Trickle-film bioreactor and methods of use thereof

A method for culturing a suspended photosynthetic organisms comprising the steps of:

• a. providing a flowing thin film photobioreactor system, wherein the flowing thin film photobioreactor system comprises (i) a light source and (ii) a trickle film insert, wherein the trickle-film insert comprises one or more perforate screens oriented vertically to 45 degrees from vertical;
• b. inoculating a culture medium comprising nutrients, the nutrients comprising a strong base and an organic acid or an ammonium salt thereof, with a phototropic organism selected from the group consisting of algae and cyanobacteria;
• c. charging the photobioreactor system with the inoculated culture medium;
• d. distributing the charged culture medium onto the trickle-film insert wherein a thin film of the charged culture medium having a thickness of 10 millimeters or less flows down the perforate screen or screens under gravity and directing light emitted from the light source toward the perforate screen or screens to expose the culture medium to the light as it flows down the perforate screen or screens, wherein the photosynthetic organisms remains suspended in the culture medium;
• and
• e. feeding the culture medium in the photobioreactor with additional nutrients in a stoichiometric balance based on anticipated nutrient consumption by the photosynthetic organism and measured culture medium pH, optical density, and/or conductivity,
• wherein the photobioreactor system provides a cell concentration of the culture medium of greater than 5 grams dry weight per liter and produces greater than 1 gram dry weight per liter per day of the photosynthetic organisms.