Chinese Journal of Biotechnology/Shengwu Gongcheng Xuebao 2007-09-01

[Potential use of the herbicide quizalofop-p-ethyl for eicosapentaenoic acid overproduction by the diatom Nitzschia laevis].

Xiao-Hong Cao, Song-Yao Li, Chun-Ling Wang, Mei-Fang Lu

Index: Sheng Wu Gong Cheng Xue Bao 23(5) , 885-90, (2007)

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Abstract

The diatom Nitzschia laevis is a good alternative source of eicosapentaenoic acid (EPA). Besides strategies for high cell density culture, EPA productivity may be further improved by herbicides. The effect of the herbicide quizalofop-p-ethyl on the growth and EPA production was studied in this paper. As the solvent of the herbicide, DMSO was proved to inhibit the growth and EPA production of N. laevis. The concentration of DMSO in the medium should not exceed 0.2%. Quizalofop-p-ethyl could cause morphology damage to the N. laevis cells. With the increasing concentration of quizalofop-p-ethyl from 0 mmol/L to 0.4 mmol/L, the dry cell weight production decreased, while at the same time, the lipid content of the dry cell mass increased. When treated with 0.1 mmol/L quizalofop-p-ethyl, the EPA content increased from 3.00% to 3.58% (of dry cell weight, DW), and the proportion of EPA (20:5) in total fatty acids (TFA) increased from 25.15% to 32.88% . These results indicated that the herbicide quizalofop-p-ethyl could stimulate the accumulation of EPA; therefore it might be useful for selecting algae colonies that overproduce EPA.