Enhanced hypoxanthine utilization and antioxidant capacity for cAMP salvage synthesis efficiently by Arthrobacter sp. CCTCC 2013431 with glutathione addition

Abstract

When hypoxanthine was used to activate the salvage pathway for cAMP synthesis, reactive oxygen species would generate in quantity resulting in low cAMP yields. cAMP fermentations with/without glutathione addition on the basis of hypoxanthine feeding were conducted. Owing to 200 mg/L glutathione added at 24 h, cAMP concentration reached 7.38 g/L with an increment of 85.89%, and cAMP conversions from hypoxanthine were improved significantly when compared with control. Intracellular ROS and malonaldehyde levels were reduced obviously, at the same time, cell viability, respiratory intensity and ATP/AMP were improved notably suggesting that glutathione relieved oxidative stress and cell damage leading to higher cell viability and energy metabolism. Moreover, xanthine oxidase activities and byproducts contents were decreased obviously, meanwhile, the expression contents and genes transcription levels of PUP and HPRT were increased significantly, indicating that glutathione enhanced hypoxanthine uptake for cAMP synthesis and decreased hypoxanthine decomposition resulting in higher cAMP yields and conversion ratios.