Synthesis of poly(3-hydroxybutyrate-co-4-hydroxybutyrate) with high 4HB composition and PHA content using 1,4-butanediol and 1,6-hexanediol for medical application
Synthesis of poly(3-hydroxybutyrate-co-4-hydroxybutyrate) with high 4HB composition and PHA content using 1,4-butanediol and 1,6-hexanediol for medical application
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DOI：
10.1007/s10965-017-1345-x
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发表时间：
2017-10-18
影响因子：
2.8
通讯作者：
Amirul, A. A.
中科院分区：
文献类型：
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作者：
Norhafini, Hambali;Thinagaran, L.;Amirul, A. A.
具有高4HB单体的聚(3-羟基丁酸酯-co-4-羟基丁酸酯)[P(3HB-co-4HB)]具有增强的生物相容性和机械性能，可用作医疗和制药领域的可植入和可吸收生物材料。转化Cupriavidus sp。发现具有附加 PHA 合酶基因 phaC 的 USMAA1020 在使用 1,6-己二醇和 1,4-丁二醇的混合底物的摇瓶培养中产生具有 86 mol% 4HB 单体组成和 69 wt% 的高 PHA 含量的 P(3HB-co-4HB)。 3 L发酵的单阶段培养已证实该菌株能够在大规模发酵中产生95 mol%的高4HB单体成分，PHA含量为75 wt%，PHA浓度高达18.7 g/L。有趣的是，该菌株能够在比野生型菌株（0.69 wt% C）更高的碳浓度（1.05 wt% C）中存活。本研究结果表明，P(3HB-co-4HB)的PHA含量和浓度分别是野生型菌株的1.3倍和2.3倍，并且积累4HB单体成分的能力比野生型菌株高2.1倍。还获得了0.123 h(-1)的较高比生长速率以及高产物产量，Y-p/x是野生型菌株的3.8倍。 TEM 图像显示细胞的 PHA 含量为 75 wt%，其中充满了显着的 PHA 颗粒。该共聚物的平均分子量（M-w）和多分散指数分别为156 kDa和3.5，拉伸强度、断裂伸长率和杨氏模量分别为22.9 MPa、463.2%和187.3 MPa。该聚合物的玻璃化转变温度（T-g）和熔融温度（T-m）分别为-48.9℃和61.9℃。
Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) [P(3HB-co-4HB)] with high 4HB monomer harbors enhanced biocompatibility and mechanical properties, which are useful as implantable and absorbable biomaterial in medical and pharmaceutical fields. Transformant Cupriavidus sp. USMAA1020 with an additional PHA synthase gene, phaC was found to produce P(3HB-co-4HB) with 86 mol% of 4HB monomer composition and high PHA content of 69 wt% in shake flask cultivation using mixed substrate of 1,6-hexanediol and 1,4-butanediol. Single-stage cultivation in 3 L fermentation has confirmed the ability of this strain to produce high 4HB monomer composition of 95 mol% in large scale fermentation with 75 wt% PHA content and high PHA concentration of 18.7 g/L. Interestingly, this strain was capable of surviving higher carbon concentration (1.05 wt% C) than the wild-type strain (0.69 wt% C). The present study results in P(3HB-co-4HB) with 1.3 and 2.3-fold PHA content and concentration respectively, with the ability to accumulate 2.1-fold 4HB monomer composition higher compared to the wild-type strain. A higher specific growth rate of 0.123 h(-1) accompanied by high product yield, Y-p/x of 3.8 times more than the wild-type strain were also obtained. Image from TEM showed cells with PHA content of 75 wt%, whichwere occupied with significant PHA granule. This copolymer possesses an average molecular weight (M-w) and a polydispersity index of 156 kDa and 3.5 respectively with a tensile strength, elongation at break and Young's modulus of 22.9 MPa, 463.2% and 187.3 MPa respectively. This polymer has a glass transition temperature (T-g) and melting temperature (T-m) of -48.9 degrees C and 61.9 degrees C respectively.