Journal
ALGAL RESEARCH-BIOMASS BIOFUELS AND BIOPRODUCTS
Volume 28, Issue -, Pages 253-263Publisher
ELSEVIER SCIENCE BV
DOI: 10.1016/j.algal.2017.09.027
Keywords
Hydrogen photoproduction; Thin-layer immobilization; Microalgae; Cyanobacteria; Oxidative stress; Carotenoids
Categories
Funding
- NordForsk NCoE program NordAqua [82845]
- Kone Foundation
- Maj and Tor Nessling Foundation [201600294]
- Academy of Finland FCoE program [307335]
- NREL Emeritus Program
Ask authors/readers for more resources
Cyanobacteria and green algae harness solar energy to split water and to fix CO2. Under specific conditions, they are capable of photoproduction of molecular hydrogen (H-2). This study compares the light-energy-to-hydrogen-energy conversion efficiency (LHCE) in two heterocystous, N-2-fixing cyanobacteria (wild-type Calothrix sp. strain 336/3 and the Delta hupL mutant of Anabaena sp. strain PCC 7120) and in the sulfur-deprived green alga, Chlamydomonas reinhardtii strain CC-124, after entrapment of the cells in thin Ca2+-alginate films. The experiments, performed under photoautotrophic conditions, showed higher LHCEs in the cyanobacteria as compared to the green alga. The highest efficiency of ca. 2.5% was obtained in films of the entrapped Delta hupL strain under low light condition (2.9 W m(-2)). Calothrix sp. 336/3 films produced H-2 with a maximum efficiency of 0.6% under 2.9 W m(-2), while C. reinhardtii films produced H-2 most efficiently under moderate light (0.14% at 12.1 W m(-2)). Exposure of the films to light above 16 W m(-2) led to noticeable oxidative stress in all three strains, which increased with light intensity. The presence of oxidative stress was confirmed by increased (i) degradation of chlorophylls and some structural carotenoids (such as beta-carotene), (ii) production of hydroxylated carotenoids (such as zeaxanthin), and (iii) carbonylation of proteins. We conclude that the H-2 photoproduction efficiency in immobilized algae and cyanobacteria can be further improved by entrapping cultures in immobilization matrices with increased permeability for gases, especially oxygen, while matrices with low porosity produced increased amounts of xanthophylls and other antioxidant compounds.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available