A Simple and Reliable Formula for Assessment of Maximum Volumetric Productivities in Photobioreactors

TL;DR

This paper introduces a simple, predictive analytical formula for assessing maximum volumetric biomass productivity in various photobioreactors, validated through experiments with cyanobacteria across different reactor designs and sizes.

Contribution

The paper presents a general formula for maximum biomass productivity in photobioreactors, independent of reactor material and design, validated through diverse experimental setups.

Findings

Formula achieves ~15% deviation in predictions.

Validated across different reactor types and sizes.

Applicable to various photoautotrophic strains.

Abstract

This paper establishes and discusses the consistency and the range of applicability of a simple, but general and predictive analytical formula, enabling to easily assess the maximum volumetric biomass growth rates (the productivities) in several kinds of photobioreactors with more or less 15 percents of deviation. Experimental validations are performed on photobioreactors of very different conceptions and designs, cultivating the cyanobacterium Arthrospira platensis, on a wide range of volumes and hemispherical incident light fluxes. The practical usefulness of the proposed formula is demonstrated by the fact that it appears completely independent of the characteristics of the material phase (as the type of reactor, the kind of mixing, the biomass concentration), according to the first principle of thermodynamics and to the Gauss-Ostrogradsky theorem. Its ability to give the maximum (only) kinetic performance of photobioreactors cultivating many different photoautotrophic strains (cyanobacteria, green algae, eukaryotic microalgae) is theoretically discussed but experimental results are reported to a future work of the authors or to any other contribution arising from the scientific community working in the field of photobioreactor engineering and potentially interested by this approach.