Authors: Huijie Zheng Jixian Gong Tao Chen Xun Chen Xueming Zhao
Publish Date: 2009/09/24
Volume: 85, Issue: 5, Pages: 1541-1549
Abstract
Improvement of acid tolerance and production of Dlactic acid by Sporolactobacillus inulinus ATCC 15538 was performed by using recursive protoplast fusion in a genome shuffling format The starting population was generated by ultraviolet irradiation diethyl sulfate mutagenesis and pHgradient filter and then subjected for the recursive protoplast fusion The concentration of lysozyme time and temperature for enzyme treatment were optimized by response surface methodology based on the central composite design Based on contour plots and variance analysis the model predicted a maximum Y multiply protoplasts formation ratio by protoplasts regeneration ratio 604 and the corresponding above used values were 775 mg/ml lysozyme 159 h and 38°C A pH5resistant recombinant F34 was obtained after three rounds of genome shuffling and its production of Dlactic acid reached 934 g/l in a 5 L bioreactor which was increased by 398 and 119 in comparison with that of UV generated strain and the original strain S inulinus ATCC 15538 respectively The subculture experiments indicated that F34 was genetically stableWe are grateful for the support of the National Natural Foundation of China NSFC20536040 NSFC20875068 the National Project of Key Fundamental Research 2007CB707802 the Development Project of Science and Technology of Tianjin 05YFGZG04500 Project of Introducing Talents of Discipline to Universities B0606 and China Postdoctoral Science Foundation Funded Project 20080440097
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