Abstract
BackgroundAgmatine is a member of biogenic amines and is an important medicine which is widely used to regulate body balance and neuroprotective effects. At present, the industrial production of agmatine mainly depends on the chemical method, but it is often accompanied by problems including cumbersome processes, harsh reaction conditions, toxic substances production and heavy environmental pollution. Therefore, to tackle the above issues, arginine decarboxylase was overexpressed heterologously and rationally designed in Corynebacterium crenatum to produce agmatine from glucose by one-step fermentation.ResultsIn this study, we report the development in the Generally Regarded as Safe (GRAS) l-arginine-overproducing C. crenatum for high-titer agmatine biosynthesis through overexpressing arginine decarboxylase based on metabolic engineering. Then, arginine decarboxylase was mutated to release feedback inhibition and improve catalytic activity. Subsequently, the specific enzyme activity and half-inhibitory concentration of I534D mutant were increased 35.7% and 48.1%, respectively. The agmatine production of the whole-cell bioconversion with AGM3 was increased by 19.3% than the AGM2. Finally, 45.26 g/L agmatine with the yield of 0.31 g/g glucose was achieved by one-step fermentation of the engineered C. crenatum with overexpression of speAI534D.ConclusionsThe engineered C. crenatum strain AGM3 in this work was proved as an efficient microbial cell factory for the industrial fermentative production of agmatine. Based on the insights from this work, further producing other valuable biochemicals derived from l-arginine by Corynebacterium crenatum is feasible.
Highlights
Agmatine is a member of biogenic amines and is an important medicine which is widely used to regulate body balance and neuroprotective effects
The industrial production of agmatine mainly depends on the chemical method, which is often accompanied by problems such as low efficiency, harsh reaction conditions and heavy environmental pollution [7]
The arginine decarboxylase from E. coli was selected to produce agmatine [25], and C. crenatum SYPA was chosen as the chassis strain in this work due to its capability to overproduce l-arginine
Summary
Construction of the engineered C. crenatum by overexpressing arginine decarboxylase Agmatine, an intermediate metabolite of the biogenic amines synthesis pathway, is produced from l-arginine as the precursor [23]. C. crenatum AGM3 grew with a rate of 0.18 h−1 to a final cell dry weight concentration of 17.71 g/L and the cell density measurement showed no significant differences between AGM2 and AGM3 These results indicate that AGM0 is unable to produce agmatine, the cell density of AGM0 was higher than the other two strains (Fig. 5b). The strain AGM2 produced 1.68 g/L l-arginine, which was not found in AGM3, which may be due to the relatively low catalytic activity and the feedback inhibition of wild-type SpeA. These results illustrated that the yield of agmatine could be increased by releasing feedback inhibition of SpeA. Those are the highest value for agmatine production from C. crenatum, demonstrating that the engineered strain C. crenatum AGM3 is a competitive platform strain for agmatine production
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