Departments of Biochemistry and Polymer Science and Engineering, University of Massachusetts, Amherst, Massachusetts 01003.
Appl Environ Microbiol. 1988 Aug;54(8):1977-82. doi: 10.1128/aem.54.8.1977-1982.1988.
Pseudomonas oleovorans was grown in homogeneous media containing n-alkanoic acids, from formate to decanoate, as the sole carbon sources. Formation of intracellular poly(beta-hydroxyalkanoates) was observed only for hexanoate and the higher n-alkanoic acids. The maximum isolated polymer yields were approximately 30% of the cellular dry weight with growth on either octanoate or nonanoate. In most cases, the major repeating unit in the polymer had the same chain length as the n-alkanoic acid used for growth, but units with two carbon atoms less or more than the acid used as a carbon source were also generally present in the polyesters formed. Indeed, copolymers containing as many as six different types of beta-hydroxyalkanoate units were formed. The weight average molecular weights of the poly(beta-hydroxyalkanoate) copolymers produced by P. oleovorans ranged from 90,000 to 370,000. In spite of the higher cell yields obtained with octanoate and nonanoate, the use of hexanoate and heptanoate yielded higher-molecular-weight polymers. These copolyesters represent an entirely new class of biodegradable thermoplastics.
铜绿假单胞菌在含有从甲酸盐到癸酸的直链烷酸的均相介质中生长，作为唯一的碳源。只有己酸和更高的直链烷酸才能观察到细胞内多（β-羟基烷酸酯）的形成。用辛酸盐或壬酸盐生长时，最大的分离聚合物产率约为细胞干重的 30%。在大多数情况下，聚合物中的主要重复单元与用作生长的直链烷酸具有相同的链长，但也通常存在比用作碳源的酸少两个碳原子或多两个碳原子的单元。实际上，形成了含有多达六种不同类型β-羟基烷酸单元的共聚物。铜绿假单胞菌产生的聚（β-羟基烷酸酯）共聚物的重均分子量范围从 90000 到 370000。尽管用辛酸盐和壬酸盐获得了更高的细胞产率，但使用己酸和庚酸可得到更高分子量的聚合物。这些共聚酯代表了一类全新的可生物降解热塑性塑料。
