title: Improvement of Bacillus subtilis for poly-γ-glutamic acid production by genome shuffling.
abstract: Poly-γ-glutamic acid (γ-PGA) is a promising microbial polymer with potential applications in industry, agriculture and medicine. The use of high γ-PGA-producing strains is an effective approach to improve productivity of γ-PGA. In this study, we developed a mutant, F3-178, from Bacillus subtilis GXA-28 using genome shuffling. The morphological characteristics of F3-178 and GXA-28 were not identical. Compared with GXA-28 (18.4 ± 0.8 g l-1), the yield of γ-PGA was 1.9-fold higher in F3-178 (34.3 ± 1.2 g l-1). Results from batch fermentation in 3.7 l fermenter showed that F3-178 was satisfactory for industrial production of γ-PGA. Metabolic studies suggested that the higher γ-PGA yield in F3-178 could be attributed to increased intracellular flux and uptake of extracellular glutamate. Real-time PCR indicated that mRNA level of pgsB in F3-178 was 18.8-fold higher than in GXA-28, suggesting the higher yield might be related to the overexpression of genes involved in γ-PGA production. This study demonstrated that genome shuffling can be used for rapid improvement of γ-PGA strains, and the possible mechanism for the improved phenotype was also explored at the metabolic and transcriptional levels.
authors: State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi University, Nanning, Guangxi, 530004, China.|Key Laboratory of Ministry of Education for Microbial and Plant Genetic Engineering, Guangxi University, Nanning, Guangxi, 530004, China.|College of Life Science and Technology, Guangxi University, Nanning, Guangxi, 530004, China.
authors: Wei
authors: W
authors: Zeng
authors: State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi University, Nanning, Guangxi, 530004, China.|Key Laboratory of Ministry of Education for Microbial and Plant Genetic Engineering, Guangxi University, Nanning, Guangxi, 530004, China.|College of Life Science and Technology, Guangxi University, Nanning, Guangxi, 530004, China.
authors: Guiguang
authors: G
authors: Chen
authors: State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi University, Nanning, Guangxi, 530004, China.|Key Laboratory of Ministry of Education for Microbial and Plant Genetic Engineering, Guangxi University, Nanning, Guangxi, 530004, China.|College of Life Science and Technology, Guangxi University, Nanning, Guangxi, 530004, China.
authors: Hao
authors: H
authors: Wu
authors: State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi University, Nanning, Guangxi, 530004, China.|Key Laboratory of Ministry of Education for Microbial and Plant Genetic Engineering, Guangxi University, Nanning, Guangxi, 530004, China.|College of Life Science and Technology, Guangxi University, Nanning, Guangxi, 530004, China.
authors: Jun
authors: J
authors: Wang
authors: State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi University, Nanning, Guangxi, 530004, China.|Key Laboratory of Ministry of Education for Microbial and Plant Genetic Engineering, Guangxi University, Nanning, Guangxi, 530004, China.|College of Life Science and Technology, Guangxi University, Nanning, Guangxi, 530004, China.
authors: Yanliao
authors: Y
authors: Liu
authors: State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi University, Nanning, Guangxi, 530004, China.|Key Laboratory of Ministry of Education for Microbial and Plant Genetic Engineering, Guangxi University, Nanning, Guangxi, 530004, China.|College of Life Science and Technology, Guangxi University, Nanning, Guangxi, 530004, China.
authors: Ye
authors: Y
authors: Guo
authors: State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi University, Nanning, Guangxi, 530004, China. zqliang@gxu.edu.cn.|Key Laboratory of Ministry of Education for Microbial and Plant Genetic Engineering, Guangxi University, Nanning, Guangxi, 530004, China. zqliang@gxu.edu.cn.|College of Life Science and Technology, Guangxi University, Nanning, Guangxi, 530004, China. zqliang@gxu.edu.cn.
authors: Zhiqun
authors: Z
authors: Liang
mesh_terms: D001412:Bacillus subtilis / Q000235:genetics* / Q000378:metabolism*; D032621:DNA Shuffling; D020869:Gene Expression Profiling; D016680:Genome, Bacterial; D018698:Glutamic Acid / Q000378:metabolism; D060847:Metabolic Engineering / Q000379:methods*; D064688:Metabolic Flux Analysis; D011099:Polyglutamic Acid / Q000031:analogs & derivatives* / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D017422:Sequence Analysis, DNA
chemical_list: C511775:poly(gamma-glutamic acid); D011099:Polyglutamic Acid; D018698:Glutamic Acid