以韦伯灵芝(Ganoderma weberianum) TZC-1为生产菌株,在前期优化的摇瓶培养条件和5L发酵罐小试生产工艺条件的基础上,对该菌株在50 L发酵罐进行中试放大,确定韦伯灵芝漆酶在50 L发酵罐的中试发酵工艺参数.结果表明:以3d种龄种子按8％的接种量转接至发酵罐进行中试发酵,发酵温度28℃,装液量30L,采用分阶段控制pH和溶解氧浓度(DO)的策略,发酵初期(0～48 h)pH控制在6.0,48 h后pH控制在4.5～5.0范围内;0～36 h内控制搅拌转速100 r/min,通气量10 L/min;36 ～72 h内控制搅拌转速150 r/min,通气量15 L/min;72 ～96 h内控制搅拌转速200 r/min,通气量20 L/min;96 h至发酵结束搅拌转速250r/min,通气量15L/min.发酵前72 h DO保持在15％ ～ 30％有利于菌丝生长,72 h后DO保持在10 ～ 15％有利于漆酶的积累.发酵144 h选择放罐,可获得18.8L发酵原液,其漆酶活力可达27 667.7 U/L,是摇瓶发酵水平的2.5倍.%Based on our previous shaking-flask and 5-L fermentor experiments,pilot-scale fermentation for laccase production was investigated in a 50-L fermentor with G.weberianum TZC-1 as producing strain.The optimal pilotscale fermentation conditions and parameters were determined.The results showed that the optimal conditions were as follows:seeds age was 3 d,inoculum size was 8％,fermentation temperature was 28 ℃,and the volume of liquid medium was 30 L.pH and dissolved oxygen (DO) were periodically controlled in the process of fermentation.pH value was 6.0 within the first 48 h and 4.5 ～ 5.0 after 48 h.The agitation speed and aeration rate are 100 r/min and 10 L/min within the first 36 h,150 r/min and 15 L/min during 36 ～ 72 h,200 r/min and 20 L/min during 72 ～ 96 h,and 250 r/min and 15 L/min after 96 h,respectively.15 ～30％ DO was favorable for mycelia growth within the first 72 h,and 10 ～ 15％ DO was favorable for accumulation of laccase after 72 h.Fermentation was finished after 144 hours and 18.8 L of enzyme liquid was obtained.The total enzyme activity was 27 667.7 U/L.This activity was 2.5 times of that from our previous shaking-flask fermentation.The results of this study would be very useful for the laccase production by large tank fermentation.
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