隐秘小环藻藻际细菌分离鉴定及其对藻细胞生长的影响  

Isolation and Identification of Phycosphere Bacteria of Cyclotella crypticaand Their Influences on Microalgal Cell Growth

作　　者：刘雨 张裕 李赟[1] 朱葆华[1] 潘克厚[1,2] Liu Yu;Zhang Yu;Li Yun;Zhu Baohua;Pan Kehou(Key Laboratory of Mariculture(Ocean University of China),Ministry of Education,Qingdao 266003,China;Laboratory for Marine Fisheries Science and Food Production Processes,Pilot National Laboratory for Marine Science and Technology(Qingdao),Qingdao 266237,China)

机构地区：[1]海水养殖教育部重点实验室(中国海洋大学),山东青岛266003 [2]青岛海洋科学与技术试点国家实验室海洋渔业科学与食物产出过程功能实验室,山东青岛266237

出　　处：《中国海洋大学学报（自然科学版）》2024年第4期27-37,共11页Periodical of Ocean University of China

基　　金：国家自然科学基金项目(41976118)资助。

摘　　要：为了解隐秘小环藻(Cyclotella cryptica)共生细菌对其生长的影响,本文运用稀释梯度涂布法分离纯化藻液中的细菌,检测了藻菌共培养液中的溶解有机碳(Dissolved organic carbon, DOC)、溶解无机碳(Dissolved inorganic carbon, DIC)及胞外聚合物(Extracellular polymeric substances, EPS)含量的变化,比较了分离菌株对微藻生物量和脂质的影响,初步探究了藻菌之间的相互作用模式。研究显示,从隐秘小环藻藻液共分离纯化8株可培养细菌,通过比对菌株的部分16S rDNA序列,完成了其分类学鉴定。其中,菌株C-1和C-7为隐秘小环藻的优势促生菌,分别将藻细胞密度提高了27.1%和23.9%。与菌株C-1共培养的隐秘小环藻,脂质含量高达43.53%,脂质产率为16.69 mg·L^(-1)·d^(-1),比无菌纯培养对照组的脂质产率提高了37.37%。碳交换研究结果显示,共培养7 d后,2个促生菌株构建的共培养体系中DOC含量显著低于无菌纯培养对照组;DIC含量显著高于无菌纯培养对照组。与无菌纯培养对照组相比,藻菌共培养导致培养上清液中EPS的多糖和蛋白含量显著降低,而细胞结合态EPS的多糖含量在前4 d高于对照组,之后显著降低,但细胞结合态EPS的蛋白含量始终高于对照组。本研究构建了隐秘小环藻与细菌的共生体系,探究了藻菌之间的互作效应,可为隐秘小环藻的规模化生产提供参考。In order to understand the effect of symbiotic bacteria on the growth of Cyclotella cryptica,eight bacterial strains were isolated from the phycosphere of C.cryptica using the traditional culture method,and identified as Erythrobacter sp.C-1、Staphylococcus sp.C-2、Staphylococcus sp.C-3、Halomonas sp.C-4、Muricauda sp.C-5、Cellulomonas sp.C-6、Marinibacterium sp.C-7 and Bacillus sp.C-8 by comparing their partial 16S rRNA(rDNA)gene sequences.The results showed that C-1 and C-7 were the dominant growth-promoting bacteria of C.cryptica,which increased the algal cell density by 27.1%and 23.9%,respectively.The lipid content of C.cryptica co-cultured with C-1 was as high as 43.53%,and the lipid yield was 16.69 mg·L^(-1)·d^(-1),37.37%higher than that of the axenic culture.DOC content in the co-culture system of C-1 and C-7 was(86.2±12.2)mg/L and(108.9±7.8)mg/L after 7 days,respectively,28.4%and 9.6%lower than that of the control,respectively.However,the DIC content was significantly higher than that of the control.Polysaccharide content of SL-EPS was(6.4±0.5)mg/L and(7.6±1.0)mg/L when the alga co-cultured with C-1 and C-7,respectively,significantly lower than that of axenic culture.Similarly,protein content of SL-EPS was(5.0±0.4)mg/L and(9.3±1.0)mg/L when the alga was co-cultured with C-1 and C-7,respectively.Compared with the control,the polysaccharide content of B-EPS in C-1 and C-7 co-culture systems increased in first four days and then decreased in coming two days.The protein content was always higher than that of the control.In this study,we constructed symbiotic systems of C.cryptic and bacteria to explore the interactions between them,which may provide a reference for the large-scale production of C.cryptic.

关 键 词：隐秘小环藻 溶解有机碳 溶解无机碳 胞外聚合物 生长 脂质含量 藻际细菌 

分 类 号：S968.41[农业科学—水产养殖]