G raduate School of Fisheries and Environmental Sciences, Nagasaki University, Nagasaki City, Nagasaki, Japan.
College of Environment and Natural Resources, Can Tho University, Can Tho City, Can Tho, Vietnam.
Biosci Biotechnol Biochem. 2024 Sep 20;88(10):1233-1241. doi: 10.1093/bbb/zbae102.
L-Proline (Pro) is an essential amino acid additive in livestock and aquaculture feeds. Previously, we created a Pro overproducing Halomonas elongata HN6 by introducing an engineered salt-inducible Pro biosynthetic mCherry-proBm1AC operon and deleting a putA gene that encoded a Pro catabolic enzyme in the genome of H. elongata OUT30018. Here, we report a generation of a novel Pro overproducing H. elongata HN10 strain with improved salt tolerance and higher Pro yield by expressing the mCherry-proBm1AC operon and deleting the putA gene in the genome of a spontaneous mutant H. elongata Glutamic acid Over-Producing, which overproduces glutamic acid (Glu) that is a precursor for Pro biosynthesis. The optimal salt concentration for growth of H. elongata HN10 was found to be 7% to 8% w/v NaCl, and the average Pro yield of 166 mg/L was achieved when H. elongata HN10 was cultivated in M63 minimal medium containing 4% w/v glucose and 8% w/v NaCl.
L-脯氨酸（Pro）是家畜和水产养殖饲料中的必需氨基酸添加剂。此前，我们通过引入工程化的盐诱导型 Pro 生物合成 mCherry-proBm1AC 操纵子并在 Halomonas elongata OUT30018 的基因组中删除编码 Pro 分解代谢酶的 putA 基因，创建了一个 Pro 过量产生的 Halomonas elongata HN6。在这里，我们报告了一种新型 Pro 过量产生的 Halomonas elongata HN10 菌株的产生，该菌株通过表达 mCherry-proBm1AC 操纵子并在自发突变株 Halomonas elongata Glutamic acid Over-Producing 的基因组中删除 putA 基因，提高了耐盐性和 Pro 产量，该突变株过量产生 Pro 生物合成的前体谷氨酸（Glu）。发现 Halomonas elongata HN10 生长的最佳盐浓度为 7%至 8% w/v NaCl，当 Halomonas elongata HN10 在含有 4% w/v 葡萄糖和 8% w/v NaCl 的 M63 最小培养基中培养时，平均 Pro 产量达到 166 mg/L。
