首次发现28℃培养至对数期且未分泌黄原胶的野油菜黄单胞菌(Xanthomonas campestris)移至4℃低温培养仍合成分泌黄原胶。黄原胶低温分泌最微细的结构单位是微丝，多根微丝进一步组成纤维、类似双螺旋或纤维束等级结构形式。低温分泌的黄原胶与28℃常温分泌的黄原胶相比有相同的化学组成与结构,但分子量、丙酮酸含量低。%We first find Xanthomonas campestris N. K-01 which don't produce xanthan at 28℃ cansynthesize and secrete the xanthan under low temperature (4℃). Little string is the most minute unit of the secreted under low temperature. Many little strings ecreted by bacterium cell extend to form a wider xanthan fiber. When depart from cell, xanthan fiber either twine to form double helix of bundle together. They are both advanced structures of the xanthan strings. Xanthan secreted under 4℃ has the same chemical composition and structure as that under 28℃, but lower moleculer weight and lower pyruvate content.
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