Decreased light-harvesting antenna size in cyanobacteria
View Patent ↗The invention provides methods and compositions for increasing photosynthetic efficiency and biomass production in cyanobacterial cultures by minimizing the phycobilisome light-harvesting antenna size through disruption of the phycocyanin-encoding CPC-operon.
1. A method of enhancing biomass accumulation of a cyanobacteria culture, the method comprising:
providing a cyanobacteria cell population comprising cyanobacteria that are genetically modified in the genome to have a disruption in an endogenous CPC-operon comprising genes encoding CPCA, CPCB, CPCC1, CPCC2, and CPCD polypeptide components of phycocyanin-containing rods, wherein the disruption decreases phycobilisome antenna size compared to counterpart wild-type cyanobacteria comprising a native CPC-operon;
growing the cyanobacterial cell population in a reactor to obtain a cyanobacterial culture;
maintaining the cyanobacteria culture under conditions in which the photosynthetically active radiation (PAR) intensity is at least 500 micromol photons per square meter per second; and the culture absorbs at least 70% of the incoming light.
2. The method of claim 1 , wherein the PAR intensity is at least 800 micromol photons per square meter per second.
3. The method of claim 1 , wherein the culture absorbs at least 80%, or at least 90% of the incoming light.
4. The method of claim 1 , wherein the disruption in the endogenous CPC-operon is inhibition of a CPCA and/or CPCB gene.
5. The method of claim 1 , wherein the disruption in the endogenous CPC-operon is inhibition of at least one of a CPCC1, CPCC2, or CPCD gene.
6. The method of claim 1 , wherein the disruption in the endogenous CPC-operon is a deletion of at least one of a CPCA, CPCB, CPCC1, CPCC2, or CPCD genes.
7. The method of claim 1 , wherein the cyanobacteria are a species of a genus selected from the group consisting of Synechocystis, Synechococcus, Cyanothece , and Thermosynechococcus.
8. The method of claim 1 , wherein the cyanobacteria are a species of a genus of filamentous cyanobacteria.
9. The method of claim 8 , wherein the genus is selected from the group consisting of Arthrospira, Nostoc , and Anabaena.
10. The method of claim 1 , wherein the disruption is deletion of the endogenous CPC-operon.
11. The method of claim 1 , wherein the disruption in the endogenous CPC-operon comprises deletion of a CPCA or CPCB gene.
12. The method of claim 1 , wherein the endogenous CPC-operon encodes a CPCA polypeptide that has at least 70% identity to the amino acid sequence of SEQ ID NO:2 or encodes a CPCB polypeptide that has at least 70% identity to SEQ ID NO:3.