产气气杆菌甘油脱氢酶诱导形成的培养条件

CULTURAL CONDITIONS OF AEROBACTER AEROGENES FOR INDUCED FORMATION OF GLYCEROL DEHYDROGENASE

筛选出一株产气气杆菌(Aerobacter aerogenes)AS1.490,经甘油诱导培养能在细胞内形成 NAD-甘油脱氢酶,每毫升培养液菌体含1—1.4单位酶活力。酶形成的最适发酵条件研究表明:培养基中含3%甘油时酶形成量最高。添加少量葡萄糖或果糖对酶形成有促进作用。无机氮源——铵盐对酶形成是必需的,以硫酸铵最佳,加入0.2%硫酸铵酶活力最高,添加硫酸铵到0.3%或0.4%时,不再增加生物量,酶量略有下降。其他铵盐效能依次为氯化铵、硝酸铵、磷酸氢二铵等。单加有机氮源不利产酶。酶形成的培养基最适起始 pH 为7.0,生物量亦最高。酶形成的最适温度为30℃,但在20—40℃范围内,生物量随温度的升高而增加。用250ml 三角瓶以35ml 装液量最适。在上述最适条件下,发酵培养18小时后,细胞生长不再增加。培养至26小时,培养基中甘油基本上完全消耗,这时酶形成量达到最高峰,以后随时间延长酶形成量迅速下降,在42小时后几乎完全消失。

An Aerobacter aerogenes strain AS 1.490producing glycerol dehydrogenase was obtai-ned.It was found that the formation of gly-cerol dehydrogenase in vivo was induced inmedium containing glycerol.The formationconditions of glycerol dehydrogenase havebeen investigated.The result obtained showedthat the enzyme formation in a medium con-taining 3% glycerol reached the maximum.The enzyme activity was enhanced by ad-dition of small quantity of glucose or fructoseinto the medium.However,addition of glu-cose instead of glycerol into the medium,al-most no activity of glycerol dehydrogenasewas detected.Inorganic nitrogen sources,am-monium salts are necessary to the formationof glycerol dehydrogenase.The activity ofglycerol dehydrogenase reached the highestwhenever 0.2% ammonium sulfate be added.Addition of organic nitrogen sources insteadof inorganic nitrogen sources was harmful tothe enzyme formation.The suitable mediumfor glycerol dehydrogenase formation consi-sted of glycerol 3%,glucose 0.1%,(NH_4)_2SO_40.2%,KH_2PO_4 1.26%,K_2HPO_4 0.54%,MgSO.7H_2O 0.02% and CaCl_2 0.01%at pH 7.0.When the bacteria was cultured in250 ml conic flask with 35 ml of the mediumon the rotary shaker at 30℃ for 26 h.The cul-ture medium with 1—1.4 units of endocellularglycerol dehydrogenase activity per ml ofliquid culture was obtained.