Kinetische Untersuchungen zum Wachstum des Mooses Physcomitrella patens unter verschiedenen Lichtbedingungen

Engineering in Life Sciences

Löser

Schott

et al. 2016

Commercial large-scale application of photobiotechnology calls for acceptable rates and high cell densities. The latter results in self-shading and a temporally declining growth rate, making the process inefficient. Upscaling phototrophic processes requires knowledge of the reaction kinetics with special attention on the μ-I relation. Model-based calculations for studying the effect of self-shading on growth were performed for three μ(I) concepts. The nonrealistic μ(I 0 ) concept results in exponential growth without limit, the widely used μ(I (x)) concept exhibits a growth behavior that significantly deviates from real processes, but the sophisticated μ(I (x)) concept describes real processes best. A Respiration Activity Monitoring System (RAMOS) with CultiLux unit was tested regarding its applicability for exploring the μ-I dependency of Arthrospira platensis. The results were not satisfactory because of self-shading due to a high cell density (which was essential for yielding detectable oxygen-evolution signals). An innovative cultivation system in which self-shading does not interfere with phototrophic growth was required. A flat-panel system was constructed (designed by CFD, short light path of 1 cm, uniform planar light supply by LED and OLED units), allowing continuous cultivation of phototrophic microbes at varied light intensities.

Section: Introductionmentioning

confidence: 99%

The challenge of scaling up photobioreactors: Modeling and approaches in small scale

Engineering in Life Sciences

Löser

Schott

et al. 2016

“…The drawbacks of this set‐up were that the cell suspension was shaded by the sensor rack above the flasks and only a single fixed light intensity was applied. In several other studies, the shake flasks were illuminated with light‐emitting diode (LED) from below , but not in combination with online (oxygen and carbon dioxide) monitoring.…”

Section: Introductionmentioning

confidence: 99%

Phototrophic growth of Arthrospira platensis in a respiration activity monitoring system for shake flasks (RAMOS®)

Engineering in Life Sciences

Lenk

Geipel

et al. 2014

Optimizing illumination is essential for optimizing the growth of phototrophic cells and their production of desired metabolites and/or biomass. This requires appropriate modulation of light and other key inputs and continuous online monitoring of their metabolic activities. Powerful noninvasive systems for cultivating heterotrophic organisms include shake flasks in online monitoring units, but they are rarely used for phototrophs because they lack the appropriate illumination design and necessary illuminatory power. This study presents the design and characterization of a photosynthetic shake flask unit, illuminated from below by warm white light‐emitting diodes with variable light intensities up to 2300 μmol m−2 s−1. The photosynthetic unit was successfully used, in combination with online monitoring of oxygen production, to cultivate Arthrospira platensis. In phototrophic growth under continuous light and a 16 h light/8 h dark cycle (light intensity: 180 μmol m−2 s−1), the oxygen transfer rate and biomass‐related oxygen production were −1.5 mmol L−1 h−1 and 0.18 mmol O2 gx−1 h−1, respectively. The maximum specific growth rate was 0.058 h−1, during the exponential growth phase, after which the biomass concentration reached 0.75 g L−1.

Shake Flask Technology

Winkler

Encyclopedia of Industrial Biotechnology

2014

For more than 150 years, shake flasks are used in research and development as reaction chambers for chemical and microbiological reactions. An uncountable number of experiments has been performed in shake flasks—a suitable tool for laboratory scale—and, therefore, a lot of data and knowledge was achieved. Owing to its simple but advantageous design, the shake—also called Erlenmeyer—flask represents an appropriate tool for cultivation of biomass in biotechnological laboratories. Recently, more engineering efforts have been performed to describe conditions in shake flasks such as gas transfer or power consumption. Further innovative approaches were developed to either enable larger shaking systems for production or monitor growth‐related parameters online, and at line. Moreover, disadvantages of this technology such as less regulation and controlling possibilities or limitations in gassing/degassing have to be taken into account. The focus of this article is to give fundamental information about the most important issues in shake flask technology for biotechnological applications. Starting with a short historical introduction, the authors highlight the most commonly used types of different flask and closure types, volumes, etc. Subsequently, functions and the introduction of important shaking‐related parameters such as shaking diameter and shaking frequency are given. Before ending up with the innovative potential of modern investigations concerning this significant technology, advantages and disadvantages of shake flask applications are discussed.