Development of an Efficient Strategy to Improve Extracellular Polysaccharide Production of Ganoderma lucidum Using L-Phenylalanine as an Enhancer

Zhongbao Ma; Mengmeng Xu; Qiong Wang; Feng Wang; Huihua Zheng; Zhenghua Gu; Youran Li; Guiyang Shi; Zhongyang Ding

doi:10.3389/fmicb.2019.02306

Development of an Efficient Strategy to Improve Extracellular Polysaccharide Production of Ganoderma lucidum Using L-Phenylalanine as an Enhancer

Front Microbiol. 2019 Oct 15:10:2306. doi: 10.3389/fmicb.2019.02306. eCollection 2019.

Authors

Zhongbao Ma^{1

2}, Mengmeng Xu^{1

2}, Qiong Wang^{1

2}, Feng Wang³, Huihua Zheng⁴, Zhenghua Gu^{1

2}, Youran Li^{1

2}, Guiyang Shi^{1

2}, Zhongyang Ding^{1

2}

Affiliations

¹ Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China.
² National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, Wuxi, China.
³ School of Food and Biological Engineering, Jiangsu University, Zhenjiang, China.
⁴ Jiangsu Alphay Biological Technology Co., Ltd., Nantong, China.

Abstract

Ganoderma lucidum has been a well-known species of basidiomycetes for a long time, and has been widely applied in the fields of food and medicine. Based on the simulation results of model iZBM1060 in our previous research, the effect of L-phenylalanine on G. lucidum extracellular polysaccharides (EPSs) was investigated in this study. EPS production reached 0.91 g/L at 0.4 g/L L-phenylalanine after a 24 h culture, which was 62.5% higher than that of control (0.56 g/L). Transcriptome and genome analysis showed that L-phenylalanine deaminase and benzoate 4-hydroxylase (related to L-phenylalanine metabolism) were significantly up-regulated, while the cell wall mannoprotein gene was down-regulated. Transmission electronic microscopy (TEM) and atomic force microscopy results showed that the cell wall thickness decreased by 58.58%, and cell wall porosity increased in cells treated with L-phenylalanine, which probably contribute to the increasing EPS production. This study provides an efficient strategy for fungal polysaccharide production with high output and low cost.

Keywords: Ganoderma lucidum; L-phenylalanine; cell wall; efficient strategy; extracellular polysaccharide.