| 摘要: |
| 从海藻及海参中分离筛选得到4株琼胶降解菌HD、JL、QJ 和HS,均为革兰氏阴性菌,确定了它们发酵产酶的最佳条件均为: 2216E海水培养基、初始Ph 7.5、琼胶底物浓度0.30%、培养温度28℃、培养时间36h。大部分酶分泌到细菌细胞外。生理生化检测、16SrDNA序列同源性及聚类分析结果表明, HD、JL、HS为白色噬琼胶菌(Agarivorans albus); QJ的16SrDNA 序列与Simiduia sp.,糖噬胞菌属(Saccharophagus sp.)和船蛆杆菌(Teredinibacter sp.)的相似性为93%～94%,在进化树上单独形成一个分支, 但生理生化特征与它们有所不同,分类地位需要进一步确定。从HD、JL 和HS中能克隆到β-琼胶酶基因,它们与其他物种的β-琼胶酶基因序列的相似性为97%～98%。 |
| 关键词: 琼胶降解菌(agarase-producing bacteria) 琼胶酶活力 鉴定 白色噬琼胶菌(Agarivorans albus) β-琼胶酶基因 |
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| 基金项目:国家自然科学基金资助项目(30972247, 30700621); 国家“ 863 ” 高技术研究发展计划(2012AA10A411, 2012AA10A406,2012AA100815); 农业部公益行业专项(200903030); 国家科技基础条件平台-水产种质资源平台 |
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| Isolation and identification of agarase-producing bacteria and analysis of optimal growth conditions for enzyme production |
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| Abstract: |
| Four Gram negative strains of agarase-producing bacteria HD, JL, QJ and HS were isolated from algaes and intestine of sea cucumber. The optimum growth conditions for enzyme production were determined as follows: 2216E marine medium, initial pH 7.5, 0.30% agar, culture temperature 28℃ with 120 rpm shaking and culture time 36 hours. The high enzymic activities were detected in the extracellular products of bacteria. Physiological and biochemical identification together with phylogenetic analysis based on 16S rDNA sequence similarity showed that HD, JL and HS belong to Agarivorans albus. QJ was related with Simiduia sp., Saccharophagus sp. and Teredinibacter sp., but its biochemical traits were different from those of these related species. Sequence of β-agarase gene was cloned from HD,JL and HS and they were highly related with those from other bacterial species. |
| Key words: agarase-producing bacteria agarase activity identification Agarivorans albus β-agarase gene |
