摘要
为探求牛支原体冻干菌的有效保护性物质,利用四因素四水平正交试验和单因素试验,通过检测冻干后牛支原体HB150的活菌数,筛选并评价脱脂乳、蔗糖、甘露醇、葡聚糖、海藻糖、尿素、BSA、赖氨酸等物质对牛支原体冻干后活菌率的影响,并最终确定不同保护制剂的最佳浓度及配比.结果显示,最佳的冻干保护剂配比(m/V)为:脱脂乳15%、蔗糖4.0%、甘露醇4.0%、葡聚糖3.0%、海藻糖2.0%、尿素1.5%、BSA 1.0%、赖氨酸0.3%.该配方于-40℃、12 Pa条件下冷冻干燥20 h,能够保持牛支原体的最高活菌率,达到(55.2±2.1)%.结果表明,所筛选的动干保护剂具有较好的保护作用,可以应用于牛支原体的实际冻干操作.
Abstract
In order to explore the effective protective substances for freeze-drying Mycoplasma bovis(M.bovis),this study employed a four-factor,four-level orthogonal design experiment alongside a single-factor experiment.The effects of skim milk,sucrose,mannitol,glucan,trehalose,urea,BSA,lysine,and other substances on the survival rate of M.bovis were detected by measuring the number of the live M.bovis HB150 post freeze-drying and the optimal concentrations and ratios of the different protective agents were ultimately established.The ratios of the main and auxiliary components of the freeze-drying protec-tants were determined through orthogonal design experiments,and the final ratios of the lyophilized protec-tants were as follows:15%skimmed milk,4.0%sucrose,4.0%mannitol,3.0%glucan,2.0%alginate,1.5%urea,1.0%BSA,and 0.3%lysine.When freeze-drying at-40℃and 12 Pa for 20 h,this formula-tion maintained the highest activity rate of M.bovis,reaching(55.2±2.1)%.The results indicated that the selected dynamic dry protectants exhibited a strong protective effect and could be effectively applied in the actual freeze-drying process of M.bovis.
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