Effect of Dissolved Oxygen on Mutanolysin Fermentation
溶氧对变溶菌素发酵的影响

Effects of several parameters relating to dissolved oxygen(DO)on mutanolysin fermentation were studied.The experiment using shake flasks shows that the medium volume and shaker agitation speed affect the production of mutanolysin.At the same time,the agitation rate together with aeation rate has effects on DO in fermentor.Mutanolysin fermentation was affected by DO greatly.Oxygen is a key restricted factor in mutanolysin fermentation.It affects the metablism and physiological action of Streptomyces globisporus S186.Whatever the DO is excessive high or low,it won't benefit the mutanolysin production.If DO is super, S.globisporus S186 will grow luxuriantly but do not produce mutanolysin,while if DO is lower,the S.globisporus S186 won't grow well even not to produce mutanolysin.During the course of fermentation,the DO changed regularly.It is similar to many antibiotic fermentation and some amino acid fermentation.As S.globisporus S186 grow in exponential phase,DO begin to decrease rapidly from 6 h and get to the lowest point at 40 h or so.Subsequently mutanolysin starts to be produced.DO rises again from 90 h.The key technoloyg of oxygen control in the fermentation is to keep the DO at a suboptimum level.In order to get a high mutanolysin yield,during the culture in fermentor the agitation rate and aeration rate should be kept at 200 r/min and 1:0.8( V:V )respectively.