title: Characterization of long-chain acyl-CoA synthetases which stimulate secretion of fatty acids in green algae Chlamydomonas reinhardtii.
abstract: BACKGROUND
  Microalgae biofuel has become the most promising renewable energy over the past few years. But limitations still exist because of its high cost. Although, efforts have been made in enhancement of lipid productivity, the major cost problem in harvesting and oil extraction is still intractable. Thus, the idea of fatty acids (FAs) secretion which can massively facilitate algae harvesting and oil extraction was investigated here.
  
  
  RESULTS
  The cDNAs of two long-chain acyl-CoA synthetases (LACSs) genes were cloned from Chlamydomonas reinhardtii and named as cracs1 and cracs2. They showed different substrate adaptation in the yeast complementation experiments. Cracs2 could utilize FAs C12:0, C14:0, C16:0, C18:0, C16:1 and C18:1, while crac1 could only utilize substrate C14:0, C16:1 and C18:1. Knockdown of cracs1 and cracs2 in C. reinhardtii resulted in accumulation of intracellular lipids. The total intracellular lipids contents of transgenic algae q-15 (knockdown of cracs1) and p-13 (knockdown of cracs2) were 45 and 55 %, respectively higher than that of cc849. Furthermore, FAs secretion was discovered in both transgenic algae. Secreted FAs can reach 8.19 and 9.66 mg/10(9) cells in q-15 and p-13, respectively.
  
  
  CONCLUSIONS
  These results demonstrated the possibility of FAs secretion by microalgae and may give a new strategy of low-cost oil extraction. According to our findings, we proposed that FAs secretion may also be achieved in other species besides Chlamydomonas reinhardtii by knocking-down cracs genes, which may promote the future industrial application of microalgae biofuels.
authors: Guangdong Engineering Research Centre for Marine Algal Biotechnology, Guangdong Key Laboratory of Plant Epigenetics, Shenzhen Key Laboratory of Marine Bioresouce and Eco-Enviromental Science, Shenzhen University, Shenzhen, 518060 People's Republic of China.|Key Laboratory of Microbial Engineering at the Institute of Biology, Industrial Enzyme Engineering Technology Research Center, Henan Academy of Sciences, Zhengzhou, 450008 People's Republic of China.
authors: Bin
authors: B
authors: Jia
authors: Guangdong Engineering Research Centre for Marine Algal Biotechnology, Guangdong Key Laboratory of Plant Epigenetics, Shenzhen Key Laboratory of Marine Bioresouce and Eco-Enviromental Science, Shenzhen University, Shenzhen, 518060 People's Republic of China.
authors: Yanzi
authors: Y
authors: Song
authors: Guangdong Engineering Research Centre for Marine Algal Biotechnology, Guangdong Key Laboratory of Plant Epigenetics, Shenzhen Key Laboratory of Marine Bioresouce and Eco-Enviromental Science, Shenzhen University, Shenzhen, 518060 People's Republic of China.
authors: Min
authors: M
authors: Wu
authors: Guangdong Engineering Research Centre for Marine Algal Biotechnology, Guangdong Key Laboratory of Plant Epigenetics, Shenzhen Key Laboratory of Marine Bioresouce and Eco-Enviromental Science, Shenzhen University, Shenzhen, 518060 People's Republic of China.
authors: Baicheng
authors: B
authors: Lin
authors: Guangdong Engineering Research Centre for Marine Algal Biotechnology, Guangdong Key Laboratory of Plant Epigenetics, Shenzhen Key Laboratory of Marine Bioresouce and Eco-Enviromental Science, Shenzhen University, Shenzhen, 518060 People's Republic of China.
authors: Kang
authors: K
authors: Xiao
authors: Guangdong Engineering Research Centre for Marine Algal Biotechnology, Guangdong Key Laboratory of Plant Epigenetics, Shenzhen Key Laboratory of Marine Bioresouce and Eco-Enviromental Science, Shenzhen University, Shenzhen, 518060 People's Republic of China.
authors: Zhangli
authors: Z
authors: Hu
authors: Guangdong Engineering Research Centre for Marine Algal Biotechnology, Guangdong Key Laboratory of Plant Epigenetics, Shenzhen Key Laboratory of Marine Bioresouce and Eco-Enviromental Science, Shenzhen University, Shenzhen, 518060 People's Republic of China.
authors: Ying
authors: Y
authors: Huang
keywords: Antisense knockdown; Chlamydomonas reinhardtii; Fatty acids secretion; Long-chain acyl-CoA synthetase