Biosynthesis and properties of poly(3-hydroxybutyrate-co-3-hydroxyalkanoates) by recombinant strains of Pseudomonas sp 61-3
Biosynthesis and properties of poly(3-hydroxybutyrate-co-3-hydroxyalkanoates) by recombinant strains of Pseudomonas sp 61-3
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DOI：
10.1021/bm9900040
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发表时间：
2000-03-01
影响因子：
6.2
通讯作者：
Doi, Y
中科院分区：
文献类型：
--
作者：
Matsusaki, H;Abe, H;Doi, Y
假单胞菌61-3（phbC：：ter）菌株是一种phbC（Ps）破坏的突变株，积累了由6-12个碳原子的（R）-3-羟基丁酸酯（3 HB）和（R）-中链长3-羟基链烷酸酯（3 HA）单元组成的无规共聚物，但共聚物中的3 HB部分小于50摩尔%，导致形成无定形聚合物。因此，编码真养罗尔斯通氏菌的β-酮硫解酶（PhbA（Re））和NADPH依赖性乙酰乙酰CoA还原酶（PhbB（Re））的基因在假单胞菌61-3 pha基因座或R.在phbC（Ps）破坏的突变体中，真养菌phb操纵子与来自假单胞菌属61-3的phaCl（Ps）基因（PHA合酶1基因）一起。重组菌株从葡萄糖合成具有非常高的3 HB组成（高达94摩尔%）的P（3 HB-co-3 HA）共聚物。P（3 HB-co-3 HA）的数均分子量在349 X 10（3）至605 X 10（3）的范围内。采用核磁共振氢谱、碳谱、差示扫描量热法和力学性能测试等手段对共聚物的结构和物理性能进行了表征。P（94% 3 HB-co-3 HA）共聚物具有良好的物理性能，是一种韧性适中的柔性材料，与低密度聚乙烯相似。
Pseudomonas sp. 61-3 (phbC::ter) strain, which is a phbC(Ps)-disrupted mutant, accumulated a random copolymer consisting of (R)-3-hydroxybutyrate (3HB) and (R)-medium-chain-length 3-hydroxyalkanoate (3HA) units of 6-12 carbon atoms, but the 3HB fraction in the copolymer was less than 50 mol %, resulting in the formation of an amorphus polymer. Therefore, the genes encoding beta -ketothiolase (PhbA(Re)) and NADPH-dependent acetoacetyl-CoA reductase (PhbB(Re)) from Ralstonia eutropha were expressed under the control of promoters for Pseudomonas sp. 61-3 pha locus or R. eutropha phb operon together with the phaCl(Ps) gene (PHA synthase 1 gene) from Pseudomonas sp. 61-3 in the phbC(Ps)-disrupted mutant. The recombinant strains synthesized P(3HB-co-3HA) copolymers with very high 3HB compositions (up to 94 mol %) from glucose. The number-average molecular weights of P(3HB-co-3HA) were in the range of 349 x 10(3) to 605 x 10(3). The structure and physical properties of P(3HB-co-3HA) copolymers were characterized by H-1- and C-13-NMR spectrometry, differential scanning calorimetry, and mechanical tensile measurement. P(94% 3HB-co-3HA) copolymer was demonstrated to have good physical properties and to be a flexible material with moderate toughness, similar to low-density polyethylene.