Engineering Sinorhizobium meliloti hemoprotein to enhance nosiheptide production in Streptomyces actuosus
首发时间:2016-04-06
Abstract:Oxygen deficiency is a critical limiting factor for nosiheptide production in Streptomyces actuosus during fermentation. To alleviate oxygen limitation and enhance the yield of nosiheptide, hemoprotein from Sinorhizobium meliloti (SmHb) was overexpressed in S. actuosus with overexpression of hemoglobin from Vitreoscilla (VHb) as a positive control. The successful expression of SmHb and VHb in S. actuosus was confirmed by SDS-PAGE and CO-difference spectra analysis. The results showed that S. actuosus recombinant strain with SmHb expression improved nosiheptide production by 138% compared with the wild strain (WT) under the low aeration condition, which was similar to S. actuosus mutant strain with VHb expression. Furthermore, two copies of SmHb gene were integrated in S. actuosus, which further increased the nosiheptide production by approximately 1.9-fold higher than original strain, and final concentration of nosiheptide was up to 2352 μg/mL. These results suggested that engineering of SmHb could be used as an efficient method for constructing a high nosiheptide-accumulating strain.
keywords: hemoprotein Nosiheptide Sinorhizobium meliloti Streptomyces actuosus
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在活跃链霉菌中过表达根瘤菌血红蛋白基因以提高那那西肽产量
摘要:活跃链霉菌在发酵过程中溶氧不足问题是限制因素。为了改善其溶氧环境,提高那西肽的产量,本实验在活跃链霉菌中过表达根瘤菌血红蛋白(SmfHb),并以过表达透明颤菌血红蛋白(VHb)的菌株作为阳性对照。经SDS-PAGE和CO差示光谱分析确认SmfHb和VHb已经成功在活跃链霉菌中表达。发酵结果显示,过表达SmfHb的菌株MG-2在低氧条件下那西肽产量比原始菌株提高138%。并且双拷贝SmfHb的菌株其那西肽产量可进一步提高,其产量高达2352 μg/mL为原始菌株的1.9倍。由此说明,过表达SmfHb可作为提高那西肽产量的一种有效方法。
关键词: 细菌血红蛋白;那西肽;根瘤菌;活跃链霉菌
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在活跃链霉菌中过表达根瘤菌血红蛋白基因以提高那那西肽产量
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