Overproduction and easy recovery of biofuels from engineered cyanobacteria, autolyzing multicellular cells.

The semi-filamentous multicellular cyanobacterium Limnothrix/Pseudanabaena sp. strain ABRG5-3 undergoes autolysis, which involves the accumulation of polyphosphate compounds and disintegration of thylakoid membranes in cells, as a unique feature that occurs due to growth conditions. In this study, the overexpression and easy recovery of alkane (a saturated hydrocarbon, C17H36) as a biofuel were examined in recombinants of the cyanobacteria ABRG5-3 and Synechocystis sp. strain PCC6803. The results obtained indicated that the accumulated mass of alkane accounted for ∼50 or 60% of the dry weight of ABRG5-3 or PCC6803 recombinant cells, respectively. Furthermore, cultivating cells in liquid medium BG11 in which the nitrogen resource had been depleted promoted the production of alkane and cell lysis, resulting in the easy recovery of target products from the supernatant.