Kelco Division, Merck & Co., Inc., San Diego, California 92123.
Appl Environ Microbiol. 1982 May;43(5):1086-91. doi: 10.1128/aem.43.5.1086-1091.1982.
A new species of Pseudomonas was isolated that produced copious amounts of an exocellular heteropolysaccharide (PS-60) after incubation for 3 days at 30 degrees C in media containing 3% glucose as a carbon source. The polysaccharide was composed of approximately 46% glucose and 30% rhamnose and, in addition, contained 21% uronic acid and 3% O-acetyl. Upon deacetylation by a mild alkaline treatment, PS-60 produced a brittle, firm, and optically clear gel. This gelling property was thermoreversible. The PS-60 gel exhibited excellent heat stability that withstood autoclaving (i.e., 121 degrees C for 15 min) for several cycles. The gel strength, melting point, and setting point of the polysaccharide were controlled primarily by the concentration of cations. PS-60 was not affected by a variety of enzymes. The results of tests involving various culture media and biochemical test media indicate that PS-60 is an excellent alternative gelling agent to agar.
一种新的假单胞菌被分离出来，在含有 3%葡萄糖作为碳源的培养基中，于 30°C 下培养 3 天后，会产生大量的胞外杂多糖（PS-60）。该多糖由约 46%的葡萄糖和 30%的鼠李糖组成，此外，还含有 21%的糖醛酸和 3%的 O-乙酰基。经过温和的碱性处理脱乙酰化后，PS-60 产生了一种易碎、坚硬、光学透明的凝胶。这种凝胶性质具有热可逆性。PS-60 凝胶具有出色的热稳定性，可承受多次高压灭菌（即 121°C 下 15 分钟）。多糖的凝胶强度、熔点和凝固点主要受阳离子浓度的控制。PS-60 不受各种酶的影响。各种培养基和生化测试培养基的测试结果表明，PS-60 是琼脂的极佳替代品凝胶剂。
