NOVELTY - The digester-photobioreactor (1) comprises a first enclosure containing photosynthetic microorganisms and a growth medium, and a second enclosure containing microorganisms and a digestive medium comprising anaerobic bacteria capable of digesting the microorganisms. The microorganisms are in contact with the growth medium and exposed to sunlight. The first chamber is connected to the second enclosure. The second enclosure defines a support wall to the first enclosure. A part of the first and second enclosure comprises a flexible structure supported by the gas pressure.    USE - The digester-photobioreactor is useful for culturing photosynthetic microorganisms such as microalgae and producing biogas to produce electricity.    ADVANTAGE - The digester-photobioreactor is capable of energy efficiently, rapidly and economically culturing the photosynthetic microorganisms such as microalgae thus producing good quality biogas with high production, protects the microorganisms from atmosphere using a sealed barrier thus avoiding the cross-contamination of the microorganisms and increasing the population of microalgae, eliminates the growth of predatory zooplankton in the culture medium, and maintains a constant temperature by providing controllable heat exchange between the units.    DETAILED DESCRIPTION - The digester-photobioreactor (1) comprises a first enclosure containing photosynthetic microorganisms and a growth medium, and a second enclosure containing microorganisms and a digestive medium comprising anaerobic bacteria capable of digesting the microorganisms. The microorganisms are in contact with the growth medium and exposed to sunlight. The first chamber is connected to the second enclosure. The second enclosure defines a support wall to the first enclosure. A part of the first and second enclosure comprises a flexible structure supported by the gas pressure contained within the first and second enclosure respectively. A part of the first enclosure is partially transparent to sunlight. The growth medium in the first enclosure comprises a growth solution in which the microorganisms are suspended. The first enclosure comprises a unit for moving and/or stirring microorganisms and growth medium. The entire wall of the first and second enclosures is constituted of a flexible structure. The digestive medium in the second enclosure comprises a digestive fluid mass in which the microorganisms and the anaerobic bacteria are distributed. The digestive mass is pumped. The first and second enclosures are connected to each other by a biomass transferring pipe. The first enclosure further comprises a partition defining a first partial volume on one side of the partition and a second partial volume on the other side of the partition. The first moving unit is present in a first passage of the enclosure, and a second moving unit is laid in a second passage of the enclosure. The first passage is located at first end of the first enclosure and the second passage is located at a second end of the first enclosure. The first and/or the second enclosure are partially filled with a liquid volume and a gas volume above the liquid so that the pressure of the liquid supports a lower part and the pressure of the gas supports an upper part of the first enclosure and/or the second enclosure. A lower part of the first and/or second enclosure is made of a rigid structure, while an upper part of the first and/or second enclosure is made of a flexible structure. The liquid in the first and second enclosure is made of the suspension of microorganisms in a growth solution, and the digestive fluid mass respectively. The first enclosure is present in the form of tube comprising two separate boxes, and comprises a controllable gas or liquid opening by which the gas or liquid is introduced into or removed from the first enclosure respectively. The second enclosure comprises a controllable gas or liquid opening by which the gas or liquid is introduced into or removed from the second enclosure.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic top view of a digester-photobioreactor.    Digester-photobioreactor (1)    Mixers (2a, 2b)    Support ends (3a, 3b)    Digesters (10a, 10b)    Base. (L)