一株微绿球藻的分离鉴定和生长特性分析

Isolation and Identification of a Strain of Nannochloropsis sp. and Analysis of its Growth Performance

从海南红树林底泥中分离得到微藻,经形态学及分子生物学鉴定,该微藻与微绿球藻属的海生椭球藻的亲缘关系更近。比较培养基中不同营养盐浓度、盐度、氮源及氮浓度、磷浓度、pH和温度对分离微绿球藻生长的影响。结果表明,该分离微藻在盐度30和74.8mg/L NaNO3(氮质量浓度为12.91mg/L)、6.6mg/L KH2PO4(磷质量浓度为1.705mg/L)、pH=6.0的f/2培养基,26°C下培养,培养7d的细胞密度最高可达5 590×104个/mL,相对生长率为0.786 1。与微绿球藻的相关报道进行比较分析,表明该分离藻是一低氮、低磷、较耐酸性环境的速生微绿球藻株系。

The relationship between lipid accumulation and gene expression in Nannochloropsis gaditana was investigated by sequencing the transcriptomes with Illumina Hiseq 2000. After trimming and quality checking, a total of 29 203 unigenes were obtained. The expression of 7 305 unigenes was up-regulated at logarithm growth phase while 9 745 were up-regulated at stationary growth phase. Based on the similarity search against NCBI databank, 13 775 unigenes were annotated. Using the KEGG pathway database, 238 pathways were constructed on which 818 unigenes were up-regulated at logarithm growth phase, and 248 pathways were constructed, on which and 1 148 unigenes were up-regulated at stationary growth phase. Altogether 195 unigenes were found to be involved in lipid metabolism, of them 53 unigenes were up-regu- lated at logarithm growth phase and 47 unigenes were up-regulated at stationary growth phase. With the help of COG database, 11 604 unigenes were clustered into 25 functional categories including material and signal transduetion, energy production and conversion, amino acid metabolism, and among others.