Effect of culture conditions on 3-hydroxypropionaldehyde detoxification in 1,3-propanediol fermentation by Klebsiella pneumoniae

摘要

1,3-Propanediol (1,3-PD) production is favored by high amount of glycerol which also contributes to the lethal 3-hydroxypropionaldehyde (3-HPA) accumulation.The influences of three culture conditions including initial glycerol concentration,stirring rate,and oxidoreduction potential (ORP) regulation on 3-HPA accumulation and 1,3-PD production were investigated.3-HPA detoxification was available at initial glycerol concentration,aeration rate and stirring rate of up to 40 g l~(-1),0.5 vvm air flow and 250 rpm,respectively.Alternatively,the stirring rate of 300 rpm was sufficient to fulfill the fermentation with initial 50 g glycerol l~(-1).In addition,3-HPA accumulation could be avoided at the initial 50 g glycerol l~(-1) under the regulated reducing conditions (-200 and -400 mV).However,ORP regulation was not convenient and feasible for the industrial production in that more carbon was distributed to weak organic acids.Consequently,two-stage fed-batch strategy was presented to achieve 3-HPA detoxification and maintain the expected high productivity of 1,3-PD,in which the batch culture stage was conducted at initial glycerol concentration and stirring rate of 40 g l~(-1) and 250 rpm,respectively,and the feeding culture stage was performed at stirring rate of 300 rpm.74.07 g 1,3-PD l~(-1) was produced in 24 h with the yield and productivity of 0.62 mol mol~(-1) and 3.08 g 1~(-1) h~(-1).