Inline monitoring of high cell density cultivation of Scenedesmus rubescens in a mesh ultra-thin layer photobioreactor by photon density wave spectroscopy

Abstract

Objective Due to multiple light scattering that occurs inside and between cells, quantitative optical spectroscopy in turbid biological suspensions is still a major challenge. This includes also optical inline determination of biomass in bioprocessing. Photon Density Wave (PDW) spectroscopy, a technique based on multiple light scattering, enables the independent and absolute determination of optical key parameters of concentrated cell suspensions, which allow to determine biomass during cultivation. Results A unique reactor type, called “mesh ultra-thin layer photobioreactor” was used to create a highly concentrated algal suspension. PDW spectroscopy measurements were carried out continuously in the reactor without any need of sampling or sample preparation, over 3 weeks, and with 10-min time resolution. Conventional dry matter content and coulter counter measurements have been employed as established offline reference analysis. The PBR allowed peak cell dry weight (CDW) of 33.4 g L−1. It is shown that the reduced scattering coefficient determined by PDW spectroscopy is strongly correlated with the biomass concentration in suspension and is thus suitable for process understanding. The reactor in combination with the fiber-optical measurement approach will lead to a better process management.

Integration of Arthrospira platensis (spirulina) into the brewing process to develop new beers with unique sensory properties

“…There is still a lack of knowledge about how to transfer the high growth rates known from lab experiments to large-scale production photobioreactors (PBR) (Khan et al, 2018). For this reason, intense research efforts have been made to improve either the understanding of the complex interaction of cells within the PBR or to improve the PBR performance itself (Enfors et al, 2001;Huang et al, 2017;Wurm and Sandmann, 2021;Sandmann et al, 2022).…”

Effect of alkali metal salt addition on disintegration of titania particles precipitated from tetraethyl orthotitanate in ethanol

“…12 Owing to these benefits, several examples were reported that demonstrate how the use of PDWS can save process time, resources, and improve the understanding of the investigated system. [13][14][15][16][17][18] In a previous work, we used inline PDWS to monitor the formation of TiPs during the hydrolysis of tetraethyl orthotitanate (TEOT) in ethanol in presence of potassium chloride (KCl). 19 This type of TiP synthesis was published before by Eiden-Assmann et al and was also conducted to obtain the results presented in this work.…”

Real‐time monitoring of biomass during Escherichia coli high‐cell‐density cultivations by in‐line photon density wave spectroscopy

“…Gutschmann et al recently applied this technology to stirred tank reactor (STR) cultivations of Ralstonia eutropha and yielded intracellular polyhydroxyalkanoate formation rates for the first time (Gutschmann et al, 2019; Gutschmann, Maldonado Simões, et al, 2023; Gutschmann, Münzberg, et al, 2023). Sandmann et al (2022) employed PDW spectroscopy to successfully measure the formation of algae biomass in a photobioreactor.…”