Optimization Of Fermentation Conditions Of Marine Bacillus Amyloliquefaciens

Bacillus is a kind of non pathogenic aerobic bacteria which is harmless to the body.It grows and reproduces rapidly and produces spores under certain conditions.The spores have special structure.Bacillus has the advantages of high temperature resistance,acid and alkali resistance,strong resistance and high stability.At the same time,bacillus can also secrete high activity of cellulase,amylase,protease and other enzymes,so it has a wide range of functions.In this study,the experimental strain was Bacillus amyloliquefaciens,which was preserved in the laboratory.The fermentation conditions and spore production conditions of Bacillus amyloliquefaciens were mainly studied,which provides theoretical basis and experimental data for further research on the role of Bacillus amyloliquefaciens in microbial fertilizer and large-scale production and application.The experimental methods and main results were as follows:（1）The results showed that Bacillus amyloliquefaciens could produce amylase,protease and cellulase,and could be used in the production and application of microbial fertilizer.（2）The fermentation medium and fermentation conditions of Bacillus amyloliquefaciens were optimized by single factor test and orthogonal test.The optimal medium composition and fermentation conditions were obtained as follows:the optimal carbon source was soluble starch,the addition amount was 1.5%,the best nitrogen source was yeast powder and peptone,the ratio of yeast powder and peptone was 3:1,the addition amount was 2%,0.5%Na Cl,the optimum temperature was 35℃,the optimum initial p H was 7,the optimum rotation speed was 180 rpm,the optimum liquid volume was 60 m L/300 ml,and the final cell concentration was 2.298×10¹¹CFU/m L.（3）The results of single factor test and showed that Mn²⁺had significant effect on the spore production of marine Bacillus amyloliquefaciens.The optimal medium for spore production was 2%soluble starch,2%mixed nitrogen source,3:1 ratio of yeast powder:peptone,0.2%Mn²⁺.The optimal culture conditions were 38℃,initial p H 6.5,shaking flask 60 m L/300 ml,and rotation speed 180 rpm The number of spores was 1.878×10¹¹CFU/m L.（4）The results showed that Bacillus amyloliquefaciens could be used in microbial fertilizer,and the optimization of bacterial concentration and spore number in fermentation broth could provide more reliable data for different directions of subsequent industrial production.