ARTP Mutagenesis of Schizochytrium sp. PKU#Mn4 and Clethodim-Based Mutant Screening for Enhanced Docosahexaenoic Acid Accumulation |
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| Authors: | Lu Liu Mohan Bai Sai Zhang Jiantao Li Xianhua Liu Biswarup Sen Guangyi Wang |
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| Institution: | 1.Center for Marine Environmental Ecology, School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China; (L.L.); (M.B.); (S.Z.); (J.L.); (X.L.);2.Polar Research Institute of China, Shanghai 200136, China;3.Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, China |
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| Abstract: | Schizochytrium species are one of the best oleaginous thraustochytrids for high-yield production of docosahexaenoic acid (DHA, 22:6). However, the DHA yields from most wild-type (WT) strains of Schizochytrium are unsatisfactory for large-scale production. In this study, we applied the atmospheric and room-temperature plasma (ARTP) tool to obtain the mutant library of a previously isolated strain of Schizochytrium (i.e., PKU#Mn4). Two rounds of ARTP mutagenesis coupled with the acetyl-CoA carboxylase (ACCase) inhibitor (clethodim)-based screening yielded the mutant A78 that not only displayed better growth, glucose uptake and ACCase activity, but also increased (54.1%) DHA content than that of the WT strain. Subsequent optimization of medium components and supplementation improved the DHA content by 75.5 and 37.2%, respectively, compared with that of mutant A78 cultivated in the unoptimized medium. Interestingly, the ACCase activity of mutant A78 in a medium supplemented with biotin, citric acid or sodium citrate was significantly greater than that in a medium without supplementation. This study provides an effective bioengineering approach for improving the DHA accumulation in oleaginous microbes. |
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| Keywords: | thraustochytrids polyunsaturated fatty acids mutagenesis atmospheric and room-temperature plasma acetyl-CoA carboxylase clethodim |
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