Improvement of Vitamin K2 Production by Escherichia sp. with Nitrogen Ion Beam Implantation Induction. (1st February 2015)

• Record Type: Journal Article
• Authors: Liu, Yan; Wang, Li; Zheng, Zhiming; Wang, Peng; Zhao, Genhai; Liu, Hui; Gong, Guohong; Wu, Hefang; Liu, Hongxia; Tan, Mu; Li, Zhemin
• Is Part Of: Plasma science and technology. Volume 17:Number 2(2015:Feb.)
• Page Start: 159
• Page End: 166
• Publication Date: 2015-02-01
• Subjects: Plasma (Ionized gases) -- Periodicals; 530.44
• DOI: 10.1088/1009-0630/17/2/11
• Languages: English
• ISSNs: 1009-0630

Abstract

<abstract xml:lang="en"> <title>Abstract</title> <p>Low-energy ion implantation as a novel mutagen has been increasingly applied in the microbial mutagenesis for its higher mutation frequency and wider mutation spectra. In this work, N⁺ ion beam implantation was used to enhance <italic>Escherichia</italic> sp. in vitamin K₂ yield. Optimization of process parameters under submerged fermentation was carried out to improve the vitamin K₂ yield of mutant FM5-632. The results indicate that an excellent mutant FM5-632 with a yield of 123.2±1.6 μg/L, that is four times that of the original strain, was achieved by eight successive implantations under the conditions of 15 keV and 60×2.6×10¹³ ions/cm². A further optimization increased the yield of the mutant by 39.7%, i.e. 172.1±1.2 μg/L which occurred in the mutant cultivated in the optimal fermentation culture medium composed of (per liter): 15.31 g glycerol, 10 g peptone, 2.89 g yeast extract, 5 g K₂HPO₄, 1 g NaCl, 0.5 g MgSO₄·7H₂O and 0.04 g cedar wood oil, incubated at 33 °C, pH 7.0 and 180 rpm for 120 h.</p> </abstract>