枯草芽孢杆菌Y-3生长特性及抗性研究

Studies on the Growth Characteristics and Resistance of Bacillus subtilis Y-3

[目的]为枯草芽孢杆菌Y-3规模化发酵和降低成本提供理论依据。[方法]以分离的枯草芽孢杆菌Y-3为研究对象，对其生长特性、耐热性、耐酸、耐胆盐以及抗菌性进行研究。[结果]枯草芽孢杆菌Y．3培养14h生物活性量达到最高。初始pH6．3-8．0、培养温度30～37℃、装液量为20—100ml枯草芽孢杆菌Y-3均生长较好。枯草芽孢杆菌Y-3热力致死曲线线性方程为：y=-4．3365x＋435．58。分别在80、90℃热接触30s。存活率为97．45％和95．93％；在pH2—4酸性环境中作用3h后存活率超过73％；在猪胆盐浓度为0．5％以下的存活率超过80％。培养枯草芽孢杆菌Y-3产生抗菌活性效果的最佳条件为：初始pH7，温度25℃、装液量50ml，最佳试验条件下的抑菌圈为3．09cm。[结论]枯草芽孢杆菌Y-3能满足发酵饲料菌种要求。

[ Objective ] The research aimed to provide the theoretical basis for large scale fermentation of Bacillus subtilis Y-3 and reducing the cost. [ Method ] With the isolated Bacillus subtilis Y-3 as the research object,its growth characteristics, heat tolerance, acid fastness, bile tolerance and antibacterial property were studied. [ Result] The number of biological activity of B. subtilis Y-3 reached the maximum after culturing 14 h. B. subtilis Y-3 grew well under the conditions of initial pH of 6.3 - 8.0 ,cultured temperature of 30 - 37 ~C ,liquid volume of 20 ~ 100 ml. The thermal death curve equation of B. subtilis Y-3 was y = -4. 3365x ＋ 435.58. The survival rate of B. subtilis Y-3 was 97.45% and 95.93% re- spectively after heat contact at 80 and 90 ~C for 30 s. The survival rate of B. subtilis Y-3 was over 73% after reacting for 3 h in acidic environ- ment of pH 2 -4. The survival rate of B. subtilis Y-3 was over 80% at the pig bile salt concentration of below 0.5% . The optimum conditions for culturing B. subtilis Y-3 and producing the antibacterial activity were as follows：initial pH of 7 ,culture temperature 25 ℃ ,the liquid volume of 50 ml. The antibacterial circle diameter under the optimum conditions was 3.09 cm. [ Conclusion ] Bacillus subtilis Y-3 could meet the re- quirements of strain requirement for fermented feed.