Mærk Mali, Jakobsen Øyvind M, Sletta Håvard, Klinkenberg Geir, Tøndervik Anne, Ellingsen Trond E, Valla Svein, Ertesvåg Helga
Department of Biotechnology and Food Science, Norwegian University of Science and Technology, Trondheim, Norway.
SINTEF Industry, Trondheim, Norway.
Front Bioeng Biotechnol. 2020 Jan 17;7:475. doi: 10.3389/fbioe.2019.00475. eCollection 2019.
produces the biopolymer alginate, which has a wide range of industrial and pharmaceutical applications. A random transposon insertion mutant library was constructed from ATCC12518Tc in order to identify genes and pathways affecting alginate biosynthesis, and about 4,000 mutant strains were screened for altered alginate production. One mutant, containing a disruption, displayed an elevated alginate production level, and several mutants with decreased or abolished alginate production were identified. The regulatory proteins AlgW and AmrZ seem to be required for alginate production in , similarly to . An mutation did however not affect alginate yield in although its homolog is needed for full alginate production. Inactivation of the fructose phosphoenolpyruvate phosphotransferase system protein FruA resulted in a mutant that did not produce alginate when cultivated in media containing various carbon sources, indicating that this system could have a role in regulation of alginate biosynthesis. Furthermore, impaired or abolished alginate production was observed for strains with disruptions of genes involved in peptidoglycan biosynthesis/recycling and biosynthesis of purines, isoprenoids, TCA cycle intermediates, and various vitamins, suggesting that sufficient access to some of these compounds is important for alginate production. This hypothesis was verified by showing that addition of thiamine, succinate or a mixture of lysine, methionine and diaminopimelate increases alginate yield in the non-mutagenized strain. These results might be used in development of optimized alginate production media or in genetic engineering of strains for alginate bioproduction.
产生生物聚合物海藻酸盐，其具有广泛的工业和制药应用。为了鉴定影响海藻酸盐生物合成的基因和途径，构建了来自ATCC12518Tc的随机转座子插入突变体文库，并筛选了约4000个突变菌株以检测海藻酸盐产量的变化。一个含有中断的突变体显示出海藻酸盐产量水平升高，并且鉴定出了几个海藻酸盐产量降低或丧失的突变体。调节蛋白AlgW和AmrZ似乎是海藻酸盐产生所必需的，这与……类似。然而，一个……突变并不影响……中的海藻酸盐产量，尽管其……同源物是完全产生海藻酸盐所必需的。果糖磷酸烯醇丙酮酸磷酸转移酶系统蛋白FruA的失活导致一个突变体，当在含有各种碳源的培养基中培养时不产生海藻酸盐，这表明该系统可能在海藻酸盐生物合成的调节中起作用。此外，对于参与肽聚糖生物合成/循环以及嘌呤、类异戊二烯、三羧酸循环中间体和各种维生素生物合成的基因被破坏的菌株，观察到海藻酸盐产量受损或丧失，这表明获得其中一些化合物对于海藻酸盐生产很重要。通过表明添加硫胺素、琥珀酸盐或赖氨酸、蛋氨酸和二氨基庚二酸的混合物可提高未诱变菌株中的海藻酸盐产量，验证了这一假设。这些结果可用于开发优化的海藻酸盐生产培养基或用于海藻酸盐生物生产的……菌株的基因工程。
