提高基因工程菌产二素链霉菌311—10产生酰化螺旋霉素的研究

STUDIES ON INCREASING PRODUCTIVITY OF THE ACYL- SPIRAMYCIN COMPONENTS OF GENETICALLY ENGINEERED STRAIN Str. ambofaciens 311-10

基因工程菌产二素链霉菌(Str.ambofaciens)311-10是一株含麦迪霉素4″—羟基酰化酶基因的螺旋霉素产生菌,可发酵直接产生酰化螺旋霉素。经质谱鉴定,所产生的酰化产物为4″—异戊酰、4″—丁酰及4″—丙酰螺旋霉素,并含有50～60％的螺旋霉素组份。为了提高酰化螺旋霉素的含量,研究了17种氨基酸及有关化合物对产二素链霉菌311-10菌株直接产生酰化螺旋霉素的影响。结果显示,在发酵过程中添加一定量α—羟基异丁酸或L—异亮氨酸,酰化螺旋霉素的的百分含量可从对照组的45％分别提高到73％和67％。如同时加入α-羟基异丁酸和L-异亮氨酸.则酰化螺旋霉素的含量可增至88％左右。研究表明含麦迪霉素4″—羟基酰化酶基因的螺旋霉素产生菌能利用L—异亮氨酸或α—羟基异丁酸作为酰基的供体。从不同发酵时间加入试验表明合适的添加时间为发酵前期24小时左右。提示L—异亮氨酸或α—羟基异丁酸不只是提供酰化螺旋霉素4”—酰化酶酰基的供体,可能对4″—酰化酶基因的转录起诱导作用。 L—精氨酸能使酰化螺旋霉素组份下降至14％左右,并能抵消α-羟基异丁酸或L-异亮氨酸对酰化螺旋霉素的促进作用。 研究提示控制基因工程菌发酵条件,可以有效地获得所需基因工程产物。

The genetically engineered strain, Str.atnbofaciens 311-10,can direct to the biosynthsis of acyl-spiramycins. Mass-spectrometry analyses indicated that three acyl-spiramycins are produced that are different from each other only in the acyl groups at C-4' these were 4''-isovaleryl-,4''-butyryl-,and 4''-propionyl et cetera, beside those about 50-60% spiramycin are produced. The purposes of the present investigation were made to direct the genetically engineered strain Str.ambofaciens 311-10 to biosynthesize predominantly acyl-spiramycin in the fermentation. An attempt was made to increase the production of acyl-spiramycin as the major component among others. Addition to the complex medium, of amino acids and its related compound, resulted in a yield of a large amount of acyl-spiramycin compared with the control culture. Among these amino acids and its related compounds, 0.2%L-isoleucme or 0.3% α-hydroxy-iso-butanoic acid showed an increase of about 67 %t 73% rates of acyl-spiramycins component respectively, compared with the control culture only about 40-50% rates of components. When added together,they showed an additive increase about 88% rates of acyl-spiramycin without changing other parameters of the fermention. On the other hand, addition of L-arginine resulted in a small amount of acyl-spiramycin produced compared with the control culture, i. e.L-arginine has an inhibitory effect. Studies on the C-4' acylase of midecamycin producer with regulatory properties from the amino acids are in progress.