The Assessment of the Real-Time Radiative Properties and Productivity of in Tubular Photobioreactors.

The development of tools to predict the photobioreactors' (PBRs) productivity is a significant concern in biotechnology. To this end, it is required to know the light availability inside the cultivation unit and combine this information with a suitable kinetic expression that links the distribution of radiant energy with the cell growth rate. In a previous study, we presented and validated a methodology for assessing the radiative properties necessary to address the light distribution inside a PBR for varying illuminating conditions through the cultivation process of a phototrophic microorganism.

Enhancement of astaxanthin production from Haematococcus pluvialis under autotrophic growth conditions by a sequential stress strategy.

The study of microalgal culture has been growing in recent decades, because the cellular structure of microalgae has diverse highly valuable metabolites that have attract attention of numerous companies and research groups. The pigment astaxanthin is considered one of the most powerful antioxidants in nature. The microalga Haematococcus pluvialis was proposed as one of the best natural astaxanthin sources, because it can accumulate high amount of the pigment.

Kinetic Model of Photoautotrophic Growth of Chlorella sp. Microalga, Isolated from the Setúbal Lagoon.

In this work, a kinetic expression relating light availability in the culture medium with the rate of microalgal growth is obtained. This expression, which is valid for low illumination conditions, was derived from the reactions that take part in the light-dependent stage of photosynthesis. The kinetic expression obtained is a function of the biomass concentration in the culture, as well as of the local volumetric rate of absorption of photons, and only includes two adjustable parameters.

Analysis and design of photobioreactors for microalgae production II: experimental validation of a radiation field simulator based on a Monte Carlo algorithm.

In a previous study, we developed a methodology to assess the intrinsic optical properties governing the radiation field in algae suspensions. With these properties at our disposal, a Monte Carlo simulation program is developed and used in this study as a predictive autonomous program applied to the simulation of experiments that reproduce the common illumination conditions that are found in processes of large scale production of microalgae, especially when using open ponds such as raceway ponds. The simulation module is validated by comparing the results of experimental measurements made on artificially illuminated algal suspension with those predicted by the Monte Carlo program.

Analysis and design of photobioreactors for microalgae production I: method and parameters for radiation field simulation.

Having capabilities for the simulation of the radiation field in suspensions of microalgae constitutes a great asset for the analysis, optimization and scaling-up of photobioreactors. In this study, a combined experimental and computational procedure is presented, specifically devised for the assessment of the coefficients of absorption and scattering, needed for the simulation of such fields. The experimental procedure consists in measuring the radiant energy transmitted through samples of suspensions of microalgae of different biomass concentrations, as well as the forward and backward scattered light.