Poly(β-hydroxybutyrate) production in oilseed leukoplasts of Brassica napus
Poly(β-hydroxybutyrate) production in oilseed leukoplasts of Brassica napus
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DOI：
10.1007/s004250050760
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发表时间：
1999-10-01
期刊：
影响因子：
4.3
通讯作者：
Gruys, KJ
中科院分区：
文献类型：
--
作者：
Houmiel, KL;Slater, S;Gruys, KJ
聚羟基烷酸酯（PHA）是一类可生物降解的聚合物，为石油基塑料提供了一种环境可持续的替代品。在植物中生产PHA是有吸引力的，因为目前的发酵技术过于昂贵。PHA均聚物聚（β-羟基丁酸酯）（PHB）先前已经在拟南芥的叶中产生（Nawrath等人，1994，Proc Natl Acad Sci USA 91. 12760-12764）。然而，甘蓝型油菜油籽可能提供了一个更好的系统，为PHB的生产，因为乙酰辅酶A，在第一步的PHB生物合成所需的底物，是普遍的脂肪酸生物合成。合成PHB需要三种酶活性：β-酮硫解酶、乙酰-乙酰-CoA还原酶和PHB合酶。编码这些酶的细菌Ralstonia eutropha的基因以模块化方式独立地工程化在种子特异性Lesquerella fendleri oleate 12-羟化酶启动子后面。将基因盒依次转移到用于转化B的单个多基因载体中。油菜。聚（β-羟基丁酸酯）积累在白细胞体的水平高达7.7%的成熟种子鲜种子重量。电子显微镜分析表明，从这些植物的白细胞体是扭曲的，但完整的，并出现扩大聚合物的积累。
Polyhydroxyalkanoates (PHAs) comprise a class of biodegradable polymers which offer an environmentally sustainable alternative to petroleum-based plastics. Production of PHAs in plants is attractive since current fermentation technology is prohibitively expensive. The PHA homopolymer poly(beta-hydroxybutyrate) (PHB) has previously been produced in leaves of Arabinopsis thaliana (Nawrath et al., 1994, Proc Natl Acad Sci USA 91. 12760-12764). However, Brassica napus oilseed may provide a better system for PHB production because acetyl-CoA, the substrate required in the first step of PHB biosynthesis, is prevalent during fatty acid biosynthesis. Three enzymatic activities are needed to synthesize PHB: a beta-ketothiolase, an aceto-acetyl-CoA reductase and a PHB synthase. Genes from the bacterium Ralstonia eutropha encoding these enzymes were independently engineered behind the seed-specific Lesquerella fendleri oleate 12-hydroxylase promoter in a modular fashion. The gene cassettes were sequentially transferred into a single, multi-gene vector which was used to transform B. napus. Poly(beta-hydroxybutyrate) accumulated in leukoplasts to levels as high as 7.7% fresh seed weight of mature seeds. Electronmicroscopy analyses indicated that leukoplasts from these plants were distorted, yet intact, and appeared to expand in response to polymer accumulation.