Optimization Of Sporpore Culture Conditions For Bacillus Coagulans

Bacillus coagulans has the properties of lactic acid bacteria,but also can produce spores,has good probiotic benefits,and the microecological preparations made are expected to replace antibiotics and disinfectants as feed additives and water quality improvers for aquaculture with their safe,efficient and residue-free characteristics.At this stage,most laboratory studies stop at the study of the biological characteristics and viable number of Bacillus coagulans,and neglect the study of spore number.In the process of processing microecological preparations in the factory,the bacterial activity is easily affected,and the spores,as their dormant bodies,have the advantages of high temperature resistance,strong resistance and strong stability,and have become a research hotspot for industrial production of microecological preparations,which is conducive to the industrial application of Bacillus coagulans.In this study,the growth curve,high temperature tolerance,p H tolerance,bacteriostatic and acid production capacity of the laboratory-preserved Bacillus coagulans were first determined to ensure that the strain was still active and stress-resistant,and could be used for the preparation of seed liquid after industrial production.As a dormant body of bacteria,the premise of increasing spore yield is to ensure a certain number of viable bacteria,so the optimization of Bacillus coagulans culture conditions should be carried out before optimizing the spore production culture conditions:through the univariate test and the response surface analysis test,the culture conditions and media components were optimized respectively,and finally the optimal culture conditions for the bacteria were 10 m L/50 m L,the inoculation amount was 5%,the temperature was 40°C,the speed was 200 r/min,and the initial p H=6.5.The best carbon source was sucrose at a concentration of 18.96 g/L,the best nitrogen source was peptone at a concentration of 23.36 g/L,and the best inorganic salt was dipotassium hydrogen phosphate at a concentration of 2 g/L.The bacterial concentration obtained after optimization can reach 7.189×10~9 cfu/m L,which is 87%higher than the number of viable bacteria before optimization.After ensuring the number of viable bacteria,the spore culture conditions were optimized by univariate test and response surface analysis test according to the results of the live bacteria number optimization conditions.Finally,the optimal culture conditions for spores production were 12 m L/50 m L,speed 210 r/min,inoculation rate of 4%,temperature of 43°C,and initial p H of 5.5.The best carbon source is glucose at a concentration of 20 g/L.The best nitrogen source was corn syrup flour with a concentration of 19.78 g/L.The best inorganic salt is calcium carbonate at a concentration of 1.94 g/L.The optimal spore stimulating factor was long-chain inulin at a concentration of 3.2 g/L.The final spore number was 1.207×10~9 cfu/m L,which was approximately 3.24 times that before optimization.In summary,the Bacillus coagulans selected in this experiment has good safety and stability,and can be applied to the preparation of probiotics.The optimization of spore production culture conditions after strain cultivation provides a preliminary work foundation for efficient cultivation of Bacillus coagulans and data support for the development of probiotics of Bacillus coagulans.