Microorganisms with increased photosynthetic capacity

Inventors

Roberts, James • CARRIERI, Damian • Heinnickel, Mark

Assignees

Lumen Bioscience Inc

Abstract

Microorganisms with increased photosynthetic capacity are described. Increased photosynthetic capacity is achieved by down-regulating activity of the RpaB pathway. The microorganisms include Cyanobacteria, including genetically-modified Cyanobacteria.

Core Innovation

The invention provides genetically-modified microorganisms, specifically Cyanobacteria, with increased photosynthetic capacity achieved by down-regulating the RpaB pathway. This is accomplished by expressing exogenous nucleotide sequences, such as SEQ ID NO: 33, which encode N-terminal fragments of the SrrA polypeptide that include a phosphor-receiver domain but lack a DNA binding domain or have a non-functional DNA binding domain. Expression of these fragments under the control of a promoter in the microorganism results in down-regulation of RpaB pathway activity.

The problem addressed by this invention is the limited photosynthetic capacity and low biomass yield of microorganisms used for applications such as biofuel, chemical, and food production. Existing approaches using photosynthetic crops and non-edible crops have limitations, including potential contributions to food shortages and low yields per unit area. Photosynthetic microorganisms, including Cyanobacteria, are capable of producing more oils, fats, and carbohydrates than plants but can be further improved by increasing their photosynthetic capacity through genetic modifications as described.

The summary indicates that these modifications not only increase photosynthetic capacity but also enhance total carbon fixation, the production of carbon-containing compounds, and growth (biomass accumulation). This enhancement is specifically linked to the introduction of exogenous nucleotide sequences that lead to the expression of interfering protein fragments, thereby decreasing RpaB pathway repression and resulting in increased photosynthetic performance relative to unmodified strains.

Claims Coverage

There are two independent claims in this patent, each describing a main inventive feature centered on genetically-modified Cyanobacteria expressing an N-terminal fragment of SrrA to down-regulate RpaB pathway activity and methods for increasing photosynthetic capacity using such modifications.

The inventive features focus on genetically-modified Cyanobacteria expressing a specific SrrA fragment to achieve reduced RpaB pathway activity, leading to improved photosynthetic properties and use of this approach in both products and methods that enhance photosynthetic output.

Stated Advantages

Documented Applications