Sanford P A, Burton K A, Watson P R, Cadmus M C, Jeanes A
Appl Microbiol. 1975 Jun;29(6):769-75. doi: 10.1128/am.29.6.769-775.1975.
When the extracellular polysaccharide from the black yeast NRRL Y-6272, composed of two parts N-acetyl-D-glucosamine and one part N-acetyl-D-glucosaminuronic acid, is isolated at maximum culture viscosity, adhering black pigment gives the polysaccharide preparations a gray-to-black appearance. Precipitation of the polysaccharide from cell-free culture supernatants with either ethanol of hexadecyltrimethylammonium bromide failed to remove the pigment. Various other methods were therefore tried for obtaining a high-viscosity polysaccharide product free of pigment. By systematically varying ingredients of defined and semidefined media, an improved medium was found that not only gave polysaccharide preparations of increased viscosity, but also increased yield. A key ingredient in this medium is L-asparagine. Also, adding autoclaved bovine serum albumin or egg albumin to this medium at the time of inoculation allowed a pigment-free polysaccharide to be isolated by standard procedures. None of several other proteins of synthetic polyamides tested were as effective as bovine serum albumin or egg albumin. In an alternate approach, pink mutants obtained by irradiation of the parent black strain with ultraviolet light, apparently produce the same extracellular polysaccharide free of any pigment but in lower yields or inferior in quality.
当从黑酵母NRRL Y - 6272中分离出由两部分N - 乙酰 - D - 葡萄糖胺和一部分N - 乙酰 - D - 葡萄糖醛酸组成的细胞外多糖时，在最大培养粘度下进行分离，附着的黑色色素使多糖制剂呈现出从灰色到黑色的外观。用乙醇或十六烷基三甲基溴化铵从无细胞培养上清液中沉淀多糖未能去除色素。因此尝试了各种其他方法来获得不含色素的高粘度多糖产品。通过系统地改变限定培养基和半限定培养基的成分，发现了一种改良培养基，它不仅能使多糖制剂的粘度增加，还能提高产量。这种培养基中的关键成分是L - 天冬酰胺。此外，在接种时向该培养基中加入高压灭菌的牛血清白蛋白或蛋清蛋白，可以通过标准程序分离出无色素的多糖。测试的其他几种合成聚酰胺蛋白质均不如牛血清白蛋白或蛋清蛋白有效。在另一种方法中，用紫外线照射亲本黑色菌株获得的粉色突变体，显然产生相同的无任何色素的细胞外多糖，但产量较低或质量较差。
