The disclosure relates to the field of reduction of CO.sub.2 emission, more in particular to CO.sub.2 capture and conversion. The disclosure further relates to the culturing of algae and an apparatus for use thereof. One object of the disclosure is to provide an alternative method for capturing and conversion of CO.sub.2 from a gaseous stream.

A culture method for microalgae that cultures unicellular green microalgae belonging to the genus Coccomyxa and groups of organisms closely related thereto, or the Watanabea clade, in an open outdoor culture system using broth having a pH of 4 or lower. A culture method for microalgae that cultures microalgae of the genus Coccomyxa and groups of organisms closely related thereto, or Pseudococcomyxa, in an open outdoor culture system using broth having a pH of 4 or lower containing ammonia nitrogen.

Systems and methods are provided for growing algae and/or other microorganisms in a controlled environment while reducing or minimizing the amount of energy required for maintaining desired conditions in the growth medium. The systems can be based on a photobioreactor having a “tube-in-tube structure”, where an outer cylindrical tube contains a heat regulation fluid that surrounds one or more inner cylinders that contain microorganisms in growth media. The heat regulation fluid in the outer cylinder, as well as the outer cylinder itself, can assist with regulating the temperature of the growth media in the inner cylinder(s).

An object of the present invention is to provide: an algae water concentration system that efficiently concentrates algae water in a culture pond into algae water containing algae having a desired size, with a simple structure and at low cost; and a method for operating the same. A cultured algae water concentration system 100 comprises: an algae water supply unit 17 that has an algae water supply container 18 that stores algae water sent from the culture pond therein, and a supply container outlet port 19 through which the algae water is taken out from the algae water supply container; and an algae water concentration unit that has a concentration container 1 for receiving and concentrating the algae water from the algae water supply unit, a filter 3 which divides the concentration container into upper and lower spaces and does not pass algae having a predetermined size or larger therethrough, a vibration device 5 that vibrates the filter in an out-of-plane direction, a concentration container algae water inlet port 7 which takes in the algae water to the concentration container and is arranged below the filter of the concentration container, a concentrated algae water outlet port 9 that is arranged below the filter of the concentration container and takes out algae water therethrough that has been concentrated in the concentration container, and a filtered water discharge port 8 that is arranged above the filter of the concentration container and discharges filtered water having passed through the filter.

The invention relates to a light injector element (20) comprising a body (21) extending according to a longitudinal axis (22), and a light source (23) placed facing an end (25) of the body (21), the light source (23) comprising a plurality of vertical-cavity surface-emitting laser (VCSEL) diodes, said plurality of diodes being arranged so as to form an emission surface (26) substantially perpendicular to the longitudinal axis (22) of the body (21).

The invention also relates to a photobioreactor (10) comprising such a light injector element (20).

The invention relates to a light injector element (20) comprising a hollow body (21) extending according to a longitudinal axis (22), and a light source (23) placed facing an end (25) of the body (21), the light source (23) being configured to emit a light beam substantially parallel to the longitudinal axis (22) of said body (21), the injector element (20) further comprising at least one optical element (35i) arranged inside the body (21) and configured to let through a fraction of the light beam propagating in a central part (36i) of the body (21), and deflect towards the outside of said body (21) a fraction of the light beam propagating in a peripheral part (37i) of the body so as to locally distribute energy emitted by the light source (23).

The invention also relates to a photobioreactor (10) and a domestic lighting element comprising such a light injector element (20).

A composition of microorganisms, comprising photoautotrophic microorganisms (16) which produce oxygen by photosynthetic water oxidation chemoheterotrophic microorganisms (17) which respire oxygen, wherein the photoautotrophic microorganisms (16) and the chemoheterotrophic microorganisms (17) are comprised in a biofilm (13), the biofilm further comprising components (15) which were secreted by the photoautotrophic microorganisms (16) and/or the chemoheterotrophic microorganisms (17),
and a reactor (1), a method for forming a biofilm, and a method for biocatalytic conversion employing such composition.

Autotrophic algal growth in high incident light situations may be conducted in a reactor with circulation of algal reaction medium between light and dark zones with very short residence time in the light zone to maintain algal growth in the reactor in a linear growth regime in which the rate of algal biomass production is proportional to the incident photosynthetic photon flux density. Process monitoring and control may permit quick processing in a single step even in open pond systems. Dissolved nitrogen levels in product may be monitored and nitrogen nutrient input may be restricted to reduce dissolved nitrogen in effluent and to increase lipid yield without a separate nitrogen starvation step.

The present invention relates to a method for producing energy by recycling materials during a fuel combustion process, wherein the fuel combustion process comprises combusting fuel introduced into the fuel combustion process. Further, the invention relates to an apparatus for producing energy by recycling materials during a fuel combustion process.

A photobioreactor device for growing photosynthetic organisms, organisms that feed on photosynthetic organisms and hydroponics is disclosed. The device may include a lighting system integrated around the circumference of the device. In embodiments, a cap configured to seal the container has ports configured to permit passage of fluid out of or into a container without removing the cap. In some embodiments, organisms are grown in a disposable bag secured between the cap and the container.