Mechanistic modeling of sulfur-deprived photosynthesis and hydrogen production in suspensions of Chlamydomonas reinhardtii

Williams, C.R. and Bees, M.A. (2014) Mechanistic modeling of sulfur-deprived photosynthesis and hydrogen production in suspensions of Chlamydomonas reinhardtii. Biotechnology and Bioengineering, 111(2), pp. 320-335. (doi: 10.1002/bit.25023)

[img]
Preview
Text
86696.pdf - Published Version
Available under License Creative Commons Attribution.

1MB

Publisher's URL: http://dx.doi.org/10.1002/bit.25023

Abstract

The ability of unicellular green algal species such as Chlamydomonas reinhardtii to produce hydrogen gas via iron-hydrogenase is well known. However, the oxygen-sensitive hydrogenase is closely linked to the photosynthetic chain in such a way that hydrogen and oxygen production need to be separated temporally for sustained photo-production. Under illumination, sulfur-deprivation has been shown to accommodate the production of hydrogen gas by partially-deactivating O2 evolution activity, leading to anaerobiosis in a sealed culture. As these facets are coupled, and the system complex, mathematical approaches potentially are of significant value since they may reveal improved or even optimal schemes for maximizing hydrogen production. Here, a mechanistic model of the system is constructed from consideration of the essential pathways and processes. The role of sulfur in photosynthesis (via PSII) and the storage and catabolism of endogenous substrate, and thus growth and decay of culture density, are explicitly modeled in order to describe and explore the complex interactions that lead to H2 production during sulfur-deprivation. As far as possible, functional forms and parameter values are determined or estimated from experimental data. The model is compared with published experimental studies and, encouragingly, qualitative agreement for trends in hydrogen yield and initiation time are found. It is then employed to probe optimal external sulfur and illumination conditions for hydrogen production, which are found to differ depending on whether a maximum yield of gas or initial production rate is required. The model constitutes a powerful theoretical tool for investigating novel sulfur cycling regimes that may ultimately be used to improve the commercial viability of hydrogen gas production from microorganisms.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Bees, Dr Martin
Authors: Williams, C.R., and Bees, M.A.
College/School:College of Science and Engineering > School of Mathematics and Statistics
Journal Name:Biotechnology and Bioengineering
Publisher:Wiley
ISSN:0006-3592
ISSN (Online):1097-0290
Copyright Holders:Copyright © 2014 The Authors
First Published:First published in Biotechnology and Bioengineering 111(2):320-335
Publisher Policy:Reproduced under a Creative Commons License

University Staff: Request a correction | Enlighten Editors: Update this record

Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
424781Bioconvection - hydrogen production and high concentrations in suspensions of swimming micro-organismsMartin BeesEngineering & Physical Sciences Research Council (EPSRC)EP/D073308/1M&S - MATHEMATICS