海洋来源褐藻胶裂解酶分离纯化及酶学性质研究

以假交替单胞菌(Pseudoalteromonas sp.zb7-4)发酵制备褐藻胶裂解酶粗酶液,采用弱阴离子DEAE交换层析分离褐藻胶裂解酶,分析纯化褐藻胶裂解酶Alg L的酶学特性.结果表明:Alg L的表观分子质量约为32 ku,比活力为(208.26±5.87)U·mg-1;其最适反应pH为7.0,在pH为6.0~10.0范围内稳定性较好,保温1 h仍能保持80%以上的相对酶活力;最适反应温度50℃,在40℃保温30 min,其残余酶活力高于80%;Cu2+、Cr3+、Co2+、Ba2+、Sr2+、Hg2+对该酶具有不同程度的抑制作用,Hg2+抑制作用最为明显;该酶具有较好的盐耐受性,在3 mol·L-1Na Cl反应体系中保温2 h,仍残余66%酶活力.动力学参数Km、Vmax、Kcat测定表明,该酶对聚古罗糖醛酸钠(PG)亲和力较高,为偏好聚甘露糖醛酸钠(PM)裂解作用的双功能酶.     

1株海洋石油降解菌的筛选鉴定及其固定化研究

从受石油污染的海洋沉积物中分离得到1株能以柴油为唯一碳源生长的菌株LHOD-2,通过形态特征、生理生化及16SrDNA序列分析,初步鉴定菌株LHOD-2属于埃氏假交替单胞菌(Pseudoalteromonas espejiana).利用聚氨酯泡沫为载体制备固定化菌,并对其降解特性进行考察.实验结果表明,菌株LHOD-2的最佳生长降解条件为温度25~30℃,pH 7.0~8.0,盐度(体积分数)3%~3.5%,转速150r/min.在最佳条件下,LHOD-2对800mg/L柴油在120h内的降解率达到85%(质量分数).聚氨酯泡沫载体具有大孔网状结构,利于菌株生长和传质,固定化菌降解柴油的速率明显高于游离菌.     

假单胞交替菌BYS-2产褐藻胶裂解酶条件研究

以褐藻酸钠作为初筛培养基的唯一碳源,从鲍鱼养殖水样中分离获得一株产褐藻胶裂解酶的假单胞交替菌BYS-2。对该菌株进行产酶条件研究,获得最适产酶配方(w/v)为：褐藻酸钠0.1%,葡萄糖0.05%,酵母膏1%,黄豆饼粉0.3%,(NH4)2HPO4 0.3%,初始培养基pH8.0;最佳产酶条件为：接种量2%(v/v),装液量50mL/250mL,发酵温度20℃,摇床转速200 r/min,在此条件下发酵24h酶活力可达5.29U/mL,比优化前(1.57 U/mL)提高2.37倍。     

Isolation, chemical characteristics and immunity activity of an extracellular polysaccharide EPSⅠ isolated from Antarctic bacterium Pseudoalteromonas sp. S-15-13

A new extracelluar polysaccharide (EPS) was isolated and purified from Antarctic bacterium S-15-13, identified as Pseudoalteromonas sp. After being separated and purified by DEAE-Sephadex A-50 ionexchange and Sephadex G-100 gel chromatography, two mains fractions (EPSⅠand EPSⅡ) were obtained. EPSⅠwas composed of mannose, glucose and galactose with a molecular weight of 23kDa and EPSⅡwas composed of mannose only with a molecular weight of 62kDa.The effect of the polysaccharide EPSⅠ on the cellular immune response of mice was investigated. Results demonstrated that EPSⅠ could markedly facilitate lymphocyte proliferation, and might be a strong immunomodulator.     

Isolation, chemical characteristics and immunity activity of an extracellular polysaccharide EPSⅠ isolated from Antarctic bacterium Pseudoalteromonas sp. S-15-13

A new extracelluar polysaccharide (EPS) was isolated and purified from Antarctic bacterium S-15-13, identified as Pseudoalteromonas sp. After being separated and purified by DEAE-Sephadex A-50 ionexchange and Sephadex G-100 gel chromatography, two mains fractions (EPSⅠ and EPSⅡ ) were obtained. EPSⅠ was composed of mannose, glucose and galactose with a molecular weight of 23kDa and EPSⅡ was composed of mannose only with a molecular weight of 62kDa. The effect of the polysaccharide EPSⅠ on the cellular immune response of mice was investigated. Results demonstrated that EPSⅠ could markedly facilitate lymphocyte proliferation, and might be a strong immunomodulator.     

Isolation, chemical characteristics and immunity activity of an extracellular polysaccharide EPS I isolated from Antarctic bacterium Pseudoalteromonas sp.S-15-13

A new extracelluar polysaccharide （EPS） was isolated and purified from Antarctic bacterium S-15-13, identified as Pseudoalteromonas sp. After being separated and purified by DEAE-Sephadex A-50 ionexchange and Sephadex G-100 gel chromatography, two mains fractions （EPS I and EPS Ⅱ ） were ob-tained. EPS I was composed of mannose, glucose and galactose with a molecular weight of 23kDa and EPS Ⅱ was composed of mannose only with a molecular weight of 62kDa. The effect of the polysaccharide EPS I on the cellular immune response of mice was investigated. Results demonstrated that EPS I could markedly facilitate lymphocyte proliferation, and might be a strong immunomodulator.