Electron carrier, electron carrier production method, and electron transfer method

An electron carrier comprising:

• a modified cyanobacterium in which at least:
• (i) a function of a protein involved in binding between an outer membrane and a cell wall of cyanobacterium is suppressed;
• or
• (ii) a channel protein which improves protein permeability of the outer membrane is expressed, wherein
• the modified cyanobacterium performs at least one of supplying electrons to an outside or taking in electrons from the outside,
• wherein in (i), a gene which causes expression of the protein involved in the binding between the outer membrane and the cell wall is deleted or inactivated,
• wherein the gene which causes expression of the protein involved in the binding between the outer membrane and the cell wall is at least one of a gene encoding an SLH domain-containing outer membrane protein or a gene encoding a cell wall-pyruvic acid modifying enzyme,
• wherein the gene encoding the SLH domain-containing outer membrane protein is:
• slr1841 having the nucleotide sequence of SEQ ID NO:
• 7;
• nies970_09470 having the nucleotide sequence of SEQ ID NO:
• 8;
• anacy_3458 having the nucleotide sequence of SEQ ID NO:
• 9;
• or
• a gene having a nucleotide sequence that is at least 50 percent identical to the nucleotide sequence of any one of the slr1841, the nies970_09470, and the anacy_3458, and
• wherein the gene encoding the cell wall-pyruvic acid modifying enzyme is:
• s1r0688 having the nucleotide sequence of SEQ ID NO:
• 10;
• synpcc7942_1529 having the nucleotide sequence of SEQ ID NO:
• 11;
• anacy_1623 having the nucleotide sequence of SEQ ID NO:
• 12;
• or
• a gene having a nucleotide sequence that is at least 50 percent identical to the nucleotide sequence of any one of the slr0688, the synpcc7942_1529, and the anacy_1623.