title: Influence of fermentation conditions on polysaccharide production and the activities of enzymes involved in the polysaccharide synthesis of Cordyceps militaris.
abstract: The influence of different fermentation conditions on intracellular polysaccharide (IPS) production and activities of the phosphoglucomutase (PGM), UDPG-pyrophosphorylase (UGP), phosphoglucose isomerase (PGI), UDPG-dehydrogenase (UGD), and glucokinase (GK) implicated in metabolite synthesis in Cordyceps militaris was evaluated. The highest IPS production (327.57 ± 6.27 mg/100 mL) was obtained when the strain was grown in the optimal medium containing glucose (40 g · L(-1)), beef extract (10 g · L(-1)), and CaCO3 (0.5 g · L(-1)), and the initial pH and temperature were 7 and 25 °C, respectively. The activities of PGM, UGP, and PGI were proved to be influenced by the fermentation conditions. A strong correlation between the activities of these enzymes and the production of IPS was found. The transcription level of the pgm gene (encoding PGM) was 1.049 times and 1.467 times compared to the ugp gene and pgi gene (encoding UGP and PGI), respectively, in the optimal culture medium. This result indicated that PGM might be the highly key enzyme to regulate the biosynthesis of IPS of C. militaris in a liquid-submerged culture. Our study might be helpful for further research on the pathway of polysaccharide biosynthesis aimed to improve the IPS production of C. militaris.
authors.affiliation: Key Laboratory of Food Nutrition and Safety, Ministry of Education, College of Food Science and Biotechnology, Tianjin University of Science and Technology, Tianjin, 300457, People's Republic of China. zhyuanzhu@tust.edu.cn.|Tianjin Food Safety & Low Carbon Manufacturing Collaborative Innovation Center, Tianjin, 300457, People's Republic of China. zhyuanzhu@tust.edu.cn.
authors.forename: Zhen-Yuan
authors.initials: ZY
authors.lastname: Zhu
authors.affiliation: Key Laboratory of Food Nutrition and Safety, Ministry of Education, College of Food Science and Biotechnology, Tianjin University of Science and Technology, Tianjin, 300457, People's Republic of China.
authors.forename: Xiao-Cui
authors.initials: XC
authors.lastname: Liu
authors.affiliation: Key Laboratory of Food Nutrition and Safety, Ministry of Education, College of Food Science and Biotechnology, Tianjin University of Science and Technology, Tianjin, 300457, People's Republic of China.
authors.forename: Feng-Ying
authors.initials: FY
authors.lastname: Dong
authors.affiliation: Key Laboratory of Food Nutrition and Safety, Ministry of Education, College of Food Science and Biotechnology, Tianjin University of Science and Technology, Tianjin, 300457, People's Republic of China.
authors.forename: Ming-Zhu
authors.initials: MZ
authors.lastname: Guo
authors.affiliation: Key Laboratory of Food Nutrition and Safety, Ministry of Education, College of Food Science and Biotechnology, Tianjin University of Science and Technology, Tianjin, 300457, People's Republic of China.
authors.forename: Xiao-Ting
authors.initials: XT
authors.lastname: Wang
authors.affiliation: Key Laboratory of Food Nutrition and Safety, Ministry of Education, College of Food Science and Biotechnology, Tianjin University of Science and Technology, Tianjin, 300457, People's Republic of China.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Institut Parisien de Chimie Moléculaire, Université Pierre et Marie Curie-Paris 6, UMR CNRS 8232, 4 place Jussieu, 75005, Paris, France.
authors.forename: Yong-Min
authors.initials: YM
authors.lastname: Zhang
mesh_terms: D032661:Cordyceps / Q000254:growth & development / Q000378:metabolism*; D003470:Culture Media / Q000737:chemistry; D004798:Enzymes / Q000378:metabolism*; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D011134:Polysaccharides / Q000096:biosynthesis*; D013696:Temperature
chemical_list: D003470:Culture Media; D004798:Enzymes; D011134:Polysaccharides
keywords: Biosynthesis; Cordyceps militaris; Enzyme activity; Intracellular polysaccharides