直投式纳豆菌发酵剂制备工艺优化

为探索出一种工艺简便、成本低且活菌数高的直投式纳豆菌（Bacillus natto）发酵剂的制备方法，该研究以大米粉为基质替代传统的种子液培养基培养纳豆菌后直接将其烘干制成直投式纳豆菌发酵剂，通过单因素及正交试验优化直投式纳豆菌发酵剂的制备工艺。结果表明，用含1.5%蛋白胨的大米粉作为培养基，在接种量4.0%、加水量40%、培养温度43 ℃条件下培养纳豆菌28 h，菌体生长良好，将培养物烘干后制成的直投式纳豆菌发酵剂中的活菌数含量达4.71×109 CFU/g。此技术操作简便，可推广至工业生产中，简化生产过程。

Optimization of preparation technology of directed vat set Bacillus natto starter culture

In order to explore preparation technology of directed vat set Bacillus natto starter culture with simple process, low cost and high viable count, the directed vat set B. natto starter culture was prepared by using rice flour replace traditional seed liquid medium and then drying. The preparation process of the directed vat set B. natto starter culture was optimized by single factor and orthogonal experiments. The results showed that using rice flour with peptone 1.5% as medium, the strain grew well under the conditions of inoculum 4.0%, water addition 40%, culture temperature 43 ℃ and time 28 h. The viable bacteria count in the directed vat set B. natto starter culture prepared after drying the culture reached 4.71×109 CFU/g. The technology was simple and could be extended to industrial production to simplify the production process.