一株海绵放线菌的分离培养、发酵条件优化及其抑制弧菌效果

为研究放线菌对海水养殖病原弧菌(哈维弧菌Vibrio harveyi和灿烂弧菌Vibrio splendidus)的抑制效果,从繁茂膜海绵Hymeniacidon perlevis中分离筛选出了一株具有抑菌活性的放线菌(FH),并采用16S r DNA基因序列进行分析,初步鉴定为球孢链霉菌Streptomyces globisporus;以抑菌活性为导向对放线菌FH菌株的发酵条件进行优化,并通过测量发酵沉淀菌丝体干质量,获得了FH菌株生长曲线,同时研究了发酵产物保存温度及时间对抑菌效果的影响,以及FH发酵产物在灭菌海水中对弧菌的抑制作用。结果表明:对FH菌株生长曲线测定结果显示,0~15 h为适应期,15~72 h为指数生长期,72~120 h为稳定期,120 h后为衰亡期;抑制弧菌效果试验显示,FH菌株发酵正交试验的最优条件为温度25℃、p H 7.5、装液量30m L(250 m L三角瓶);在正交试验最优条件下,FH菌株发酵培养72 h获得的粗提物抑制哈维弧菌和灿烂弧菌的效果最好;FH菌株发酵粗提物在4℃和-20℃下保存60 d和在室温保存7 d,其抑菌效果无显著性差异(P0.05);在100 m L灭菌海水中,FH菌株发酵产物2 m L可有效抑制哈维弧菌和灿烂弧菌的繁殖。研究表明,海绵放线菌及其发酵产物在海水养殖领域具有潜在应用价值。

Isolation,optimization of fermentation conditions and inhibition of Vibrio in a sponge-associated actinobacterium FH

A sponge-associated actinobacterium FH with strong bioactivity was isolated from marine sponge Hy-meniacidon perlevis, and identified by 16S rDNA gene sequence analysis as Streptomyces globisporus. The inhibition of Vibrio harveyi and Vibrio splendidus by FH strain was studied and the fermentation condition of FH strain was op-timized, including influence of preservation temperature and time on the antibacterial effect of fermented product. The dry weight of mycelium revealed that the growth curve of FH strain showed a lag phase in 0-15 h, log phase in 15-72 h, stationary phase in 72-120 h and decline phase after 120 h. The optimal fermentation of FH strain was observed under conditions of temperature 25 ℃, pH 7. 5 and loading volume 30 mL in the orthogonal experiment, with the best antibacterial effect on Vibrio harveyi and Vibrio splendidus by the crude extracts of FH strain fermented in 72 h under this condition. However, there was no significant difference in the antibacterial effects in the crude extracts of FH strain stored at 4 ℃ and -20 ℃ for 60 days and stored 7 days at room temperature ( P>0. 05 ) . Ad-dition of 2 mL fermentation product of FH strain in 100 mL sterilized seawater led to effectively inhibit the growth of Vibrio harveyi and Vibrio splendidus. The findings indicated that the sponge-associated actinobacterium FH and its fermentation product had potential application in the field of mariculture.