Optimised spectral effects of programmable LED arrays (PLA)s on bioelectricity generation from algal-biophotovoltaic devices

Fong-Lee Ng; Siew-Moi Phang; Boon Leong Lan; Vineetha Kalavally; Cheng-Han Thong; Kian-Ted Chong; Vengadesh Periasamy; Karthikeyan Chandrasekaran; G Gnana Kumar; Kamran Yunus; Adrian C Fisher

doi:10.1038/s41598-020-72823-9

Optimised spectral effects of programmable LED arrays (PLA)s on bioelectricity generation from algal-biophotovoltaic devices

Sci Rep. 2020 Sep 30;10(1):16105. doi: 10.1038/s41598-020-72823-9.

Authors

Affiliations

¹ Institute of Ocean and Earth Sciences (IOES), University of Malaya, Kuala Lumpur, Malaysia.
² Institute of Ocean and Earth Sciences (IOES), University of Malaya, Kuala Lumpur, Malaysia. phang@um.edu.my.
³ Faculty of Applied Sciences, UCSI University, Kuala Lumpur, Malaysia. phang@um.edu.my.
⁴ Electrical and Computer Systems Engineering and Advanced Engineering Platform, School of Engineering, Monash University, Sunway, Malaysia.
⁵ Institute for Advanced Studies, University of Malaya, Kuala Lumpur, Malaysia.
⁶ Low Dimensional Materials Research Centre (LDMRC), Department of Physics, University of Malaya, Kuala Lumpur, Malaysia.
⁷ Department of Physical Chemistry, School of Chemistry, Madurai Kamaraj University, Madurai, Tamil Nadu, 625021, India.
⁸ Department of Chemical Engineering and Biotechnology, University of Cambridge, Philipa Fawcett Drive, Cambridge, CB3 0AS, UK.

Abstract

The biophotovoltaic cell (BPV) is deemed to be a potent green energy device as it demonstrates the generation of renewable energy from microalgae; however, inadequate electron generation from microalgae is a significant impediment for functional employment of these cells. The photosynthetic process is not only affected by the temperature, CO₂ concentration and light intensity but also the spectrum of light. Thus, a detailed understanding of the influences of light spectrum is essential. Accordingly, we developed spectrally optimized light using programmable LED arrays (PLA)s to study the effect on algae growth and bioelectricity generation. Chlorella is a green microalga and contains chlorophyll-a (chl-a), which is the major light harvesting pigment that absorbs light in the blue and red spectrum. In this study, Chlorella is grown under a PLA which can optimally simulate the absorption spectrum of the pigments in Chlorella. This experiment investigated the growth, photosynthetic performance and bioelectricity generation of Chlorella when exposed to an optimally-tuned light spectrum. The algal BPV performed better under PLA with a peak power output of 0.581 mW m^-2 for immobilized BPV device on day 8, which is an increase of 188% compared to operation under a conventional white LED light source. The photosynthetic performance, as measured using pulse amplitude modulation (PAM) fluorometry, showed that the optimized spectrum from the PLA gave an increase of 72% in the rETRmax value (190.5 μmol electrons m^-2 s^-1), compared with the conventional white light source. Highest algal biomass (1100 mg L^-1) was achieved in the immobilized system on day eight, which translates to a carbon fixation of 550 mg carbon L^-1. When artificial light is used for the BPV system, it should be optimized with the light spectrum and intensity best suited to the absorption capability of the pigments in the cells. Optimum artificial light source with algal BPV device can be integrated into a power management system for low power application (eg. environment sensor for indoor agriculture system).

Publication types

Research Support, Non-U.S. Gov't