Culturing of Selenastrum on diluted composting fluids; conversion of waste to valuable algal biomass in presence of bacteria

Marika Tossavainen; Anne Nykänen; Kalle Valkonen; Anne Ojala; Silja Kostia; Martin Romantschuk

doi:10.1016/j.biortech.2017.04.013

Culturing of Selenastrum on diluted composting fluids; conversion of waste to valuable algal biomass in presence of bacteria

Bioresour Technol. 2017 Aug:238:205-213. doi: 10.1016/j.biortech.2017.04.013. Epub 2017 Apr 7.

Authors

Marika Tossavainen¹, Anne Nykänen², Kalle Valkonen², Anne Ojala³, Silja Kostia⁴, Martin Romantschuk⁵

Affiliations

¹ Department of Environmental Sciences, University of Helsinki, Niemenkatu 73, 15140 Lahti, Finland. Electronic address: marika.tossavainen@helsinki.fi.
² Department of Environmental Sciences, University of Helsinki, Niemenkatu 73, 15140 Lahti, Finland.
³ Department of Environmental Sciences, University of Helsinki, Niemenkatu 73, 15140 Lahti, Finland; Department of Forest Sciences, P.O. Box 27, 00014 University of Helsinki, Finland.
⁴ Faculty of Technology, Lahti University of Applied Sciences, Ståhlberginkatu 10, 15110 Lahti, Finland.
⁵ Department of Environmental Sciences, University of Helsinki, Niemenkatu 73, 15140 Lahti, Finland; Institute of Environmental Sciences, Kazan Federal University, 420008 Kazan, Russia.

PMID: 28433909
DOI: 10.1016/j.biortech.2017.04.013

Abstract

Growth and fatty acid production of microalga Selenastrum sp. with associated bacteria was studied in lab-scale experiments in three composting leachate liquids. Nutrient reduction in cultures was measured at different initial substrate strengths. A small, pilot-scale photobioreactor (PBR) was used to verify lab-scale results. Similar growth conditions supported growth of both Selenastrum and bacteria. CO₂ feed enhanced the production of biomass and lipids in PBR (2.4gL^-1 and 17% DW) compared to lab-scale (0.1-1.6gL^-1 and 4.0-6.5% DW) experiments. Also prolonged cultivation time increased lipid content in PBR. At both scales, NH₄-N with an initial concentration of ca. 40mgL^-1 was completely removed from the biowaste leachate. In lab-scale, maximal COD reduction was over 2000mgL^-1, indicating mixotrophic growth of Selenastrum. Co-cultures are efficient in composting leachate liquid treatment, and conversion of waste to biomass is a promising approach to improve the bioeconomy of composting plants.

Keywords: Co-culture; Fatty acid; Microalgae; Nutrient reduction; Wastewater.

MeSH terms

Bacteria
Biomass
Chlorophyta
Microalgae*
Photobioreactors*
Wastewater

Substances

Waste Water