Patent ID: 8597914

Claim:
A method of producing a fermentable sugar using a photobioreactor, the method comprising: (A) inoculating a photobioreactor with a transgenic cyanobacteria engineered to accumulate at least one fermentable sugar selected from the group consisting of sucrose and trehalose, wherein the transgenic cyanobacteria comprises an artificial DNA construct comprising (i) a promoter functional in the transgenic cyanobacteria; (ii) a nucleotide sequence encoding (a) a first polypeptide comprising SEQ ID NO: 2 or a sequence 95% identical thereto having sucrose phosphate synthase and sucrose phosphate phosphatase (ASF) activity; or (b) a second polypeptide and a third polypeptide, wherein (1) the second polypeptide comprises SEQ ID NO: 4 or a polypeptide that is 95% identical to SEQ ID NO: 4 having sucrose phosphate synthase (SPS) activity and the third polypeptide comprises SEQ ID NO: 6 or a polypeptide that is 95% identical to SEQ ID NO: 6 having sucrose phosphate phosphatase (SPP) activity; or (2) the second polypeptide comprises SEQ ID NO: 77 or a polypeptide that is 95% identical to SEQ ID NO: 77 having trehalose phosphate synthase (TPS) activity and the third polypeptide comprises SEQ ID NO: 79 or a polypeptide that is 95% identical to SEQ ID NO: 79 having trehalose phosphate phosphatase (TPP) activity; and (iii) a transcriptional termination sequence, wherein the transgenic cyanobacteria accumulates increased levels of the fermentable sugar compared to a cyanobacteria cell not comprising the DNA construct; (B) cultivating the transgenic cyanobacteria in or on the photobioreactor; and (C) isolating accumulated fermentable sugar.