基于改性玉米秸秆纤维固定色氨酸合成酶基因工程菌合成L-2-甲基-色氨酸

摘要：利用固定化色氨酸合成酶细胞合成L-2-甲基-色氨酸。采用戊二醛作为交联剂、海藻酸钠作为包埋剂和改性玉米秸秆纤维作为填充剂固定色氨酸合成酶基因工程菌，探究并建立最优固定因素水平条件，提高该固定化菌的酶活力以及其稳定性，响应面法优化固定化色氨酸合成酶基因工程菌合成L-2-甲基-色氨酸。研究结果表明，底物L-丝氨酸浓度为10 g/L，温度为35℃，pH为8.0，L-2-甲基-色氨酸合成量达到5.3 g/L，底物L-丝氨酸转化率为41.6%，产物L-2-甲基-色氨酸收率为25.3%，固定化色氨酸合成酶基因工程菌可连续使用12批次。

Synthesis of L -2-methyl-tryptophan by immobilized cells of tryptophan synthetase engineering bacteria by modified corn straw stalk cellulose

Abstract: Synthesis of L -2-methyl-tryptophan by immobilized cells of tryptophan synthetase cells was investigated. Using glutaraldehyde as crosslinking agent, sodium alginate as embedding agent, and modified corn straw stalk cellulose as filling agent immobilize the genetic engineering bacteria with tryptophan synthetase. Synthesis of L-2-methyl-tryptophan by immobilized cells of tryptophan synthetase engineering bacteria was carried out by response surface method. The effect of fumaric acid concentration, pH and reaction temperature was investigated. The optimized preparation conditions were as follows: 10 g/L L-serine, 35ºC, pH 8.0, the concentration of L-2-methyl-tryptophan was 5.3 g/L. The bioconversion rate of L-serine reached 41.6%. The yield of L-2-methyl-tryptophan was 25.3%. The immobilized bacteria could be used continuously for 12 times. The immobilized cells of tryptophan synthetase engineering bacteria by modified corn straw stalk cellulose have good stability.