A microorganism which is genetically modified so that it produces a first essential biomass precursor by metabolizing CO.sub.2 using a recombinant carbon fixation enzyme is disclosed. The microorganism produces a second biomass precursor by metabolizing an organic carbon source and not by metabolizing CO.sub.2. The microorganism does not use the organic carbon source for producing the first essential biomass precursor.

Materials and methods for extracting and purifying proteins are provided. For example, the materials and methods provided herein can be used for extracting and purifying proteins that denature at low temperature.

Provided herein are modified Rubisco large subunit proteins and nucleid acids encoding such proteins, as well as photosynthetic organism transformed with said nucleic acids and expressing said proteins. In certain embodiments, photosynthetic organisms containing said modified Rubisco large subunit proteins exhibit increased biomass production.

The present invention provides a plant expressing a target protein, a method of preparing the same and a method of preparing a composition for oral administration of a biopharmaceutical using the same. A target protein expression system using plant cells according to the present invention solves conventional problems in plant cell culture, provides a method of producing a large quantity of target proteins including a biopharmaceutical protein and allowing a target protein to have a resistance to a protease present in a digestive organ, and therefore is very effective to enable commercialization of plant-derived biopharmaceuticals.

Aspects of the present disclosure relate to genetically altered plants with increased activity of one or more of a PPDK regulatory protein (PDRP), a Rubisco activase (Rea) protein, or a Rubisco protein that have increased photosynthetic efficiency under fluctuating light conditions. Further, aspects of the present disclosure relate to methods of producing and cultivating the genetically altered plants of the present disclosure.

A microorganism which is genetically modified so that it produces a first essential biomass precursor by metabolizing CO.sub.2 using a recombinant carbon fixation enzyme is disclosed. The microorganism produces a second biomass precursor by metabolizing an organic carbon source and not by metabolizing CO.sub.2. The microorganism does not use the organic carbon source for producing the first essential biomass precursor.

The disclosure describes methods for the purification of protein-enriched extracts to provide concentrates and isolates and methods for incorporation of such materials into products. The purification methods are adapted for removal of nicotine and may have other benefits, e.g., lightening the color of the protein-enriched extracts. The methods generally include treatment with peracetic acid or hydrogen peroxide and filtrations. A protein composition in the form of a concentrate or isolate is provided, the protein composition including RuBisCO, F2 fraction proteins, or combination thereof extracted from a plant of the Nicotiana species, wherein the protein composition is characterized by relatively low nicotine content.

The disclosure describes methods for the purification of protein-enriched extracts to provide concentrates and isolates and methods for incorporation of such materials into products. The purification methods are adapted for removal of nicotine and may have other benefits, e.g., lightening the color of the protein-enriched extracts. The methods generally include treatment with peracetic acid or hydrogen peroxide and filtrations. A protein composition in the form of a concentrate or isolate is provided, the protein composition including RuBisCO, F2 fraction proteins, or combination thereof extracted from a plant of the Nicotiana species, wherein the protein composition is characterized by relatively low nicotine content.

Ribulose-1,5-bisphosphate oxygenase (RuBisCO) protein fibers and a method of producing them are disclosed herein. The method of producing one or more RuBisCO protein fibers including obtaining RuBisCO, for example from tobacco, combining the RuBisCO with one or more plasticizers, heating the combination of the RuBisCO and the one or more plasticizers up to about 140 degrees C., filtering the heated combination through an about 20 m filter, and passing the filtered combination through an orifice to produce one or more RuBisCO protein fibers.

Ribulose-1,5-bisphosphate oxygenase (RuBisCO) protein films and a method of producing RuBisCO films are disclosed herein. A method of producing one or more RuBisCO protein films includes obtaining RubBisCO, for example from tobacco, combining the RuBisCO with one or more solvents, where the one or more solvents may be about 10% w/v the RuBisCO, mixing the RuBisCO and the one or more solvents to form a slurry, heating the slurry to about 70 degrees C., cooling the slurry to at least about 45 degrees C., dispensing the slurry into one or more molds for film formation, drying the slurry in the one more molds, and removing the one or more RuBisCO protein films formed within the one or more molds.