中文摘要：

Pseudomonas sp．QDA是从海水中发现的产生褐藻多糖的细菌，无致病性。为提高QDA菌株褐藻多糖的产量。本文利用PCR克隆了粘性菌株P．aeguginosa FRD1的atgT基因，连接入质粒pMF36-Kan，构建了重组表达载体pMF36-Kan-algT。利用三亲接合法将pMF36-Kan-algT转入菌株QDA中。糖醛酸含量测定结果表明，atgT基因过量表达菌株的褐藻多糖产量比出发菌株QDA平均提高了3．3倍，其中菌株A25提高了4．5倍。通过培养条件的进一步优化，A25菌株的褐藻多糖产量与菌株QDA相比提高到8．18倍。

英文摘要：

Pseudomonas sp. QDA, which was isolated from seawater, has the ability of yielding alginate. In order to enhance the alginate production of Pseudomonas sp. QDA, algT gene of mucoid strain Pseudomonas aeruginosa FRD1 was cloned by PCR and ligated into plasmid pMF36-Kan. The resulting plasmid pMF36- Kan-algT was transferred into ODA by triparental mating. The average alginate production of algT over-expressed clones are 3.3 folds higher than that of wild strain QDA, and clone A25 has the highest yield and is about 4.5 folds higher than that of wild strain QDA. After further optimization of the culture condition, the alginate production of A25 is 7.18 folds higher than that of wild strain QDA.