微高压二氧化碳（p-HPCD）是一种新型的非热杀菌技术，其应用的CO2压力远小于高压二氧化碳技术中CO2压力，但其杀菌机理尚不明确。前期研究发现p-HPCD胁迫下酿酒酵母发生氧化应激，已知细胞氧化应激与细胞损伤密切相关，因此本项目拟着眼于p-HPCD打破酿酒酵母氧化还原稳态的分子机制研究。首先拟以相同条件微高压N2胁迫为对照，采用基因芯片、基因敲除等技术研究p-HPCD胁迫诱导酿酒酵母氧化应激的特异性及抗氧化防御对酵母p-HPCD胁迫耐性的影响规律；然后拟采用电子顺磁共振波谱仪等技术表征细胞内自由基，研究p-HPCD胁迫下自由基的产生规律；最后拟采用呼吸链阻断、基因敲除等技术，从氧自由基清除系统和铜离子稳态两方面，揭示p-HPCD胁迫诱导酿酒酵母氧化应激的分子机制。本项目研究成果将为p-HPCD技术杀菌机理的阐明开拓新思路，对于促进该技术在食品微生物安全控制领域中的快速发展具有重要意义。

Petit-High Pressure Carbon Dioxide (p-HPCD) is a novel non-thermal pasteurization technology. The CO2 pressure employed in p-HPCD is far less than pressure used in High Pressure Carbon Dioxide (HPCD) pasteurization technology. However, the exact pasteurized mechanism of p-HPCD is still unclear. Our previous study found that p-HPCD induced oxidative stress and over-expression of genes involved in copper homeostasis in Saccharomyces cerevisiae. It is well known that cellular redox homeostasis is closely related to cell damage. Therefore，this project will focus on the mechanism of oxidative stress induced by p-HPCD in yeast. The specificity of oxidative stress induced by p-HPCD in yeast will be firstly validated using nitrogen under the same treatment condition as a reference through gene expression profile analysis. Effect of antioxidative protection system on tolerance of yeast cell to p-HPCD stress will be then analyzed by measuring growth phenotypes of mutants deleted for key genes. Secondly, characterization of free radicals in yeast cells responding to p-HPCD will be performed by electron paramagnetic resonance and other assays. Finally, for the purpose of elucidating the mechanism of oxidative stress induced by p-HPCD, reactive oxygen species scavenging system and copper homeostasis in yeast cells in response to p-HPCD will be evaluated through knocking out specific genes and blocking respiratory chain. This project will contribute to find out the key metabolic pathways resulting in cell death under p-HPCD stress and provide new ideas for further elucidating the mechanism of p-HPCD pasteurization technology, which is of great importance for its rapid development in the control of food microbiological safety.