （RSM） model provided an easy and effective way to determine the interactive effect of fermentation conditions on production of antibacterial compounds by N-1. Therefore, the optimized fermentation medium can be applied to produce maximum amounts of antibacterial compounds under laboratory and commercial fer- mentation conditions, which will facilitate the discovery of new active compounds.