4株小球藻缺陷培养条件的优化及藻株CE14的分子鉴定

通过采集海口周边热带淡水水样，用平板分离纯化法获得158株纯藻，选择其中4株（CE1，CE14，CE18，CE31）经初步鉴定的小球藻进行缺陷培养（HSM，HSM-N，HSM—S，HSM-P4种培养基培养）及油脂含量测定，结果显示：N和S2种元素缺乏对这4株小球藻生物量影响较大，且使这4株小球藻的含油量显著高于在HSM培养基培养的含油量；P元素的缺乏对这4株小球藻生物量影响较小，仅使CE1和CE18的油脂含量显著上升。CE14生长迅速，油脂含量高，其在HSM-S培养基中的油脂含量高于其他3种培养基，占细胞干重的86．55％。对CE14进行18S rDNA鉴定，得出CE14藻株属于绿藻门，绿藻纲，绿球藻目，小球藻科，小球藻属，与Chlorella vulgaris的18S rDNA基因的相似度为99％。

Optimal Culture of 4 Chlorellas Strains and Molecular Identification of Alga Strain CE14

Energy crisis and environmental pollution have become increasingly prominent with the extensive use of fossil fuels, which is widely considered to be unsustainable. Biodiesel is a potential alternative to fossil fuels. Microalgae have been considered the most promising biodiesel sources. Microalgae were collected from tropical freshwater water sampled around Haikou, and 185 strains of pure algae were obtained by fiat-panel separation. Of the strains four were preliminarily identified as chlorella strains, CE1, CE14, CE18 and CE31, and were cultured on 4 different high salt minimal （HSM） media, HSM, HSM-N （N-deficient）, HSM-S, and HSM-P. Their biomass and lipid content were determined. The cultural media deficient of N and S gave notable impact on biomass production of all the four chlorella strains, and significantly increased their lipid contents as compared with the control. The cultural medium deficient of P had less influence on biomass production of the four chlo- rella strains, but increased notably lipid contents of strains CE1 and CE18. The strain CE14 grew very fast and contained high liquid, and its lipid content was the highest when cultured under the medium HSM-S as against other three media and accounted for 86.55% of the cell dry weight. This strain was identified based on 18S rD- NA sequencing and designated as the genus Chlorella, family Chlorellaceae, order Chlorocaccales, class Chloro- phyceae, division Chlorophyta, and its gene shared 99% similarity with the 18S rDNA gene of Chlorella vulgar- is. CE14 is a promising potential alga source for production of biodiesel fuel.