title: Mutagenesis breeding of high echinocandin B producing strain and further titer improvement with culture medium optimization.
abstract: A combination of microbial strain improvement and statistical optimization is investigated to maximize echinocandin B (ECB) production from Aspergillus nidulans ZJB-0817. A classical sequential mutagenesis was studied first by using physical (ultraviolet irradiation at 254 nm) and chemical mutagens (lithium chloride and sodium nitrite). Mutant strain ULN-59 exhibited 2.1-fold increase in ECB production to 1583.1 ± 40.9 mg/L when compared with the parent strain (750.8 ± 32.0 mg/L). This is the first report where mutagenesis is applied in Aspergillus to improve ECB production. Further, fractional factorial design and central composite design were adopted to optimize the culture medium for increasing ECB production by the mutant ULN-59. Results indicated that four culture media including peptone, K2HPO4, mannitol and L-ornithine had significant effects on ECB production. The optimized medium provided another 1.4-fold increase in final ECB concentration to 2285.6 ± 35.6 mg/L compared to the original medium. The results of this study indicated the combined application of a classical mutation and medium optimization can improve effectively ECB production from A. nidulans and could be a promising tool to improve other secondary metabolites production by fungal strains.
authors.affiliation: Institute of Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, China.
authors.forename: Shu-Ping
authors.initials: SP
authors.lastname: Zou
authors.affiliation: Institute of Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhong
authors.affiliation: Institute of Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, China.
authors.forename: Chao-Jie
authors.initials: CJ
authors.lastname: Xia
authors.affiliation: Institute of Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, China.
authors.forename: Ya-Nan
authors.initials: YN
authors.lastname: Gu
authors.affiliation: Institute of Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, China.
authors.forename: Kun
authors.initials: K
authors.lastname: Niu
authors.affiliation: Institute of Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, China. zhengyg@zjut.edu.cn.
authors.forename: Yu-Guo
authors.initials: YG
authors.lastname: Zheng
authors.affiliation: Institute of Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, China.
authors.forename: Yin-Chu
authors.initials: YC
authors.lastname: Shen
mesh_terms: D001233:Aspergillus nidulans / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D061249:Batch Cell Culture Techniques / Q000379:methods*; D003470:Culture Media / Q000378:metabolism*; D054714:Echinocandins / Q000096:biosynthesis* / Q000235:genetics; D005656:Fungal Proteins / Q000096:biosynthesis* / Q000235:genetics; D024861:Genetic Enhancement / Q000379:methods*; D009153:Mutagens / Q000494:pharmacology*; D009154:Mutation / Q000187:drug effects / Q000235:genetics / Q000528:radiation effects; D013045:Species Specificity; D014466:Ultraviolet Rays
chemical_list: D003470:Culture Media; D054714:Echinocandins; D005656:Fungal Proteins; D009153:Mutagens; C007572:echinocandin B
keywords: Aspergillus nidulans; Echinocandin B; Response surface methodology; Sequential mutagenesis;  Medium optimization