微贮用植物乳杆菌固定化菌剂的制备

乳酸菌与纤维素降解菌因其可防止微贮饲料酸败、增加秸秆饲料的营养价值等优点,在秸秆微贮过程中起重要作用。但由于乳酸菌的繁殖会抑制纤维素降解菌的活性,如何实现微贮过程中两种微生物分时发挥功能是解决上述问题的关键。文中利用固定化技术将乳酸菌制备成含有玉米秸秆粉的固定化菌剂以达到缓释的目的。首先制作固定化空白小球得出复合固定化载体成球的最佳浓度,利用玉米芯吸附植物乳杆菌S1得到复合固定化载体,以对S1的包埋率、成球效果等为指标,通过对比两种固定化方法 (包埋法与包埋-交联法),得到固定化植物乳杆菌S1的最佳条件。研究表明,使用6%PVA+0.4%SA+0.3%CMC-Na进行包埋-交联时成球效果最好,使用1.2%SA+0.5%CMC-Na进行直接包埋时成球效果最好。通过对比5种固定化工艺,将1.2%SA+0.5%CMC-Na和吸附玉米粉组成的固定化载体混合物逐滴滴入4%氯化钙中直接包埋24 h得到的固定化小球其机械强度以及包埋率均优于其他工艺。因此,利用玉米芯吸附-海藻酸钠包埋的方法可以有效提高植物乳杆菌包埋效率,为使用固定化技术制备微贮饲料菌剂奠定基础。

Preparation of immobilized Lactobacillus plantarum agent for silage

Lactic acid bacteria and cellulose degrading bacteria play an important role in fermentation process of silage, because they can prevent the rancidity and increase the nutritive value of silage. But the propagation of lactic acid bacteria will inhibit the activity of cellulose degrading bacteria in the silage fermentation system. This problem can be solved by releasing lactic acid bacteria and cellulose degrading bacteria in different time. Therefore, we immobilized lactic acid bacteria as a microbial agent for sustained release. Firstly, the optimal balling concentration of the composite immobilized carrier and composite immobilized carrier were obtained by immobilization of blank balls and corncob adsorbed Lactobacillus plantarum S1 respectively. The best immobilization condition of L. plantarum S1 was obtained by comparing the immobilized rate and balling effect of two kinds of balls, which were embedded by sodium alginate (SA), CMC-Na and embedded-crosslinked by SA, CMC-Na, polyvinyl alcohol (PVA). The results showed that the best balling concentration was achieved by using 6% PVA+0.4% SA+0.3% CMC-Na for embedding-crosslinking and 1.2% SA+0.5% CMC-Na for direct embedding respectively. In addition, comparing with the mechanical strength and embedding rate of five kinds of immobilization process, the best immobilized process was obtained by adding of the mixture of immobilized carriers (1.2%SA+ 0.5%CMC-Na) and corncob adsorbed L. plantarum S1 slowly into 4% CaCl2 for 24 hours. The corncob adsorption and SA embedding methodology can effectively increase the embedding efficiency of Lactobacillus plantarum S1.