Choi Tae-Rim, Park Ye-Lim, Song Hun-Suk, Lee Sun Mi, Park Sol Lee, Lee Hye Soo, Kim Hyun-Joong, Bhatia Shashi Kant, Gurav Ranjit, Choi Kwon-Young, Lee Yoo Kyung, Yang Yung-Hun
Department of Biological Engineering, College of Engineering, Konkuk University, Hwayang-dong, Gwangjin-gu, Seoul 05029, Korea.
Institute for Ubiquitous Information Technology and Applications, Konkuk University, Seoul 05029, Korea.
Polymers (Basel). 2021 Apr 26;13(9):1398. doi: 10.3390/polym13091398.
Arctic bacteria employ various mechanisms to survive harsh conditions, one of which is to accumulate carbon and energy inside the cell in the form of polyhydroxyalkanoate (PHA). Whole-genome sequencing of a new Arctic soil bacterium sp. B14-6 revealed two PHA-production-related gene clusters containing four PHA synthase genes (). sp. B14-6 produced poly(6% 3-hydroxybutyrate--94% 3-hydroxyalkanoate) from various carbon sources, containing short-chain-length PHA (scl-PHA) and medium-chain-length PHA (mcl-PHA) composed of various monomers analyzed by GC-MS, such as 3-hydroxybutyrate, 3-hydroxyhexanoate, 3-hydroxyoctanoate, 3-hydroxydecanoate, 3-hydroxydodecenoic acid, 3-hydroxydodecanoic acid, and 3-hydroxytetradecanoic acid. By optimizing the PHA production media, we achieved 34.6% PHA content using 5% fructose, and 23.7% PHA content using 5% fructose syrup. Differential scanning calorimetry of the scl--mcl PHA determined a glass transition temperature (T) of 15.3 °C, melting temperature of 112.8 °C, crystallization temperature of 86.8 °C, and 3.82% crystallinity. In addition, gel permeation chromatography revealed a number average molecular weight of 3.6 × 10, weight average molecular weight of 9.1 × 10, and polydispersity index value of 2.5. Overall, the novel sp. B14-6 produced a polymer with high medium-chain-length content, low T, and low crystallinity, indicating its potential use in medical applications.
北极细菌采用多种机制在恶劣条件下生存，其中之一是以聚羟基脂肪酸酯（PHA）的形式在细胞内积累碳和能量。一种新的北极土壤细菌B14-6的全基因组测序揭示了两个与PHA产生相关的基因簇，其中包含四个PHA合酶基因。B14-6从各种碳源产生聚（6% 3-羟基丁酸酯-94% 3-羟基链烷酸酯），其中含有通过气相色谱-质谱分析的由各种单体组成的短链长度PHA（scl-PHA）和中链长度PHA（mcl-PHA），如3-羟基丁酸、3-羟基己酸、3-羟基辛酸、3-羟基癸酸、3-羟基十二碳烯酸、3-羟基十二烷酸和3-羟基十四烷酸。通过优化PHA生产培养基，我们使用5%果糖时PHA含量达到34.6%，使用5%果糖糖浆时PHA含量达到23.7%。对scl-mcl PHA进行差示扫描量热法测定，玻璃化转变温度（Tg）为15.3℃，熔点为112.8℃，结晶温度为86.8℃，结晶度为3.82%。此外，凝胶渗透色谱显示数均分子量为3.6×10，重均分子量为9.1×10，多分散指数值为2.5。总体而言，新型B14-6产生了一种具有高中链长度含量、低Tg和低结晶度的聚合物，表明其在医学应用中的潜在用途。
