Direct and highly productive conversion of cyanobacteria Arthrospira platensis to ethanol with CaCl2 addition

Shimpei Aikawa, Kentaro Inokuma, Satoshi Wakai, Kengo Sasaki, Chiaki Ogino, Jo Shu Chang, Tomohisa Hasunuma, Akihiko Kondo

研究成果: Article同行評審

12 引文 斯高帕斯(Scopus)


Background: The cyanobacterium Arthrospira platensis shows promise as a carbohydrate feedstock for biofuel production. The glycogen accumulated in A. platensis can be extracted by lysozyme-degrading the peptidoglycan layer of the bacterial cell walls. The extracted glycogen can be converted to ethanol through hydrolysis by amylolytic enzymes and fermentation by the yeast Saccharomyces cerevisiae. Thus, in the presence of lysozyme, a recombinant yeast expressing α-amylase and glucoamylase can convert A. platensis directly to ethanol, which would simplify the procedure for ethanol production. However, the ethanol titer and productivity in this process are lower than in ethanol production from cyanobacteria and green algae in previous reports. Results: To increase the ethanol titer, a high concentration of A. platensis biomass was employed as the carbon source for the ethanol production using a recombinant amylase-expressing yeast. The addition of lysozyme to the fermentation medium increased the ethanol titer, but not the ethanol productivity. The addition of CaCl2 increased both the ethanol titer and productivity by causing the delamination of polysaccharide layer on the cell surface of A. platensis. In the presence of lysozyme and CaCl2, ethanol titer, yield, and productivity improved to 48 g L-1, 93% of theoretical yield, and 1.0 g L-1 h-1 from A. platensis, corresponding to 90 g L-1 of glycogen. Conclusions: We developed an ethanol conversion process using a recombinant amylase-expressing yeast from A. platensis with a high titer, yield, and productivity by adding both lysozyme and CaCl2. The direct and highly productive conversion process from A. platensis via yeast fermentation could be applied to multiple industrial bulk chemicals.

期刊Biotechnology for Biofuels
出版狀態Published - 2018 2月 27

All Science Journal Classification (ASJC) codes

  • 生物技術
  • 應用微生物與生物技術
  • 可再生能源、永續發展與環境
  • 能源(全部)
  • 管理、監督、政策法律


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