低温等离子体刺激雨生红球藻促产虾青素的效应及机理研究

Irradiation of non-thermal low-temperature plasma on microorganisms can induce a variety of biological effects, including the hormesis effect under certain conditions. Haematococcus pluvialis (H. pluvialis) is a freshwater species of Chlorophyta from the family Haematococcaceae, well known for its high content of the strong antioxidant astaxanthin (a strong antioxidant) of microorganism, and it is still a challenge to promote growth and improve the yield of astaxanthin. In our preliminary experiments, we found that plasma irradiation can promote the growth of H. pluvialis and promote the production of astaxanthin, but the mechanism is still elusive. It is well known that plasma can produce reactive oxygen species (ROS), and ROS can initiate the special protective mechanism of H. pluvialis, we therefore have the hypothesis that this effect is mainly caused by ROS-oxidative stress stimulation under plasma irradiation. Therefore, in this project we put forward to employ non-thermal plasma as a novel method to stimulate H. pluvialis growth and promote astaxanthin production, and also to explore the underlying mechanism. In the research, we will on one hand explore the optimal conditions for plasma treatment result, while on the other hand scrutinize the involved biological processes. We will analyze the effect of different types of ROS, metabolites, antioxidant enzyme activities, so as to clarify the two different defense mechanisms, namely, the antioxidant defense mechanism and the astaxanthin defense mechanism, as well as the relationship between them. As such, this study will not only contribute to the better understanding of the effect of non-thermal low-temperature plasma on microorganisms, but also open a new door for the application of low-temperature plasma, and may provide a new solution for the promotion of production of astaxanthin in H. pluvialis in practical application.

低温等离子体可引起丰富的生物效应，包括生物刺激效应。雨生红球藻是自然界高产天然虾青素（一种强抗氧化剂）的微生物，人们对进一步提高虾青素产量有重要需求。在研究中我们发现，低温等离子体在非诱变条件下可以促进雨生红球藻生长和提高虾青素产量，但具体原因并不清楚。因为低温等离子体可产生丰富的活性氧（ROS），而ROS可以激发雨生红球藻特殊保护机制，所以我们推测这主要是等离子体产生ROS引起氧化胁迫下的刺激作用。为此，本项目提出低温等离子体刺激雨生红球藻促产虾青素的方案，并由此探索相关作用机理。研究中，一方面优化等离子体处理条件，另一方面对相关生物过程进行分析，通过分析活性氧、代谢产物、抗氧化酶活等，探讨其中的抗氧化酶保护机制和虾青素保护机制以及两者之间关系和转化过程。该项研究不仅可加深等离子体对生物作用机理的认识，而且可拓宽低温等离子体技术应用，有望为雨生红球藻高产虾青素提供新的技术和方法。

低温等离子体可引起丰富的生物效应，包括对生物的刺激效应。雨生红球藻是自然界高产天然虾青素的微藻生物。本项目研究发现，适当条件下低温等离子体可以有效促进雨生红球藻生长和提高虾青素产量，并对有关机理进行阐释。本研究按照项目书计划进行，执行顺利；在项目组成员努力下，研究达到了预期目的和要求，并取得多项研究成果。本项目取得主要创新性成果包括：1）优化了低温等离子体刺激雨生红球藻生长和产虾青素的条件，发现内源和外源多种激素对雨生红球藻促产虾青素的刺激作用，并研究了强光辐照下高产虾青素的有关机制；2）发现低温等离子体通过产生ROS诱导雨生红球藻氧化应激，并研究了等离子体氧化胁迫下多种生物效应及机制；3）发现等离子体刺激作用可以通过调节H3K4me3来调节CRTISO的表达来提升藻生长相关激素并促进虾青素合成的表观遗传学机制。研究成果相继发表在相关专业的重要国际期刊上，如：Bioresource Technology、Algal Research、Bioresource Technology Reports等。由国家自然科学基金资助（标注项目批准号11775272)所发表相关的国际期刊学术论文8篇，研究成果得到同行专家关注和认可，项目负责人多次参加国内外会议并做大会邀请报告。总之，在国家自然科学基金的资助和支持下，经过四年来不懈的努力，在等离子体刺激雨生红球藻促产虾青素技术方法以及机理研究方面都取得了重要进展。这项研究对加深等离子体对包括雨生红球藻在内作用机理认识、拓宽低温等离子体技术在虾青素生物合成方面的应用，提供了新的技术方法和理论根据。