Author:
Yang Shaomei,Wang Anlong,Li Jiachang,Shao Yunhang,Sun Fengjie,Li Shucheng,Cao Kai,Liu Hongliang,Xiong Peng,Gao Zhengquan
Abstract
Abstract
Background
Heme is an iron/porphyrin complex compound, widely used in the health care, food, and pharmaceutical industries. It is more advantageous and attractive to develop microbial cell factories to produce heme by fermentation, with lower production costs and environmentally more friendly procedures than those of the traditional extraction based on animal blood. In this study, Bacillus subtilis, a typical industrial model microorganism of food safety grade, was used for the first time as the host to synthesize heme.
Results
The heme biosynthetic pathway was engineered as four modules, the endogenous C5 pathway, the heterologous C4 pathway, the uroporphyrinogen (urogen) III synthesis pathway, and the downstream synthesis pathway. Knockout of hemX encoding the negative effector of the concentration of HemA, overexpression of hemA encoding glutamyl-tRNA reductase, and knockout of rocG encoding the major glutamate dehydrogenase in the C5 pathway, resulted in an increase of 427% in heme production. Introduction of the heterologous C4 pathway showed a negligible effect on heme biosynthesis. Overexpression of hemCDB, which encoded hydroxymethylbilane synthase, urogen III synthase, and porphobilinogen synthase participating in the urogen III synthesis pathway, increased heme production by 39%. Knockouts of uroporphyrinogen methyltransferase gene nasF and both heme monooxygenase genes hmoA and hmoB in the downstream synthesis pathway increased heme production by 52%. The engineered B. subtilis produced 248.26 ± 6.97 mg/L of total heme with 221.83 ± 4.71 mg/L of extracellular heme during the fed-batch fermentation in 10 L fermenter.
Conclusions
Strengthening endogenous C5 pathway, urogen III synthesis pathway and downstream synthesis pathway promoted the biosynthesis of heme in B. subtilis. The engineered B. subtilis strain has great potential as a microbial cell factory for efficient industrial heme production.
Funder
National Natural Science Foundation of China
Natural Science Foundation of Shandong Province
Publisher
Springer Science and Business Media LLC
Subject
Applied Microbiology and Biotechnology,Bioengineering,Biotechnology
Reference40 articles.
1. Gallio AE, Fung SP, Cammack-Najera A, Hudson AJ, Raven EL. Understanding the logistics for the distribution of heme in cells. J Am Chem Soc. 2021;1:1541–55.
2. Chiabrando D, Vinchi F, Fiorito V, Mercurio S, Tolosano E. Heme in pathophysiology: a matter of scavenging, metabolism and trafficking across cell membranes.Front Pharmacol. 2014;5;61.
3. Beas JZ, Videira M, Saraiva LM. Regulation of bacterial haem biosynthesis.Coord Chem Rev. 2022;452;214286.
4. Hoppe M, Brün B, Larsson MP, Moraeus L, Hulthén L. Heme iron-based dietary intervention for improvement of iron status in young women. Nutr. 2013;29:89–95.
5. Pizarro F, Olivares M, Valenzuela C, Brito A, Weinborn V, Sebastián F, Arredondo M. The effect of proteins from animal source foods on heme iron bioavailability in humans.Food Chem.2016;196;733-8.
Cited by
2 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献