Light spectral effect on a consortium of filamentous green algae grown on anaerobic digestate piggery effluent (ADPE)

Webb, J.P., van Keulen, M.ORCID: 0000-0001-6235-5788, Wong, S.K.S., Hamley, E., Nwoba, E.ORCID: 0000-0003-0397-2369 and Moheimani, N.R.ORCID: 0000-0003-2310-4147 (2020) Light spectral effect on a consortium of filamentous green algae grown on anaerobic digestate piggery effluent (ADPE). Algal Research, 46 . Article 101723.

Abstract

The use of LEDs for the commercial cultivation of macroalgae is becoming commonplace, as is adding value to glass structures such as green houses and aquaculture ponds via the use of transparent photovoltaic cells. The effect on photosynthesis and primary production by down regulating light to the red (600–700 nm) and blue (400–525 nm) parts of the spectrum was assessed on a consortium of two filamentous chlorophyte macroalgae species (Rhizoclonium sp. and Ulothrix sp.). The aim of the study was to determine the optimal wavelength for growth and to assess potential nutrient removal rates in anaerobic digestion piggery effluent. Under red and blue light oxygen evolution was reduced compared to the white light controls (WL = 3.490 > RL = 2.700 > BL = 0.800 mg O2 g biomass−1 h−1). Spectrum-adapted chlorophyll fluorescence results indicated that the highest rETRmax (9.080 ± 0.380 μmol electrons m−2 s−1) occurred when blue light was used. This was 10% greater than rETRmax when red light was used. Both blue and red light grown macroalgae showed significantly higher rETRmax compared to white light. Long-term adaptation to blue light yielded the highest rETRmax (5.550 ± 0.230 μmol electrons m−2 s−1), with an effective quantum yield (Fq/Fm′) of 0.75 ± 0.003. Productivity of the macroalgal consortium was greatest under white light (WL = 0.210 > RL = 0.129, BL = 0.110 g L−1 d−1); however red light yielded a three-fold increase in productivity when standardized against the irradiance received at the Light Harvesting Complex (RL = 6.45 × 10−3 > BL = 4.036 × 10−3 > RL = 2.377 × 10−3 g L−1 d−1 μmol photons m−2 s−1 (±SE)). These results indicate that red light provides the optimal light wavelength for maximum growth of the macroalgal consortium used.

Item Type:	Journal Article
Murdoch Affiliation(s):	Algae R&D Centre School of Veterinary and Life Sciences
Publisher:	Elsevier BV
Copyright:	© 2019 Elsevier B.V.
URI:	http://researchrepository.murdoch.edu.au/id/eprint/54736

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