Sample characteristics and pigment concentration of arctic snow and permafrost algal strains@en

Ten algal strains from snow and permafrost substrates were tested for their ability to produce secondary carotenoids and a-tocopherol in response to high light and decreased nitrogen levels. The Culture Collection of Cryophilic Algae at Fraunhofer IBMT in Potsdam served as the bioresource for this study. Eight of the strains belong to the Chlorophyceae and two strains are affiliated to the Trebouxiophyceae. While under low light, all 10 strains produced the normal spectrum of primary pigments known to be present in Chlorophyta, only the eight chlorophyceaen strains were able to synthesize secondary carotenoids under stress conditions, namely canthaxanthin, echinenone and astaxanthin; seven of them were also able to synthesize minor amounts of adonixanthin and an unidentified hydroxyechinenone. The two trebouxiophyceaen species of Raphidonema exhibited an unusually high pool of primary xanthophyll cycle pigments, possibly serving as a buffering reservoir against excessive irradiation. They also proved to be good alpha-tocopherol producers, which might also support the deactivation of reactive oxygen species. This study showed that some strains might be interesting novel candidates for biotechnological applications. Cold-adapted, snow and permafrost algae might serve as valuable production strains still exhibiting acceptable growth rates during the cold season in temperate regions.

本研究针对10株分离自积雪与永久冻土基质的藻类菌株，检测其在高光胁迫与低氮胁迫条件下合成次级类胡萝卜素与α-生育酚（alpha-tocopherol）的能力。本研究的生物资源来自波茨坦弗劳恩霍夫生物医学技术研究所（Fraunhofer IBMT）的嗜冷藻类培养保藏中心。其中8株隶属于绿藻纲（Chlorophyceae），剩余2株隶属于共球藻纲（Trebouxiophyceae）。在低光环境下，10株菌株均可合成绿藻门（Chlorophyta）物种中常见的标准初级色素谱；但仅8株绿藻纲菌株可在胁迫条件下合成次级类胡萝卜素，分别为角黄素（canthaxanthin）、海胆酮（echinenone）与虾青素（astaxanthin），其中7株还可少量合成多黄质（adonixanthin）以及一种未鉴定的羟基海胆酮（hydroxyechinenone）。两株共球藻纲针丝藻属（Raphidonema）的菌株拥有异常丰富的初级叶黄素循环色素库，可作为缓冲储备抵御过量辐照；同时它们也是优良的α-生育酚生产菌株，其产物或可辅助清除活性氧物种（reactive oxygen species）。本研究证实，部分菌株可作为颇具潜力的新型生物技术应用候选菌株。适应低温环境的积雪与永久冻土藻类，可作为极具价值的生产菌株，在温带地区的低温季节仍能维持可接受的生长速率。