Publications by authors named "Pascal van Alphen"

Photoautotrophic growth of Synechocystis sp. PCC 6803 in a flat-panel photobioreactor, run in turbidostat mode under increasing intensities of orange-red light (636 nm), showed a maximal growth rate (0.12 h) at 300 μmol m s, whereas first signs of photoinhibition were detected above 800 μmol m s.

View Article and Find Full Text PDF

gathered momentum in modelling studies and biotechnological applications owing to multiple factors like fast growth, ability to fix carbon dioxide into valuable products, and the relative ease of genetic manipulation. physiology and metabolism, and consequently, the productivity of -based photobioreactors (PBRs), are heavily light modulated. Here, we set up a turbidostat-controlled lab-scale cultivation system in order to study the influence of varying orange-red light intensities on growth characteristics and photosynthetic activity.

View Article and Find Full Text PDF

Photosynthetic activity and respiration share the thylakoid membrane in cyanobacteria. We present a series of spectrally resolved fluorescence experiments where whole cells of the cyanobacterium Synechocystis sp. PCC 6803 and mutants thereof underwent a dark-to-light transition after different dark-adaptation (DA) periods.

View Article and Find Full Text PDF

Many conditions have to be optimized in order to be able to grow the cyanobacterium Synechocystis sp. PCC 6803 (Synechocystis) for an extended period of time under physiologically well-defined and constant conditions. It is still poorly understood what limits growth of this organism in batch and continuous cultures in BG-11, the standard medium used to grow Synechocystis.

View Article and Find Full Text PDF

Cyanobacterial thylakoid membranes are known to host photosynthetic and respiratory complexes. This hampers a straight forward interpretation of the highly dynamic fluorescence originating from photosynthetic units. The present study focuses on dark-to-light transitions in whole cells of a PSI-deficient mutant of the cyanobacterium Synechocystis sp.

View Article and Find Full Text PDF

Unlabelled: Investigating the physiology of cyanobacteria cultured under a diel light regime is relevant for a better understanding of the resulting growth characteristics and for specific biotechnological applications that are foreseen for these photosynthetic organisms. Here, we present the results of a multiomics study of the model cyanobacterium Synechocystis sp. strain PCC 6803, cultured in a lab-scale photobioreactor in physiological conditions relevant for large-scale culturing.

View Article and Find Full Text PDF

Cyanobacteria have developed responses to maintain the balance between the energy absorbed and the energy used in different pigment-protein complexes. One of the relatively rapid (a few minutes) responses is activated when the cells are exposed to high light intensities. This mechanism thermally dissipates excitation energy at the level of the phycobilisome (PB) antenna before it reaches the reaction center.

View Article and Find Full Text PDF

The societal importance of renewable carbon-based commodities and energy carriers has elicited a particular interest for high performance phototrophic microorganisms. Selection of optimal strains is often based on direct comparison under laboratory conditions of maximal growth rate or additional valued features such as lipid content. Instead of reporting growth rate in culture, estimation of photosynthetic efficiency (quantum yield of PSII) by pulse-amplitude modulated (PAM) fluorimetry is an often applied alternative method.

View Article and Find Full Text PDF

The cyanobacterial circadian clock has been well-studied and shown to be both robust and a dominant factor in the control of gene expression in Synechococcus elongatus PCC7942. In Synechocystis sp. PCC6803, the circadian clock is assumed to function similarly, yet appears to control transcription to a far lesser extent and its circadian rhythm was reported to not be sustained, or at least rapidly damped, under continuous illumination.

View Article and Find Full Text PDF

The general stress response of Bacillus subtilis can be activated by a wide range of signals, including low intensities of visible light. It is regulated by a dedicated σ factor via a complex signal transduction pathway that makes use of stressosomes: hetero-oligomeric complexes that include one or more of the RsbR proteins (RsbRA, RsbRB, RsbRC, and RsbRD). The response to blue light is mediated by the photoreceptor YtvA.

View Article and Find Full Text PDF