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    Targeted gene deletions for polysaccharide slime formers
    2.
    发明申请
    Targeted gene deletions for polysaccharide slime formers 有权
    多糖粘液形成物的靶向基因缺失

    公开(公告)号：US20060199201A1

    公开(公告)日：2006-09-07

    申请号：US11347341

    申请日：2006-02-03

    申请人： Nancy Harding ,  Yamini Patel ,  Russell Coleman

    发明人： Nancy Harding ,  Yamini Patel ,  Russell Coleman

    IPC分类号： C12Q1/68 ,  A61K31/715 ,  C12P19/34 ,  C12P19/04 ,  A01N43/04 ,  C08B37/00 ,  C12N1/21 ,  C12N15/74

    CPC分类号： C12N15/74 ,  C07K14/195 ,  C12N15/52 ,  C12P19/04

    摘要： Sphingomonas strains have extracellular polysaccharide (e.g., gellan, diutan) that is firmly attached to the cell surface. This attachment may limit polysaccharide production by impairing uptake of nutrients into the cell or due to limited sites for polysaccharide biosynthesis on the cell surface. Two genes for polysaccharide biosynthesis, designated gelM and gelN in gellan-producing strains and dpsM and dpsN in diutan-producing strains, have been inactivated by deletion mutations and shown to produce polysaccharide that is not firmly attached to the cell surface, i.e., slime form. Another gene for polysaccharide biosynthesis, designated gelI in gellan producing strains, was inactivated by insertion mutation and also shown to produce the slime phenotype. The homologous gene dpsi in the diutan producing strain should also be involved in the attachment of the polysaccharide to the cell surface. The slime characteristic was demonstrated by the ability of the cells to be centrifuged and the lack of cell clumping as seen under the microscope or in diluted suspensions. The diutan slime mutants had somewhat increased productivity and the recovered diutan product had significantly improved rheology. Gellan slime mutants had lower broth viscosity which facilitates mixing during fermentation; however, the recovered gellan product had lower gel strength than the gellan produced from a capsular strain. A deletion in a gene gelR, which encodes a protein with homology to surface proteins and outer membrane proteins and weak homology to proteins with polysaccharide degradation activity, was shown to restore higher gel strength to the slime form of gellan, and to produce gellan of higher gel strength than that of the capsular gellan producing strains.

    摘要翻译： 鞘氨醇单胞菌属菌株具有牢固附着于细胞表面的细胞外多糖（例如，结冷糖，二氘）。 这种附着可能通过损害营养物质进入细胞或由于细胞表面上多糖生物合成的有限位点而限制多糖产生。 用于多糖生物合成的两个基因，在凝胶产生菌株中命名为gelM和gelN，并且在产生二萜的菌株中的dpsM和dpsN已经被缺失突变失活，并且显示产生不牢固附着于细胞表面的多糖，即粘液形式 。 用于多糖生物合成的另一基因，在凝胶产生菌株中称为gelI，通过插入突变失活，并且还显示产生粘液表型。 二萜生产菌株中的同源基因dpsi也应参与多糖与细胞表面的连接。 通过细胞离心的能力和在显微镜下或在稀释的悬浮液中观察到的细胞团聚的缺乏证明了粘液特性。 di an sl ime mut mut ants。。。。。。。。。。。。。。。。。。。。 凝胶粘液突变体具有较低的肉汤粘度，有利于发酵期间的混合; 然而，回收的结冷胶产品的凝胶强度低于从荚膜菌株产生的结冷胶。 基因gelR中的缺失，其编码与表面蛋白质和外膜蛋白质具有同源性的蛋白质和与具有多糖降解活性的蛋白质具有弱同源性的蛋白质，被证明能够恢复与粘液形式的结冷胶的更高的凝胶强度，并且产生更高的结晶 凝胶强度高于荚膜凝胶产生菌株。

    Genetically purified gellan gum
    3.
    发明申请
    Genetically purified gellan gum 有权
    基因纯化的结冷胶

    公开(公告)号：US20060003051A1

    公开(公告)日：2006-01-05

    申请号：US11156953

    申请日：2005-06-20

    申请人： Joseph Cleary ,  Russell Coleman ,  Nancy Harding ,  Yamini Patel

    发明人： Joseph Cleary ,  Russell Coleman ,  Nancy Harding ,  Yamini Patel

    IPC分类号： A23C9/12

    CPC分类号： C08L5/00 ,  A23C9/137 ,  A23C9/1544 ,  A23L29/272 ,  C08B37/006 ,  C12N9/16 ,  C12N9/2402 ,  C12N9/2405 ,  C12P19/04 ,  C12Y302/01031

    摘要： Mutational inactivation of proteins involved in para-cresol production in certain milk products results in improved taste and odor. The undesirable para-cresol forms over time as a result of enzymes produced by the bacterium that produces gellan gum. Since the gellan is typically used in a relatively unpurified form, the enzymes are added to the milk along with the gellan. Inactivation of the enzymes is a genetic means of eliminating the enzymes without requiring any additional purification or processing.

    摘要翻译： 涉及某些乳制品中对甲酚生产的蛋白质的突变失活导致改善的味道和气味。 作为由产生结冷胶的细菌产生的酶的结果，不期望的对甲酚随时间而变化。 由于结冷胶通常以相对未纯化的形式使用，所以将酶与吉兰糖一起加入到牛奶中。 酶的失活是消除酶的遗传手段，而不需要任何额外的纯化或加工。