一株海藻糖合成酶产生菌的鉴定及产酶条件优化

目的对一株海洋来源的产海藻糖合成酶菌株进行鉴定及产酶条件的初步优化。方法通过16SrDNA基因序列的同源性分析，对一株来源于东海海水的海藻糖合成酶产生菌进行鉴定，并通过单因素分析初步研究其培养特性和最佳的发酵条件。结果该菌16SrDNA序列与GenBank中已知序列相比，最高相似度为100％，鉴定为假单胞菌属（Pseudomonas），命名为Pseudomonassp．A50。其最佳碳源和氮源分别为2％麦芽糖和0．5％酵母膏，最佳NaCl浓度为2．5％，在初始pH7．8，接种量1％，装液量125mL／250mL，28℃，130r／min发酵48h，海藻糖合成酶活力达到最高。结论此产海藻糖合成酶菌株为假单胞菌属，优化后，海藻糖合成酶活力达到14．16U／mL。

Identification of a Pseudomonas sp. strain and optimization of the fermentation conditions of trehalose synthase

Objective To identify a trehalose synthase-producing strain isolated from ocean water and investigate the optimal composition of the medium and fermentation conditions. Methods 16S rDNA gene sequence was ana- lyzed for identification. The medium and fermentation parameters are obtained by single factor experiments. Results The new strain was named Pseudomoncts sp. A50. The optimal carbon and nitrogen sources were 1.5% maltose and 0.5% yeast powder, respectively. The optimal concentration of NaCl was 2.5%. The optimal liquid volume was 125 mL in 250 mL erlenmeyer; the inoculum was 1% , with the initial pH of 7.8. After cultivated for 48 hours in shaker at 28℃, 130 rpm, the maximum enzyme activity was obtained. Conclusion The new strain was classified as Pseudvmonas sp.. Under the optimal cultivation conditions, the maximum enzyme activity was up to 14.16 U/mL.