摘要
为探究1株鸡白痢沙门菌噬菌体STP98-a的液体发酵条件及噬菌体发酵液的后处理工艺,本试验在100 mL液体增殖体系下,通过对STP98-a培养时间、噬菌体与宿主菌接种比例及起始宿主菌活菌数进行优化,确定STP98-a的液体发酵工艺;发酵液离心后收集上清液,以0.22μm滤膜过滤后加不同冻干保护剂,以冷冻干燥法制备噬菌体冻干粉,通过测定冻干粉效价,计算噬菌体存活率,确定STP98-a的最优冻干保护剂;并将确定的STP98-a最优发酵工艺及发酵液后处理工艺应用于20 L发酵体系进行验证。结果表明:(1)当噬菌体与宿主菌接种比例0.001,起始宿主菌活菌数10^(9)CFU/mL,37℃、180 r/min发酵2 h时,STP98-a效价最高,达2.00×10^(10)PFU/mL。(2)冻干保护剂筛选结果显示,在复合冻干保护剂(脱脂奶粉20%、海藻糖1%、蔗糖2%)下冻干效果最好,噬菌体STP98-a存活率为86%。(3)在20 L发酵体系下,STP98-a发酵液效价达1.50×10^(11)PFU/mL,冻干粉效价达2.72×10^(11)PFU/g。综上,噬菌体发酵工艺及后处理工艺的确定使发酵罐大批量生产噬菌体这一技术得以实现。
The objective of this study was to investigate the liquid fermentation conditions of a Salmonella pullorum phage STP98-a and the post-treatment process of fermentation broth.The fermentation process of Salmonella pullorum phage STP98-a was determined by optimizing the culture time,inoculation ratio of phage to host bacteria and initial viable number of host bacteria in 100 mL liquid proliferation system.The bacteriophage solution was centrifuged,filtered through a 0.22μm membrane and then lyophilized with protectant.The freeze-drying effect was evaluated by the phage survival rate.Finally,the determined optimal fermentation process and fermentation broth treatment process were applied to the 20 L fermentation system for verification.The results showed that the highest titer of STP98-a was 2.00×10^(10)PFU/mL when the inoculation ratio of phage to host bacteria was 0.001,the initial viable number of host bacteria was 10^(9) CFU/mL,and the fermentation time was 2 h at 37 ℃ and 180 r/min.The screening results of bacteriophage freeze-drying protectants showed that the freeze-drying effect was the best under the compound freeze-drying protectants skimmed milk powder 20%,trehalose 1%,sucrose 2%,and the phage survival rate was 86%.The 20 L fermentation system verified that the phage titer of the fermentation broth was 1.50×10^(11)PFU/mL and the lyophilized powder had a titer of 2.72×10^(11)PFU/g.In conclusion,the determination of bacteriophage fermentation process and post-treatment process enables the mass production of bacteriophage in the fermenter.
作者
汪祥燕
辛国芹
赵学峰
WANG Xiangyan;XIN Guoqin;ZHAO Xuefeng(Shandong Baolai-LeeLai Bioengineering Co.,Ltd.,Tai’an,Shandong Province 271000,China;Shandong Livestock Product Quality and Safety Center,Jinan,Shandong Province 250100,China)
出处
《中国饲料》
北大核心
2022年第5期32-36,共5页
China Feed
基金
国家重点研发计划项目(2017YFD0501006)。
关键词
鸡白痢沙门菌噬菌体
发酵工艺
冻干保护剂
发酵验证
Salmonella pullorum lytic phage
fermentation process
freeze-drying protectant
fermentation verification
作者简介
通讯作者:汪祥燕(1988-),女,硕士,研究方向为微生态制剂菌株筛选及功能鉴定,E-mall:wangwang_1009@126.com。
