溶氧浓度对微生物谷氨酰胺转胺酶发酵的影响

研究了不同溶氧(DO)浓度对微生物谷氨酰胺转胺酶(M TG)发酵的影响。结果表明,当溶氧浓度为2.88 m g/L时,M TG活性和菌体干重最高,分别达到4.32 U/mL和23.5 g/L,底物利用率为81.6%;当溶氧浓度继续升高时,发酵后期M TG活性下降显著。为此采用了分阶段溶氧控制策略,即在0~34 h控制溶氧浓度为2.88m g/L,34 h后控制溶氧浓度为0.96 m g/L,最终M TG活性达到4.72 U/mL,菌体干重达到27.32 g/L,较恒定2.88 m g/L溶氧浓度时分别提高了9.26%和16.26%,其底物利用率达83.2%。

Effects of DO concentrations on Microbial Transglutaminase Fermentation

The effects of DO concentrations on MTG batch fermentation were studied.The results showed,when DO concentration was 2.88 mg/L,MTG activity and dry cell weight reached the highest,which were 4.32 U/mL and 23.5 g/L respectively,and substrate utilization ratio was 81.6 %.However,the higher DO concentration could remarkably reduce the MTG activity at later phase.Therefore,the strategy of stepwise DO concentration control MTG batch fermentation was introduced: at 0~34 h,DO concentration were controlled at 2.88 mg/L,and after 34 h,it went down from 2.88 mg/L to 0.96 mg/L.And finally,MTG activity reached 4.72 U/mL and dry cell weight reached 27.32 g/L,9.26 % and 16.26% higher than when DO conantration was 2.88 mg/L respectively,and substrate utilization ratio was 83.2%.